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• How to cope with developing against a poor 3rd party API/application?

  - by wsanville

  I'm a web developer, and my organization has recently started to use a proprietary ASP.NET CMS for our web sites. I was excited to get started using the CMS, thinking it would bring a lot of value to our end users and be fun to work with, since my skills are a good match for the types of projects we're using it for. That was about a year ago. Since then, we've ran into all kinds of issues, from blatant bugs in the product, to nasty edge cases in the APIs, to extremely poor documentation for developers. On about a weekly basis, we are forced to pursue workarounds and rewrite some of the out of the box functionality, and even find some of the basic features unusable. In many cases, since this is a closed source application (and obfuscated of course), there's nothing we can do as developers to solve these issues. So my question is, how does one attempt to develop a good application in such a scenario? The application mostly works when using the the exact out of the box behavior, or using one of the company's starter sites. However, my attempts to use the underlying APIs to implement slightly different, yet reasonable behavior has proved to be extremely time consuming (not to mention just as buggy), given the lack of good information about the APIs. I've given this a lot of thought, and my conflicting viewpoints are the following: Strongly advise against any customization to the CMS, as development time will rise exponentially, or even have an extremely high chance of failing. While this is accurate, I do not want to give the impression that I am not willing to code my own solutions to problems and take the initiative to implement something difficult or complex. I don't want to be perceived as someone who is not motivated, lazy, or not knowledgeable to do anything complex, because this is simply not the case. I love coding my own solutions, trying new/difficult things, I just dislike the vendor app we're using. Continue on the path I'm on now, which is hacking my way past all issues I encounter and try my best to deliver an application that meets the needs and specs exactly. My goals are to make it as seamless and easy to use as possible to the end user, even when integrating the CMS with our other applications internally. The problem I'm finding with this approach is it is very time consuming. I open support cases with the vendor on a regular basis to solve issues and to gain knowledge of their APIs, but this is extremely time consuming, and in some cases it leads to dead ends. I post on the vendors forums on a regular basis but have become frustrated as most of my posts get 0 replies. So, what would you, a reasonable developer, do in this case? How can I make the best of the situation? And just for fun, here are some of the code smells and anti-patterns I've dealt with using the product (aside from their own code blatantly failing): Use of StringBuilder to concatenate a giant string that is hard coded and does not change. They use it to concatenate their Javascript and write it out into the body tags of their pages. Methods that accept object or Microsoft.VisualBasic.Collection as the parameters. In the case of the VB Collection, the data is not a list of any kind, it's used instead of making a class. Methods that return a Hashtable of VB Collections Method names of the form MethodName_v45, MethodName_v20, etc... Multiple classes with the same name in different namespaces with different functionality/behavior. Intellisense that reads "Note: this parameter is non functional" Complete lack of coding standards, API is filled with magic numbers and magic strings. Properties with a getter of type object that accepts totally different things, like enum or strings, and throw exceptions at runtime when you pass in something not supported. And much, much, more...

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• curl can't verify cert using capath, but can with cacert option

  - by phylae

  I am trying to use curl to connect to a site using HTTPS. But curl is failing to verify the SSL cert. $ curl --verbose --capath ./certs/ --head https://example.com/ * About to connect() to example.com port 443 (#0) * Trying 1.1.1.1... connected * Connected to example.com (1.1.1.1) port 443 (#0) * successfully set certificate verify locations: * CAfile: none CApath: ./certs/ * SSLv3, TLS handshake, Client hello (1): * SSLv3, TLS handshake, Server hello (2): * SSLv3, TLS handshake, CERT (11): * SSLv3, TLS alert, Server hello (2): * SSL certificate problem, verify that the CA cert is OK. Details: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed * Closing connection #0 curl: (60) SSL certificate problem, verify that the CA cert is OK. Details: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed More details here: http://curl.haxx.se/docs/sslcerts.html curl performs SSL certificate verification by default, using a "bundle" of Certificate Authority (CA) public keys (CA certs). If the default bundle file isn't adequate, you can specify an alternate file using the --cacert option. If this HTTPS server uses a certificate signed by a CA represented in the bundle, the certificate verification probably failed due to a problem with the certificate (it might be expired, or the name might not match the domain name in the URL). If you'd like to turn off curl's verification of the certificate, use the -k (or --insecure) option. I know about the -k option. But I do actually want to verify the cert. The certs directory has been properly hashed with c_rehash . and it contains: A Verisign intermediate cert Two self-signed certs The above site should be verified with the Verisign intermediate cert. When I use the --cacert option instead (and point directly to the Verisign cert) curl is able to verify the SSL cert. $ curl --verbose --cacert ./certs/verisign-intermediate-ca.crt --head https://example.com/ * About to connect() to example.com port 443 (#0) * Trying 1.1.1.1... connected * Connected to example.com (1.1.1.1) port 443 (#0) * successfully set certificate verify locations: * CAfile: ./certs/verisign-intermediate-ca.crt CApath: /etc/ssl/certs * SSLv3, TLS handshake, Client hello (1): * SSLv3, TLS handshake, Server hello (2): * SSLv3, TLS handshake, CERT (11): * SSLv3, TLS handshake, Server finished (14): * SSLv3, TLS handshake, Client key exchange (16): * SSLv3, TLS change cipher, Client hello (1): * SSLv3, TLS handshake, Finished (20): * SSLv3, TLS change cipher, Client hello (1): * SSLv3, TLS handshake, Finished (20): * SSL connection using RC4-SHA * Server certificate: * subject: C=US; ST=State; L=City; O=Company; OU=ou1; CN=example.com * start date: 2011-04-17 00:00:00 GMT * expire date: 2012-04-15 23:59:59 GMT * common name: example.com (matched) * issuer: C=US; O=VeriSign, Inc.; OU=VeriSign Trust Network; OU=Terms of use at https://www.verisign.com/rpa (c)10; CN=VeriSign Class 3 Secure Server CA - G3 * SSL certificate verify ok. > HEAD / HTTP/1.1 > User-Agent: curl/7.19.7 (x86_64-pc-linux-gnu) libcurl/7.19.7 OpenSSL/0.9.8k zlib/1.2.3.3 libidn/1.15 > Host: example.com > Accept: */* > < HTTP/1.1 404 Not Found HTTP/1.1 404 Not Found < Cache-Control: must-revalidate,no-cache,no-store Cache-Control: must-revalidate,no-cache,no-store < Content-Type: text/html;charset=ISO-8859-1 Content-Type: text/html;charset=ISO-8859-1 < Content-Length: 1267 Content-Length: 1267 < Server: Jetty(7.2.2.v20101205) Server: Jetty(7.2.2.v20101205) < * Connection #0 to host example.com left intact * Closing connection #0 * SSLv3, TLS alert, Client hello (1): In addition, if I try hitting one of the sites using a self signed cert and the --capath option, it also works. (Let me know if I should post an example of that.) This implies that curl is finding the cert directory, and it is properly hash. Finally, I am able to verify the SSL cert with openssl, using its -CApath option. $ openssl s_client -CApath ./certs/ -connect example.com:443 CONNECTED(00000003) depth=3 /C=US/O=VeriSign, Inc./OU=Class 3 Public Primary Certification Authority verify return:1 depth=2 /C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=(c) 2006 VeriSign, Inc. - For authorized use only/CN=VeriSign Class 3 Public Primary Certification Authority - G5 verify return:1 depth=1 /C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=Terms of use at https://www.verisign.com/rpa (c)10/CN=VeriSign Class 3 Secure Server CA - G3 verify return:1 depth=0 /C=US/ST=State/L=City/O=Company/OU=ou1/CN=example.com verify return:1 --- Certificate chain 0 s:/C=US/ST=State/L=City/O=Company/OU=ou1/CN=example.com i:/C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=Terms of use at https://www.verisign.com/rpa (c)10/CN=VeriSign Class 3 Secure Server CA - G3 --- Server certificate -----BEGIN CERTIFICATE----- <cert removed> -----END CERTIFICATE----- subject=/C=US/ST=State/L=City/O=Company/OU=ou1/CN=example.com issuer=/C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=Terms of use at https://www.verisign.com/rpa (c)10/CN=VeriSign Class 3 Secure Server CA - G3 --- No client certificate CA names sent --- SSL handshake has read 1563 bytes and written 435 bytes --- New, TLSv1/SSLv3, Cipher is RC4-SHA Server public key is 2048 bit Secure Renegotiation IS NOT supported Compression: NONE Expansion: NONE SSL-Session: Protocol : TLSv1 Cipher : RC4-SHA Session-ID: D65C4C6D52E183BF1E7543DA6D6A74EDD7D6E98EB7BD4D48450885188B127717 Session-ID-ctx: Master-Key: 253D4A3477FDED5FD1353D16C1F65CFCBFD78276B6DA1A078F19A51E9F79F7DAB4C7C98E5B8F308FC89C777519C887E2 Key-Arg : None Start Time: 1303258052 Timeout : 300 (sec) Verify return code: 0 (ok) --- QUIT DONE How can I get curl to verify this cert using the --capath option?

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• (Ordered) Set Partitions in fixed-size Blocks

  - by Eugen

  Here is a function I would like to write but am unable to do so. Even if you don't / can't give a solution I would be grateful for tips. For example, I know that there is a correlation between the ordered represantions of the sum of an integer and ordered set partitions but that alone does not help me in finding the solution. So here is the description of the function I need: The Task Create an efficient* function List<int[]> createOrderedPartitions(int n_1, int n_2,..., int n_k) that returns a list of arrays of all set partions of the set {0,...,n_1+n_2+...+n_k-1} in number of arguments blocks of size (in this order) n_1,n_2,...,n_k (e.g. n_1=2, n_2=1, n_3=1 -> ({0,1},{3},{2}),...). Here is a usage example: int[] partition = createOrderedPartitions(2,1,1).get(0); partition[0]; // -> 0 partition[1]; // -> 1 partition[2]; // -> 3 partition[3]; // -> 2 Note that the number of elements in the list is (n_1+n_2+...+n_n choose n_1) * (n_2+n_3+...+n_n choose n_2) * ... * (n_k choose n_k). Also, createOrderedPartitions(1,1,1) would create the permutations of {0,1,2} and thus there would be 3! = 6 elements in the list. * by efficient I mean that you should not initially create a bigger list like all partitions and then filter out results. You should do it directly. Extra Requirements If an argument is 0 treat it as if it was not there, e.g. createOrderedPartitions(2,0,1,1) should yield the same result as createOrderedPartitions(2,1,1). But at least one argument must not be 0. Of course all arguments must be = 0. Remarks The provided pseudo code is quasi Java but the language of the solution doesn't matter. In fact, as long as the solution is fairly general and can be reproduced in other languages it is ideal. Actually, even better would be a return type of List<Tuple<Set>> (e.g. when creating such a function in Python). However, then the arguments wich have a value of 0 must not be ignored. createOrderedPartitions(2,0,2) would then create [({0,1},{},{2,3}),({0,2},{},{1,3}),({0,3},{},{1,2}),({1,2},{},{0,3}),...] Background I need this function to make my mastermind-variation bot more efficient and most of all the code more "beautiful". Take a look at the filterCandidates function in my source code. There are unnecessary / duplicate queries because I'm simply using permutations instead of specifically ordered partitions. Also, I'm just interested in how to write this function. My ideas for (ugly) "solutions" Create the powerset of {0,...,n_1+...+n_k}, filter out the subsets of size n_1, n_2 etc. and create the cartesian product of the n subsets. However this won't actually work because there would be duplicates, e.g. ({1,2},{1})... First choose n_1 of x = {0,...,n_1+n_2+...+n_n-1} and put them in the first set. Then choose n_2 of x without the n_1 chosen elements beforehand and so on. You then get for example ({0,2},{},{1,3},{4}). Of course, every possible combination must be created so ({0,4},{},{1,3},{2}), too, and so on. Seems rather hard to implement but might be possible. Research I guess this goes in the direction I want however I don't see how I can utilize it for my specific scenario. http://rosettacode.org/wiki/Combinations

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• set different images to uitableview cell

  - by Sudha

  I am making an app in which one of the view has a tableview. Tableview cell has two conditions. There are two images which are going to be set on uitableview cell according to the condition i.e. - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{ NSString *que =[[userqueries objectAtIndex:indexPath.row]objectForKey:@"question"]; NSString *ans =[[userqueries objectAtIndex:indexPath.row]objectForKey:@"answer"]; static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil){ cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease]; cell.imageView.image=nil; if ((que.length!=0)&&(ans.length!=0)) { UIImageView* imag = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 320, 75)]; imag.image = [UIImage imageNamed:@"ques.png"]; [cell.contentView addSubview:imag]; questext = [[UITextView alloc]initWithFrame:CGRectMake(10, 0, 300, 35)]; questext.backgroundColor = [UIColor clearColor]; questext.delegate = self; questext.tag = 101; questext.textAlignment = UITextAlignmentLeft; questext.editable = NO; questext.scrollEnabled = YES; [cell addSubview:questext]; anstext = [[UITextView alloc]initWithFrame:CGRectMake(10, 37, 300, 35)]; anstext.backgroundColor = [UIColor clearColor]; anstext.delegate = self; anstext.tag = 102; anstext.scrollEnabled = YES; anstext.textAlignment = UITextAlignmentLeft; anstext.editable = NO; [cell addSubview:anstext]; } else { UIImageView* imag = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 320, 40)]; imag.image = [UIImage imageNamed:@"answ.png"]; [cell.contentView addSubview:imag]; onlyques = [[UITextView alloc]initWithFrame:CGRectMake(10, 0, 300, 35)]; onlyques.backgroundColor= [UIColor clearColor]; [onlyques setScrollEnabled:YES]; onlyques.delegate = self; onlyques.tag = 103; onlyques.textAlignment = UITextAlignmentLeft; onlyques.editable = NO; onlyques.scrollEnabled = YES; [cell addSubview:onlyques]; } } questext = (UITextView*)[cell viewWithTag:101]; questext.text = que; anstext = (UITextView*)[cell viewWithTag:102]; anstext.text = ans; onlyques = (UITextView*)[cell viewWithTag:103]; onlyques.text = que; return cell; } But image is not appearing properly. As I scroll up and down the table view ,images get changes automatically. Please look upon my code and help me in finding the error. second image is when I scroll up and down the table view and first image is in the starting. please help me. if any one knows how to load different images to uitableview cell. thanks in advance.

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• linux script, standard directory locations.

  - by Thingomy

  I am trying to write a bash script to do a task, I have done pretty well so far, and have it working to an extent, but I want to set it up so it's distributable to other people, and will be opening it up as open source, so I want to start doing things the "conventional" way. Unfortunately I'm not all that sure what the conventional way is. Ideally I want a link to an in depth online resource that discusses this and surrounding topics in depth, but I'm having difficulty finding keywords that will locate this on google. At the start of my script I set a bunch of global variables that store the names of the dirs that it will be accessing, this means that I can modify the dir's quickly, but this is programming shortcuts, not user shortcuts, I can't tell the users that they have to fiddle with this stuff. Also, I need for individual users' settings not to get wiped out on every upgrade. Questions: Name of settings folder: ~/.foo/ -- this is well and good, but how do I keep my working copy and my development copy separate? tweek the reference in the source of the dev version? If my program needs to maintain and update library of data (gps tracklog data in this case) where should this directory be? the user will need to access some of this data, but it's mostly for internal use. I personally work in cygwin, and I like to keep this data on separate drive, so the path is wierd, I suspect many users could find this. for a default however I'm thinking ~/gpsdata/ -- would this be normal, or should I hard code a system that ask the user at first run where to put it, and stores this in the settings folder? whatever happens I'm going ot have to store the directory reference in a file in the settings folder. The program needs a data "inbox" that is a folder that the user can dump files, then run the script to process these files. I was thinking ~/gpsdata/in/ ?? though there will always be an option to add a file or folder to the command line to use that as well (it processed files all locations listed, including the "inbox") Where should the script its self go? it's already smart enough that it can create all of it's ancillary/settings files (once I figure out the "correct" directory) if run with "./foo --setup" I could shove it in /usr/bin/ or /bin or ~/.foo/bin (and add that to the path) what's normal? I need to store login details for a web service that it will connect to (using curl -u if it matters) plan on including a setting whereby it asks for a username and password every execution, but it currently stores it plane text in a file in ~/.foo/ -- I know, this is not good. The webservice (osm.org) does support oauth, but I have no idea how to get curl to use it -- getting curl to speak to the service in the first place was a hack. Is there a simple way to do a really basic encryption on a file like this to deter idiots armed with notepad? Sorry for the list of questions, I believe they are closely related enough for a single post. This is all stuff that stabbing at, but would like clarification/confirmation over.

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• How to properly use the .each() command in jQuery

  - by sadmicrowave

  I have a script that checks the class (integer) of a , runs a switch statement to change that integer value to text and appends the text to another in the same listitem tag. I use the .each() function because each listitem starts with class=_[user ID] -- each user can have up to 5 entries.. Enough explaining -- heres the code: <HTML> <li class='_44074'><div class='_12' style='width:380px;'><div style='width:60px; float:left;'>1st</div><div class='verify-type' style='float:left; width:160px;'></div><div style='float:left; width:120px;'>04/26/10 07:29 AM</div></div></li> <li class='_44074'><div class='_6' style='width:380px;'><div style='width:60px; float:left;'>2nd</div><div class='verify-type' style='float:left; width:160px;'></div><div style='float:left; width:120px;'>04/23/10 03:29 PM</div></div></li> <li class='_44074'><div class='_12' style='width:380px;'><div style='width:60px; float:left;'>3rd</div><div class='verify-type' style='float:left; width:160px;'></div><div style='float:left; width:120px;'>04/23/10 03:18 PM</div></div></li> <li class='_44074'><div class='_2' style='width:380px;'><div style='width:60px; float:left;'>4th</div><div class='verify-type' style='float:left; width:160px;'></div><div style='float:left; width:120px;'>04/23/10 02:28 PM</div></div></li> </HTML> when I use the .each() function to scan through each of the listitems begining with the entered user id it only finds the first value (in this case _12) and applies that to all the entries; instead of finding _12, _6, _12, _2 it finds _12, _12, _12, _12...here is the java: $("div#history-menu div#history-text li." + valueid).each(function(){ valueid = $("div#center-box input").val(); checkedvalue=""; checkedvalue = $("div#history-menu div#history-text li." + valueid + " div").attr('class'); switch(checkedvalue){ case '_2':lcCheckedMessage = "Shoes"; break; case '_4':lcCheckedMessage = "Shoe Straps"; break; case '_6':lcCheckedMessage = "Shoes & Shoe Straps"; break; case '_8':lcCheckedMessage = "Wrist Straps"; break; case '_10':lcCheckedMessage = "Shoes & Wrist Strap"; break; case '_12':lcCheckedMessage = "Shoe Straps & Wrist Strap"; break; }; $("div#history-menu div#history-text li." + valueid + " ." + checkedvalue + " .verify-type").text(lcCheckedMessage); });

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• Clearcase - selective merge.

  - by Keshav

  Hi, I have a peculiar Clearcase doubt. I cannot fully describe why I'm doing such a confusing architecture, but I need to do it (thanks to the mistake done by someone long back). Ok, here's a bit of detail: B1 is a contaminated branch where both my group's changes and another group's changes got mixed together so badly that there is no way of finding which code is whose). So the solution proposed is to create a new branch called B2 (at the same level as B1) and put all the unmodified code of the other group on it (The way to do that would be to merge B1 with B2 and then go about removing all changes from it till it becomes original). Then create a CR branch on B1 and keep only my group's newly added files or modified files on that branch. Finally create an integration branch out of B2 and merge the changes from CR branch of B1 to integration branch of B2. So here is what I did: (The use case is where I have dir D where file a, b and c are there. My group ended up modifying file a while b and c are not modified at all). There is a branch B1 on which there are files a, b and c. There is another branch B2. A merge is done from B1 to B2. Now B2 also has a, b and c. At this point both branch B1 and B2 are same. Now I delete file a from branch B2 (rmname). Now B2 has b and c only. I put a label to this branch called Label1. This makes the code with label Label1 as the unmodified code from other group. Now I create a sub branch called CR1 from B1 and delete all the files that are there in B2 branch (i.e b and c) such that it contains only the modified code from original code on it. In my case it is file a. At this point branch B2 with label Label1 has files b and c (those are unmodified code) and branch CR1 coming off B1 has only a (that is modified by us). Now I create another branch called integration branch that comes off B2 Label1. And then I do a merge of CR branch on to that expecting that it will have all three files a, b and c for me. All I'd need to do is to do a version tree view and see who modified what. But the problem I face is that since I had done a rmname of file a on branch B2 earlier to putting Label. The merge does not really take the file a from CR branch. How to I get around that problem. I want to selectively merge. Is it possible? sorry if it is a bad design. I'm not really conversant with Clear case and have limited options and time to clear some one else's mess.

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• Java algorithm for normalizing audio

  - by Marty Pitt

  I'm trying to normalize an audio file of speech. Specifically, where an audio file contains peaks in volume, I'm trying to level it out, so the quiet sections are louder, and the peaks are quieter. I know very little about audio manipulation, beyond what I've learnt from working on this task. Also, my math is embarrassingly weak. I've done some research, and the Xuggle site provides a sample which shows reducing the volume using the following code: (full version here) @Override public void onAudioSamples(IAudioSamplesEvent event) { // get the raw audio byes and adjust it's value ShortBuffer buffer = event.getAudioSamples().getByteBuffer().asShortBuffer(); for (int i = 0; i < buffer.limit(); ++i) buffer.put(i, (short)(buffer.get(i) * mVolume)); super.onAudioSamples(event); } Here, they modify the bytes in getAudioSamples() by a constant of mVolume. Building on this approach, I've attempted a normalisation modifies the bytes in getAudioSamples() to a normalised value, considering the max/min in the file. (See below for details). I have a simple filter to leave "silence" alone (ie., anything below a value). I'm finding that the output file is very noisy (ie., the quality is seriously degraded). I assume that the error is either in my normalisation algorithim, or the way I manipulate the bytes. However, I'm unsure of where to go next. Here's an abridged version of what I'm currently doing. Step 1: Find peaks in file: Reads the full audio file, and finds this highest and lowest values of buffer.get() for all AudioSamples @Override public void onAudioSamples(IAudioSamplesEvent event) { IAudioSamples audioSamples = event.getAudioSamples(); ShortBuffer buffer = audioSamples.getByteBuffer().asShortBuffer(); short min = Short.MAX_VALUE; short max = Short.MIN_VALUE; for (int i = 0; i < buffer.limit(); ++i) { short value = buffer.get(i); min = (short) Math.min(min, value); max = (short) Math.max(max, value); } // assign of min/max ommitted for brevity. super.onAudioSamples(event); } Step 2: Normalize all values: In a loop similar to step1, replace the buffer with normalized values, calling: buffer.put(i, normalize(buffer.get(i)); public short normalize(short value) { if (isBackgroundNoise(value)) return value; short rawMin = // min from step1 short rawMax = // max from step1 short targetRangeMin = 1000; short targetRangeMax = 8000; int abs = Math.abs(value); double a = (abs - rawMin) * (targetRangeMax - targetRangeMin); double b = (rawMax - rawMin); double result = targetRangeMin + ( a/b ); // Copy the sign of value to result. result = Math.copySign(result,value); return (short) result; } Questions: Is this a valid approach for attempting to normalize an audio file? Is my math in normalize() valid? Why would this cause the file to become noisy, where a similar approach in the demo code doesn't?

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• Please help fix and optimize this query

  - by user607217

  I am working on a system to find potential duplicates in our customers table (SQL 2005). I am using the built-in SOUNDEX value that our software computes when customers are added/updated, but I also implemented the double metaphone algorithm for better matching. This is the most-nested query I have created, and I can't help but think there is a better way to do it and I'd like to learn. In the inner-most query I am joining the customer table to the metaphone table I created, then finding customers that have identical pKey (primary phonetic key). I take that, union that with customers that have matching soundex values, and then proceed to score those matches with various text similarity functions. This is currently working, but I would also like to add a union of customers whose aKey (alternate phonetic key) match. This would be identical to "QUERY A" except to substitute on (c1Akey = c2Akey) for the join. However, when I attempt to include that, I get errors when I try to execute my query. Here is the code: --Create aggregate ranking select c1Name, c2Name, nDiff, c1Addr, c2Addr, aDiff, c1SSN, c2SSN, sDiff, c1DOB, c2DOB, dDiff, nDiff+aDiff+dDiff+sDiff as Score ,(sDiff+dDiff)*1.5 + (nDiff+dDiff)*1.5 + (nDiff+sDiff)*1.5 + aDiff *.5 + nDiff *.5 as [Rank] FROM ( --Create match scores for different fields SELECT c1Name, c2Name, c1Addr, c2Addr, c1SSN, c2SSN, c1LTD, c2LTD, c1DOB, c2DOB, dbo.Jaro(c1name, c2name) AS nDiff, dbo.JaroWinkler(c1addr, c2addr) AS aDiff, CASE WHEN c1dob = '1901-01-01' OR c2dob = '1901-01-01' OR c1dob = '1800-01-01' OR c2dob = '1800-01-01' THEN .5 ELSE dbo.SmithWaterman(c1dob, c2dob) END AS dDiff, CASE WHEN c1ssn = '000-00-0000' OR c2ssn = '000-00-0000' THEN .5 ELSE dbo.Jaro(c1ssn, c2ssn) END AS sDiff FROM -- Generate list of possible matches based on multiple phonetic matching fields ( select * from -- List of similar names from pKey field of ##Metaphone table --QUERY A BEGIN (select customers.custno as c1Custno, name as c1Name, haddr as c1Addr, ssn as c1SSN, lasttripdate as c1LTD, dob as c1DOB, soundex as c1Soundex, pkey as c1Pkey, akey as c1Akey from Customers WITH (nolock) join ##Metaphone on customers.custno = ##Metaphone.custno) as c1 JOIN (select customers.custno as c2Custno, name as c2Name, haddr as c2Addr, ssn as c2SSN, lasttripdate as c2LTD, dob as c2DOB, soundex as c2Soundex, pkey as c2Pkey, akey as c2Akey from Customers with (nolock) join ##Metaphone on customers.custno = ##Metaphone.custno) as c2 on (c1Pkey = c2Pkey) and (c1Custno < c2Custno) WHERE (c1Name <> 'PARENT, GUARDIAN') and c1soundex != c2soundex --QUERY A END union --List of similar names from pregenerated SOUNDEX field (select t1.custno, t1.name, t1.haddr, t1.ssn, t1.lasttripdate, t1.dob, t1.[soundex], 0, 0, t2.custno, t2.name, t2.haddr, t2.ssn, t2.lasttripdate, t2.dob, t2.[soundex], 0, 0 from Customers t1 WITH (nolock) join customers t2 with (nolock) on t1.[soundex] = t2.[soundex] and t1.custno < t2.custno where (t1.name <> 'PARENT, GUARDIAN')) ) as a ) as b where (sDiff+dDiff)*1.5 + (nDiff+dDiff)*1.5 + (nDiff+sDiff)*1.5 + aDiff *.5 + nDiff *.5 >= 7.5 order by [rank] desc, score desc Previously, I was using joins such as on c1.pkey = c2.pkey or c1.akey = c2.akey or c1.soundex = c2.soundex but the performance was horrendous, and using unions seems to be working a lot better. Out of 103K customers, tt is currently generating a list of 8.5M potential matches (based on the phonetic codes) in 2.25 minutes, and then taking another 2 to score, rank and filter those down to about 3000. So I am happy with the performance, I just can't help but think there is a better way to structure this, and I need help adding the extra union condition. Thanks!

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• Comparing 2 tables column values and copying the next column content to the second table

  - by Sullan

  Hi All.. I am comparing between two tables first column each. If there is find a match i am copying the text from the adjacent cell of the first table to the second table. I am able to compare strings and get the value, but finding it difficult to print it in the second table. I am getting the value in the var "replaceText", but how to print it in the second table ?? Please help... Sample code is as follows.. <script type="text/javascript"> jQuery.noConflict(); jQuery(document).ready(function(){ jQuery('.itemname').each(function(){ var itemName = jQuery(this).text(); jQuery('.comparerow').each(function() { var compareRow = jQuery(this).text(); if (itemName == compareRow) { var replaceText = jQuery(this).next('td').text(); alert(replaceText); } }); }); }); </script> HTML is as follows <table width="100%"><thead> <tr> <th align="left" >Name</th><th>Description</th></tr></thead> <tbody> <tr> <td class="comparerow">IX0001</td> <td class="desc">Desc 1 </td> </tr> <tr> <td class="comparerow">IX0002</td> <td class="desc" >Desc 2 </td> </tr> <tr> <td class="comparerow">IX0003</td> <td class="desc">Desc 3 </td> </tr> <tr> <td class="comparerow">IX0004</td> <td class="desc">Desc 4 </td> </tr> </tbody> </table> <br /> <table width="100%"> <tr> <th>Name</th><th>Description</th> </tr> <tr > <td class="itemname">IX0001</td><td></td> </tr> <tr> <td class="itemname">IX0002</td><td></td> </tr> <tr> <td class="itemname">IX0003</td><td></td> </tr> </table>

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• How can I keep my MVC Views, models, and model binders as clean as possible?

  - by MBonig

  I'm rather new to MVC and as I'm getting into the whole framework more and more I'm finding the modelbinders are becoming tough to maintain. Let me explain... I am writing a basic CRUD-over-database app. My domain models are going to be very rich. In an attempt to keep my controllers as thin as possible I've set it up so that on Create/Edit commands the parameter for the action is a richly populated instance of my domain model. To do this I've implemented a custom model binder. As a result, though, this custom model binder is very specific to the view and the model. I've decided to just override the DefaultModelBinder that ships with MVC 2. In the case where the field being bound to my model is just a textbox (or something as simple), I just delegate to the base method. However, when I'm working with a dropdown or something more complex (the UI dictates that date and time are separate data entry fields but for the model it is one Property), I have to perform some checks and some manual data munging. The end result of this is that I have some pretty tight ties between the View and Binder. I'm architecturally fine with this but from a code maintenance standpoint, it's a nightmare. For example, my model I'm binding here is of type Log (this is the object I will get as a parameter on my Action). The "ServiceStateTime" is a property on Log. The form values of "log.ServiceStartDate" and "log.ServiceStartTime" are totally arbitrary and come from two textboxes on the form (Html.TextBox("log.ServiceStartTime",...)) protected override object GetPropertyValue(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor, IModelBinder propertyBinder) { if (propertyDescriptor.Name == "ServiceStartTime") { string date = bindingContext.ValueProvider.GetValue("log.ServiceStartDate").ConvertTo(typeof (string)) as string; string time = bindingContext.ValueProvider.GetValue("log.ServiceStartTime").ConvertTo(typeof (string)) as string; DateTime dateTime = DateTime.Parse(date + " " + time); return dateTime; } if (propertyDescriptor.Name == "ServiceEndTime") { string date = bindingContext.ValueProvider.GetValue("log.ServiceEndDate").ConvertTo(typeof(string)) as string; string time = bindingContext.ValueProvider.GetValue("log.ServiceEndTime").ConvertTo(typeof(string)) as string; DateTime dateTime = DateTime.Parse(date + " " + time); return dateTime; } The Log.ServiceEndTime is a similar field. This doesn't feel very DRY to me. First, if I refactor the ServiceStartTime or ServiceEndTime into different field names, the text strings may get missed (although my refactoring tool of choice, R#, is pretty good at this sort of thing, it wouldn't cause a build-time failure and would only get caught by manual testing). Second, if I decided to arbitrarily change the descriptors "log.ServiceStartDate" and "log.ServiceStartTime", I would run into the same problem. To me, runtime silent errors are the worst kind of error out there. So, I see a couple of options to help here and would love to get some input from people who have come across some of these issues: Refactor any text strings in common between the view and model binders out into const strings attached to the ViewModel object I pass from controller to the aspx/ascx view. This pollutes the ViewModel object, though. Provide unit tests around all of the interactions. I'm a big proponent of unit tests and haven't started fleshing this option out but I've got a gut feeling that it won't save me from foot-shootings. If it matters, the Log and other entities in the system are persisted to the database using Fluent NHibernate. I really want to keep my controllers as thin as possible. So, any suggestions here are greatly welcomed! Thanks

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• Getting 404 in Android app while trying to get xml from localhost

  - by Patrick

  This must be something really stupid, trying to solve this issue for a couple of days now and it's really not working. I searched everywhere and there probably is someone with the same problem, but I can't seem to find it. I'm working on an Android app and this app pulls some xml from a website. Since this website is down a lot, I decided to save it and run it locally. Now what I did; - I downloaded the kWs app for hosting the downloaded xml file - I put the file in the right directory and could access it through the mobile browser, but not with my app (same code as I used with pulling it from some other website, not hosted by me, only difference was the URL obviously) So I tried to host it on my PC and access it with my app from there. Again the same results, the mobile browsers had no problem finding it, but the app kept saying 404 Not Found: "The requested URL /test.xml&parama=Someone&paramb= was not found on this server." Note: Don't mind the 2 parameters I am sending, I needed that to get the right stuff from the website that wasn't hosted by me. My code: public String getStuff(String name){ String URL = "http://10.0.0.8/test.xml"; ArrayList<NameValuePair> params = new ArrayList<NameValuePair>(2); params.add(new BasicNameValuePair("parama", name)); params.add(new BasicNameValuePair("paramb", "")); APIRequest request = new APIRequest(URL, params); try { RequestXML rxml = new RequestXML(); AsyncTask<APIRequest, Void, String> a = rxml.execute(request); ... } catch(Exception e) { e.printStackTrace(); } return null; } That should be working correctly. Now the RequestXML class part: class RequestXML extends AsyncTask<APIRequest, Void, String>{ @Override protected String doInBackground(APIRequest... uri) { HttpClient httpclient = new DefaultHttpClient(); String completeUrl = uri[0].url; // ... Add parameters to URL ... HttpGet request = null; try { request = new HttpGet(new URI(completeUrl)); } catch (URISyntaxException e1) { e1.printStackTrace(); } HttpResponse response; String responseString = ""; try { response = httpclient.execute(request); StatusLine statusLine = response.getStatusLine(); if(statusLine.getStatusCode() == HttpStatus.SC_OK){ // .. It crashes here, because statusLine.getStatusCode() returns a 404 instead of a 200. The xml is just plain xml, nothing special about it. I changed the contents of the .htaccess file into "ALLOW FROM ALL" (works, cause the browser on my mobile device can access it and shows the correct xml). I am running Android 4.0.4 and I am using the default browser AND chrome on my mobile device. I am using MoWeS to host the website on my PC. Any help would be appreciated and if you need to know anything before you can find an answer to this problem, I'll be more than happy to give you that info. Thank you for you time! Cheers.

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• Printing out variables in c changes values of variables

  - by George Wilson

  I have an odd problem with some c-programme here. I was getting some wrong values in a matrix I was finding the determinant of and so I started printing variables - yet found that by printing values out the actual values in the code changed. I eventually narrowed it down to one specific printf statement - highlighted in the code below. If I comment out this line then I start getting incorrect values in my determinent calculations, yet by printing it out I get the value out I expect Code below: #include <math.h> #include <stdio.h> #include <stdlib.h> #define NUMBER 15 double determinant_calculation(int size, double array[NUMBER][NUMBER]); int main() { double array[NUMBER][NUMBER], determinant_value; int size; array[0][0]=1; array[0][1]=2; array[0][2]=3; array[1][0]=4; array[1][1]=5; array[1][2]=6; array[2][0]=7; array[2][1]=8; array[2][2]=10; size=3; determinant_value=determinant_calculation(size, array); printf("\n\n\n\n\n\nDeterminant value is %lf \n\n\n\n\n\n", determinant_value); return 0; } double determinant_calculation(int size, double array[NUMBER][NUMBER]) { double determinant_matrix[NUMBER][NUMBER], determinant_value; int x, y, count=0, sign=1, i, j; /*initialises the array*/ for (i=0; i<(NUMBER); i++) { for(j=0; j<(NUMBER); j++) { determinant_matrix[i][j]=0; } } /*does the re-cursion method*/ for (count=0; count<size; count++) { x=0; y=0; for (i=0; i<size; i++) { for(j=0; j<size; j++) { if (i!=0&&j!=count) { determinant_matrix[x][y]=array[i][j]; if (y<(size-2)) { y++; } else { y=0; x++; } } } } //commenting this for loop out changes the values of the code determinent prints -7 when commented out and -3 (expected) when included! for (i=0; i<size; i++) { for(j=0; j<size; j++){ printf("%lf ", determinant_matrix[i][j]); } printf("\n"); } if(size>2) { determinant_value+=sign*(array[0][count]*determinant_calculation(size-1 ,determinant_matrix)); } else { determinant_value+=sign*(array[0][count]*determinant_matrix[0][0]); } sign=-1*sign; } return (determinant_value); } I know its not the prettiest (or best way) of doing what I'm doing with this code but it's what I've been given - so can't make huge changes. I don't suppose anyone could explain why printing out the variables can actually change the values? or how to fix it because ideally i don't want to!!

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• UIButton performance in UITableViewCell vs UIView

  - by marcel salathe

  I'd like to add a UIButton to a custom UITableViewCell (programmatically). This is easy to do, but I'm finding that the "performance" of the button in the cell is slow - that is, when I touch the button, there is quite a bit of delay until the button visually goes into the highlighted state. The same type of button on a regular UIView is very responsive in comparison. In order to isolate the problem, I've created two views - one is a simple UIView, the other is a UITableView with only one UITableViewCell. I've added buttons to both views (the UIView and the UITableViewCell), and the performance difference is quite striking. I've searched the web and read the Apple docs but haven't really found the cause of the problem. My guess is that it somehow has to do with the responder chain, but I can't quite put my finger on it. I must be doing something wrong, and I'd appreciate any help. Thanks. Demo code: ViewController.h #import <UIKit/UIKit.h> @interface ViewController : UIViewController <UITableViewDelegate, UITableViewDataSource> @property UITableView* myTableView; @property UIView* myView; ViewController.m #import "ViewController.h" #import "CustomCell.h" @implementation ViewController @synthesize myTableView, myView; - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil { self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; if (self) { [self initMyView]; [self initMyTableView]; } return self; } - (void) initMyView { UIView* newView = [[UIView alloc] initWithFrame:CGRectMake(0,0,[[UIScreen mainScreen] bounds].size.width,100)]; self.myView = newView; // button on regularView UIButton* myButton = [UIButton buttonWithType:UIButtonTypeRoundedRect]; [myButton addTarget:self action:@selector(pressedMyButton) forControlEvents:UIControlEventTouchUpInside]; [myButton setTitle:@"I'm fast" forState:UIControlStateNormal]; [myButton setFrame:CGRectMake(20.0, 10.0, 160.0, 30.0)]; [[self myView] addSubview:myButton]; } - (void) initMyTableView { UITableView *newTableView = [[UITableView alloc] initWithFrame:CGRectMake(0,100,[[UIScreen mainScreen] bounds].size.width,[[UIScreen mainScreen] bounds].size.height-100) style:UITableViewStyleGrouped]; self.myTableView = newTableView; self.myTableView.delegate = self; self.myTableView.dataSource = self; } -(void) pressedMyButton { NSLog(@"pressedMyButton"); } - (void)viewDidLoad { [super viewDidLoad]; [[self view] addSubview:self.myView]; [[self view] addSubview:self.myTableView]; } - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 1; } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return 1; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { CustomCell *customCell = [tableView dequeueReusableCellWithIdentifier:@"CustomCell"]; if (customCell == nil) { customCell = [[CustomCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@"CustomCell"]; } return customCell; } @end CustomCell.h #import <UIKit/UIKit.h> @interface CustomCell : UITableViewCell @property (retain, nonatomic) UIButton* cellButton; @end CustomCell.m #import "CustomCell.h" @implementation CustomCell @synthesize cellButton; - (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier { self = [super initWithStyle:style reuseIdentifier:reuseIdentifier]; if (self) { // button within cell cellButton = [UIButton buttonWithType:UIButtonTypeRoundedRect]; [cellButton addTarget:self action:@selector(pressedCellButton) forControlEvents:UIControlEventTouchUpInside]; [cellButton setTitle:@"I'm sluggish" forState:UIControlStateNormal]; [cellButton setFrame:CGRectMake(20.0, 10.0, 160.0, 30.0)]; [self addSubview:cellButton]; } return self; } - (void) pressedCellButton { NSLog(@"pressedCellButton"); } @end

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• Perl Script to search and replace in .SQL query file with user inputs

  - by T.Mount

  I have a .SQL file containing a large number of queries. They are being run against a database containing data for multiple states over multiple years. The machine I am running this on can only handle running the queries for one state, in one year, at a time. I am trying to create a Perl script that takes user input for the state abbreviation, the state id number, and the year. It then creates a directory for that state and year. Then it opens the "base" .SQL file and searches and replaces the base state id and year with the user input, and saves this new .SQL file to the created directory. The current script I have (below) stops at open(IN,'<$infile') with "Can't open [filename]" It seems that it is having difficulty finding or opening the .SQL file. I have quadruple-checked to make sure the paths are correct, and I have even tried replacing the $path with an absolute path for the base file. If it was having trouble with creating the new file I'd have more direction, but since it can't find/open the base file I do not know how to proceed. #!/usr/local/bin/perl use Cwd; $path = getcwd(); #Cleans up the path $path =~ s/\\/\//sg; #User inputs print "What is the 2 letter state abbreviation for the state? Ex. 'GA'\n"; $stlet = <>; print "What is the 2 digit state abbreviation for the state? Ex. '13'\n"; $stdig = <>; print "What four-digit year are you doing the calculations for? Ex. '2008'\n"; $year = <>; chomp $stlet; chomp $stdig; chomp $year; #Creates the directory mkdir($stlet); $new = $path."\/".$stlet; mkdir("$new/$year"); $infile = '$path/Base/TABLE_1-26.sql'; $outfile = '$path/$stlet/$year/TABLE_1-26.sql'; open(IN,'<$infile') or die "Can't open $infile: $!\n"; open(OUT,">$infile2") or die "Can't open $outfile: $!\n"; print "Working..."; while (my $search = <IN>) { chomp $search; $search =~ s/WHERE pop.grp = 132008/WHERE pop.grp = $stdig$year/g; print OUT "$search\n"; } close(IN); close(OUT); I know I also probably need to tweak the regular expression some, but I'm trying to take things one at a time. This is my first Perl script, and I haven't really been able to find anything that handles .SQL files like this that I can understand. Thank you!

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• Double Linked List header node keeps returning first value as 0

  - by Craig

  I will preface to say that this is my first question. I am currently getting my Masters degree in Information Security and I had to take C++ programming this semester. So this is homework related. I am not looking for you to answer my homework but I am running into a peculiar situation. I have created the program to work with a doubly linked list and everything works fine. However when I have the user create a list of values the first node keeps returning 0. I have tried finding some reading on this and I cannot locate any reference to it. My question is then is the header node(first node) always going to be zero? Or am I doing something wrong. case: 'C': cout<<"Please enter a list:"<<endl; while(n!=-999){ myList.insert(n); cin>> n;} break; I now enter: 12321, 1234,64564,346346. The results in 0, 12321, 1234, 64564,346346. Is this what should happen or am I doing something wrong? Also as this is my first post please feel free to criticize or teach me how to color code the keywords. Anyway this is a homework assignment so I am only looking for guidance and constructive criticism. Thank you all in advance So I cannot figure out the comment sections on this forum so I will edit the original post The first section is the constructor code: template <class Type> doublyLinkedList<Type>::doublyLinkedList() { first= NULL; last = NULL; count = 0; } Then there is my insert function : template <class Type> void doublyLinkedList<Type>::insert(const Type& insertItem) { nodeType<Type> *current; //pointer to traverse the list nodeType<Type> *trailCurrent; //pointer just before current nodeType<Type> *newNode; //pointer to create a node bool found; newNode = new nodeType<Type>; //create the node newNode->info = insertItem; //store the new item in the node newNode->next = NULL; newNode->back = NULL; if(first == NULL) //if the list is empty, newNode is //the only node { first = newNode; last = newNode; count++; } else { found = false; current = first; while (current != NULL && !found) //search the list if (current->info >= insertItem) found = true; else { trailCurrent = current; current = current->next; } if (current == first) //insert newNode before first { first->back = newNode; newNode->next = first; first = newNode; count++; } else { //insert newNode between trailCurrent and current if (current != NULL) { trailCurrent->next = newNode; newNode->back = trailCurrent; newNode->next = current; current->back = newNode; } else { trailCurrent->next = newNode; newNode->back = trailCurrent; last = newNode; } count++; }//end else }//end else }//end Then I have an initialization function too: template <class Type> void doublyLinkedList<Type>::initializeList() { destroy(); } Did I miss anything?

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• JavaScript Optimisation

  - by Jayie

  I am using JavaScript to work out all the combinations of badminton doubles matches from a given list of players. Each player teams up with everyone else. EG. If I have the following players a, b, c & d. Their combinations can be: a & b V c & d a & c V b & d a & d V b & c I am using the code below, which I wrote to do the job, but it's a little inefficient. It loops through the PLAYERS array 4 times finding every single combination (including impossible ones). It then sorts the game out into alphabetical order and stores it in the GAMES array if it doesn't already exist. I can then use the first half of the GAMES array to list all game combinations. The trouble is if I have any more than 8 players it runs really slowly because the combination growth is exponential. Does anyone know a better way or algorithm I could use? The more I think about it the more my brain hurts! var PLAYERS = ["a", "b", "c", "d", "e", "f", "g"]; var GAMES = []; var p1, p2, p3, p4, i1, i2, i3, i4, entry, found, i; var pos = 0; var TEAM1 = []; var TEAM2 = []; // loop through players 4 times to get all combinations for (i1 = 0; i1 < PLAYERS.length; i1++) { p1 = PLAYERS[i1]; for (i2 = 0; i2 < PLAYERS.length; i2++) { p2 = PLAYERS[i2]; for (i3 = 0; i3 < PLAYERS.length; i3++) { p3 = PLAYERS[i3]; for (i4 = 0; i4 < PLAYERS.length; i4++) { p4 = PLAYERS[i4]; if ((p1 != p2 && p1 != p3 && p1 != p4) && (p2 != p1 && p2 != p3 && p2 != p4) && (p3 != p1 && p3 != p2 && p3 != p4) && (p4 != p1 && p4 != p2 && p4 != p3)) { // sort teams into alphabetical order (so we can compare them easily later) TEAM1[0] = p1; TEAM1[1] = p2; TEAM2[0] = p3; TEAM2[1] = p4; TEAM1.sort(); TEAM2.sort(); // work out the game and search the array to see if it already exists entry = TEAM1[0] + " & " + TEAM1[1] + " v " + TEAM2[0] + " & " + TEAM2[1]; found = false; for (i=0; i < GAMES.length; i++) { if (entry == GAMES[i]) found = true; } // if the game is unique then store it if (!found) { GAMES[pos] = entry; document.write((pos+1) + ": " + GAMES[pos] + "<br>"); pos++; } } } } } } Thanks in advance. Jason.

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• Java: Object Array assignment in for loop

  - by Hackster

  I am trying to use Dijkstra's algorithm to find the shortest path from a specific vertex (v0) to the rest of them. That is solved and works well with this code from this link below: http://en.literateprograms.org/index.php?title=Special:DownloadCode/Dijkstra%27s_algorithm_(Java)&oldid=15444 I am having trouble with assigning the Edge array in a for loop from the user input, as opposed to hard-coding it like it is here. Any help assigning a new edge to Edge[] adjacencies from each vertex? Keeping in mind it could be 1 or multiple edges. class Vertex implements Comparable<Vertex> { public final String name; public Edge[] adjacencies; public double minDistance = Double.POSITIVE_INFINITY; public Vertex previous; public Vertex(String argName) { name = argName; } public String toString() { return name; } public int compareTo(Vertex other){ return Double.compare(minDistance, other.minDistance); } } class Edge{ public final Vertex target; public final double weight; public Edge(Vertex argTarget, double argWeight){ target = argTarget; weight = argWeight; } } public static void main(String[] args) { Vertex v[] = new Vertex[3]; Vertex v[0] = new Vertex("Harrisburg"); Vertex v[1] = new Vertex("Baltimore"); Vertex v[2] = new Vertex("Washington"); v0.adjacencies = new Edge[]{ new Edge(v[1], 1), new Edge(v[2], 3) }; v1.adjacencies = new Edge[]{ new Edge(v[0], 1), new Edge(v[2], 1),}; v2.adjacencies = new Edge[]{ new Edge(v[0], 3), new Edge(v[1], 1) }; Vertex[] vertices = { v0, v1, v2}; /*Three vertices with weight: V0 connects (V1,1),(V2,3) V1 connects (V0,1),(V2,1) V2 connects (V1,1),(V2,3) */ computePaths(v0); for (Vertex v : vertices){ System.out.println("Distance to " + v + ": " + v.minDistance); List<Vertex> path = getShortestPathTo(v); System.out.println("Path: " + path); } } } The above code works well in finding the shortest path from v0 to all the other vertices. The problem occurs when assigning the new edge[] to edge[] adjacencies. For example this does not produce the correct output: for (int i = 0; i < total_vertices; i++){ s = br.readLine(); char[] line = s.toCharArray(); for (int j = 0; j < line.length; j++){ if(j % 4 == 0 ){ //Input: vertex weight vertex weight: 1 1 2 3 int vert = Integer.parseInt(String.valueOf(line[j])); int w = Integer.parseInt(String.valueOf(line[j+2])); v[i].adjacencies = new Edge[] {new Edge(v[vert], w)}; } } } As opposed to this: v0.adjacencies = new Edge[]{ new Edge(v[1], 1), new Edge(v[2], 3) }; How can I take the user input and make an Edge[], to pass it to adjacencies? The problem is it could be 0 edges or many. Any help would be much appreciated Thanks!

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• Using LINQ Distinct: With an Example on ASP.NET MVC SelectListItem

  - by Joe Mayo

  One of the things that might be surprising in the LINQ Distinct standard query operator is that it doesn’t automatically work properly on custom classes. There are reasons for this, which I’ll explain shortly. The example I’ll use in this post focuses on pulling a unique list of names to load into a drop-down list. I’ll explain the sample application, show you typical first shot at Distinct, explain why it won’t work as you expect, and then demonstrate a solution to make Distinct work with any custom class. The technologies I’m using are  LINQ to Twitter, LINQ to Objects, Telerik Extensions for ASP.NET MVC, ASP.NET MVC 2, and Visual Studio 2010. The function of the example program is to show a list of people that I follow.  In Twitter API vernacular, these people are called “Friends”; though I’ve never met most of them in real life. This is part of the ubiquitous language of social networking, and Twitter in particular, so you’ll see my objects named accordingly. Where Distinct comes into play is because I want to have a drop-down list with the names of the friends appearing in the list. Some friends are quite verbose, which means I can’t just extract names from each tweet and populate the drop-down; otherwise, I would end up with many duplicate names. Therefore, Distinct is the appropriate operator to eliminate the extra entries from my friends who tend to be enthusiastic tweeters. The sample doesn’t do anything with the drop-down list and I leave that up to imagination for what it’s practical purpose could be; perhaps a filter for the list if I only want to see a certain person’s tweets or maybe a quick list that I plan to combine with a TextBox and Button to reply to a friend. When the program runs, you’ll need to authenticate with Twitter, because I’m using OAuth (DotNetOpenAuth), for authentication, and then you’ll see the drop-down list of names above the grid with the most recent tweets from friends. Here’s what the application looks like when it runs: As you can see, there is a drop-down list above the grid. The drop-down list is where most of the focus of this article will be. There is some description of the code before we talk about the Distinct operator, but we’ll get there soon. This is an ASP.NET MVC2 application, written with VS 2010. Here’s the View that produces this screen: <%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<TwitterFriendsViewModel>" %> <%@ Import Namespace="DistinctSelectList.Models" %> <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server">     Home Page </asp:Content><asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">     <fieldset>         <legend>Twitter Friends</legend>         <div>             <%= Html.DropDownListFor(                     twendVM => twendVM.FriendNames,                     Model.FriendNames,                     "<All Friends>") %>         </div>         <div>             <% Html.Telerik().Grid<TweetViewModel>(Model.Tweets)                    .Name("TwitterFriendsGrid")                    .Columns(cols =>                     {                         cols.Template(col =>                             { %>                                 <img src="<%= col.ImageUrl %>"                                      alt="<%= col.ScreenName %>" />                         <% });                         cols.Bound(col => col.ScreenName);                         cols.Bound(col => col.Tweet);                     })                    .Render(); %>         </div>     </fieldset> </asp:Content> As shown above, the Grid is from Telerik’s Extensions for ASP.NET MVC. The first column is a template that renders the user’s Avatar from a URL provided by the Twitter query. Both the Grid and DropDownListFor display properties that are collections from a TwitterFriendsViewModel class, shown below: using System.Collections.Generic; using System.Web.Mvc; namespace DistinctSelectList.Models { /// /// For finding friend info on screen /// public class TwitterFriendsViewModel { /// /// Display names of friends in drop-down list /// public List FriendNames { get; set; } /// /// Display tweets in grid /// public List Tweets { get; set; } } } I created the TwitterFreindsViewModel. The two Lists are what the View consumes to populate the DropDownListFor and Grid. Notice that FriendNames is a List of SelectListItem, which is an MVC class. Another custom class I created is the TweetViewModel (the type of the Tweets List), shown below: namespace DistinctSelectList.Models { /// /// Info on friend tweets /// public class TweetViewModel { /// /// User's avatar /// public string ImageUrl { get; set; } /// /// User's Twitter name /// public string ScreenName { get; set; } /// /// Text containing user's tweet /// public string Tweet { get; set; } } } The initial Twitter query returns much more information than we need for our purposes and this a special class for displaying info in the View.  Now you know about the View and how it’s constructed. Let’s look at the controller next. The controller for this demo performs authentication, data retrieval, data manipulation, and view selection. I’ll skip the description of the authentication because it’s a normal part of using OAuth with LINQ to Twitter. Instead, we’ll drill down and focus on the Distinct operator. However, I’ll show you the entire controller, below,  so that you can see how it all fits together: using System.Linq; using System.Web.Mvc; using DistinctSelectList.Models; using LinqToTwitter; namespace DistinctSelectList.Controllers { [HandleError] public class HomeController : Controller { private MvcOAuthAuthorization auth; private TwitterContext twitterCtx; /// /// Display a list of friends current tweets /// /// public ActionResult Index() { auth = new MvcOAuthAuthorization(InMemoryTokenManager.Instance, InMemoryTokenManager.AccessToken); string accessToken = auth.CompleteAuthorize(); if (accessToken != null) { InMemoryTokenManager.AccessToken = accessToken; } if (auth.CachedCredentialsAvailable) { auth.SignOn(); } else { return auth.BeginAuthorize(); } twitterCtx = new TwitterContext(auth); var friendTweets = (from tweet in twitterCtx.Status where tweet.Type == StatusType.Friends select new TweetViewModel { ImageUrl = tweet.User.ProfileImageUrl, ScreenName = tweet.User.Identifier.ScreenName, Tweet = tweet.Text }) .ToList(); var friendNames = (from tweet in friendTweets select new SelectListItem { Text = tweet.ScreenName, Value = tweet.ScreenName }) .Distinct() .ToList(); var twendsVM = new TwitterFriendsViewModel { Tweets = friendTweets, FriendNames = friendNames }; return View(twendsVM); } public ActionResult About() { return View(); } } } The important part of the listing above are the LINQ to Twitter queries for friendTweets and friendNames. Both of these results are used in the subsequent population of the twendsVM instance that is passed to the view. Let’s dissect these two statements for clarification and focus on what is happening with Distinct. The query for friendTweets gets a list of the 20 most recent tweets (as specified by the Twitter API for friend queries) and performs a projection into the custom TweetViewModel class, repeated below for your convenience: var friendTweets = (from tweet in twitterCtx.Status where tweet.Type == StatusType.Friends select new TweetViewModel { ImageUrl = tweet.User.ProfileImageUrl, ScreenName = tweet.User.Identifier.ScreenName, Tweet = tweet.Text }) .ToList(); The LINQ to Twitter query above simplifies what we need to work with in the View and the reduces the amount of information we have to look at in subsequent queries. Given the friendTweets above, the next query performs another projection into an MVC SelectListItem, which is required for binding to the DropDownList.  This brings us to the focus of this blog post, writing a correct query that uses the Distinct operator. The query below uses LINQ to Objects, querying the friendTweets collection to get friendNames: var friendNames = (from tweet in friendTweets select new SelectListItem { Text = tweet.ScreenName, Value = tweet.ScreenName }) .Distinct() .ToList(); The above implementation of Distinct seems normal, but it is deceptively incorrect. After running the query above, by executing the application, you’ll notice that the drop-down list contains many duplicates.  This will send you back to the code scratching your head, but there’s a reason why this happens. To understand the problem, we must examine how Distinct works in LINQ to Objects. Distinct has two overloads: one without parameters, as shown above, and another that takes a parameter of type IEqualityComparer<T>.  In the case above, no parameters, Distinct will call EqualityComparer<T>.Default behind the scenes to make comparisons as it iterates through the list. You don’t have problems with the built-in types, such as string, int, DateTime, etc, because they all implement IEquatable<T>. However, many .NET Framework classes, such as SelectListItem, don’t implement IEquatable<T>. So, what happens is that EqualityComparer<T>.Default results in a call to Object.Equals, which performs reference equality on reference type objects.  You don’t have this problem with value types because the default implementation of Object.Equals is bitwise equality. However, most of your projections that use Distinct are on classes, just like the SelectListItem used in this demo application. So, the reason why Distinct didn’t produce the results we wanted was because we used a type that doesn’t define its own equality and Distinct used the default reference equality. This resulted in all objects being included in the results because they are all separate instances in memory with unique references. As you might have guessed, the solution to the problem is to use the second overload of Distinct that accepts an IEqualityComparer<T> instance. If you were projecting into your own custom type, you could make that type implement IEqualityComparer<T>, but SelectListItem belongs to the .NET Framework Class Library.  Therefore, the solution is to create a custom type to implement IEqualityComparer<T>, as in the SelectListItemComparer class, shown below: using System.Collections.Generic; using System.Web.Mvc; namespace DistinctSelectList.Models { public class SelectListItemComparer : EqualityComparer { public override bool Equals(SelectListItem x, SelectListItem y) { return x.Value.Equals(y.Value); } public override int GetHashCode(SelectListItem obj) { return obj.Value.GetHashCode(); } } } The SelectListItemComparer class above doesn’t implement IEqualityComparer<SelectListItem>, but rather derives from EqualityComparer<SelectListItem>. Microsoft recommends this approach for consistency with the behavior of generic collection classes. However, if your custom type already derives from a base class, go ahead and implement IEqualityComparer<T>, which will still work. EqualityComparer is an abstract class, that implements IEqualityComparer<T> with Equals and GetHashCode abstract methods. For the purposes of this application, the SelectListItem.Value property is sufficient to determine if two items are equal.   Since SelectListItem.Value is type string, the code delegates equality to the string class. The code also delegates the GetHashCode operation to the string class.You might have other criteria in your own object and would need to define what it means for your object to be equal. Now that we have an IEqualityComparer<SelectListItem>, let’s fix the problem. The code below modifies the query where we want distinct values: var friendNames = (from tweet in friendTweets select new SelectListItem { Text = tweet.ScreenName, Value = tweet.ScreenName }) .Distinct(new SelectListItemComparer()) .ToList(); Notice how the code above passes a new instance of SelectListItemComparer as the parameter to the Distinct operator. Now, when you run the application, the drop-down list will behave as you expect, showing only a unique set of names. In addition to Distinct, other LINQ Standard Query Operators have overloads that accept IEqualityComparer<T>’s, You can use the same techniques as shown here, with SelectListItemComparer, with those other operators as well. Now you know how to resolve problems with getting Distinct to work properly and also have a way to fix problems with other operators that require equality comparisons. @JoeMayo

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• Parallelism in .NET – Part 3, Imperative Data Parallelism: Early Termination

  - by Reed

  Although simple data parallelism allows us to easily parallelize many of our iteration statements, there are cases that it does not handle well.  In my previous discussion, I focused on data parallelism with no shared state, and where every element is being processed exactly the same. Unfortunately, there are many common cases where this does not happen.  If we are dealing with a loop that requires early termination, extra care is required when parallelizing. Often, while processing in a loop, once a certain condition is met, it is no longer necessary to continue processing.  This may be a matter of finding a specific element within the collection, or reaching some error case.  The important distinction here is that, it is often impossible to know until runtime, what set of elements needs to be processed. In my initial discussion of data parallelism, I mentioned that this technique is a candidate when you can decompose the problem based on the data involved, and you wish to apply a single operation concurrently on all of the elements of a collection.  This covers many of the potential cases, but sometimes, after processing some of the elements, we need to stop processing. As an example, lets go back to our previous Parallel.ForEach example with contacting a customer.  However, this time, we’ll change the requirements slightly.  In this case, we’ll add an extra condition – if the store is unable to email the customer, we will exit gracefully.  The thinking here, of course, is that if the store is currently unable to email, the next time this operation runs, it will handle the same situation, so we can just skip our processing entirely.  The original, serial case, with this extra condition, might look something like the following: foreach(var customer in customers) { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { // Exit gracefully if we fail to email, since this // entire process can be repeated later without issue. if (theStore.EmailCustomer(customer) == false) break; customer.LastEmailContact = DateTime.Now; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, we’re processing our loop, but at any point, if we fail to send our email successfully, we just abandon this process, and assume that it will get handled correctly the next time our routine is run.  If we try to parallelize this using Parallel.ForEach, as we did previously, we’ll run into an error almost immediately: the break statement we’re using is only valid when enclosed within an iteration statement, such as foreach.  When we switch to Parallel.ForEach, we’re no longer within an iteration statement – we’re a delegate running in a method. This needs to be handled slightly differently when parallelized.  Instead of using the break statement, we need to utilize a new class in the Task Parallel Library: ParallelLoopState.  The ParallelLoopState class is intended to allow concurrently running loop bodies a way to interact with each other, and provides us with a way to break out of a loop.  In order to use this, we will use a different overload of Parallel.ForEach which takes an IEnumerable<T> and an Action<T, ParallelLoopState> instead of an Action<T>.  Using this, we can parallelize the above operation by doing: Parallel.ForEach(customers, (customer, parallelLoopState) => { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { // Exit gracefully if we fail to email, since this // entire process can be repeated later without issue. if (theStore.EmailCustomer(customer) == false) parallelLoopState.Break(); else customer.LastEmailContact = DateTime.Now; } }); There are a couple of important points here.  First, we didn’t actually instantiate the ParallelLoopState instance.  It was provided directly to us via the Parallel class.  All we needed to do was change our lambda expression to reflect that we want to use the loop state, and the Parallel class creates an instance for our use.  We also needed to change our logic slightly when we call Break().  Since Break() doesn’t stop the program flow within our block, we needed to add an else case to only set the property in customer when we succeeded.  This same technique can be used to break out of a Parallel.For loop. That being said, there is a huge difference between using ParallelLoopState to cause early termination and to use break in a standard iteration statement.  When dealing with a loop serially, break will immediately terminate the processing within the closest enclosing loop statement.  Calling ParallelLoopState.Break(), however, has a very different behavior. The issue is that, now, we’re no longer processing one element at a time.  If we break in one of our threads, there are other threads that will likely still be executing.  This leads to an important observation about termination of parallel code: Early termination in parallel routines is not immediate.  Code will continue to run after you request a termination. This may seem problematic at first, but it is something you just need to keep in mind while designing your routine.  ParallelLoopState.Break() should be thought of as a request.  We are telling the runtime that no elements that were in the collection past the element we’re currently processing need to be processed, and leaving it up to the runtime to decide how to handle this as gracefully as possible.  Although this may seem problematic at first, it is a good thing.  If the runtime tried to immediately stop processing, many of our elements would be partially processed.  It would be like putting a return statement in a random location throughout our loop body – which could have horrific consequences to our code’s maintainability. In order to understand and effectively write parallel routines, we, as developers, need a subtle, but profound shift in our thinking.  We can no longer think in terms of sequential processes, but rather need to think in terms of requests to the system that may be handled differently than we’d first expect.  This is more natural to developers who have dealt with asynchronous models previously, but is an important distinction when moving to concurrent programming models. As an example, I’ll discuss the Break() method.  ParallelLoopState.Break() functions in a way that may be unexpected at first.  When you call Break() from a loop body, the runtime will continue to process all elements of the collection that were found prior to the element that was being processed when the Break() method was called.  This is done to keep the behavior of the Break() method as close to the behavior of the break statement as possible. We can see the behavior in this simple code: var collection = Enumerable.Range(0, 20); var pResult = Parallel.ForEach(collection, (element, state) => { if (element > 10) { Console.WriteLine("Breaking on {0}", element); state.Break(); } Console.WriteLine(element); }); If we run this, we get a result that may seem unexpected at first: 0 2 1 5 6 3 4 10 Breaking on 11 11 Breaking on 12 12 9 Breaking on 13 13 7 8 Breaking on 15 15 What is occurring here is that we loop until we find the first element where the element is greater than 10.  In this case, this was found, the first time, when one of our threads reached element 11.  It requested that the loop stop by calling Break() at this point.  However, the loop continued processing until all of the elements less than 11 were completed, then terminated.  This means that it will guarantee that elements 9, 7, and 8 are completed before it stops processing.  You can see our other threads that were running each tried to break as well, but since Break() was called on the element with a value of 11, it decides which elements (0-10) must be processed. If this behavior is not desirable, there is another option.  Instead of calling ParallelLoopState.Break(), you can call ParallelLoopState.Stop().  The Stop() method requests that the runtime terminate as soon as possible , without guaranteeing that any other elements are processed.  Stop() will not stop the processing within an element, so elements already being processed will continue to be processed.  It will prevent new elements, even ones found earlier in the collection, from being processed.  Also, when Stop() is called, the ParallelLoopState’s IsStopped property will return true.  This lets longer running processes poll for this value, and return after performing any necessary cleanup. The basic rule of thumb for choosing between Break() and Stop() is the following. Use ParallelLoopState.Stop() when possible, since it terminates more quickly.  This is particularly useful in situations where you are searching for an element or a condition in the collection.  Once you’ve found it, you do not need to do any other processing, so Stop() is more appropriate. Use ParallelLoopState.Break() if you need to more closely match the behavior of the C# break statement. Both methods behave differently than our C# break statement.  Unfortunately, when parallelizing a routine, more thought and care needs to be put into every aspect of your routine than you may otherwise expect.  This is due to my second observation: Parallelizing a routine will almost always change its behavior. This sounds crazy at first, but it’s a concept that’s so simple its easy to forget.  We’re purposely telling the system to process more than one thing at the same time, which means that the sequence in which things get processed is no longer deterministic.  It is easy to change the behavior of your routine in very subtle ways by introducing parallelism.  Often, the changes are not avoidable, even if they don’t have any adverse side effects.  This leads to my final observation for this post: Parallelization is something that should be handled with care and forethought, added by design, and not just introduced casually.

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• Parallelism in .NET – Part 4, Imperative Data Parallelism: Aggregation

  - by Reed

  In the article on simple data parallelism, I described how to perform an operation on an entire collection of elements in parallel.  Often, this is not adequate, as the parallel operation is going to be performing some form of aggregation. Simple examples of this might include taking the sum of the results of processing a function on each element in the collection, or finding the minimum of the collection given some criteria.  This can be done using the techniques described in simple data parallelism, however, special care needs to be taken into account to synchronize the shared data appropriately.  The Task Parallel Library has tools to assist in this synchronization. The main issue with aggregation when parallelizing a routine is that you need to handle synchronization of data.  Since multiple threads will need to write to a shared portion of data.  Suppose, for example, that we wanted to parallelize a simple loop that looked for the minimum value within a dataset: double min = double.MaxValue; foreach(var item in collection) { double value = item.PerformComputation(); min = System.Math.Min(min, value); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This seems like a good candidate for parallelization, but there is a problem here.  If we just wrap this into a call to Parallel.ForEach, we’ll introduce a critical race condition, and get the wrong answer.  Let’s look at what happens here: // Buggy code! Do not use! double min = double.MaxValue; Parallel.ForEach(collection, item => { double value = item.PerformComputation(); min = System.Math.Min(min, value); }); This code has a fatal flaw: min will be checked, then set, by multiple threads simultaneously.  Two threads may perform the check at the same time, and set the wrong value for min.  Say we get a value of 1 in thread 1, and a value of 2 in thread 2, and these two elements are the first two to run.  If both hit the min check line at the same time, both will determine that min should change, to 1 and 2 respectively.  If element 1 happens to set the variable first, then element 2 sets the min variable, we’ll detect a min value of 2 instead of 1.  This can lead to wrong answers. Unfortunately, fixing this, with the Parallel.ForEach call we’re using, would require adding locking.  We would need to rewrite this like: // Safe, but slow double min = double.MaxValue; // Make a "lock" object object syncObject = new object(); Parallel.ForEach(collection, item => { double value = item.PerformComputation(); lock(syncObject) min = System.Math.Min(min, value); }); This will potentially add a huge amount of overhead to our calculation.  Since we can potentially block while waiting on the lock for every single iteration, we will most likely slow this down to where it is actually quite a bit slower than our serial implementation.  The problem is the lock statement – any time you use lock(object), you’re almost assuring reduced performance in a parallel situation.  This leads to two observations I’ll make: When parallelizing a routine, try to avoid locks. That being said: Always add any and all required synchronization to avoid race conditions. These two observations tend to be opposing forces – we often need to synchronize our algorithms, but we also want to avoid the synchronization when possible.  Looking at our routine, there is no way to directly avoid this lock, since each element is potentially being run on a separate thread, and this lock is necessary in order for our routine to function correctly every time. However, this isn’t the only way to design this routine to implement this algorithm.  Realize that, although our collection may have thousands or even millions of elements, we have a limited number of Processing Elements (PE).  Processing Element is the standard term for a hardware element which can process and execute instructions.  This typically is a core in your processor, but many modern systems have multiple hardware execution threads per core.  The Task Parallel Library will not execute the work for each item in the collection as a separate work item. Instead, when Parallel.ForEach executes, it will partition the collection into larger “chunks” which get processed on different threads via the ThreadPool.  This helps reduce the threading overhead, and help the overall speed.  In general, the Parallel class will only use one thread per PE in the system. Given the fact that there are typically fewer threads than work items, we can rethink our algorithm design.  We can parallelize our algorithm more effectively by approaching it differently.  Because the basic aggregation we are doing here (Min) is communitive, we do not need to perform this in a given order.  We knew this to be true already – otherwise, we wouldn’t have been able to parallelize this routine in the first place.  With this in mind, we can treat each thread’s work independently, allowing each thread to serially process many elements with no locking, then, after all the threads are complete, “merge” together the results. This can be accomplished via a different set of overloads in the Parallel class: Parallel.ForEach<TSource,TLocal>.  The idea behind these overloads is to allow each thread to begin by initializing some local state (TLocal).  The thread will then process an entire set of items in the source collection, providing that state to the delegate which processes an individual item.  Finally, at the end, a separate delegate is run which allows you to handle merging that local state into your final results. To rewriting our routine using Parallel.ForEach<TSource,TLocal>, we need to provide three delegates instead of one.  The most basic version of this function is declared as: public static ParallelLoopResult ForEach<TSource, TLocal>( IEnumerable<TSource> source, Func<TLocal> localInit, Func<TSource, ParallelLoopState, TLocal, TLocal> body, Action<TLocal> localFinally ) The first delegate (the localInit argument) is defined as Func<TLocal>.  This delegate initializes our local state.  It should return some object we can use to track the results of a single thread’s operations. The second delegate (the body argument) is where our main processing occurs, although now, instead of being an Action<T>, we actually provide a Func<TSource, ParallelLoopState, TLocal, TLocal> delegate.  This delegate will receive three arguments: our original element from the collection (TSource), a ParallelLoopState which we can use for early termination, and the instance of our local state we created (TLocal).  It should do whatever processing you wish to occur per element, then return the value of the local state after processing is completed. The third delegate (the localFinally argument) is defined as Action<TLocal>.  This delegate is passed our local state after it’s been processed by all of the elements this thread will handle.  This is where you can merge your final results together.  This may require synchronization, but now, instead of synchronizing once per element (potentially millions of times), you’ll only have to synchronize once per thread, which is an ideal situation. Now that I’ve explained how this works, lets look at the code: // Safe, and fast! double min = double.MaxValue; // Make a "lock" object object syncObject = new object(); Parallel.ForEach( collection, // First, we provide a local state initialization delegate. () => double.MaxValue, // Next, we supply the body, which takes the original item, loop state, // and local state, and returns a new local state (item, loopState, localState) => { double value = item.PerformComputation(); return System.Math.Min(localState, value); }, // Finally, we provide an Action<TLocal>, to "merge" results together localState => { // This requires locking, but it's only once per used thread lock(syncObj) min = System.Math.Min(min, localState); } ); Although this is a bit more complicated than the previous version, it is now both thread-safe, and has minimal locking.  This same approach can be used by Parallel.For, although now, it’s Parallel.For<TLocal>.  When working with Parallel.For<TLocal>, you use the same triplet of delegates, with the same purpose and results. Also, many times, you can completely avoid locking by using a method of the Interlocked class to perform the final aggregation in an atomic operation.  The MSDN example demonstrating this same technique using Parallel.For uses the Interlocked class instead of a lock, since they are doing a sum operation on a long variable, which is possible via Interlocked.Add. By taking advantage of local state, we can use the Parallel class methods to parallelize algorithms such as aggregation, which, at first, may seem like poor candidates for parallelization.  Doing so requires careful consideration, and often requires a slight redesign of the algorithm, but the performance gains can be significant if handled in a way to avoid excessive synchronization.

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• The How-To Geek Holiday Gift Guide (Geeky Stuff We Like)

  - by The Geek

  Welcome to the very first How-To Geek Holiday Gift Guide, where we’ve put together a list of our absolute favorites to help you weed through all of the junk out there to pick the perfect gift for anybody. Though really, it’s just a list of the geeky stuff we want. We’ve got a whole range of items on the list, from cheaper gifts that most anybody can afford, to the really expensive stuff that we’re pretty sure nobody is giving us. Stocking Stuffers Here’s a couple of ideas for items that won’t break the bank. LED Keychain Micro-Light   Magcraft 1/8-Inch Rare Earth Cube Magnets Best little LED keychain light around. If they don’t need the penknife of the above item this is the perfect gift. I give them out by the handfuls and nobody ever says anything but good things about them. I’ve got ones that are years old and still running on the same battery.  Price: $8   Geeks cannot resist magnets. Jason bought this pack for his fridge because he was sick of big clunky magnets… these things are amazing. One tiny magnet, smaller than an Altoid mint, can practically hold a clipboard right to the fridge. Amazing. I spend more time playing with them on the counter than I do actually hanging stuff.  Price: $10 Lots of Geeky Mugs   Astronomy Powerful Green Laser Pointer There’s loads of fun, geeky mugs you can find on Amazon or anywhere else—and they are great choices for the geek who loves their coffee. You can get the Caffeine mug pictured here, or go with an Atari one, Canon Lens, or the Aperture mug based on Portal. Your choice. Price: $7   No, it’s not a light saber, but it’s nearly bright enough to be one—you can illuminate low flying clouds at night or just blind some aliens on your day off. All that for an extremely low price. Loads of fun. Price: $15       Geeky TV Shows and Books Sometimes you just want to relax and enjoy a some TV or a good book. Here’s a few choices. The IT Crowd Fourth Season   Doctor Who, Complete Fifth Series Ridiculous, funny show about nerds in the IT department, loved by almost all the geeks here at HTG. Justin even makes this required watching for new hires in his office so they’ll get his jokes. You can pre-order the fourth season, or pick up seasons one, two, or three for even cheaper. Price: $13   It doesn’t get any more nerdy than Eric’s pick, the fifth all-new series of Doctor Who, where the Daleks are hatching a new master plan from the heart of war-torn London. There’s also alien vampires, humanoid reptiles, and a lot more. Price: $52 Battlestar Galactica Complete Series   MAKE: Electronics: Learning Through Discovery Watch the epic fight to save the human race by finding the fabled planet Earth while being hunted by the robotic Cylons. You can grab the entire series on DVD or Blu-ray, or get the seasons individually. This isn’t your average sci-fi TV show. Price: $150 for Blu-ray.   Want to learn the fundamentals of electronics in a fun, hands-on way? The Make:Electronics book helps you build the circuits and learn how it all works—as if you had any more time between all that registry hacking and loading software on your new PC. Price: $21       Geeky Gadgets for the Gadget-Loving Geek Here’s a few of the items on our gadget list, though lets be honest: geeks are going to love almost any gadget, especially shiny new ones. Klipsch Image S4i Premium Noise-Isolating Headset with 3-Button Apple Control   GP2X Caanoo MAME/Console Emulator If you’re a real music geek looking for some serious quality in the headset for your iPhone or iPod, this is the pair that Alex recommends. They aren’t terribly cheap, but you can get the less expensive S3 earphones instead if you prefer. Price: $50-100   Eric says: “As an owner of an older version, I can say the GP2X is one of my favorite gadgets ever. Touted a “Retro Emulation Juggernaut,” GP2X runs Linux and may be the only open source software console available. Sounds too good to be true, but isn’t.” Price: $150 Roku XDS Streaming Player 1080p   Western Digital WD TV Live Plus HD Media Player If you do a lot of streaming over Netflix, Hulu Plus, Amazon’s Video on Demand, Pandora, and others, the Roku box is a great choice to get your content on your TV without paying a lot of money.  It’s also got Wireless-N built in, and it supports full 1080P HD. Price: $99   If you’ve got a home media collection sitting on a hard drive or a network server, the Western Digital box is probably the cheapest way to get that content on your TV, and it even supports Netflix streaming too. It’ll play loads of formats in full HD quality. Price: $99 Fujitsu ScanSnap S300 Color Mobile Scanner   Doxie, the amazing scanner for documents Trevor said: “This wonderful little scanner has become absolutely essential to me. My desk used to just be a gigantic pile of papers that I didn’t need at the moment, but couldn’t throw away ‘just in case.’ Now, every few weeks, I’ll run that paper pile through this and then happily shred the originals!” Price: $300   If you don’t scan quite as often and are looking for a budget scanner you can throw into your bag, or toss into a drawer in your desk, the Doxie scanner is a great alternative that I’ve been using for a while. It’s half the price, and while it’s not as full-featured as the Fujitsu, it might be a better choice for the very casual user. Price: $150       (Expensive) Gadgets Almost Anybody Will Love If you’re not sure that one of the more geeky presents is gonna work, here’s some gadgets that just about anybody is going to love, especially if they don’t have one already. Of course, some of these are a bit on the expensive side—but it’s a wish list, right? Amazon Kindle       The Kindle weighs less than a paperback book, the screen is amazing and easy on the eyes, and get ready for the kicker: the battery lasts at least a month. We aren’t kidding, either—it really lasts that long. If you don’t feel like spending money for books, you can use it to read PDFs, and if you want to get really geeky, you can hack it for custom screensavers. Price: $139 iPod Touch or iPad       You can’t go wrong with either of these presents—the iPod Touch can do almost everything the iPhone can do, including games, apps, and music, and it has the same Retina display as the iPhone, HD video recording, and a front-facing camera so you can use FaceTime. Price: $229+, depending on model. The iPad is a great tablet for playing games, browsing the web, or just using on your coffee table for guests. It’s well worth buying one—but if you’re buying for yourself, keep in mind that the iPad 2 is probably coming out in 3 months. Price: $500+ MacBook Air  The MacBook Air comes in 11” or 13” versions, and it’s an amazing little machine. It’s lightweight, the battery lasts nearly forever, and it resumes from sleep almost instantly. Since it uses an SSD drive instead of a hard drive, you’re barely going to notice any speed problems for general use. So if you’ve got a lot of money to blow, this is a killer gift. Price: $999 and up. Stuck with No Idea for a Present? Gift Cards! Yeah, you’re not going to win any “thoughtful present” awards with these, but you might just give somebody what they really want—the new Angry Birds HD for their iPad, Cut the Rope, or anything else they want. ITunes Gift Card   Amazon.com Gift Card Somebody in your circle getting a new iPod, iPhone, or iPad? You can get them an iTunes gift card, which they can use to buy music, games or apps. Yep, this way you can gift them a copy of Angry Birds if they don’t already have it. Or even Cut the Rope.   No clue what to get somebody on your list? Amazon gift cards let them buy pretty much anything they want, from organic weirdberries to big screen TVs. Yeah, it’s not as thoughtful as getting them a nice present, but look at the bright side: maybe they’ll get you an Amazon gift card and it’ll balance out. That’s the highlights from our lists—got anything else to add? Share your geeky gift ideas in the comments. Latest Features How-To Geek ETC The How-To Geek Holiday Gift Guide (Geeky Stuff We Like) LCD? LED? Plasma? The How-To Geek Guide to HDTV Technology The How-To Geek Guide to Learning Photoshop, Part 8: Filters Improve Digital Photography by Calibrating Your Monitor Our Favorite Tech: What We’re Thankful For at How-To Geek The How-To Geek Guide to Learning Photoshop, Part 7: Design and Typography Happy Snow Bears Theme for Chrome and Iron [Holiday] Download Full Command and Conquer: Tiberian Sun Game for Free Scorched Cometary Planet Wallpaper Quick Fix: Add the RSS Button Back to the Firefox Awesome Bar Dropbox Desktop Client 1.0.0 RC for Windows, Linux, and Mac Released Hang in There Scrat! – Ice Age Wallpaper

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• Dual Boot issues with Windows 7 and Ubuntu

  - by Michael

  I'm finding myself in a rather unique situation. I've read through just about every resource I can find about this and while things have helped me understand some background, I haven't yet been able to find a solution. So I'm asking here. I originally had just a Windows 7 64-bit OS installation on my desktop. Learning that I couldn't do anything with Apache, PHP and MySql from within a 64-bit system, I did some research and found out that I could use Ubuntu. I've installed the latest version: 11.04. I created a CD to install Ubuntu from and the install went just fine. I installed it side-by-side with Windows 7. I can boot into Ubuntu just fine through the dual-boot option. When I reboot to load Windows though, the Grub2 list shows Windows 7 (loader) and when I select this option the Windows System Recovery loads instead of the actual OS. I haven't made it past there because I didn't know what to do. I just shut the computer down and rebooted into Ubuntu. I've been working for the last hour and a half to try to figure out how to boot into the Windows 7 OS and I haven't got a clue. While I'm somewhat proficient with Windows 7, I'm totally new to Ubuntu, so if you do know what needs to happen, please keep it simple enough that I'll be able to understand. Thanks for all your help in advance. Here's the results after using the Boot Info Script: Boot Info Script 0.55 dated February 15th, 2010 ============================= Boot Info Summary: ============================== => Grub 2 is installed in the MBR of /dev/sda and looks on the same drive in partition #5 for cbh. => Windows is installed in the MBR of /dev/sdb => Grub 2 is installed in the MBR of /dev/mapper/pdc_bdadcfbdif and looks on the same drive in partition #5 for cbh. sda1: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Mounting failed: fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy sda2: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Mounting failed: fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy sda3: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Mounting failed: fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy sdb1: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files/dirs: /bootmgr /Boot/BCD sdb2: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files/dirs: sdb3: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files/dirs: /bootmgr /boot/BCD sdb4: _________________________________________________________________________ File system: Extended Partition Boot sector type: - Boot sector info: sdb5: _________________________________________________________________________ File system: ext4 Boot sector type: - Boot sector info: Operating System: Ubuntu 11.04 Boot files/dirs: /boot/grub/grub.cfg /etc/fstab /boot/grub/core.img sdb6: _________________________________________________________________________ File system: swap Boot sector type: - Boot sector info: pdc_bdadcfbdif1: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files/dirs: /bootmgr /Boot/BCD pdc_bdadcfbdif2: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Windows 7 Boot files/dirs: /bootmgr /Boot/BCD /Windows/System32/winload.exe pdc_bdadcfbdif3: _________________________________________________________________________ File system: Boot sector type: Unknown Boot sector info: Mounting failed: fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy mount: unknown filesystem type '' =========================== Drive/Partition Info: ============================= Drive: sda ___________________ _____________________________________________________ Disk /dev/sda: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders, total 1465149168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start End Size Id System /dev/sda1 * 2,048 206,847 204,800 7 HPFS/NTFS /dev/sda2 206,911 1,440,372,735 1,440,165,825 7 HPFS/NTFS /dev/sda3 1,440,372,736 1,464,856,575 24,483,840 7 HPFS/NTFS Drive: sdb ___________________ _____________________________________________________ Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start End Size Id System /dev/sdb1 * 2,048 206,847 204,800 7 HPFS/NTFS /dev/sdb2 206,911 1,342,554,688 1,342,347,778 7 HPFS/NTFS /dev/sdb3 1,930,344,448 1,953,521,663 23,177,216 7 HPFS/NTFS /dev/sdb4 1,342,556,158 1,930,344,447 587,788,290 5 Extended /dev/sdb5 1,342,556,160 1,896,806,399 554,250,240 83 Linux /dev/sdb6 1,896,808,448 1,930,344,447 33,536,000 82 Linux swap / Solaris Drive: pdc_bdadcfbdif ___________________ _____________________________________________________ Disk /dev/mapper/pdc_bdadcfbdif: 750.0 GB, 749999947776 bytes 255 heads, 63 sectors/track, 91182 cylinders, total 1464843648 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start End Size Id System /dev/mapper/pdc_bdadcfbdif1 * 2,048 206,847 204,800 7 HPFS/NTFS /dev/mapper/pdc_bdadcfbdif2 206,911 1,440,372,735 1,440,165,825 7 HPFS/NTFS /dev/mapper/pdc_bdadcfbdif3 1,440,372,736 1,464,856,575 24,483,840 7 HPFS/NTFS /dev/mapper/pdc_bdadcfbdif3 ends after the last sector of /dev/mapper/pdc_bdadcfbdif blkid -c /dev/null: ____________________________________________________________ Device UUID TYPE LABEL /dev/mapper/pdc_bdadcfbdif1 888E54CC8E54B482 ntfs SYSTEM /dev/mapper/pdc_bdadcfbdif2 C2766BF6766BEA1D ntfs OS /dev/mapper/pdc_bdadcfbdif: PTTYPE="dos" /dev/sda1 888E54CC8E54B482 ntfs SYSTEM /dev/sda2 C2766BF6766BEA1D ntfs OS /dev/sda3 BE6CA31D6CA2CF87 ntfs HP_RECOVERY /dev/sda promise_fasttrack_raid_member /dev/sdb1 20B65685B6565B7C ntfs SYSTEM /dev/sdb2 B4467A314679F508 ntfs HP /dev/sdb3 6E10B7A410B77227 ntfs FACTORY_IMAGE /dev/sdb4: PTTYPE="dos" /dev/sdb5 266f9801-cf4f-4acc-affa-2092be035f0c ext4 /dev/sdb6 1df35749-a887-45ff-a3de-edd52239847d swap /dev/sdb: PTTYPE="dos" error: /dev/mapper/pdc_bdadcfbdif3: No such file or directory error: /dev/sdc: No medium found error: /dev/sdd: No medium found error: /dev/sde: No medium found error: /dev/sdf: No medium found error: /dev/sdg: No medium found ============================ "mount | grep ^/dev output: =========================== Device Mount_Point Type Options /dev/sdb5 / ext4 (rw,errors=remount-ro,commit=0) =========================== sdb5/boot/grub/grub.cfg: =========================== # # DO NOT EDIT THIS FILE # # It is automatically generated by grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### BEGIN /etc/grub.d/00_header ### if [ -s $prefix/grubenv ]; then set have_grubenv=true load_env fi set default="0" if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { insmod vbe insmod vga insmod video_bochs insmod video_cirrus } insmod part_msdos insmod ext2 set root='(/dev/sdb,msdos5)' search --no-floppy --fs-uuid --set=root 266f9801-cf4f-4acc-affa-2092be035f0c if loadfont /usr/share/grub/unicode.pf2 ; then set gfxmode=auto load_video insmod gfxterm fi terminal_output gfxterm insmod part_msdos insmod ext2 set root='(/dev/sdb,msdos5)' search --no-floppy --fs-uuid --set=root 266f9801-cf4f-4acc-affa-2092be035f0c set locale_dir=($root)/boot/grub/locale set lang=en_US insmod gettext if [ "${recordfail}" = 1 ]; then set timeout=-1 else set timeout=10 fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray if background_color 44,0,30; then clear fi ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### if [ ${recordfail} != 1 ]; then if [ -e ${prefix}/gfxblacklist.txt ]; then if hwmatch ${prefix}/gfxblacklist.txt 3; then if [ ${match} = 0 ]; then set linux_gfx_mode=keep else set linux_gfx_mode=text fi else set linux_gfx_mode=text fi else set linux_gfx_mode=keep fi else set linux_gfx_mode=text fi export linux_gfx_mode if [ "$linux_gfx_mode" != "text" ]; then load_video; fi menuentry 'Ubuntu, with Linux 2.6.38-8-generic-pae' --class ubuntu --class gnu-linux --class gnu --class os { recordfail set gfxpayload=$linux_gfx_mode insmod part_msdos insmod ext2 set root='(/dev/sdb,msdos5)' search --no-floppy --fs-uuid --set=root 266f9801-cf4f-4acc-affa-2092be035f0c linux /boot/vmlinuz-2.6.38-8-generic-pae root=UUID=266f9801-cf4f-4acc- affa-2092be035f0c ro quiet splash vt.handoff=7 initrd /boot/initrd.img-2.6.38-8-generic-pae } menuentry 'Ubuntu, with Linux 2.6.38-8-generic-pae (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail set gfxpayload=$linux_gfx_mode insmod part_msdos insmod ext2 set root='(/dev/sdb,msdos5)' search --no-floppy --fs-uuid --set=root 266f9801-cf4f-4acc-affa-2092be035f0c echo 'Loading Linux 2.6.38-8-generic-pae ...' linux /boot/vmlinuz-2.6.38-8-generic-pae root=UUID=266f9801-cf4f-4acc-affa-2092be035f0c ro single echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-2.6.38-8-generic-pae } ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry "Memory test (memtest86+)" { insmod part_msdos insmod ext2 set root='(/dev/sdb,msdos5)' search --no-floppy --fs-uuid --set=root 266f9801-cf4f-4acc-affa-2092be035f0c linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod part_msdos insmod ext2 set root='(/dev/sdb,msdos5)' search --no-floppy --fs-uuid --set=root 266f9801-cf4f-4acc-affa-2092be035f0c linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry "Windows 7 (loader) (on /dev/sdb1)" --class windows --class os { insmod part_msdos insmod ntfs set root='(/dev/sdb,msdos1)' search --no-floppy --fs-uuid --set=root 20B65685B6565B7C chainloader +1 } menuentry "Windows Recovery Environment (loader) (on /dev/sdb3)" --class windows --class os { insmod part_msdos insmod ntfs set root='(/dev/sdb,msdos3)' search --no-floppy --fs-uuid --set=root 6E10B7A410B77227 drivemap -s (hd0) ${root} chainloader +1 } ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/40_custom ### # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. ### END /etc/grub.d/40_custom ### ### BEGIN /etc/grub.d/41_custom ### if [ -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ### =============================== sdb5/etc/fstab: =============================== # /etc/fstab: static file system information. # # Use 'blkid -o value -s UUID' to print the universally unique identifier # for a device; this may be used with UUID= as a more robust way to name # devices that works even if disks are added and removed. See fstab(5). # # <file system> <mount point> <type> <options> <dump> <pass> proc /proc proc nodev,noexec,nosuid 0 0 # / was on /dev/sdb5 during installation UUID=266f9801-cf4f-4acc-affa-2092be035f0c / ext4 errors=remount-ro 0 1 # swap was on /dev/sdb6 during installation UUID=1df35749-a887-45ff-a3de-edd52239847d none swap sw 0 0 =================== sdb5: Location of files loaded by Grub: =================== 900.1GB: boot/grub/core.img 825.0GB: boot/grub/grub.cfg 688.7GB: boot/initrd.img-2.6.38-8-generic-pae 688.0GB: boot/vmlinuz-2.6.38-8-generic-pae 688.7GB: initrd.img 688.0GB: vmlinuz =========================== Unknown MBRs/Boot Sectors/etc ======================= Unknown BootLoader on pdc_bdadcfbdif3 =======Devices which don't seem to have a corresponding hard drive============== sdc sdd sde sdf sdg =============================== StdErr Messages: =============================== ERROR: dos: partition address past end of RAID device hexdump: /dev/mapper/pdc_bdadcfbdif3: No such file or directory hexdump: /dev/mapper/pdc_bdadcfbdif3: No such file or directory ERROR: dos: partition address past end of RAID device

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• Revisiting ANTS Performance Profiler 7.4

  - by James Michael Hare

  Last year, I did a small review on the ANTS Performance Profiler 6.3, now that it’s a year later and a major version number higher, I thought I’d revisit the review and revise my last post. This post will take the same examples as the original post and update them to show what’s new in version 7.4 of the profiler. Background A performance profiler’s main job is to keep track of how much time is typically spent in each unit of code. This helps when we have a program that is not running at the performance we expect, and we want to know where the program is experiencing issues. There are many profilers out there of varying capabilities. Red Gate’s typically seem to be the very easy to “jump in” and get started with very little training required. So let’s dig into the Performance Profiler. I’ve constructed a very crude program with some obvious inefficiencies. It’s a simple program that generates random order numbers (or really could be any unique identifier), adds it to a list, sorts the list, then finds the max and min number in the list. Ignore the fact it’s very contrived and obviously inefficient, we just want to use it as an example to show off the tool: 1: // our test program 2: public static class Program 3: { 4: // the number of iterations to perform 5: private static int _iterations = 1000000; 6: 7: // The main method that controls it all 8: public static void Main() 9: { 10: var list = new List<string>(); 11: 12: for (int i = 0; i < _iterations; i++) 13: { 14: var x = GetNextId(); 15: 16: AddToList(list, x); 17: 18: var highLow = GetHighLow(list); 19: 20: if ((i % 1000) == 0) 21: { 22: Console.WriteLine("{0} - High: {1}, Low: {2}", i, highLow.Item1, highLow.Item2); 23: Console.Out.Flush(); 24: } 25: } 26: } 27: 28: // gets the next order id to process (random for us) 29: public static string GetNextId() 30: { 31: var random = new Random(); 32: var num = random.Next(1000000, 9999999); 33: return num.ToString(); 34: } 35: 36: // add it to our list - very inefficiently! 37: public static void AddToList(List<string> list, string item) 38: { 39: list.Add(item); 40: list.Sort(); 41: } 42: 43: // get high and low of order id range - very inefficiently! 44: public static Tuple<int,int> GetHighLow(List<string> list) 45: { 46: return Tuple.Create(list.Max(s => Convert.ToInt32(s)), list.Min(s => Convert.ToInt32(s))); 47: } 48: } So let’s run it through the profiler and see what happens! Visual Studio Integration First, let’s look at how the ANTS profilers integrate with Visual Studio’s menu system. Once you install the ANTS profilers, you will get an ANTS menu item with several options: Notice that you can either Profile Performance or Launch ANTS Performance Profiler. These sound similar but achieve two slightly different actions: Profile Performance: this immediately launches the profiler with all defaults selected to profile the active project in Visual Studio. Launch ANTS Performance Profiler: this launches the profiler much the same way as starting it from the Start Menu. The profiler will pre-populate the application and path information, but allow you to change the settings before beginning the profile run. So really, the main difference is that Profile Performance immediately begins profiling with the default selections, where Launch ANTS Performance Profiler allows you to change the defaults and attach to an already-running application. Let’s Fire it Up! So when you fire up ANTS either via Start Menu or Launch ANTS Performance Profiler menu in Visual Studio, you are presented with a very simple dialog to get you started: Notice you can choose from many different options for application type. You can profile executables, services, web applications, or just attach to a running process. In fact, in version 7.4 we see two new options added: ASP.NET Web Application (IIS Express) SharePoint web application (IIS) So this gives us an additional way to profile ASP.NET applications and the ability to profile SharePoint applications as well. You can also choose your level of detail in the Profiling Mode drop down. If you choose Line-Level and method-level timings detail, you will get a lot more detail on the method durations, but this will also slow down profiling somewhat. If you really need the profiler to be as unintrusive as possible, you can change it to Sample method-level timings. This is performing very light profiling, where basically the profiler collects timings of a method by examining the call-stack at given intervals. Which method you choose depends a lot on how much detail you need to find the issue and how sensitive your program issues are to timing. So for our example, let’s just go with the line and method timing detail. So, we check that all the options are correct (if you launch from VS2010, the executable and path are filled in already), and fire it up by clicking the [Start Profiling] button. Profiling the Application Once you start profiling the application, you will see a real-time graph of CPU usage that will indicate how much your application is using the CPU(s) on your system. During this time, you can select segments of the graph and bookmark them, giving them mnemonic names. This can be useful if you want to compare performance in one part of the run to another part of the run. Notice that once you select a block, it will give you the call tree breakdown for that selection only, and the relative performance of those calls. Once you feel you have collected enough information, you can click [Stop Profiling] to stop the application run and information collection and begin a more thorough analysis. Analyzing Method Timings So now that we’ve halted the run, we can look around the GUI and see what we can see. By default, the times are shown in terms of percentage of time of the total run of the application, though you can change it in the View menu item to milliseconds, ticks, or seconds as well. This won’t affect the percentages of methods, it only affects what units the times are shown. Notice also that the major hotspot seems to be in a method without source, ANTS Profiler will filter these out by default, but you can right-click on the line and remove the filter to see more detail. This proves especially handy when a bottleneck is due to a method in the BCL. So now that we’ve removed the filter, we see a bit more detail: In addition, ANTS Performance Profiler gives you the ability to decompile the methods without source so that you can dive even deeper, though typically this isn’t necessary for our purposes. When looking at timings, there are generally two types of timings for each method call: Time: This is the time spent ONLY in this method, not including calls this method makes to other methods. Time With Children: This is the total of time spent in both this method AND including calls this method makes to other methods. In other words, the Time tells you how much work is being done exclusively in this method, and the Time With Children tells you how much work is being done inclusively in this method and everything it calls. You can also choose to display the methods in a tree or in a grid. The tree view is the default and it shows the method calls arranged in terms of the tree representing all method calls and the parent method that called them, etc. This is useful for when you find a hot-spot method, you can see who is calling it to determine if the problem is the method itself, or if it is being called too many times. The grid method represents each method only once with its totals and is useful for quickly seeing what method is the trouble spot. In addition, you can choose to display Methods with source which are generally the methods you wrote (as opposed to native or BCL code), or Any Method which shows not only your methods, but also native calls, JIT overhead, synchronization waits, etc. So these are just two ways of viewing the same data, and you’re free to choose the organization that best suits what information you are after. Analyzing Method Source If we look at the timings above, we see that our AddToList() method (and in particular, it’s call to the List<T>.Sort() method in the BCL) is the hot-spot in this analysis. If ANTS sees a method that is consuming the most time, it will flag it as a hot-spot to help call out potential areas of concern. This doesn’t mean the other statistics aren’t meaningful, but that the hot-spot is most likely going to be your biggest bang-for-the-buck to concentrate on. So let’s select the AddToList() method, and see what it shows in the source window below: Notice the source breakout in the bottom pane when you select a method (from either tree or grid view). This shows you the timings in this method per line of code. This gives you a major indicator of where the trouble-spot in this method is. So in this case, we see that performing a Sort() on the List<T> after every Add() is killing our performance! Of course, this was a very contrived, duh moment, but you’d be surprised how many performance issues become duh moments. Note that this one line is taking up 86% of the execution time of this application! If we eliminate this bottleneck, we should see drastic improvement in the performance. So to fix this, if we still wanted to maintain the List<T> we’d have many options, including: delay Sort() until after all Add() methods, using a SortedSet, SortedList, or SortedDictionary depending on which is most appropriate, or forgoing the sorting all together and using a Dictionary. Rinse, Repeat! So let’s just change all instances of List<string> to SortedSet<string> and run this again through the profiler: Now we see the AddToList() method is no longer our hot-spot, but now the Max() and Min() calls are! This is good because we’ve eliminated one hot-spot and now we can try to correct this one as well. As before, we can then optimize this part of the code (possibly by taking advantage of the fact the list is now sorted and returning the first and last elements). We can then rinse and repeat this process until we have eliminated as many bottlenecks as possible. Calls by Web Request Another feature that was added recently is the ability to view .NET methods grouped by the HTTP requests that caused them to run. This can be helpful in determining which pages, web services, etc. are causing hot spots in your web applications. Summary If you like the other ANTS tools, you’ll like the ANTS Performance Profiler as well. It is extremely easy to use with very little product knowledge required to get up and running. There are profilers built into the higher product lines of Visual Studio, of course, which are also powerful and easy to use. But for quickly jumping in and finding hot spots rapidly, Red Gate’s Performance Profiler 7.4 is an excellent choice. Technorati Tags: Influencers,ANTS,Performance Profiler,Profiler

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• Productivity Tips

  - by Brian T. Jackett

  A few months ago during my first end of year review at Microsoft I was doing an assessment of my year.  One of my personal goals to come out of this reflection was to improve my personal productivity.  While I hear many people say “I wish I had more hours in the day so that I could get more done” I feel like that is the wrong approach.  There is an inherent assumption that you are being productive with your time that you already have and thus more time would allow you to be as productive given more time.    Instead of wishing I could add more hours to the day I’ve begun adopting a number of processes or behavior changes in my personal life to make better use of my time with the goal of improving productivity.  The areas of focus are as follows: Focus Processes Tools Personal health Email Note: A number of these topics have spawned from reading Scott Hanselman’s blog posts on productivity, reading of David Allen’s book Getting Things Done, and discussions with friends and coworkers who had great insights into this topic.   Focus Pre-reading / viewing: Overcome your work addiction Millennials paralyzed by choice Its Not What You Read Its What You Ignore (Scott Hanselman video)    I highly recommend Scott Hanselman’s video above and this post before continuing with this article.  It is well worth the 40+ mins price of admission for the video and couple minutes for article.  One key takeaway for me was listing out my activities in an average week and realizing which ones held little or no value to me.  We all have a finite amount of time to work each day.  Do you know how much time and effort you spend on various aspects of your life (family, friends, religion, work, personal happiness, etc.)?  Do your actions and commitments reflect your priorities?    The biggest time consumers with little value for me were time spent on social media services (Twitter and Facebook), playing an MMO video game, and watching TV.  I still check up on Facebook, Twitter, Microsoft internal chat forums, and other services to keep contact with others but I’ve reduced that time significantly.  As for TV I’ve cut the cord and no longer subscribe to cable TV.  Instead I use Netflix, RedBox, and over the air channels but again with reduced time consumption.  With the time I’ve freed up I’m back to working out 2-3 times a week and reading 4 nights a week (both of which I had been neglecting previously).  I’ll mention a few tools for helping measure your time in the Tools section.   Processes    Do not multi-task.  I’ll say it again.  Do not multi-task.  There is no such thing as multi tasking.  The human brain is optimized to work on one thing at a time.  When you are “multi-tasking” you are really doing 2 or more things at less than 100%, usually by a wide margin.  I take pride in my work and when I’m doing something less than 100% the results typically degrade rapidly.    Now there are some ways of bending the rules of physics for this one.  There is the notion of getting a double amount of work done in the same timeframe.  Some examples would be listening to podcasts / watching a movie while working out, using a treadmill as your work desk, or reading while in the bathroom.    Personally I’ve found good results in combining one task that does not require focus (making dinner, playing certain video games, working out) and one task that does (watching a movie, listening to podcasts).  I believe this is related to me being a visual and kinesthetic (using my hands or actually doing it) learner.  I’m terrible with auditory learning.  My fiance and I joke that sometimes we talk and talk to each other but never really hear each other.   Goals / Tasks    Goals can give us direction in life and a sense of accomplishment when we complete them.  Goals can also overwhelm us and give us a sense of failure when we don’t complete them.  I propose that you shift your perspective and not dwell on all of the things that you haven’t gotten done, but focus instead on regularly setting measureable goals that are within reason of accomplishing.    At the end of each time frame have a retrospective to review your progress.  Do not feel guilty about what you did not accomplish.  Feel proud of what you did accomplish and readjust your goals for the next time frame to more attainable goals.  Here is a sample schedule I’ve seen proposed by some.  I have not consistently set goals for each timeframe, but I do typically set 3 small goals a day (this blog post is #2 for today). Each day set 3 small goals Each week set 3 medium goals Each month set 1 large goal Each year set 2 very large goals   Tools    Tools are an extension of our human body.  They help us extend beyond what we can physically and mentally do.  Below are some tools I use almost daily or have found useful as of late. Disclaimer: I am not getting endorsed to promote any of these products.  I just happen to like them and find them useful. Instapaper – Save internet links for reading later.  There are many tools like this but I’ve found this to be a great one.  There is even a “read it later” JavaScript button you can add to your browser so when you navigate to a site it will then add this to your list. Stacks for Instapaper – A Windows Phone 7 app for reading my Instapaper articles on the go.  It does require a subscription to Instapaper (nominal $3 every three months) but is easily worth the cost.  Alternatively you can set up your Kindle to sync with Instapaper easily but I haven’t done so. SlapDash Podcast – Apps for Windows Phone and  Windows 8 (possibly other platforms) to sync podcast viewing / listening across multiple devices.  Now that I have my Surface RT device (which I love) this is making my consumption easier to manage. Feed Reader – Simple Windows 8 app for quickly catching up on my RSS feeds.  I used to have hundreds of unread items all the time.  Now I’m down to 20-50 regularly and it is much easier and faster to consume on my Surface RT.  There is also a free version (which I use) and I can’t see much different between the free and paid versions currently. Rescue Time – Have you ever wondered how much time you’ve spent on websites vs. email vs. “doing work”?  This service tracks your computer actions and then lets you report on them.  This can help you quantitatively identify areas where your actions are not in line with your priorities. PowerShell – Windows automation tool.  It is now built into every client and server OS.  This tool has saved me days (and I mean the full 24 hrs worth) of time and effort in the past year alone.  If you haven’t started learning PowerShell and you administrating any Windows OS or server product you need to start today. Various blogging tools – I wrote a post a couple years ago called How I Blog about my blogging process and tools used.  Almost all of it still applies today.   Personal Health    Some of these may be common sense or debatable, but I’ve found them to help prioritize my daily activities. Get plenty of sleep on a regular basis.  Sacrificing sleep too many nights a week negatively impacts your cognition, attitude, and overall health. Exercise at least three days.  Exercise could be lifting weights, taking the stairs up multiple flights of stairs, walking for 20 mins, or a number of other "non-traditional” activities.  I find that regular exercise helps with sleep and improves my overall attitude. Eat a well balanced diet.  Too much sugar, caffeine, junk food, etc. are not good for your body.  This is not a matter of losing weight but taking care of your body and helping you perform at your peak potential.   Email    Email can be one of the biggest time consumers (i.e. waster) if you aren’t careful. Time box your email usage.  Set a meeting invite for yourself if necessary to limit how much time you spend checking email. Use rules to prioritize your email.  Email from external customers, my manager, or include me directly on the To line go into my inbox.  Everything else goes a level down and I have 30+ rules to further sort it, mostly distribution lists. Use keyboard shortcuts (when available).  I use Outlook for my primary email and am constantly hitting Alt + S to send, Ctrl + 1 for my inbox, Ctrl + 2 for my calendar, Space / Tab / Shift + Tab to mark items as read, and a number of other useful commands.  Learn them and you’ll see your speed getting through emails increase. Keep emails short.  No one Few people like reading through long emails.  The first line should state exactly why you are sending the email followed by a 3-4 lines to support it.  Anything longer might be better suited as a phone call or in person discussion.   Conclusion    In this post I walked through various tips and tricks I’ve found for improving personal productivity.  It is a mix of re-focusing on the things that matter, using tools to assist in your efforts, and cutting out actions that are not aligned with your priorities.  I originally had a whole section on keyboard shortcuts, but with my recent purchase of the Surface RT I’m finding that touch gestures have replaced numerous keyboard commands that I used to need.  I see a big future in touch enabled devices.  Hopefully some of these tips help you out.  If you have any tools, tips, or ideas you would like to share feel free to add in the comments section.         -Frog Out   Links Scott Hanselman Productivity posts http://www.hanselman.com/blog/CategoryView.aspx?category=Productivity Overcome your work addiction http://blogs.hbr.org/hbsfaculty/2012/05/overcome-your-work-addiction.html?awid=5512355740280659420-3271   Millennials paralyzed by choice http://priyaparker.com/blog/millennials-paralyzed-by-choice   Its Not What You Read Its What You Ignore (video) http://www.hanselman.com/blog/ItsNotWhatYouReadItsWhatYouIgnoreVideoOfScottHanselmansPersonalProductivityTips.aspx   Cutting the cord – Jeff Blankenburg http://www.jeffblankenburg.com/2011/04/06/cutting-the-cord/   Building a sitting standing desk – Eric Harlan http://www.ericharlan.com/Everything_Else/building-a-sitting-standing-desk-a229.html   Instapaper http://www.instapaper.com/u   Stacks for Instapaper http://www.stacksforinstapaper.com/   Slapdash Podcast Windows Phone -  http://www.windowsphone.com/en-us/store/app/slapdash-podcasts/90e8b121-080b-e011-9264-00237de2db9e Windows 8 - http://apps.microsoft.com/webpdp/en-us/app/slapdash-podcasts/0c62e66a-f2e4-4403-af88-3430a821741e/m/ROW   Feed Reader http://apps.microsoft.com/webpdp/en-us/app/feed-reader/d03199c9-8e08-469a-bda1-7963099840cc/m/ROW   Rescue Time http://www.rescuetime.com/   PowerShell Script Center http://technet.microsoft.com/en-us/scriptcenter/bb410849.aspx

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