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• Why is there so much XML in Java these days?

  - by BD at Rivenhill

  This is really more of a philosophy/design issue. I did some work in Java back in the middle 90's and again in the early 2000's and now I'm coming back to it after spending a lot of time in C/C++ and it seems like there was an explosion of XML dependency while I was gone. Major build system tools like ant and maven depend on XML for their configuration, but I'm actually more concerned with all the frameworks, such as Spring, Hibernate, etc. My experience is that powerful supporting libraries like these are where a developer can really get leverage for building programs with lots of features without writing a lot of code, but it really seems like I'm getting one language for the price of two here. I write a bunch of Java classes, but then I also write a bunch of XML files to glue them together. The things that get done in the XML are things that I can see reasonable ways of doing in straight code without the middleman, and they don't really seem to be treated exactly like configuration files: they change rarely and they end up getting committed to source code control like the Java code itself, but they are distributed with the resulting application and need to be unpacked and installed in the classpath in order to get the application to work. I'm working with server applications that are not web-based, so maybe the domain is a bit different from what most people are doing, but I just can't help feeling that I must be doing something wrong here. Can someone point me to a good source of information for why these design choices were made and what problems they are meant to solve so that I can analyze my own experiences in this context?

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• How to limit TCP writes to particular size and then block untlil the data is read

  - by ustulation

  {Qt 4.7.0 , VS 2010} I have a Server written in Qt and a 3rd party client executable. Qt based server uses QTcpServer and QTcpSocket facilities (non-blocking). Going through the articles on TCP I understand the following: the original implementation of TCP mentioned the negotiable window size to be a 16-bit value, thus maximum being 65535 bytes. But implementations often used the RFC window-scale-extension that allows the sliding window size to be scalable by bit-shifting to yield a maximum of 1 gigabyte. This is implementation defined. This could have resulted in majorly different window sizes on receiver and sender end as the server uses Qt facilities without hardcoding any window size limit. Client 1st asks for all information it can based on the previous messages from the server before handling the new (accumulating) incoming messages. So at some point Server receives a lot of messages each asking for data of several MB's. This the server processes and puts it into the sender buffer. Client however is unable to handle the messages at the same pace and it seems that client’s receiver buffer is far smaller (65535 bytes maybe) than sender’s transmit window size. The messages thus get accumulated at sender’s end until the sender’s buffer is full too after which the TCP writes on sender would block. This however does not happen as sender buffer is much larger. Hence this manifests as increase in memory consumption on the sender’s end. To prevent this from happening, I used Qt’s socket’s waitForBytesWritten() with timeout set to -1 for infinite waiting period. This as I see from the behaviour blocks the thread writing TCP data until the data has actually been sensed by the receiver’s window (which will happen when earlier messages have been processed by the client at application level). This has caused memory consumption at Server end to be almost negligible. is there a better alternative to this (in Qt) if i want to restrict the memory consumption at server end to say x MB's? Also please point out if any of my understandings is incorrect.

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• Read in double type from txt file - C++

  - by Greenhouse Gases

  Hi there I'm in the midst of a university project and have decided to implement a method that can accept information from a text file (in this instance called "locations.txt"). input from the text file will look like this: London 345 456 Madrid 234 345 Beinjing 345 456 Frankfurt 456 567 The function looks like this currently (and you will notice I am missing the While condition to finish adding input when reaches end of text in locations.txt, i tried using eof but this didnt work?!). Also get function expects a char and so cant accept input thats a double which is what the latitude and longitude are defined as... void populateList(){ ifstream inputFile; inputFile.open ("locations.txt"); temp = new locationNode; // declare the space for a pointer item and assign a temporary pointer to it while(HASNT REACHED END OF TEXT FILE!!) { inputFile.getline(temp-nodeCityName, MAX_LENGTH); // inputFile.get(temp-nodeLati, MAX_LENGTH); // inputFile.get(temp-nodeLongi, MAX_LENGTH); temp-Next = NULL; //set to NULL as when one is added it is currently the last in the list and so can not point to the next if(start_ptr == NULL){ // if list is currently empty, start_ptr will point to this node start_ptr = temp; } else { temp2 = start_ptr; // We know this is not NULL - list not empty! while (temp2-Next != NULL) { temp2 = temp2-Next; // Move to next link in chain until reach end of list } temp2->Next = temp; } } inputFile.close(); } Any help you can provide would be most useful. If I need to provide anymore detail I will do, I'm in a bustling canteen atm and concentrating is hard!!

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• Computing, storing, and retrieving values to and from an N-Dimensional matrix

  - by Adam S

  This question is probably quite different from what you are used to reading here - I hope it can provide a fun challenge. Essentially I have an algorithm that uses 5(or more) variables to compute a single value, called outcome. Now I have to implement this algorithm on an embedded device which has no memory limitations, but has very harsh processing constraints. Because of this, I would like to run a calculation engine which computes outcome for, say, 20 different values of each variable and stores this information in a file. You may think of this as a 5(or more)-dimensional matrix or 5(or more)-dimensional array, each dimension being 20 entries long. In any modern language, filling this array is as simple as having 5(or more) nested for loops. The tricky part is that I need to dump these values into a file that can then be placed onto the embedded device so that the device can use it as a lookup table. The questions now, are: What format(s) might be acceptable for storing the data? What programs (MATLAB, C#, etc) might be best suited to compute the data? C# must be used to import the data on the device - is this possible given your answer to #1?

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• When is a bool not a bool (compiler warning C4800)

  - by omatai

  Consider this being compiled in MS Visual Studio 2005 (and probably others): CPoint point1( 1, 2 ); CPoint point2( 3, 4 ); const bool point1And2Identical( point1 == point2 ); // C4800 warning const bool point1And2TheSame( ( point1 == point2 ) == TRUE ); // no warning What the...? Is the MSVC compiler brain-dead? As far as I can tell, TRUE is #defined as 1, without any type information. So by what magic is there any difference between these two lines? Surely the type of the expression inside the brackets is the same in both cases? [This part of the question now satisfactorily answered in the comments just below] Personally, I think that avoiding the warning by using the == TRUE option is ugly (though less ugly than the != 0 alternative, despite being more strictly correct), and it is better to use #pragma warning( disable:4800 ) to imply "my code is good, the compiler is an ass". Agree? Note - I have seen all manner of discussion on C4800 talking about assigning ints to bools, or casting a burger combo with large fries (hold the onions) to a bool, and wondering why there are strange results. I can't find a clear answer on what seems like a much simpler question... that might just shine line on C4800 in general.

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• Pass a variable from the source file to an included file in PHP

  - by Alpha1

  For my website I want to store the general format of the site in a single PHP file in a single location, and each of the different pages content in the local location of the page. I then want to pass the title and content address to the included file via a variable. However I can't get the included format file to read the variables storing the title and content data. AKA, the called file for the individual page would be: <?php $title = 'Some Title'; $source_file = 'content.php'; readfile('http:...../format.php'); ?> The format file would be: <html> ... <title> <?php echo $title; ?> </title> ... <?php include($source_file); ?> ... I recall reading somewhere I need to include something to get the variables at the start of the format file, however I can't remember what it is or find where I found that information.

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• Get Highest Res Favicon

  - by Jeremy

  I'm making a website that needs to dynamically obtain the favicon of sites upon request. I've found a few api's that can accomplish this fairly well, and so far I'm liking http://www.fvicon.com/. The final image for my website will be 64x64px, and some websites such as Google and Wordpress have nice images of this size that are easily retrieved via this api. Though, of course, most websites only have a 16x16 favicon image and scaling that image to 64x64 has very bad quality loss. Examples: (high res) http://a.fvicon.com/wordpress.com?format=png&width=64&height=64 (low res) http://a.fvicon.com/yahoo.com?format=png&width=64&height=64 Keeping this in mind, I'm planning on somehow determining whether a high-res image is available and, if so, the website will use this image. If not, I want to use a pre-made 64x64 icon with the smaller icon layered over it. What I'm having trouble with is determining if there is a high res favicon available or not. Also, I'm curious if there's a better approach to this situation. I'd rather not use smaller images (64x64 works out really well for this project). The lowest res I'm willing to drop to is 48x48 but even then there will be a significant quality loss for scaling up 16x16 favicons. Any ideas? If you need any more information I will gladly provide it. Thank you!

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• Drupal module for complex hours of operation / office hours

  - by Eronarn

  Background: I am building a website in Drupal that links together a wide variety of social service providers for the purposes of discovery, collaboration, and all that good stuff. The goal is to make a website that is simple to browse for consumers of these services and simple to update for providers of these services. The beta has been very well received, but I want to switch to a different information schema before the site goes live. Specific question: I am looking for a module (or other solution) that... Stores this data in Drupal (i.e., no GCal) Supports a wide variety of repeats Is intuitive for people editing the node (no Cron-style interfaces, please!) I have looked into several modules on drupal.org and none seem to meet all of these criteria. I've also searched here, and while this question is similar: http://stackoverflow.com/questions/2794149/drupal-create-a-node-with-employee-working-hours my needs are too complex for the offered solution. Some of these providers have "hours" such as "the third Wednesday of every month", or "open during Winter months", or separate hotline & office hours. Likewise, the Date Repeat module doesn't cut it as stands currently. I'm comfortable hacking what I need into an existing module - I just don't want to duplicate effort! If you have a suggestion on what module might be a good starting point, I'd appreciate that input, too. Thanks. <3

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• The application has stopped unexpectedly: How to Debug?

  - by Android Eve

  Please note, unlike many other questions having the subject title "application has stopped unexpectedly", I am not asking for troubleshooting a particular problem. Rather, I am asking for an outline of the best strategy for an Android/Eclipse/Java rookie to tackle this formidable task of digesting huge amounts of information in order to develop (and debug!) a simple Android application. In my case, I took the sample skeleton app from the SDK, modified it slightly and what did I get the moment I try to run it? The application (process.com.example.android.skeletonapp) has stopped unexpectedly. Please try again. OK, so I know that I have to look LogCat. It's full of timestamped lines staring at me... What do I do now? What do I need to look for? Is there a way to single-step the program, to find the statement that makes the app crash? (I thought Java programs never crash, but apparently I was mistaken) How do I place a breakpoint? Can you recommend an Android debug tutorial online, other than this one?

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• Ruby on Rails login using legacy user database

  - by ricsmania

  Hello, I have a Rails application that connects to a legacy database (Oracle) and displays some information from a particular user. Right now the user is passed as a URL parameter, but this has obvious security issues because users should only be able to see their own data. To solve that, I want to implement a user login, and I did some research and came across 2 components for that, restful_authentication and authlogic. The problem is that I need to use an existing user/password database instead of creating a new one, which is the common way to use those components. The password is encrypted by a custom Oracle package, but let's assume it is stored as plain text to make things simpler. I only need very basic functionality, which is login a user and keep them logged in forever until logout. No changes to the database will be made by this application, so there's no need for sign up, e-mail activation, reset password, etc. Can someone point me in the right direction on how to do that? Is any of those 2 components a good solution? If not, what would be recommended? Thanks!

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• std::map keys in C++

  - by Soumava

  I have a requirement to create two different maps in C++. The Key is of type CHAR * and the Value is a pointer to a struct. I am filling 2 maps with these pairs, in separate iterations. After creating both maps I need find all such instances in which the value of the string referenced by the CHAR * are same. For this i am using the following code : typedef struct _STRUCTTYPE { .. } STRUCTTYPE, *PSTRUCTTYPE; typedef pair {CHAR *,PSTRUCTTYPE} kvpair; .. CHAR *xyz; PSTRUCTTYPE abc; after filling the information; Map.insert (kvpair(xyz,abc)); the above is repeated x times for the first map, and y times for the second map. after both are filled out; std::map {CHAR *, PSTRUCTTYPE} :: iterator Iter,findIter; for (Iter=iteratedMap-begin();Iter!=iteratedMap-end();mapIterator++) { char *key = Iter-first; printf("%s\n",key); findIter=otherMap-find(key); //printf("%u",findIter-second); if (findIter!=otherMap-end()) { printf("Match!\n"); } } The above code does not show any match, although the list of keys in both maps show obvious matches. My understanding is that the equals operator for CHAR * just equates the memory address of the pointers. My question is, what should i do to alter the equals operator for this type of key or could I use a different datatype for the string? *note : {} has been used instead of angle brackets as the content inside angle brackets was not showing up in the post.

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• Display latest date from a HTML attribute

  - by Tron

  I currently have several classes which contain a date inside an attribute. <div id="container"> <div class="date" date="19/11/2013"></div> <div class="date" date="06/11/2013"></div> </div> <div id="result"></div> What I would like to do, is find the latest date and display it on the page. So far, I've found the information in the attribute, checked that it doesn't exist in the array then and pushed it into an array. I'm not entirely sure of the best approach from here, but ideally i would like to find the latest date and then append it to the results container. $('.date').each(function () { var dateArray = []; var date = $(this).attr('date'); if ($.inArray(date, dateArray) == -1) { dateArray.push(date); } $('#result').append(dateArray); }); Any assistance on the above would be greatly appreciated. Thanks :)

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• Does Socket open another thread? Does it return something?

  - by Roman

  In the client application I call new Socket(serverIP,serverPort). As a result the client application sends a request to the server application to open a socket. Does it start a new thread? I mean which of the following is true? Client application sends a request and immediately starts to execute following commands (not weighting for the answer). Client sends the request and weights for the answer. As soon as the answer is obtained, the client application continues to execute following commands. The second case seems to be more realistic and logical for me. However, I do not understand what happens if the server does not open a socket and it does not say that it does not "want" to open the second (it can happen if the server does not exist or network is broken). What will happen in this case? Will server weight forever? In general it would be nice for the client to know what is the result of its request for the socket. For example I can imagine the following situations: The socket is opened by the server. The server refuses to open a socket. So, server exists, it got the request from the client but it says "no". There is no response from the server. I know that new Socket(serverIP,serverPort) does not "return" this kind of information. But it throws exceptions. One of them is "UnkownHostException". When it is thrown? When the server is not responding for a while (for how long)? ADDED: I just found out that UnknownHostException is thrown to indicate that the IP address of a host could not be determined. So, it is unrelated with the above described situations (server is not responding, server refuses to open a socket).

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• Data structure to build and lookup set of integer ranges

  - by actual

  I have a set of uint32 integers, there may be millions of items in the set. 50-70% of them are consecutive, but in input stream they appear in unpredictable order. I need to: Compress this set into ranges to achieve space efficient representation. Already implemented this using trivial algorithm, since ranges computed only once speed is not important here. After this transformation number of resulting ranges is typically within 5 000-10 000, many of them are single-item, of course. Test membership of some integer, information about specific range in the set is not required. This one must be very fast -- O(1). Was thinking about minimal perfect hash functions, but they do not play well with ranges. Bitsets are very space inefficient. Other structures, like binary trees, has complexity of O(log n), worst thing with them that implementation make many conditional jumps and processor can not predict them well giving poor performance. Is there any data structure or algorithm specialized in integer ranges to solve this task?

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• Compiling a C++ application on Windows 7, but execute it on Win2003 Server

  - by dabs

  I have a C++ application (quite complex, multiple projects) in Visual Studio 2008, that produces a single dll. Recently I switched to Windows 7, but had previously been compiling under Windows XP. Suddenly the dll in question cannot be loaded by another application, i.e. on a machine running Windows 2003 Server. I've been trying various things: I've installed the VC9.0 redistributable package on the server Also copied various .dll's from that package to the application folder The project is of course compiled in release mode When I run depends.exe on the client machine, I do get the following error: "Error: The Side-by-Side configuration information for "my_dll.dll" contains errors. This application has failed to start because the application configuration is incorrect. Reinstalling the application may fix this problem (14001). Warning: At least one module has an unresolved import due to a missing export function in a delay-load dependent module." and the icon for shlwapi.dll has a red overlay icon. This didn't happen when I was compiling under WinXP, so I'm guessing that there really is no problem with the .dll's on the client machine, but somewhere there is a reference to that particular version of some dll. Does anyone know what would be the best way to resolve this? Regards, Daníel

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• Outlook VSTO AddIn for Meetings

  - by BigDubb

  We have created a VSTO addin for Outlook Meetings. As part of this we trap on the SendEvent of the message on the FormRegionShowing event: _apptEvents.Send += new Microsoft.Office.Interop.Outlook.ItemEvents_SendEventHandler(_apptEvents_Send); The method _apptEvents_Send then tests on a couple of properties and exits where appropriate. private void _apptEvents_Send(ref bool Cancel) { if (!_Qualified) { MessageBox.Show("Meeting has not been qualified", "Not Qualified Meeting", MessageBoxButtons.OK, MessageBoxIcon.Information); chkQualified.Focus(); Cancel = true; } } The problem that we're having is that some users' messages get sent twice. Once when the meeting is sent and a second time when the user re-opens outlook. I've looked for memory leaks, thinking that something might not be getting disposed of properly, and have added explicit object disposal on all finally calls to try and make sure resources are managed, but still getting the functionality incosistently across the organization. i.e. I never encountered the problem during development, nor other developers during testing. All users are up to date on framework (3.5 SP1) and Hotfixes for Outlook. Does anyone have any ideas on what might be causing this? Any ideas anyone might have would be greatly appreciated.

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• Where to place interactive objects in JavaScript?

  - by Chris

  I'm creating a web based application (i.e. JavaScript with jQuery and lots of SVG) where the user interacts with "objects" on the screen (think of DIVs that can be draged around, resized and connected by arraows - like a vector drawing programm or a graphical programming language). As each "object" contains individual information but is allways belonging to a "class" of elements it's obvious that this application should be programmed by using an OOP approach. But where do I store the "objects" best? Should I create a global structure ("registry") with all (JS native) objects and tell them "draw yourself on the DOM"? Or should I avoid such a structure and think of the (relevant) DOM nodes as my objects and attach the relevant data as .data() to them? The first approach is very MVC - but I guess the attachment of all the event handlers will be non trivial. The second approach will handle the events in a trivial way and it doesn't create a duplicate structure, but I guess the usual OO stuff (like methods) will be more complex. What do you recomend? I think the answer will be JavaScript and SVG specific as "usual" programming languages don't have such a highly organized output "canvas".

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• Datastructure choices for highspeed and memory efficient detection of duplicate of strings

  - by Jonathan Holland

  I have a interesting problem that could be solved in a number of ways: I have a function that takes in a string. If this function has never seen this string before, it needs to perform some processing. If the function has seen the string before, it needs to skip processing. After a specified amount of time, the function should accept duplicate strings. This function may be called thousands of time per second, and the string data may be very large. This is a highly abstracted explanation of the real application, just trying to get down to the core concept for the purpose of the question. The function will need to store state in order to detect duplicates. It also will need to store an associated timestamp in order to expire duplicates. It does NOT need to store the strings, a unique hash of the string would be fine, providing there is no false positives due to collisions (Use a perfect hash?), and the hash function was performant enough. The naive implementation would be simply (in C#): Dictionary<String,DateTime> though in the interest of lowering memory footprint and potentially increasing performance I'm evaluating a custom data structures to handle this instead of a basic hashtable. So, given these constraints, what would you use? EDIT, some additional information that might change proposed implementations: 99% of the strings will not be duplicates. Almost all of the duplicates will arrive back to back, or nearly sequentially. In the real world, the function will be called from multiple worker threads, so state management will need to be synchronized.

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• Display data FROM Sheet1 on Sheet2 based on conditional value

  - by Shawn

  Imagine a worksheet with 30 pieces of information, such as: A1= Start Date A2 = End Date A3 = Resource Name A4 = Cost .... A30 = Whatever B1 = 1/1/2010 B2 = 2/15/2010 B3 = Joe Smith B4 = $10,000.00 ... B30 = Blah Blah Now imagine a third column, C. The purpose of the third column is to determine WHICH report that row of data needs to appear in. C1 = Report 1 C2 = Report 1 and Report 2 C3 = Report 4 and Report 7 C4 = Report 1 and Report 5 ... C30 = Report 2 Each report is on Sheets 2, 3, 4, 5 and so on (depending on how many I decide to create). As you can see form my example above, some data may need to appear in multiple reports. For example, the data in Row 3 (Resource Name: Joe Smith) needs to appear in Report 4 and Report 7. That is to say, it needs to DYNAMICALLY appear on two additional worksheets. If I change the values in column C, then the reports need to update automatically. How can I create the worksheets which will serve as the reports such that they only diaplay the rows which have been "flagged" to be displayed in that report? Thanks!

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• What would be a better implementation of shared variable among subclass

  - by Churk

  So currently I have a spring unit testing application. And it requires me to get a session cookie from a foreign authentication source. Problem what that is, this authentication process is fairly expensive and time consuming, and I am trying to create a structure where I am authenticate once, by any subclass, and any subsequent subclass is created, it will reuse this session cookie without hitting the authentication process again. My problem right now is, the static cookie is null each time another subclass is created. And I been reading that using static as a global variable is a bad idea, but I couldn't think of another way to do this because of Spring framework setting things during run time and how I would set the cookie so that all other classes can use it. Another piece of information. The variable is being use, but is change able during run time. It is not a single user being signed in and used across the board. But more like a Sub1 would call login, and we have a cookie. Then multiple test will be using that login until SubX will come in and say, I am using different credential, so I need to login as something else. And repeats. Here is a outline of my code: public class Parent implements InitializingBean { protected static String BASE_URL; public static Cookie cookie; ... All default InitializingBean methods ... afterPropertiesSet() { cookie = // login process returns a cookie } } public class Sub1 extends Parent { @resource public String baseURL; @PostConstruct public void init() { // set parents with my baseURL; BASE_URL = baseURL; } public void doSomething() { // Do something with cookie, because it should have been set by parent class } } public class Sub2 extends Parent { @resource public String baseURL; @PostConstruct public void init() { // set parents with my baseURL; BASE_URL = baseURL; } public void doSomethingElse() { // Do something with cookie, because it should have been set by parent class } }

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• Can anyone recommend a payment processing script or service that is as (nearly?) as convenient and c

  - by Jason Livesay

  I have been going through all of the different PayPal integration options and trying to decide which will be the best one for this particular application. I realized that I really want to give users a few options for payment. For example, it might be more convenient to enter their credit card information rather than being sent over to PayPal, or they may have already setup their Google Checkout and so want to use that. So that brings me fairly quickly to the realization that maybe I don't want to program one or two or three API integrations myself and I should look at some shopping cart software. However, we really don't need a whole shopping cart -- we will have a specific form and some other custom coding and the only part of the shopping cart we would really use would be the checkout page to handle accepting payment/integrating with PayPal/Google Checkout/Authorize.net. I like how simple eJunkie makes things and the fact that it accepts PayPal and Google Checkout and Authorize.net. The problem is that the Add To Cart buttons aren't going to cut it. I need to be able to programmatically enter items into the cart. Maybe I can just use an open source PHP shopping cart and skip the store front somehow.

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• lapply slower than for-loop when used for a BiomaRt query. Is that expected?

  - by ptocquin

  I would like to query a database using BiomaRt package. I have loci and want to retrieve some related information, let say description. I first try to use lapply but was surprise by the time needed for the task to be performed. I thus tried a more basic for-loop and get a faster result. Is that expected or is something wrong with my code or with my understanding of apply ? I read other posts dealing with *apply vs for-loop performance (Here, for example) and I was aware that improved performance should not be expected but I don't understand why performance here is actually lower. Here is a reproducible example. 1) Loading the library and selecting the database : library("biomaRt") athaliana <- useMart("plants_mart_14") athaliana <- useDataset("athaliana_eg_gene",mart=athaliana) 2) Querying the database : loci <- c("at1g01300", "at1g01800", "at1g01900", "at1g02335", "at1g02790", "at1g03220", "at1g03230", "at1g04040", "at1g04110", "at1g05240" ) I create a function for the use in lapply : foo <- function(loci) { getBM("description","tair_locus",loci,athaliana) } When I use this function on the first element : > system.time(foo(cwp_loci[1])) utilisateur système écoulé 0.020 0.004 1.599 When I use lapply to retrieve the data for all values : > system.time(lapply(loci, foo)) utilisateur système écoulé 0.220 0.000 16.376 I then created a new function, adding a for-loop : foo2 <- function(loci) { for (i in loci) { getBM("description","tair_locus",loci[i],athaliana) } } Here is the result : > system.time(foo2(loci)) utilisateur système écoulé 0.204 0.004 10.919 Of course, this will be applied to a big list of loci, so the best performing option is needed. I thank you for assistance. EDIT Following recommendation of @MartinMorgan Simply passing the vector loci to getBM greatly improves the query efficiency. Simpler is better. > system.time(lapply(loci, foo)) utilisateur système écoulé 0.236 0.024 110.512 > system.time(foo2(loci)) utilisateur système écoulé 0.208 0.040 116.099 > system.time(foo(loci)) utilisateur système écoulé 0.028 0.000 6.193

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• Short snippet summarizing a webpage?

  - by Legend

  Is there a clean way of grabbing the first few lines of a given link that summarizes that link? I have seen this being done in some online bookmarking applications but have no clue on how they were implemented. For instance, if I give this link, I should be able to get a summary which is roughly like: I'll admit it, I was intimidated by MapReduce. I'd tried to read explanations of it, but even the wonderful Joel Spolsky left me scratching my head. So I plowed ahead trying to build decent pipelines to process massive amounts of data Nothing complex at first sight but grabbing these is the challenging part. Just the first few lines of the actual post should be fine. Should I just use a raw approach of grabbing the entire html and parsing the meta tags or something fancy like that (which obviously and unfortunately is not generalizable to every link out there) or is there a smarter way to achieve this? Any suggestions? Update: I just found InstaPaper do this but am not sure if it is getting the information from RSS feeds or some other way.

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• how to emulate thread local storage at user space in C++ ?

  - by vprajan

  I am working on a mobile platform over Nucleus RTOS. It uses Nucleus Threading system but it doesn't have support for explicit thread local storage i.e, TlsAlloc, TlsSetValue, TlsGetValue, TlsFree APIs. The platform doesn't have user space pthreads as well. I found that __thread storage modifier is present in most of the C++ compilers. But i don't know how to make it work for my kind of usage. How does __thread keyword can be mapped with explicit thread local storage? I read many articles but nothing is so clear for giving me the following basic information will __thread variable different for each thread ? How to write to that and read from it ? does each thread has exactly one copy of the variable ? following is the pthread based implementation: pthread_key_t m_key; struct Data : Noncopyable { Data(T* value, void* owner) : value(value), owner(owner) {} int* value; }; inline ThreadSpecific() { int error = pthread_key_create(&m_key, destroy); if (error) CRASH(); } inline ~ThreadSpecific() { pthread_key_delete(m_key); // Does not invoke destructor functions. } inline T* get() { Data* data = static_cast<Data*>(pthread_getspecific(m_key)); return data ? data->value : 0; } inline void set(T* ptr) { ASSERT(!get()); pthread_setspecific(m_key, new Data(ptr, this)); } How to make the above code use __thread way to set & get specific value ? where/when does the create & delete happen? If this is not possible, how to write custom pthread_setspecific, pthread_getspecific kind of APIs. I tried using a C++ global map and index it uniquely for each thread and retrieved data from it. But it didn't work well.

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• $_SESSION v. $_COOKIE

  - by taeja87

  I learned about $_SESSION about several weeks ago when creating a login page. I can successfully login and use it with variables. Currently I am trying to understand $_SESSION and $_COOKIE. Please correct me if I am wrong, I can use $_SESSION when logging in and moving around pages. With $_COOKIE, it is used to remember when I last visit and preferences. Another thing involving cookies is that when websites use advertisements (for example: Google AdSense), they use the cookies to track when visitor click on a advertisement, right? I can use both ($_SESSION & $_COOKIE)? I read somewhere that you can store the session_id as value for the cookie. Also, I read about security which let to me finding this: What do I need to store in the php session when user logged in?. Is using session_regenerate_id good for when a user comes back to the site? And this: How to store a cookie with php involving uniqid. For those wanting to know about the login, I use email and password. That way the user can be able to change their username. I look forward to learning more about these two from anybody who would like to share their knowledge about it. If I asked too many question, you can just answer the one that you have more experience with. If you need more information, just ask since I might have forgotten to include something. Thank You. Found this: What risks should I be aware of before allowing advertisements being placed on my website?

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