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• compiling opencv 2.4 on a 64 bit mac in Xcode

  - by Walt

  I have an opencv project that I've been developing under ubuntu 12.04, on a parellels VM on a mac which has an x86_64 architecture. There have been many screen switching performance issues that I believe are due to the VM, where linux video modes flip around for a couple seconds while camera access is made by the opencv application. I decided to moved the project into Xcode on the mac side of the computer to continue the opencv development. However, I'm not that familiar with xcode and am having trouble getting the project to build correctly there. I have xcode installed. I downloaded and decompressed the latest version of opencv on the mac, and ran: ~/src/opencv/build/cmake-gui -G Xcode .. per the instructions from willowgarage and various other locations. This appeared to work fine (however I'm wondering now if I'm missing an architecture setting in here, although it is 64-bit intel in Xcode). I then setup an xcode project with the source files from the linux project and changed the include directories to use /opt/local/include/... rather than the /usr/local/include/... I switched xcode to use the LLVM GCC compiler in the build settings for the project then set the Apple LLVM Dialog for C++ to Language Dialect to GNU++11 (which seems possibly inconsistant with the line above) I'm not using a makefile in xcode, (that I'm aware of - it has its own project file...) I was also running into a linker issue that looked like they may be resolved with the addition of this linker flag: -lopencv_video based on a similar posting here: other thread however in that case the person was using a Makefile in their project. I've tried adding this linker flag under "Other Linker Flags" in xcode build settings but still get build errors. I think I may have two issues here, one with the architecture settings when building the opencv libraries with Cmake, and one with the linker flag settings in my project. Currently the build error list looks like this: Undefined symbols for architecture x86_64: "cv::_InputArray::_InputArray(cv::Mat const&)", referenced from: _main in main.o "cv::_OutputArray::_OutputArray(cv::Mat&)", referenced from: _main in main.o "cv::Mat::deallocate()", referenced from: cv::Mat::release() in main.o "cv::Mat::copySize(cv::Mat const&)", referenced from: cv::Mat::Mat(cv::Mat const&)in main.o cv::Mat::operator=(cv::Mat const&)in main.o "cv::Mat::Mat(_IplImage const*, bool)", referenced from: _main in main.o "cv::imread(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, int)", referenced from: _main in main.o ---SNIP--- ld: symbol(s) not found for architecture x86_64 collect2: ld returned 1 exit status Can anyone provide some guidance on what to try next? Thanks, Walt

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• Display label character by character using javascript

  - by Muhammad Sajid

  Hi, I am creating Hang a Man using PHP, MySQL & Javascript. Every thing is going perfect, I get a word randomly from DB show it as a label apply it a class where display = none. Now when I click on a Character that character become disable fine which i actually want but the label-character does not show. My code is: <link href="style.css" rel="stylesheet" type="text/css" media="screen" /> <?php include( 'config.php' ); $question = questions(); // Get question. $alpha = alphabats(); // Get alphabets. ?> <script language="javascript"> function clickMe( name ){ var question = '<?php echo $question; ?>'; var questionLen = <?php echo strlen($question); ?>; for ( var i = 0; i < questionLen; i++ ){ if ( question[i] == name ){ var link = document.getElementById( name ); link.style.display = 'none'; var label = document.getElementById( 'questionLabel' + i ); label.style.display = 'block'; } } } </script> <div> <table align="center" style="border:solid 1px"> <tr> <?php for ( $i = 0; $i < 26; $i++ ) { echo "<td><a href='#' id=$alpha[$i] name=$alpha[$i] onclick=clickMe('$alpha[$i]');>". $alpha[$i] ."</a>&nbsp;</td>"; } ?> </tr> </table> <br/> <table align="center" style="border:solid 1px"> <tr> <?php for ( $i = 0; $i < strlen($question); $i++ ) { echo "<td class='question'><label id=questionLabel$i >". $question[$i] ."</label></td>"; } ?> </tr> </table> </div>

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• Uses of a C++ Arithmetic Promotion Header

  - by OlduvaiHand

  I've been playing around with a set of templates for determining the correct promotion type given two primitive types in C++. The idea is that if you define a custom numeric template, you could use these to determine the return type of, say, the operator+ function based on the class passed to the templates. For example: // Custom numeric class template <class T> struct Complex { Complex(T real, T imag) : r(real), i(imag) {} T r, i; // Other implementation stuff }; // Generic arithmetic promotion template template <class T, class U> struct ArithmeticPromotion { typedef typename X type; // I realize this is incorrect, but the point is it would // figure out what X would be via trait testing, etc }; // Specialization of arithmetic promotion template template <> class ArithmeticPromotion<long long, unsigned long> { typedef typename unsigned long long type; } // Arithmetic promotion template actually being used template <class T, class U> Complex<typename ArithmeticPromotion<T, U>::type> operator+ (Complex<T>& lhs, Complex<U>& rhs) { return Complex<typename ArithmeticPromotion<T, U>::type>(lhs.r + rhs.r, lhs.i + rhs.i); } If you use these promotion templates, you can more or less treat your user defined types as if they're primitives with the same promotion rules being applied to them. So, I guess the question I have is would this be something that could be useful? And if so, what sorts of common tasks would you want templated out for ease of use? I'm working on the assumption that just having the promotion templates alone would be insufficient for practical adoption. Incidentally, Boost has something similar in its math/tools/promotion header, but it's really more for getting values ready to be passed to the standard C math functions (that expect either 2 ints or 2 doubles) and bypasses all of the integral types. Is something that simple preferable to having complete control over how your objects are being converted? TL;DR: What sorts of helper templates would you expect to find in an arithmetic promotion header beyond the machinery that does the promotion itself?

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• How to code a keyboard button to switch between 2 modes?

  - by le.shep20

  Hi! i'm doing a project, i'm not going to details but i will simplify my idea, i'm using Morse Code ( dot and dash) and i have 2 methods: convert_MorseToChar() and Convert_MorseTonum() in the convert_MorseToChar() method there is swich to compare the input from a user which will be Morse codes and mapping it to characters: private String convert_MorseToChar(ref string Ch) { switch (Ch) { Case ".-": MorsetoChar = "a" break; Case "-...": MorsetoChar = "b" break; Case "-.-.": MorsetoChar = "c" break; Case "-..": MorsetoChar = "d" break; Case ".": MorsetoChar = "e" break; } } and the other method Convert_MorseToNum(), ues the SAME combinations of Morse codes but mapping them to numbers: private String Convert_MorseToNum(ref string Ch) { switch (Ch) { Case ".-": MorsetoChar = "1" break; Case "-...": MorsetoChar = "2" break; Case "-.-.": MorsetoChar = "3" break; Case "-..": MorsetoChar = "4" break; Case ".": MorsetoChar = "5" break; } } now the senario is: there are 2 Textbox, one the user will write Morse codes in it and the other is for the output. The user will write dot "." and dash "-" from the keyboard and press Enter then the program will go to ONE of the 2 methods to convert the Morse codes. Now what tells the program where to go to convert?? my question is: I want to create mode key to swich between 2 modes: MorseTochar and MorseToNum. i want the down arrow key to act like a mode, when a user press the down arrow then it the program will be in MorseToChar mode, when ever the user input the program directly use the method convert_MorseToChar to convert to characters. and when the user press the down arrow agian, the prohram will swich to MorseToNum mode here when ever the user input as morsecode, the program will directly use the method Convert_MorseToNum() to convert to numbers. HOW I CAN DO THAT Pleaaaas!!! help me! Please excuse my English, English is not my native language :)

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• Problems using FluentNHibernate + SQLite with .NET4?

  - by stiank81

  I have a WPF application running with VS2010 .Net3.5 using Nhibernate with FluentNHibernate + SQLite, and all works fine. Now I want to change to use .Net4, but this has turned into a more painful experience then I expected.. When setting up the connection a FluentConfigurationException is thrown from FluentConfiguration.BuildConfiguration saying: An invalid or incomplete configuration was used while creating a SessionFactory. Check PotentialReasons collection, and InnerException for more details. The inner exception gives us more information: Could not create the driver from NHibernate.Driver.SQLite20Driver, NHibernate, Version=2.1.2.4000, Culture=neutral, PublicKeyToken=aa95f207798dfdb4. It has an InnerException again: Exception has been thrown by the target of an invocation. Which again has an InnerException: The IDbCommand and IDbConnection implementation in the assembly System.Data.SQLite could not be found. Ensure that the assembly System.Data.SQLite is located in the application directory or in the Global Assembly Cache. If the assembly is in the GAC, use element in the application configuration file to specify the full name of the assembly. Now - to me it sounds like it doesn't find System.Data.SQLite.dll, but I can't understand this. Everywhere this is referenced I have "Copy Local", and I have verified that it is in every build folder for projects using SQLite. I have also copied it manually to every Debug folder of the solution - without luck. Notes: This is exactly the same code that worked just fine before I upgraded to .Net4. I did see some x64 x86 mismatch problems earlier, but I have switched to use x86 as the target platform and for all referenced dlls. I have verified that all files in the Debug-folder are x86. I have tried the precompiled Fluent dlls, I have tried compiling myself, and I have compiled my own version of Fluent using .Net4. I see that there are also others that have seen this problem, but I haven't really seen any solution yet. After @devio's answer I tried adding a reference to the SQLite dll. This didn't change anything, but I hope I made it right though.. This is what I added to the root node of the app.config file: <runtime> <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1"> <qualifyAssembly partialName="System.Data.SQLite" fullName="System.Data.SQLite, Version=1.0.60.0, Culture=neutral, PublicKeyToken=db937bc2d44ff139" /> </assemblyBinding> </runtime> Anyone out there using Fluent with .Net4 and SQLite successfully? Help! I'm lost...

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• Java multithreaded server - each connection returns data. Processing on main thread?

  - by oliwr

  I am writing a client with an integrated server that should wait indefinitely for new connections - and handle each on a Thread. I want to process the received byte array in a system wide available message handler on the main thread. However, currently the processing is obviously done on the client thread. I've looked at Futures, submit() of ExecutorService, but as I create my Client-Connections within the Server, the data would be returned to the Server thread. How can I return it from there onto the main thread (in a synchronized packet store maybe?) to process it without blocking the server? My current implementation looks like this: public class Server extends Thread { private int port; private ExecutorService threadPool; public Server(int port) { this.port = port; // 50 simultaneous connections threadPool = Executors.newFixedThreadPool(50); } public void run() { try{ ServerSocket listener = new ServerSocket(this.port); System.out.println("Listening on Port " + this.port); Socket connection; while(true){ try { connection = listener.accept(); System.out.println("Accepted client " + connection.getInetAddress()); connection.setSoTimeout(4000); ClientHandler conn_c= new ClientHandler(connection); threadPool.execute(conn_c); } catch (IOException e) { System.out.println("IOException on connection: " + e); } } } catch (IOException e) { System.out.println("IOException on socket listen: " + e); e.printStackTrace(); threadPool.shutdown(); } } } class ClientHandler implements Runnable { private Socket connection; ClientHandler(Socket connection) { this.connection=connection; } @Override public void run() { try { // Read data from the InputStream, buffered int count; byte[] buffer = new byte[8192]; InputStream is = connection.getInputStream(); ByteArrayOutputStream out = new ByteArrayOutputStream(); // While there is data in the stream, read it while ((count = is.read(buffer)) > 0) { out.write(buffer, 0, count); } is.close(); out.close(); System.out.println("Disconnect client " + connection.getInetAddress()); connection.close(); // handle the received data MessageHandler.handle(out.toByteArray()); } catch (IOException e) { System.out.println("IOException on socket read: " + e); e.printStackTrace(); } return; } }

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• Is the Scala 2.8 collections library a case of "the longest suicide note in history" ?

  - by oxbow_lakes

  First note the inflammatory subject title is a quotation made about the manifesto of a UK political party in the early 1980s. This question is subjective but it is a genuine question, I've made it CW and I'd like some opinions on the matter. Despite whatever my wife and coworkers keep telling me, I don't think I'm an idiot: I have a good degree in mathematics from the University of Oxford and I've been programming commercially for almost 12 years and in Scala for about a year (also commercially). I have just started to look at the Scala collections library re-implementation which is coming in the imminent 2.8 release. Those familiar with the library from 2.7 will notice that the library, from a usage perspective, has changed little. For example... > List("Paris", "London").map(_.length) res0: List[Int] List(5, 6) ...would work in either versions. The library is eminently useable: in fact it's fantastic. However, those previously unfamiliar with Scala and poking around to get a feel for the language now have to make sense of method signatures like: def map[B, That](f: A => B)(implicit bf: CanBuildFrom[Repr, B, That]): That For such simple functionality, this is a daunting signature and one which I find myself struggling to understand. Not that I think Scala was ever likely to be the next Java (or /C/C++/C#) - I don't believe its creators were aiming it at that market - but I think it is/was certainly feasible for Scala to become the next Ruby or Python (i.e. to gain a significant commercial user-base) Is this going to put people off coming to Scala? Is this going to give Scala a bad name in the commercial world as an academic plaything that only dedicated PhD students can understand? Are CTOs and heads of software going to get scared off? Was the library re-design a sensible idea? If you're using Scala commercially, are you worried about this? Are you planning to adopt 2.8 immediately or wait to see what happens? Steve Yegge once attacked Scala (mistakenly in my opinion) for what he saw as its overcomplicated type-system. I worry that someone is going to have a field day spreading fud with this API (similarly to how Josh Bloch scared the JCP out of adding closures to Java). Note - I should be clear that, whilst I believe that Josh Bloch was influential in the rejection of the BGGA closures proposal, I don't ascribe this to anything other than his honestly-held beliefs that the proposal represented a mistake.

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• How is IObservable<double>.Average supposed to work?

  - by Dan Tao

  Update Looks like Jon Skeet was right (big surprise!) and the issue was with my assumption about the Average extension providing a continuous average (it doesn't). For the behavior I'm after, I wrote a simple ContinuousAverage extension method, the implementation of which I am including here for the benefit of others who may want something similar: public static class ObservableExtensions { private class ContinuousAverager { private double _mean; private long _count; public ContinuousAverager() { _mean = 0.0; _count = 0L; } // undecided whether this method needs to be made thread-safe or not // seems that ought to be the responsibility of the IObservable (?) public double Add(double value) { double delta = value - _mean; _mean += (delta / (double)(++_count)); return _mean; } } public static IObservable<double> ContinousAverage(this IObservable<double> source) { var averager = new ContinuousAverager(); return source.Select(x => averager.Add(x)); } } I'm thinking of going ahead and doing something like the above for the other obvious candidates as well -- so, ContinuousCount, ContinuousSum, ContinuousMin, ContinuousMax ... perhaps ContinuousVariance and ContinuousStandardDeviation as well? Any thoughts on that? Original Question I use Rx Extensions a little bit here and there, and feel I've got the basic ideas down. Now here's something odd: I was under the impression that if I wrote this: var ticks = Observable.FromEvent<QuoteEventArgs>(MarketDataProvider, "MarketTick"); var bids = ticks .Where(e => e.EventArgs.Quote.HasBid) .Select(e => e.EventArgs.Quote.Bid); var bidsSubscription = bids.Subscribe( b => Console.WriteLine("Bid: {0}", b) ); var avgOfBids = bids.Average(); var avgOfBidsSubscription = avgOfBids.Subscribe( b => Console.WriteLine("Avg Bid: {0}", b) ); I would get two IObservable<double> objects (bids and avgOfBids); one would basically be a stream of all the market bids from my MarketDataProvider, the other would be a stream of the average of these bids. So something like this: Bid Avg Bid 1 1 2 1.5 1 1.33 2 1.5 It seems that my avgOfBids object isn't doing anything. What am I missing? I think I've probably misunderstood what Average is actually supposed to do. (This also seems to be the case for all of the aggregate-like extension methods on IObservable<T> -- e.g., Max, Count, etc.)

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• CSS, Aboslute divs in a relativly positioned div

  - by ace

  Given the following code, how can I make the height of wrapper div extend all the way down. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta content="en-us" http-equiv="Content-Language" /> <meta content="text/html; charset=utf-8" http-equiv="Content-Type" /> <title>Untitled 1</title> <style type="text/css"> .wrapperDiv { position: relative; width: 800px; background-color: #FFFF00; margin-right: auto; margin-left: auto; } .content { position: absolute; width: 95%; top: 55px; background-color: #008000; } .footer { position: absolute; width: 95%; height: 50px; background-color: #FF00FF; bottom: 5px; } .header { position: absolute; width: 95%; height: 50px; background-color: #CCFF33; top: 5px; } </style> </head> <body> <div id="wrapper" class="wrapperDiv"> <div id="layer2" class="footer"> 3</div> <div id="layer3" class="header"> 1</div> <div id="layer1" class="content"> 2<br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> END</div> </div> </body> </html>

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• ASP.Net Checkbox value at postback is wrong?

  - by Duracell

  We have a checkbox that is initially disabled and checked. It is then enabled on the client side through javascript. If the user then unchecks the box and presses the button to invoke a postback, the state of the checkbox remains as checked on the server side. This is obviously undesirable behaviour. Here is an example. <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="testcb.aspx.cs" Inherits="ESC.testcb" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> </head> <body> <form id="form1" runat="server"> <script type="text/javascript"> function buttonClick() { var cb = document.getElementById('<%= CheckBox1.ClientID %>'); cb.disabled = false; cb.parentNode.disabled = false; } </script> <div> <asp:CheckBox ID="CheckBox1" runat="server" Checked="true" Enabled="false" /> <asp:Button ID="Button1" runat="server" Text="Button" OnClientClick="buttonClick(); return false;" /> <asp:Button ID="Button2" runat="server" Text="Button2" OnClick="button2Click" /> </div> </form> </body> </html> And the Server-side code: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; namespace ESC { public partial class testcb : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void button2Click(object sender, EventArgs e) { string h = ""; } } } So we break at the "string h" line and check the value of CheckBox1.Checked. It is true, even if it is unchecked on the form.

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• .NET: Interface Problem VB.net Getter Only Interface

  - by snmcdonald

  Why does an interface override a class definition and violate class encapsulation? I have included two samples below, one in C# and one in VB.net? VB.net Module Module1 Sub Main() Dim testInterface As ITest = New TestMe Console.WriteLine(testInterface.Testable) ''// Prints False testInterface.Testable = True ''// Access to Private!!! Console.WriteLine(testInterface.Testable) ''// Prints True Dim testClass As TestMe = New TestMe Console.WriteLine(testClass.Testable) ''// Prints False ''//testClass.Testable = True ''// Compile Error Console.WriteLine(testClass.Testable) ''// Prints False End Sub End Module Public Class TestMe : Implements ITest Private m_testable As Boolean = False Public Property Testable As Boolean Implements ITest.Testable Get Return m_testable End Get Private Set(ByVal value As Boolean) m_testable = value End Set End Property End Class Interface ITest Property Testable As Boolean End Interface C# using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace InterfaceCSTest { class Program { static void Main(string[] args) { ITest testInterface = new TestMe(); Console.WriteLine(testInterface.Testable); testInterface.Testable = true; Console.WriteLine(testInterface.Testable); TestMe testClass = new TestMe(); Console.WriteLine(testClass.Testable); //testClass.Testable = true; Console.WriteLine(testClass.Testable); } } class TestMe : ITest { private bool m_testable = false; public bool Testable { get { return m_testable; } private set { m_testable = value; } } } interface ITest { bool Testable { get; set; } } } More Specifically How do I implement a interface in VB.net that will allow for a private setter. For example in C# I can declare: class TestMe : ITest { private bool m_testable = false; public bool Testable { get { return m_testable; } private set //No Compile Error here! { m_testable = value; } } } interface ITest { bool Testable { get; } } However, if I declare an interface property as readonly in VB.net I cannot create a setter. If I create a VB.net interface as just a plain old property then interface declarations will violate my encapsulation. Public Class TestMe : Implements ITest Private m_testable As Boolean = False Public ReadOnly Property Testable As Boolean Implements ITest.Testable Get Return m_testable End Get Private Set(ByVal value As Boolean) ''//Compile Error m_testable = value End Set End Property End Class Interface ITest ReadOnly Property Testable As Boolean End Interface So my question is, how do I define a getter only Interface in VB.net with proper encapsulation? I figured the first example would have been the best method. However, it appears as if interface definitions overrule class definitions. So I tried to create a getter only (Readonly) property like in C# but it does not work for VB.net. Maybe this is just a limitation of the language?

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• What could cause this difference in behaviour from iphone OS3.0 to iOS4.0?

  - by frankodwyer

  I am getting a strange EXC_BAD_ACCESS error when running my app on iOS4. The app has been pretty solid on OS3.x for some time - not even seeing crash logs in this area of the code (or many at all) in the wild. I've tracked the error down to this code: main class: - (void) sendPost:(PostRequest*)request { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; NSURLResponse* response; NSError* error; NSData *serverReply = [NSURLConnection sendSynchronousRequest:request.request returningResponse:&response error:&error]; ServerResponse* serverResponse=[[ServerResponse alloc] initWithResponse:response error:error data:serverReply]; [request.objectToNotifyWhenDone performSelectorOnMainThread:request.targetToNotifyWhenDone withObject:serverResponse waitUntilDone:YES]; [pool drain]; } (Note: sendPost is run on a separate thread for each invocation of it. PostRequest is just a class to encapsulate a request and a selector to notify when complete) ServerResponse.m: @synthesize response; @synthesize replyString; @synthesize error; @synthesize plist; - (ServerResponse*) initWithResponse:(NSURLResponse*)resp error:(NSError*)err data:(NSData*)serverReply { self.response=resp; self.error=err; self.plist=nil; self.replyString=nil; if (serverReply) { self.replyString = [[[NSString alloc] initWithBytes:[serverReply bytes] length:[serverReply length] encoding: NSASCIIStringEncoding] autorelease]; NSPropertyListFormat format; NSString *errorStr; plist = [NSPropertyListSerialization propertyListFromData:serverReply mutabilityOption:NSPropertyListImmutable format:&format errorDescription:&errorStr]; } return self; } ServerResponse.h: @property (nonatomic, retain) NSURLResponse* response; @property (nonatomic, retain) NSString* replyString; @property (nonatomic, retain) NSError* error; @property (nonatomic, retain) NSDictionary* plist; - (ServerResponse*) initWithResponse:(NSURLResponse*)response error:(NSError*)error data:(NSData*)serverReply; This reliably crashes with a bad access in the line: self.error=err; ...i.e. in the synthesized property setter! I'm stumped as to why this should be, given the code worked on the previous OS and hasn't changed since (even the binary compiled with the previous SDK crashes the same way, but not on OS3.0) - and given it is a simple property method. Any ideas? Could the NSError implementation have changed between releases or am I missing something obvious?

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• Using a type parameter and a pointer to the same type parameter in a function template

  - by Darel

  Hello, I've written a template function to determine the median of any vector or array of any type that can be sorted with sort. The function and a small test program are below: #include <algorithm> #include <vector> #include <iostream> using namespace::std; template <class T, class X> void median(T vec, size_t size, X& ret) { sort(vec, vec + size); size_t mid = size/2; ret = size % 2 == 0 ? (vec[mid] + vec[mid-1]) / 2 : vec[mid]; } int main() { vector<double> v; v.push_back(2); v.push_back(8); v.push_back(7); v.push_back(4); v.push_back(9); double a[5] = {2, 8, 7, 4, 9}; double r; median(v.begin(), v.size(), r); cout << r << endl; median(a, 5, r); cout << r << endl; return 0; } As you can see, the median function takes a pointer as an argument, T vec. Also in the argument list is a reference variable X ret, which is modified by the function to store the computed median value. However I don't find this a very elegant solution. T vec will always be a pointer to the same type as X ret. My initial attempts to write median had a header like this: template<class T> T median(T *vec, size_t size) { sort(vec, vec + size); size_t mid = size/2; return size % 2 == 0 ? (vec[mid] + vec[mid-1]) / 2 : vec[mid]; } I also tried: template<class T, class X> X median(T vec, size_t size) { sort(vec, vec + size); size_t mid = size/2; return size % 2 == 0 ? (vec[mid] + vec[mid-1]) / 2 : vec[mid]; } I couldn't get either of these to work. My question is, can anyone show me a working implementation of either of my alternatives? Thanks for looking!

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• Html Agility Pack: DescendantsOrSelf() not returning HTML element

  - by Program.X

  I have some HTML, eg: <%@ Page Title="About Us" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeBehind="ContentManagedTargetPage.aspx.cs" Inherits="xxx.ContentManagedTargetPage" %> <%@ Register TagPrefix="CxCMS" Namespace="xxx.ContentManagement.ASPNET.UI" Assembly="xxx.ContentManagement.ASPNET" %> <asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent"> </asp:Content> <asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent"> <h2> Content Managed </h2> <p> Put content here. [<CxCMS:ContentManagedPlaceHolder Key="keyThingy" runat="server" />] </p> </asp:Content> And I want to find all the instances of the CxCMS:ContentManagedPlaceHolder element. I'm using HTML Agility Pack, which seems the best fit. However, despite looking at the [meagre] documentation, I can't get my code to work. I would expect the following to work: string searchForElement = "CxCMS:ContentManagedPlaceHolder"; IEnumerable<HtmlNode> contentPlaceHolderHtmlNodes = HtmlDocument.DocumentNode.Descendants(searchForElement); int count = contentPlaceHolderHtmlNodes.Count(); But I get nothing back. If I change to DescendantsOrSelf, I get the document node back, "#document" - which is incorrect: string searchForElement = "CxCMS:ContentManagedPlaceHolder"; IEnumerable<HtmlNode> contentPlaceHolderHtmlNodes = HtmlDocument.DocumentNode.DescendantsOrSelf(searchForElement); int count = contentPlaceHolderHtmlNodes.Count(); I also tried using LINQ: string searchForElement = "CxCMS:ContentManagedPlaceHolder"; IEnumerable<HtmlNode> contentPlaceHolderHtmlNodes = HtmlDocument.DocumentNode.DescendantsOrSelf().Where(q=>q.Name==searchForElement); int count = contentPlaceHolderHtmlNodes.Count(); As neither of these methods work, I moved onto using SelectNodes, instead: string searchForElement = "CxCMS:ContentManagedPlaceHolder"; string xPath="//"+searchForElement // "//CxCMS:ContentManagedPlaceHolder" var nodes= HtmlDocument.DocumentNode.SelectNodes(xPath); This just throws the exception: "Namespace Manager or XsltContext needed. This query has a prefix, variable, or user-defined function.". I can't find any way of adding namespace management to the HtmlDocument object. What am I missing, here? The DescendantsOrSelf() method works if using a "standard" HTML tag, such as "p", but not the one I have. Surely it should work? (It needs to!)

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• quartz: preventing concurrent instances of a job in jobs.xml

  - by Jason S

  This should be really easy. I'm using Quartz running under Apache Tomcat 6.0.18, and I have a jobs.xml file which sets up my scheduled job that runs every minute. What I would like to do, is if the job is still running when the next trigger time rolls around, I don't want to start a new job, so I can let the old instance complete. Is there a way to specify this in jobs.xml (prevent concurrent instances)? If not, is there a way I can share access to an in-memory singleton within my application's Job implementation (is this through the JobExecutionContext?) so I can handle the concurrency myself? (and detect if a previous instance is running) update: After floundering around in the docs, here's a couple of approaches I am considering, but either don't know how to get them to work, or there are problems. Use StatefulJob. This prevents concurrent access... but I'm not sure what other side-effects would occur if I use it, also I want to avoid the following situation: Suppose trigger times would be every minute, i.e. trigger#0 = at time 0, trigger #1 = 60000msec, #2 = 120000, #3 = 180000, etc. and the trigger#0 at time 0 fires my job which takes 130000msec. With a plain Job, this would execute triggers #1 and #2 while job trigger #0 is still running. With a StatefulJob, this would execute triggers #1 and #2 in order, immediately after #0 finishes at 130000. I don't want that, I want #1 and #2 not to run and the next trigger that runs a job should take place at #3 (180000msec). So I still have to do something else with StatefulJob to get it to work the way I want, so I don't see much of an advantage to using it. Use a TriggerListener to return true from vetoJobExecution(). Although implementing the interface seems straightforward, I have to figure out how to setup one instance of a TriggerListener declaratively. Can't find the docs for the xml file. Use a static shared thread-safe object (e.g. a semaphore or whatever) owned by my class that implements Job. I don't like the idea of using singletons via the static keyword under Tomcat/Quartz, not sure if there are side effects. Also I really don't want them to be true singletons, just something that is associated with a particular job definition. Implement my own Trigger which extends SimpleTrigger and contains shared state that could run its own TriggerListener. Again, I don't know how to setup the XML file to use this trigger rather than the standard <trigger><simple>...</simple></trigger>.

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• Historical / auditable database

  - by Mark

  Hi all, This question is related to the schema that can be found in one of my other questions here. Basically in my database I store users, locations, sensors amongst other things. All of these things are editable in the system by users, and deletable. However - when an item is edited or deleted I need to store the old data; I need to be able to see what the data was before the change. There are also non-editable items in the database, such as "readings". They are more of a log really. Readings are logged against sensors, because its the reading for a particular sensor. If I generate a report of readings, I need to be able to see what the attributes for a location or sensor was at the time of the reading. Basically I should be able to reconstruct the data for any point in time. Now, I've done this before and got it working well by adding the following columns to each editable table: valid_from valid_to edited_by If valid_to = 9999-12-31 23:59:59 then that's the current record. If valid_to equals valid_from, then the record is deleted. However, I was never happy with the triggers I needed to use to enforce foreign key consistency. I can possibly avoid triggers by using the extension to the "PostgreSQL" database. This provides a column type called "period" which allows you to store a period of time between two dates, and then allows you to do CHECK constraints to prevent overlapping periods. That might be an answer. I am wondering though if there is another way. I've seen people mention using special historical tables, but I don't really like the thought of maintainling 2 tables for almost every 1 table (though it still might be a possibility). Maybe I could cut down my initial implementation to not bother checking the consistency of records that aren't "current" - i.e. only bother to check constraints on records where the valid_to is 9999-12-31 23:59:59. Afterall, the people who use historical tables do not seem to have constraint checks on those tables (for the same reason, you'd need triggers). Does anyone have any thoughts about this? PS - the title also mentions auditable database. In the previous system I mentioned, there is always the edited_by field. This allowed all changes to be tracked so we could always see who changed a record. Not sure how much difference that might make. Thanks.

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• Should I use Python or Assembly for a super fast copy program

  - by PyNEwbie

  As a maintenance issue I need to routinely (3-5 times per year) copy a repository that is now has over 20 million files and exceeds 1.5 terabytes in total disk space. I am currently using RICHCOPY, but have tried others. RICHCOPY seems the fastest but I do not believe I am getting close to the limits of the capabilities of my XP machine. I am toying around with using what I have read in The Art of Assembly Language to write a program to copy my files. My other thought is to start learning how to multi-thread in Python to do the copies. I am toying around with the idea of doing this in Assembly because it seems interesting, but while my time is not incredibly precious it is precious enough that I am trying to get a sense of whether or not I will see significant enough gains in copy speed. I am assuming that I would but I only started really learning to program 18 months and it is still more or less a hobby. Thus I may be missing some fundamental concept of what happens with interpreted languages. Any observations or experiences would be appreciated. Note, I am not looking for any code. I have already written a basic copy program in Python 2.6 that is no slower than RICHCOPY. I am looking for some observations on which will give me more speed. Right now it takes me over 50 hours to make a copy from a disk to a Drobo and then back from the Drobo to a disk. I have a LogicCube for when I am simply duplicating a disk but sometimes I need to go from a disk to Drobo or the reverse. I am thinking that given that I can sector copy a 3/4 full 2 terabyte drive using the LogicCube in under seven hours I should be able to get close to that using Assembly, but I don't know enough to know if this is valid. (Yes, sometimes ignorance is bliss) The reason I need to speed it up is I have had two or three cycles where something has happened during copy (fifty hours is a long time to expect the world to hold still) that has caused me to have to trash the copy and start over. For example, last week the water main broke under our building and shorted out the power.

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• Javascript closures with google geocoder

  - by DaNieL

  Hi all, i still have some problems with javascript closures, and input/output variables. Im playing with google maps api for a no profit project: users will place the marker into a gmap, and I have to save the locality (with coordinates) in my db. The problem comes when i need to do a second geocode in order to get a unique pairs of lat and lng for a location: lets say two users place the marker in the same town but in different places, I dont want to have the same locality twice in the database with differents coords. I know i can do the second geocode after the user select the locality, but i want to understand what am i mistaking here: // First geocoding, take the marker coords to get locality. geocoder.geocode( { 'latLng': new google.maps.LatLng($("#lat").val(), $("#lng").val()), 'language': 'it' }, function(results_1, status_1){ // initialize the html var inside this closure var html = ''; if(status_1 == google.maps.GeocoderStatus.OK) { // do stuff here for(i = 0, geolen = results_1[0].address_components.length; i != geolen) { // Second type of geocoding: for each location from the first geocoding, // i want to have a unique [lat,lan] geocoder.geocode( { 'address': results_1[0].address_components[i].long_name }, function(results_2, status_2){ // Here come the problem. I need to have the long_name here, and // 'html' var should increment. coords = results_2[0].geometry.location.toUrlValue(); html += 'some html to let the user choose the locality'; } ); } // Finally, insert the 'html' variable value into my dom... //but it never gets updated! } else { alert("Error from google geocoder:" + status_1) } } ); I tryed with: // Second type of geocoding: for each location from the first geocoding, i want // to have a unique [lat,lan] geocoder.geocode( { 'address': results_1[0].address_components[i].long_name }, (function(results_2, status_2, long_name){ // But in this way i'll never get results_2 or status_2, well, results_2 // get long_name value, status_2 and long_name is undefined. // However, html var is correctly updated. coords = results_2[0].geometry.location.toUrlValue(); html += 'some html to let the user choose the locality'; })(results_1[0].address_components[i].long_name) ); And with: // Second type of geocoding: for each location from the first geocoding, i want to have // a unique [lat,lan] geocoder.geocode( { 'address': results_1[0].address_components[i].long_name }, (function(results_2, status_2, long_name){ // But i get an obvious "results_2 is not defined" error (same for status_2). coords = results_2[0].geometry.location.toUrlValue(); html += 'some html to let the user choose the locality, that can be more than one'; })(results_2, status_2, results_1[0].address_components[i].long_name) ); Any suggestion? EDIT: My problem is how to pass an additional arguments to the geocoder inner function: function(results_2, status_2, long_name){ //[...] } becose if i do that with a clousure, I mess with the original parameters (results_2 and status_2)

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• SharePoint 2010 Custom WCF Service - Windows and FBA Authentication

  - by e-rock

  I have SharePoint 2010 configured for Claims Based Authentication with both Windows and Forms Based Authentication (FBA) for external users. I also need to develop custom WCF Services. The issue is that I want Windows credentials passed into the WCF Service(s); however, I cannot seem to get the Windows credentials passed into the services. My custom WCF service appears to be using Anonymous authentication (which has to be enabled in IIS in order to display the FBA login screen). The example I have tried to follow is found at http://msdn.microsoft.com/en-us/library/ff521581.aspx. The WCF service gets deployed to _vti_bin (ISAPI folder). Here is the code for the .svc file <%@ ServiceHost Language="C#" Debug="true" Service="MyCompany.CustomerPortal.SharePoint.UI.ISAPI.MyCompany.Services.LibraryManagers.LibraryUploader, $SharePoint.Project.AssemblyFullName$" Factory="Microsoft.SharePoint.Client.Services.MultipleBaseAddressBasicHttpBindingServiceHostFactory, Microsoft.SharePoint.Client.ServerRuntime, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" CodeBehind="LibraryUploader.svc.cs" %> Here is the code behind for the .svc file [ServiceContract] public interface ILibraryUploader { [OperationContract] string SiteName(); } [BasicHttpBindingServiceMetadataExchangeEndpoint] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Required)] public class LibraryUploader : ILibraryUploader { //just try to return site title right now… public string SiteName() { WindowsIdentity identity = ServiceSecurityContext.Current.WindowsIdentity; ClaimsIdentity claimsIdentity = new ClaimsIdentity(identity); return SPContext.Current.Web.Title; } } The WCF test client I have just to test it out (WPF app) uses the following code to call the WCF service... private void Button1Click(object sender, RoutedEventArgs e) { BasicHttpBinding binding = new BasicHttpBinding(); binding.Security.Mode = BasicHttpSecurityMode.TransportCredentialOnly; binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.Ntlm; EndpointAddress endpoint = new EndpointAddress( "http://dev.portal.data-image.local/_vti_bin/MyCompany.Services/LibraryManagers/LibraryUploader.svc"); LibraryUploaderClient libraryUploader = new LibraryUploaderClient(binding, endpoint); libraryUploader.ClientCredentials.Windows.AllowedImpersonationLevel = System.Security.Principal.TokenImpersonationLevel.Impersonation; MessageBox.Show(libraryUploader.SiteName()); } I am somewhat inexperienced with IIS security settings/configurations when it comes to Claims and trying to use both Windows and FBA. I am also inexperienced when it comes to WCF configurations for security. I usually develop internal biz apps and let Visual Studio decide what to use because security is rarely a concern.

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• Armchair Linguists: 'code' vs. 'codes'--or why I write 'code' and my manager asks for 'codes'

  - by Ukko

  I wanted to tap into the collective wisdom here to see if I can get some insight into one of my pet peeves, people who thread "code" as a countable noun. Let me also preface this by saying that I am not talking about anyone who speaks english as a second language, this is a native phenomenon. For those of us who slept through grammar class there are two classes of nouns which basically refer to things that are countable and non-countable (sometimes referred to as count and noncount). For instance 'sand' is a non-count noun and 'apple' is count. You can talk about "two apples" but "two sands" does not parse. The bright students then would point out a word like "beer" where is looks like this is violated. Beer as a substance is certainly a non-count noun, but I can ask for "two beers" without offending the grammar police. The reason is that there are actually two words tied up in that one utterance, Definition #1 is a yummy golden substance and Definition #2 is a colloquial term for a container of said substance. #1 is non-count and #2 is countable. This gets to my problem with "codes" as a countable noun. In my mind the code that we programmers write is non-count, "I wrote some code today." When used in the plural like "Have you got the codes" I can only assume that you are asking if I have the cryptographically significant numbers for launching a missile or the like. Every time my peer in marketing asks about when we will have the new codes ready I have a vision of rooms of code breakers going over the latest Enigma coded message. I corrected the usage in all the documents I am asked to review, but then I noticed that our customer was also using the work "codes" when they meant "code". At this point I have realized that there is a significant sub-population that uses "codes" and they seem to be impervious to what I see as the dominant "correct" usage. This is the part I want some help on, has anyone else noticed this phenomenon? Do you know what group it is associated with, old Fortran programmer perhaps? Is it a regionalism? I have become quick to change my terms when I notice a customer's usage, but it would be nice to know if I am sending a proposal somewhere what style they expect. I would hate to get canned with a review of "Ha, these guy's must be morons they don't even know 'code' is plural!"

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• Issues with mx:method, mx.rpc.remoting.mxml.RemoteObject, and sub-classing mx.rpc.remoting.mxml.Remo

  - by Ryan Wilson

  I am looking to subclass RemoteObject. Instead of: <mx:RemoteObject ... > <mx:method ... /> <mx:method ... /> </mx:RemoteObject> I want to do something like: <remoting:CustomRemoteObject ...> <mx:method ... /> <mx:method ... /> </remoting:CustomRemoteObject> where CustomRemoteObject extends mx.rpc.remoting.mxml.RemoteObject like so: package remoting { import mx.rpc.remoting.mxml.RemoteObject; public class CustomRemoteObject extends RemoteObject { public function CustomRemoteObject(destination:String=null) { super(destination); } } } However, when doing so and declaring a CustomRemoteObject in MXML as above, the flex compiler shows the error: Could not resolve <mx:method> to a component implementation At first I thought it had something to do with CustomRemoteObject failing to do something, despite that (or since) it had no change except as to the name. So, I copied the source from mx.rpc.remoting.mxml.RemoteObject into CustomRemoteObject and modified it so the only difference was a refactoring of the class and package name. But still, the same error. Unlike many MXML components, I cannot cmd+click <mx:method> in FlashBuilder to open the source. Likewise, I have not found a reference in mx.rpc.remoting.mxml.RemoteObject, mx.rpc.remoting.RemoteObject, or mx.rpc.remoting.AbstractService, and have been unsuccessful in find its source online. Which leads me to the questions in the title: What exactly is <mx:method>? (yes, I know it's a declaration of a RemoteObject method, and I know how to use it, but it's peculiar in regard to other components) Why did my attempt at subclassing RemoteObject fail, despite it effectually being a rename? Perhaps the root, why can mx.rpc.remoting.mxml.RemoteObject as an MXML declaration accept <mx:method> child tags, yet the source of said class cannot when refactored in name only?

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• Objective-C: properties not being saved or passed

  - by Gerald Yeo

  Hi, i'm a newbie to iphone development. I'm doing a navigation-based app, and I'm having trouble passing values to a new view. @interface RootViewController : UITableViewController { NSString *imgurl; NSMutableArray *galleryArray; } @property (nonatomic, retain) NSString *imgurl; @property (nonatomic, retain) NSMutableArray *galleryArray; - (void)showAll; @end #import "RootViewController.h" #import "ScrollView.h" #import "Model.h" #import "JSON/JSON.h" @implementation RootViewController @synthesize galleryArray, imgurl; - (void)viewDidLoad { UIBarButtonItem *showButton = [[[UIBarButtonItem alloc] initWithTitle:NSLocalizedString(@"Show All", @"") style:UIBarButtonItemStyleBordered target:self action:@selector(showAll)] autorelease]; self.navigationItem.rightBarButtonItem = showButton; NSString *jsonString = [[Model sharedInstance] jsonFromURLString:@"http://www.ddbstaging.com/gerald/gallery.php"]; NSDictionary *resultDictionary = [jsonString JSONValue]; if (resultDictionary == nil) { UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Webservice Down" message:@"The webservice you are accessing is currently down. Please try again later." delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil]; [alert show]; [alert release]; } else { galleryArray = [[NSMutableArray alloc] init]; galleryArray = [resultDictionary valueForKey:@"gallery"]; imgurl = (NSString *)[galleryArray objectAtIndex:0]; NSLog(@" -> %@", galleryArray); NSLog(imgurl); } } - (void)showAll { NSLog(@" -> %@", galleryArray); NSLog(imgurl); ScrollView *controller = [[ScrollView alloc] initWithJSON:galleryArray]; [self.navigationController pushViewController:controller animated:YES]; } The RootViewController startup and the json data loads up fine. I can see it from the first console trace. However, once I click on the Show All button, the app crashes. It doesn't even trace the galleryArray and imgurl properyly. Maybe additional pairs of eyes can spot my mistakes. Any help is greatly appreciated! [Session started at 2010-05-08 16:16:07 +0800.] 2010-05-08 16:16:07.242 Photos[5892:20b] -> ( ) GNU gdb 6.3.50-20050815 (Apple version gdb-967) (Tue Jul 14 02:11:58 UTC 2009) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i386-apple-darwin".sharedlibrary apply-load-rules all Attaching to process 5892. (gdb)

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• access exception when invoking method of an anonymous class using java reflection

  - by Asaf David

  Hello I'm trying to use an event dispatcher to allow a model to notify subscribed listeners when it changes. the event dispatcher receives a handler class and a method name to call during dispatch. the presenter subscribes to the model changes and provide a Handler implementation to be called on changes. Here's the code (I'm sorry it's a bit long). EventDispacther: package utils; public class EventDispatcher<T> { List<T> listeners; private String methodName; public EventDispatcher(String methodName) { listeners = new ArrayList<T>(); this.methodName = methodName; } public void add(T listener) { listeners.add(listener); } public void dispatch() { for (T listener : listeners) { try { Method method = listener.getClass().getMethod(methodName); method.invoke(listener); } catch (Exception e) { System.out.println(e.getMessage()); } } } } Model: package model; public class Model { private EventDispatcher<ModelChangedHandler> dispatcher; public Model() { dispatcher = new EventDispatcher<ModelChangedHandler>("modelChanged"); } public void whenModelChange(ModelChangedHandler handler) { dispatcher.add(handler); } public void change() { dispatcher.dispatch(); } } ModelChangedHandler: package model; public interface ModelChangedHandler { void modelChanged(); } Presenter: package presenter; public class Presenter { private final Model model; public Presenter(Model model) { this.model = model; this.model.whenModelChange(new ModelChangedHandler() { @Override public void modelChanged() { System.out.println("model changed"); } }); } } Main: package main; public class Main { public static void main(String[] args) { Model model = new Model(); Presenter presenter = new Presenter(model); model.change(); } } Now, I except to get the "model changed" message. However, I'm getting an java.lang.IllegalAccessException: Class utils.EventDispatcher can not access a member of class presenter.Presenter$1 with modifiers "public". I understand that the class to blame is the anonymous class i created inside the presenter, however I don't know how to make it any more 'public' than it currently is. If i replace it with a named nested class it seem to work. It also works if the Presenter and the EventDispatcher are in the same package, but I can't allow that (several presenters in different packages should use the EventDispatcher) any ideas?

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• ASP.NET MVC - PartialView html not changing via jQuery html() call

  - by Bryan Roth

  When I change the selection in a DropDownList, a PartialView gets updated via a GET request. When updating the PartialView via the jQuery html() function, the html returned is correct but when it displayed in the browser it is not correct. For example, certain checkboxes within the PartialView should become enabled but they remain disabled even though the html returned says they should be. When I do a view source in the browser the html never gets updated. I'm a little perplexed. Thoughts? Search.aspx <%@ Page Title="" Language="VB" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage" %> <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server"> Search </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <script type="text/javascript"> $(document).ready(function () { $("#Sections").change(function () { var section = $("#Sections").val(); var township = $("#Townships").val(); var range = $("#Ranges").val(); $.get("Search/Search?section=" + section + "&township=" + township + "&range=" + range, function (response) { $("#cornerDiv").html(response) }); }); }); </script> <h2>Search</h2> <%--The line below is a workaround for a VB / ASPX designer bug--%> <%=""%> <% Using Ajax.BeginForm("Search", New AjaxOptions With {.UpdateTargetId = "searchResults", .LoadingElementId = "loader"})%> Township <%= Html.DropDownList("Townships")%> Range <%= Html.DropDownList("Ranges")%> Section <%= Html.DropDownList("Sections")%> <div id="cornerDiv"> <% Html.RenderPartial("Corners")%> </div> <input type="submit" value="Search" /> <span id="loader">Searching...</span> <% End Using%> <div id="searchResults"></div> </asp:Content>

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• Function lfit in numerical recipes, providing a test function

  - by Simon Walker

  Hi I am trying to fit collected data to a polynomial equation and I found the lfit function from Numerical Recipes. I only have access to the second edition, so am using that. I have read about the lfit function and its parameters, one of which is a function pointer, given in the documentation as void (*funcs)(float, float [], int)) with the help The user supplies a routine funcs(x,afunc,ma) that returns the ma basis functions evaluated at x = x in the array afunc[1..ma]. I am struggling to understand how this lfit function works. An example function I found is given below: void fpoly(float x, float p[], int np) /*Fitting routine for a polynomial of degree np-1, with coe?cients in the array p[1..np].*/ { int j; p[1]=1.0; for (j=2;j<=np;j++) p[j]=p[j-1]*x; } When I run through the source code for the lfit function in gdb I can see no reference to the funcs pointer. When I try and fit a simple data set with the function, I get the following error message. Numerical Recipes run-time error... gaussj: Singular Matrix ...now exiting to system... Clearly somehow a matrix is getting defined with all zeroes. I am going to involve this function fitting in a large loop so using another language is not really an option. Hence why I am planning on using C/C++. For reference, the test program is given here: int main() { float x[5] = {0., 0., 1., 2., 3.}; float y[5] = {0., 0., 1.2, 3.9, 7.5}; float sig[5] = {1., 1., 1., 1., 1.}; int ndat = 4; int ma = 4; /* parameters in equation */ float a[5] = {1, 1, 1, 0.1, 1.5}; int ia[5] = {1, 1, 1, 1, 1}; float **covar = matrix(1, ma, 1, ma); float chisq = 0; lfit(x,y,sig,ndat,a,ia,ma,covar,&chisq,fpoly); printf("%f\n", chisq); free_matrix(covar, 1, ma, 1, ma); return 0; } Also confusing the issue, all the Numerical Recipes functions are 1 array-indexed so if anyone has corrections to my array declarations let me know also! Cheers

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