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  • Comparing UIColors or CGColor or CGColorSpace

    - by wiznaibus
    I'm having an issue comparing UIColors. I have an image, which I have successfully extracted the color on the image at which the user clicked. Now I want to compare that color with other colors, but I'm getting some strange results. Here's what I've tried: CGColorRef pixelColor = [[buttonImage colorAtPixel:point] CGColor]; UIColor* color = [UIColor colorWithCGColor:pixelColor]; UIColor* aqua = [UIColor colorWithRed:0.521569 green:0.768627 blue:0.254902 alpha:1]; if (CGColorEqualToColor(color.CGColor, aqua.CGColor)) { DLog(@"Apparently, it works"); } DLog(@"%@", color.CGColor); DLog(@"%@", aqua.CGColor); Output: 2011-05-21 19:48:27.144 Coffee[66860:207] -[DescriptorsViewController touchesEnded:withEvent:] <CGColor 0x4d1eb80> [<CGColorSpace 0x4d1a070> (kCGColorSpaceDeviceRGB)] ( 0.521569 0.768627 0.254902 1 ) 2011-05-21 19:48:27.145 Coffee[66860:207] -[DescriptorsViewController touchesEnded:withEvent:] <CGColor 0x4d1f750> [<CGColorSpace 0x4d1a070> (kCGColorSpaceDeviceRGB)] ( 0.521569 0.768627 0.254902 1 ) It looks like the CGColor addresses are different, but the CGColorSpaces are the same, but I can't figure out how to compare the CGColorSpaces I've also tried this: CGColorRef pixelColor = [[buttonImage colorAtPixel:point] CGColor]; UIColor* color = [UIColor colorWithCGColor:pixelColor]; UIColor* aqua = [UIColor colorWithRed:0.521569 green:0.768627 blue:0.254902 alpha:1]; if ([color isEqual:aqua]) { DLog(@"Apparently, it works"); } DLog(@"%@", color.CGColor); DLog(@"%@", aqua.CGColor); The same silliness occurs. 2011-05-21 20:02:49.277 Coffee[67013:207] -[DescriptorsViewController touchesEnded:withEvent:] <CGColor 0x4d3b810> [<CGColorSpace 0x5912010> (kCGColorSpaceDeviceRGB)] ( 0.521569 0.768627 0.254902 1 ) 2011-05-21 20:02:49.278 Coffee[67013:207] -[DescriptorsViewController touchesEnded:withEvent:] <CGColor 0x4d3ba20> [<CGColorSpace 0x5912010> (kCGColorSpaceDeviceRGB)] ( 0.521569 0.768627 0.254902 1 )`

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  • get lattitude and longitude of a place against its zipcode

    - by yunas
    Hello i have used the following code to get the location of the particular place on map using the following piece of code NSString * urlString = [[NSString alloc] initWithFormat:@"http://maps.google.com/maps/geo?key=%@&output=xml&q=%@",GoogleMapsAPIKey,[placeName stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]; result: <?xml version="1.0" encoding="UTF-8" ?> <kml xmlns="http://earth.google.com/kml/2.0"><Response> <name>postdam</name> <Status> <code>200</code> <request>geocode</request> </Status> <Placemark id="p1"> <address>Potsdam, Germany</address> <AddressDetails Accuracy="4" xmlns="urn:oasis:names:tc:ciq:xsdschema:xAL:2.0"><Country><CountryNameCode>DE</CountryNameCode><CountryName>Deutschland</CountryName><AdministrativeArea><AdministrativeAreaName>Brandenburg</AdministrativeAreaName><SubAdministrativeArea><SubAdministrativeAreaName>Potsdam</SubAdministrativeAreaName><Locality><LocalityName>Potsdam</LocalityName></Locality></SubAdministrativeArea></AdministrativeArea></Country></AddressDetails> <ExtendedData> <LatLonBox north="52.4513968" south="52.3424614" east="13.1866602" west="12.9305414" /> </ExtendedData> <Point><coordinates>13.0586008,52.3969627,0</coordinates></Point> </Placemark> </Response></kml> but now i want to get the information agianst the zipcode how to do that using the maps.google.com ???

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  • How can i use Google-o-Meter or Google Vizualisation API with Jenkins

    - by kamal
    Here is a sample that displays a static chart: google.load("visualization", "1.0", {packages:["imagechart"]}); google.setOnLoadCallback(drawChart); function drawChart() { var dataTable = new google.visualization.DataTable(); dataTable.addColumn('string'); dataTable.addColumn('number'); dataTable.addColumn('string'); // Row data is [chl, data point, point label] dataTable.addRows([ ['January',40,undefined], ['February',60,'Initial recall'], ['March',60,'Product withdrawn'], ['April',45,undefined], ['May',47,'Relaunch'], ['June',75,undefined], ['July',70,undefined], ['August',72,undefined] ]); var options = {cht: 'lc', chds:'0,160', annotationColumns:[{column:2, size:12, type:'flag', priority:'high'},]}; var chart = new google.visualization.ImageChart(document.getElementById('line_div')); chart.draw(dataTable, options); } How can i replace the static values and variables in dataTable.addRows([ with real live data ? In case the compete code is not visible, refer to : http://code.google.com/apis/visualization/documentation/gallery/genericimagechart.html When this Javascript is copied to the "Description" it renders a chart, what i want to know is how to replace the name/value in dataTable.addRows, to the name/values coming from Jenkins

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  • Is it possible to write a class that interacts with controls on my WPF form?

    - by Adam S
    Hi all, I'm trying to write a class that I can use to interact with a group of similar controls in my wpf application. I have hit a few roadblocks and now I am wondering if this is a poor approach to begin with. I want to do this primarily to make my code more manageable - I have to interact with around 200 - 300 controls with my code, and it could get very tricky to have all my code in the main window class. Here's something I'd like to be able to do: class ProcControl { private CheckBox * [] Boxes = new CheckBox[10]; ProcControl() { //set boxes 0-9 to point to the actual checkboxes } //provides mass checking/unchecking functionality public void Refactor(CheckBox box) { //see what box it is int box_index = 0; while (Boxes[box_index] != box) { box_index++; } } } This doesn't work as it is right now. I have not figured out how to get my Boxes[] array to point to the actual checkboxes on my form, so I can't interact with them yet. Is it even possible to make an array that points to a bunch of controls so that I may process their properties in a nice manner? Why can't I access the controls at all from inside my class?

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  • Ideas for a rudimentary software licensing implementation

    - by Ross
    I'm trying to decide how to implement a very basic licensing solution for some software I wrote. The software will run on my (hypothetical) clients' machines, with the idea being that the software will immediately quit (with a friendly message) if the client is running it on greater-than-n machines (n being the number of licenses they have purchased). Additionally, the clients are non-tech-savvy to the point where "basic" is good enough. Here is my current design, but given that I have little to no experience in the topic, I wanted to ask SO before I started any development on it: A remote server hosts a MySQL database with a table containing two columns: client-key and license quantity The client-side application connects to the MySQL database on startup, offering it's client-key that I've put into a properties file packaged into the distribution (I would create a new distribution for each new client) Chances are, I'll need a second table to store validation history, so that with some short logic, the software can decide if it can be run on a given machine (maybe a sliding window of n machines using the software per 24 hours) If the software cannot establish a connection to the MySQL database, or decides that it's over the n allowed machines per day, it closes The connection info for the remote server hosting the MySQL database should be hard-coded into the app? (That sounds like a bad idea, but otherwise they could point it to some other always-validates-to-success server) I think that about covers my initial design. The intent being that while it certainly isn't full-proof, I think I've made it at least somewhat difficult to create an easily-sharable cracking solution. Also, I can easily adjust the license amount for a given client/key pair. I gotta figure this has been done a million times before, so tell me about a better solution that's just as simple to implement and provides the same (low) amount of security. In the event that external libraries are used, I prefer Java, as that's what the software has been written in.

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  • Rails : fighting long http response times with ajax. Is it a good idea? Please, help with implementa

    - by baranov
    Hi, everybody! I've googled some tutorials, browsed some SO answers, and was unable to find a recipe for my problem. I'm writing a web site which is supposed to display almost realtime stock chart. Data is stored in constantly updating MySQL database, I wrote a find_by_sql query code which fetches all the data I need to get my chart drawn. Everything is ok, except performance - it takes from one second to one minute for different queries to fetch all the data from the database, this time includes necessary (My)SQL-server side calculations. This is simply unacceptable. I got the following idea: if the data is queried from the MySQL server one point a time instead of entire dataset, it takes only about 1-100ms to get an individual point. I imagine the data fetch process might be browser-driven. After the user presses the button in order to get a chart drawn, controller makes one request to the database and renders, say, a progress bar, say 1% ready. When the browser gets the response, it immediately makes an (ajax) request, and the server fetches the next piece of data and renders "2%". And so on, until all the data is ready and the server displays the requested chart. Could this be implemented in rails+js, is there a tutorial for solving a similar problem on the Web? I suppose if the thing is feasible at all, somebody should have already done this before. I have read several articles about ajax, I believe I do understand general principles, but never did nontrivial ajax programming myself. Thanks for your time!

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  • Why did this work with Visual C++, but not with gcc?

    - by Carlos Nunez
    I've been working on a senior project for the last several months now, and a major sticking point in our team's development process has been dealing wtih rifts between Visual-C++ and gcc. (Yes, I know we all should have had the same development environment.) Things are about finished up at this point, but I ran into a moderate bug just today that had me wondering whether Visual-C++ is easier on newbies (like me) by design. In one of my headers, there is a function that relies on strtok to chop up a string, do some comparisons and return a string with a similar format. It works a little something like the following: int main() { string a, b, c; //Do stuff with a and b. c = get_string(a,b); } string get_string(string a, string b) { const char * a_ch, b_ch; a_ch = strtok(a.c_str(),","); b_ch = strtok(b.c_str(),","); } strtok is infamous for being great at tokenizing, but equally great at destroying the original string to be tokenized. Thus, when I compiled this with gcc and tried to do anything with a or b, I got unexpected behavior, since the separator used was completely removed in the string. Here's an example in case I'm unclear; if I set a = "Jim,Bob,Mary" and b="Grace,Soo,Hyun", they would be defined as a="JimBobMary" and b="GraceSooHyun" instead of staying the same like I wanted. However, when I compiled this under Visual C++, I got back the original strings and the program executed fine. I tried dynamically allocating memory to the strings and copying them the "standard" way, but the only way that worked was using malloc() and free(), which I hear is discouraged in C++. While I'm curious about that, the real question I have is this: Why did the program work when compiled in VC++, but not with gcc? (This is one of many conflicts that I experienced while trying to make the code cross-platform.) Thanks in advance! -Carlos Nunez

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  • In Java, howd do I iterate through lines in a textfile from back to front

    - by rogue780
    Basically I need to take a text file such as : Fred Bernie Henry and be able to read them from the file in the order of Henry Bernie Fred The actual file I'm reading from is 30MB and it would be a less than perfect solution to read the whole file, split it into an array, reverse the array and then go from there. It takes way too long. My specific goal is to find the first occurrence of a string (in this case it's "InitGame") and then return the position beginning of the beginning of that line. I did something like this in python before. My method was to seek to the end of the file - 1024, then read lines until I get to the end, then seek another 1024 from my previous starting point and, by using tell(), I would stop when I got to the previous starting point. So I would read those blocks backwards from the end of the file until I found the text I was looking for. So far, I'm having a heck of a time doing this in Java. Any help would be greatly appreciated and if you live near Baltimore it may even end up with you getting some fresh baked cookies. Thanks!

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  • Updating extra attributes in a has_many, :through relationship using Rails

    - by Robbie
    I've managed to set up a many-to-many relationship between the following models Characters Skills PlayerSkills PlayerSkills, right now, has an attribute that Skills don't normally have: a level. The models look something like this (edited for conciseness): class PlayerSkill < ActiveRecord::Base belongs_to :character belongs_to :skill end class Skill < ActiveRecord::Base has_many :player_skills has_many :characters, :through => :player_skills attr_accessible :name, :description end class Character < ActiveRecord::Base belongs_to :user has_many :player_skills has_many :skills, :through => :player_skills end So nothing too fancy in the models... The controller is also very basic at this point... it's pretty much a stock update action. The form I'm looking to modify is characters#edit. Right now it renders a series of checkboxes which add/remove skills from the characters. This is great, but the whole point of using has_many :through was to track a "level" as well. Here is what I have so far: - form_for @character do |f| = f.error_messages %p = f.label :name %br = f.text_field :name %p = f.label :race %br = f.text_field :race %p = f.label :char_class %br = f.text_field :char_class %p - @skills.each do |skill| = check_box_tag "character[skill_ids][]", skill.id, @character.skills.include?(skill) =h skill.name %br %p = f.submit After it renders "skill.name", I need it to print a text_field that updates player_skill. The problem, of course, is that player_skill may or may not exist! (Depending on if the box was already ticked when you loaded the form!) From everything I've read, has_many :through is great because it allows you to treat the relationship itself as an entity... but I'm completely at a loss as to how to handle the entity in this form. As always, thanks in advance for any and all help you can give me!

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  • Calculate total batch upload transfer percent with limited information

    - by GONeale
    Hi there, I have a system which uploads to a server file by file and displays a progress bar on file upload progress, then underneath a second progress bar which I want to indicate percentage of batch complete across all files queued to upload. Information and algorithms I can work out are: Bytes Sent / Total Bytes To Send = First progress bar (eg. 512KB of 1024KB (50%)) That works fine. However supposing I have two other files left to upload, but both file sizes are unknown (as this is only known once the file is about to commence upload, at which point it is compressed and file size is determined) how would I go about making my third progress bar? I didn't think this would be possible as I would need "Total Bytes Sent" / "Total Bytes To Send", to replicate the logic of my first progress bar on a larger scale, however I did get a version working: "Current file number we are on" / "total number of files to send" returning the percentage through the batch, however obviously will not incrementally update and it's pretty crude. So on further thinking I thought if I could incorporate the current file % with this algorithm I could perhaps get the correct progress percentage of my batch's current point. I tried this algorithm, but alas to no such avail (sorry to any math heads, it's probably quite apparent why it won't work) ("Current file number we are on" / "total number of files to send") * ("Bytes Sent" / "Total Bytes To Send") For example I thought I was on the right track when testing with this example: 2/3 (2nd of 3rd file) = 66% (this is right so far) but then when I added * 0.20 (for indicating only 20% of 2nd file has uploaded) we went back to 13%. What I need is only a little over 33%! I did try the inverse at 0.80 and a (2/3 * (2/3 * 0.2)) Can this be done without knowing entire bytes in batch to upload? Please help! Thank you!

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  • Reading email address from contacts fails with weird memory issue

    - by CapsicumDreams
    Hi all, I'm stumped. I'm trying to get a list of all the email address a person has. I'm using the ABPeoplePickerNavigationController to select the person, which all seems fine. I'm setting my ABRecordRef personDealingWith; from the person argument to - (BOOL)peoplePickerNavigationController:(ABPeoplePickerNavigationController *)peoplePicker shouldContinueAfterSelectingPerson:(ABRecordRef)person property:(ABPropertyID)property identifier:(ABMultiValueIdentifier)identifier { and everything seems fine up till this point. The first time the following code executes, all is well. When subsequently run, I can get issues. First, the code: // following line seems to make the difference (issue 1) // NSLog(@"%d", ABMultiValueGetCount(ABRecordCopyValue(personDealingWith, kABPersonEmailProperty))); // construct array of emails ABMultiValueRef multi = ABRecordCopyValue(personDealingWith, kABPersonEmailProperty); CFIndex emailCount = ABMultiValueGetCount(multi); if (emailCount 0) { // collect all emails in array for (CFIndex i = 0; i < emailCount; i++) { CFStringRef emailRef = ABMultiValueCopyValueAtIndex(multi, i); [emailArray addObject:(NSString *)emailRef]; CFRelease(emailRef); } } // following line also matters (issue 2) CFRelease(multi); If compiled as written, the are no errors or static analysis problems. This crashes with a *** -[Not A Type retain]: message sent to deallocated instance 0x4e9dc60 error. But wait, there's more! I can fix it in either of two ways. Firstly, I can uncomment the NSLog at the top of the function. I get a leak from the NSLog's ABRecordCopyValue every time through, but the code seems to run fine. Also, I can comment out the CFRelease(multi); at the end, which does exactly the same thing. Static compilation errors, but running code. So without a leak, this function crashes. To prevent a crash, I need to haemorrhage memory. Neither is a great solution. Can anyone point out what's going on?

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  • Create a menu in a perspective in Eclipse

    - by Krt_Malta
    Hi. I am developing an Eclipse plug-in and I'd like to associate a new menu (at the top of the screen along with File, Edit etc) with a perspective I'm creating. I did the menu ok but it is being displayed even in other perspectives. How can I associate it only with my perspective? This is the code I am using in plugin.xml: <plugin> <extension point="org.eclipse.ui.perspectives"> <perspective class="org.eclipse.ui.articles.perspective.API_Development" id="org.eclipse.ui.articles.perspective.API_Development" name="API Development"> </perspective> </extension> <extension point="org.eclipse.ui.actionSets"> <actionSet label="Sample Action Set" visible="true" id="API_Development_Menu.actionSet"> <menu label="API Development" id="sampleMenu"> <separator name="sampleGroup"> </separator> </menu> </actionSet> </extension> </plugin> Thanks and regards, Kurt

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  • Rotate a feature Image in Open Layers - Javascript variable from JSON.

    - by Ozaki
    I have an open layers map. It adds and removes my "imageFeature" every 10secs or so. I have a JSON feed that gives me the rotation that I need, I have a request to get that rotation and set it as a variable of rotationv. Everything works but the fact when the image is recreated it does not update the rotation. My code is as follows: JSON request: var rotationv = (function () { rotationv = null; $.ajax({ 'async': false, 'global': true, 'url': urldefault, 'dataType': "json", 'success': function (data) { rotationv = data.rotation; } }); return rotationv })(); Creating image feature: imageFeature = new OpenLayers.Feature.Vector( new OpenLayers.Geometry.Point(mylon, mylat), { rotation: rotationv } ); The image is set in the styling elsewhere. Why does this not rotate my image? Debugging with firebug I now notice that "rotationv" is updating as per it should be. But when the point is destroyed then added again it does not apply the new rotation... Add: I realised that the "image" is applied as per the layer. So I need to figure out how to re apply the stylemap to the layer so it will trigger the "update" on the page. //redefine layer 2 so it can be updated// //test.js is just a 0.0 testref// var layer2 = new OpenLayers.Layer.GML("Layer 2", "test.js", { format: OpenLayers.Format.GeoJSON, styleMap: styleMap }); But even if I add the above into my function still no luck. Included map.addLayers([layer2]); into the function as well.

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  • Google Maps API - Get points along route between lat/long

    - by user311374
    I have a web site that I am trying to get completed and I need to have the user click points on a map and then work out the route on the roads between the two points. So the user clicks the first point on 1st street, and then clicks another point on 4th street, and the map will find the best way to get there and plot the route on the map. I am assuming this can be done using directions and parse it up, but I have been searching for an hour now and can't find what I am looking for (maybe bad search terms). I need to be able to plot the map manually (?) so I can calculate the distance, etc... of the route as the user continues to click. The site that is in beta is http://www.RunMyRoute.com/UserRoutes/Create and you can see I am trying to create running routes. I want the user to have the option for the route to follow the roads versus just a straight line between two points on the map. Any help on this would be great! Simon.

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  • Find all cycles in graph, redux

    - by Shadow
    Hi, I know there are a quite some answers existing on this question. However, I found none of them really bringing it to the point. Some argue that a cycle is (almost) the same as a strongly connected components (s. http://stackoverflow.com/questions/546655/finding-all-cycles-in-graph/549402#549402) , so one could use algorithms designed for that goal. Some argue that finding a cycle can be done via DFS and checking for back-edges (s. boost graph documentation on file dependencies). I now would like to have some suggestions on whether all cycles in a graph can be detected via DFS and checking for back-edges? My opinion is that it indeed could work that way as DFS-VISIT (s. pseudocode of DFS) freshly enters each node that was not yet visited. In that sense, each vertex exhibits a potential start of a cycle. Additionally, as DFS visits each edge once, each edge leading to the starting point of a cycle is also covered. Thus, by using DFS and back-edge checking it should indeed be possible to detect all cycles in a graph. Note that, if cycles with different numbers of participant nodes exist (e.g. triangles, rectangles etc.), additional work has to be done to discriminate the acutal "shape" of each cycle.

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  • How can I extend this SQL query to find the k nearest neighbors?

    - by Smigs
    I have a database full of two-dimensional data - points on a map. Each record has a field of the geometry type. What I need to be able to do is pass a point to a stored procedure which returns the k nearest points (k would also be passed to the sproc, but that's easy). I've found a query at http://blogs.msdn.com/isaac/archive/2008/10/23/nearest-neighbors.aspx which gets the single nearest neighbour, but I can't figure how to extend it to find the k nearest neighbours. This is the current query - T is the table, g is the geometry field, @x is the point to search around, Numbers is a table with integers 1 to n: DECLARE @start FLOAT = 1000; WITH NearestPoints AS ( SELECT TOP(1) WITH TIES *, T.g.STDistance(@x) AS dist FROM Numbers JOIN T WITH(INDEX(spatial_index)) ON T.g.STDistance(@x) < @start*POWER(2,Numbers.n) ORDER BY n ) SELECT TOP(1) * FROM NearestPoints ORDER BY n, dist The inner query selects the nearest non-empty region and the outer query then selects the top result from that region; the outer query can easily be changed to (e.g.) SELECT TOP(20), but if the nearest region only contains one result, you're stuck with that. I figure I probably need to recursively search for the first region containing k records, but without using a table variable (which would cause maintenance problems as you have to create the table structure and it's liable to change - there're lots of fields), I can't see how.

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  • Deploying ASP.NET MVC to IIS6: pages are just blank

    - by BryanGrimes
    I have an MVC app that is actually on a couple other servers but I didn't do the deploy. For this deploy I have added the wildcard to aspnet_isapi.dll which has gotten rid of the 404 error. But the pages are not pulling up, rather everything is just blank. I can't seem to find any IIS configuration differences. The Global asax.cs file does have routing defined, but as I've seen on a working server, that file isn't just hanging out in the root or anything so obvious. What could I be missing here? All of the servers are running IIS6 and I have compared the setups and they look the same to me at this point. Thanks... Bryan EDIT for the comments thus far: I've looked in the event logs with no luck, and scoured various IIS logs per David Wang: blogs.msdn.com. Below is the Global.asax.cs file... public class MvcApplication : System.Web.HttpApplication { public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.IgnoreRoute("error.axd"); // for Elmah // For deployment to IIS6 routes.Add(new Route ( "{controller}.mvc/{action}/{id}", new RouteValueDictionary(new { action = "Index", id = (string)null }), new MvcRouteHandler() )); routes.MapRoute( "WeeklyTimeSave", "Time/Save", new { controller = "Time", action = "Save" } ); routes.MapRoute( "WeeklyTimeAdd", "Time/Add", new { controller = "Time", action = "Add" } ); routes.MapRoute( "WeeklyTimeEdit", "Time/Edit/{id}", new { controller = "Time", action = "Edit", id = "" } ); routes.MapRoute( "FromSalesforce", "Home/{id}", new { controller = "Home", action = "Index", id = "" }); routes.MapRoute( "Default2", "{controller}/{id}", new { controller = "Home", action = "Index", id = "" } ); routes.MapRoute( "Default", "{controller}/{action}/{id}", new { controller = "Home", action = "Index", id = "" } ); } protected void Application_Start() { RegisterRoutes(RouteTable.Routes); } } Maybe this is as stupid as the asax file not being somewhere it needs to be, but heck if I know at this point.

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  • SQL Server Index cost

    - by yellowstar
    I have read that one of the tradeoffs for adding table indexes in SQL Server is the increased cost of insert/update/delete queries to benefit the performance of select queries. I can conceptually understand what happens in the case of an insert because SQL Server has to write entries into each index matching the new rows, but update and delete are a little more murky to me because I can't quite wrap my head around what the database engine has to do. Let's take DELETE as an example and assume I have the following schema (pardon the pseudo-SQL) TABLE Foo col1 int ,col2 int ,col3 int ,col4 int PRIMARY KEY (col1,col2) INDEX IX_1 col3 INCLUDE col4 Now, if I issue the statement DELETE FROM Foo WHERE col1=12 AND col2 > 34 I understand what the engine must do to update the table (or clustered index if you prefer). The index is set up to make it easy to find the range of rows to be removed and do so. However, at this point it also needs to update IX_1 and the query that I gave it gives no obvious efficient way for the database engine to find the rows to update. Is it forced to do a full index scan at this point? Does the engine read the rows from the clustered index first and generate a smarter internal delete against the index? It might help me to wrap my head around this if I understood better what is going on under the hood, but I guess my real question is this. I have a database that is spending a significant amount of time in delete and I'm trying to figure out what I can do about it. When I display the execution plan for the deletion, it just shows an entry for "Clustered Index Delete" on table Foo which lists in the details section the other indices that need to be updated but I don't get any indication of the relative cost of these other indices. Are they all equal in this case? Is there some way that I can estimate the impact of removing one or more of these indices without having to actually try it?

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  • Divide a path into N sections using Java or PostgreSQL/PostGIS

    - by Guido
    Imagine a GPS tracking system that is following the position of several objects. The points are stored in a database (PostgreSQL + PostGIS). Each path is composed by a different number of points. That is the reason why, in order to compare a pair of paths, I need to divide every path in a set of 100 points. Do you know any PostGIS function that already implement this algorithm? I've not been able to find it. If not, I'd like to solve it using Java. In this case I'd like to know an efficient and easy to implement algorithm to divide a path into N points. The most simple example could be to divide this path into three points: position 1 : x=1, y=2 position 2 : x=1, y=3 And the result should be: position 1 : x=1, y=2 (starting point) position 2 : x=5, y=2.5 position 3 : x=9, y=3 (end point) Edit: By 'compare a pair of paths' I mean to calculate the distance between two paths. I plan to divide each path in 100 points, and sum the euclidean distance between each one of these points as the distance between the two paths.

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  • A doubt on DOM parser used with Python

    - by fixxxer
    I'm using the following python code to search for a node in an XML file and changing the value of an attribute of one of it's children.Changes are happening correctly when the node is displayed using toxml().But, when it is written to a file, the attributes rearrange themselves(as seen in the Source and the Final XML below). Could anyone explain how and why this happen? Python code: #!/usr/bin/env python import xml from xml.dom.minidom import parse dom=parse("max.xml") #print "Please enter the store name:" for sku in dom.getElementsByTagName("node"): if sku.getAttribute("name") == "store": sku.childNodes[1].childNodes[5].setAttribute("value","Delhi,India") print sku.toxml() xml.dom.ext.PrettyPrint(dom, open("new.xml", "w")) a part of the Source XML: <node name='store' node_id='515' module='mpx.lib.node.simple_value.SimpleValue' config_builder='' inherant='false' description='Configurable Value'> <match> <property name='1' value='point'/> <property name='2' value='0'/> <property name='val' value='Store# 09204 Staten Island, NY'/> <property name='3' value='str'/> </match> </node> Final XML : <node config_builder="" description="Configurable Value" inherant="false" module="mpx.lib.node.simple_value.SimpleValue" name="store" node_id="515"> <match> <property name="1" value="point"/> <property name="2" value="0"/> <property name="val" value="Delhi,India"/> <property name="3" value="str"/> </match> </node>

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  • How to get debugging of an App Engine application working?

    - by Chris Lacy
    I've got 10+ years in C/C++, and it appears Visual Studio has spoilt me during that time. In Visual Studio, debbuging issimple: I just add a breakpoint to a line of code, and as soon as that code is executed, my breakpoint triggers, at which point I can view a callstack, local/member variables, etc. I'm trying to achieve this functionality under App Engine. I assume that is possible? All the searching I've done to this point has led me to using Pydev in Eclipse. As best I can tell, I am successfully launching my simple 'hello world' program in Debug mode. But the IDE doesn't even seem to have an option to set a breakpoint? I must be missing something. I've googled long and hard about this, but am having no luck. Most results trace back to the same old threads that don't deal directly with my issue. Can anyone shed some light on how you get basic debugging setup using Pydev/Eclipse with App Engine? Alternatively, if there's an easier way to debug App Engine than using Pydev/Eclipse, I'd love to hear about it. Thanks in advance.

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  • What is faster- Java or C# (Or good old C)?

    - by Rexsung
    I'm currently deciding on a platform to build a scientific computational product on, and am deciding on either C#, Java, or plain C with Intels compiler on Core2 Quad CPU's. It's mostly integer arithmetic. My benchmarks so far show Java and C are about on par with each other, and dotNET/C# trails by about 5%- however a number of my coworkers are claiming that dotNET with the right optimizations will beat both of these given enough time for the JIT to do its work. I always assume that the JIT would have done it's job within a few minutes of the app starting (Probably a few seconds in my case, as it's mostly tight loops), so I'm not sure whether to believe them Can anyone shed any light on the situation? Would dotNET beat Java? (Or am I best just sticking with C at this point?). The code is highly multithreaded and data sets are several terabytes in size. Haskell/erlang etc are not options in this case as there is a significant quantity of existing legacy C code that will be ported to the new system, and porting C to Java/C# is a lot simpler than to Haskell or Erlang. (Unless of course these provide a significant speedup). Edit: We are considering moving to C# or Java because they may, in theory, be faster. Every percent we can shave off our processing time saves us tens of thousands of dollars per year. At this point we are just trying to evaluate whether C, Java, or c# would be faster.

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  • Debugging a HTTP Handler from Visual Studio

    - by O.O.
    I am trying to debug a HTTP Handler in Visual Studio and the break point is not getting hit. Does anyone have an idea on how to go about debugging HTTP Handlers in Visual Studio? I am using VS 2010 Premium, .NET 4.0 on a Windows 7 machine. In my Web Application I have a HTTP Handler in /HTTPHandler/TrackingHandler.cs The following is in my web config file: <system.webServer> <handlers> <add name="TrackingHandler" path="/tx/*" verb="*" type="ProjectNamespace.TrackingHandler" resourceType="Unspecified" preCondition="integratedMode" /> </handlers> </system.webServer> My HTTP Handler looks like below namespace ProjectNamespace { public class TrackingHandler : IHttpHandler { public bool IsReusable { get { return true; } } public void ProcessRequest(HttpContext context) { //Breakpoint on the very first line below string tracker = Path.GetFileName(context.Request.PhysicalPath); ....... } } } I start my Web Application using any random page in Visual Studio Debug using the builtin Web Server. I then maually edit the URL to point to the /tx/ directory and some random string after it. For e.g. my current URL looks like http://localhost:53699/tx/sdfs. I thought this should pull up the breakpoint on the first line of ProcessRequest() but it does not. I’d be grateful for any ideas. O. O.

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  • How do I efficiently write a "toggle database value" function in AJAX?

    - by AmbroseChapel
    Say I have a website which shows the user ten images and asks them to categorise each image by clicking on buttons. A button for "funny", a button for "scary", a button for "pretty" and so on. These buttons aren't exclusive. A picture can be both funny and scary. The user clicks the "funny" button. An AJAX request is sent off to the database to mark that image as funny. The "funny" button lights up, by assigning a class in the DOM to mark it as "on". But the user made a mistake. They meant to hit the next button over. They should click "funny" again to turn it off, right? At this point I'm not sure whats the most efficient way to proceed. The database knows that the "funny" flag is set, but it's inefficient to query the database every time a button is clicked to say, is this flag set or not, then go on with a second database call to toggle it. Should I infer the state of the database flag from the DOM, i.e. if that button has the class "on" then the flag must be set, and branch at that point? Or would it be better to have a data structure in Javascript in the page which duplicates the state of each image in the database, so that every time I set the database flag to true, I also set the value in the Javascript data to true and so on?

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  • How can I add the column data type after adding the column headers to my datatable?

    - by Kevin
    Using the code below (from a console app I've cobbled together), I add seven columns to my datatable. Once this is done, how can I set the data type for each column? For instance, column 1 of the datatable will have the header "ItemNum" and I want to set it to be an Int. I've looked at some examples on thet 'net, but most all of them show creating the column header and column data type at once, like this: loadDT.Columns.Add("ItemNum", typeof(Int)); At this point in my program, the column already has a name. I just want to do something like this (not actual code): loadDT.Column[1].ChangeType(typeof(int)); Here's my code so far (that gives the columns their name): // get column headings for datatable by reading first line of csv file. StreamReader sr = new StreamReader(@"c:\load_forecast.csv"); headers = sr.ReadLine().Split(','); foreach (string header in headers) { loadDT.Columns.Add(header); } Obviously, I'm pretty new at this, but trying very hard to learn. Can someone point me in the right direction? Thanks!

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