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Search found 246 results on 10 pages for 'elliott samuel lemberger'.

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  • explicit copy constructor or implicit parameter by value

    - by R Samuel Klatchko
    I recently read (and unfortunately forgot where), that the best way to write operator= is like this: foo &operator=(foo other) { swap(*this, other); return *this; } instead of this: foo &operator=(const foo &other) { foo copy(other); swap(*this, copy); return *this; } The idea is that if operator= is called with an rvalue, the first version can optimize away construction of a copy. So when called with a rvalue, the first version is faster and when called with an lvalue the two are equivalent. I'm curious as to what other people think about this? Would people avoid the first version because of lack of explicitness? Am I correct that the first version can be better and can never be worse?

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  • java library for reading RSS and ATOM feeds

    - by Samuel
    I am looking for libraries which can read RSS / ATOM feeds in my J2EE application (based on JBoss Seam). Is Rome the only application there for reading feeds? I am assuming the Seam RSS integration is only for generating RSS feeds and not for reading feeds.

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  • how can exec change the behavior of exec'ed program

    - by R Samuel Klatchko
    I am trying to track down a very odd crash. What is so odd about it is a workaround that someone discovered and which I cannot explain. The workaround is this small program which I'll refer to as 'runner': #include <stdio.h> #include <unistd.h> #include <string.h> #include <errno.h> int main(int argc, char *argv[]) { if (argc == 1) { fprintf(stderr, "Usage: %s prog [args ...]\n", argv[0]); return 1; } execvp(argv[1], argv + 1); fprintf(stderr, "execv failed: %s\n", strerror(errno)); // If exec returns because the program is not found or we // don't have the appropriate permission return 255; } As you can see, all this program does is use execvp to replace itself with a different program. The program crashes when it is directly invoked from the command line: /path/to/prog args # this crashes but works fine when it is indirectly invoked via my runner shim: /path/to/runner /path/to/prog args # works successfully For the life of me, I can figure out how having an extra exec can change the behavior of the program being run (as you can see the program does not change the environment). Some background on the crash. The crash itself is happening in the C++ runtime. Specifically, when the program does a throw, the crashing version incorrectly thinks there is no matching catch (although there is) and calls terminate. When I invoke the program via runner, the exception is properly caught. My question is any idea why the extra exec changes the behavior of the exec'ed program?

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  • TargetProcess + SVN

    - by samuel morhaim
    I have a TargetProcess machine, and my developers keep committing code to SVN. How can I have TP automatically group builds so that I can know which bugs, were committed during which builds? Thank you.

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  • non-copyable objects and value initialization: g++ vs msvc

    - by R Samuel Klatchko
    I'm seeing some different behavior between g++ and msvc around value initializing non-copyable objects. Consider a class that is non-copyable: class noncopyable_base { public: noncopyable_base() {} private: noncopyable_base(const noncopyable_base &); noncopyable_base &operator=(const noncopyable_base &); }; class noncopyable : private noncopyable_base { public: noncopyable() : x_(0) {} noncopyable(int x) : x_(x) {} private: int x_; }; and a template that uses value initialization so that the value will get a known value even when the type is POD: template <class T> void doit() { T t = T(); ... } and trying to use those together: doit<noncopyable>(); This works fine on msvc as of VC++ 9.0 but fails on every version of g++ I tested this with (including version 4.5.0) because the copy constructor is private. Two questions: Which behavior is standards compliant? Any suggestion of how to work around this in gcc (and to be clear, changing that to T t; is not an acceptable solution as this breaks POD types). P.S. I see the same problem with boost::noncopyable.

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  • Calculate posterior distribution of unknown mis-classification with PRTools in MATLAB

    - by Samuel Lampa
    I'm using the PRTools MATLAB library to train some classifiers, generating test data and testing the classifiers. I have the following details: N: Total # of test examples k: # of mis-classification for each classifier and class I want to do: Calculate and plot Bayesian posterior distributions of the unknown probabilities of mis-classification (denoted q), that is, as probability density functions over q itself (so, P(q) will be plotted over q, from 0 to 1). I have that (math formulae, not matlab code!): P(q|k,N) = Posterior * Prior / Normalization constant = P(k|q,N) * P(q|N) / P(k|N) The prior is set to 1, so I only need to calculate the posterior and normalization constant. I know that the posterior can be expressed as (where B(N,k) is the binomial coefficient): P(k|q,N) = B(N,k) * q^k * (1-q)^(N-k) ... so the Normalization constant is simply an integral of the posterior above, from 0 to 1: P(k|N) = B(N,k) * integralFromZeroToOne( q^k * (1-q)^(N-k) ) (The Binomial coefficient ( B(N,k) ) can be omitted thoughappears in both the posterior and normalization constant, so it can be omitted.) Now, I've heard that the integral for the normalization constant should be able to be calculated as a series ... something like: k!(N-k)! / (N+1)! Is that correct? (I have some lecture notes from with this series, but can't figure out if it is for the normalization constant integral, or for the posterior distribution of mis-classification (q)) Also, hints are welcome as how to practically calculate this? (factorials are easily creating truncation errors right?) ... AND, how to practically calculate the final plot (the posterior distribution over q, from 0 to 1).

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  • How do I abort a socket.recv() from another thread in python?

    - by Samuel Skånberg
    I have a main thread that waits for connection. It spawns client threads that will echo the response from the client (telnet in this case). But say that I want to close down all sockets and all threads after some time, like after 1 connection. How would I do? If I do clientSocket.close() from the main thread, it won't stop doing the recv. It will only stop if I first send something through telnet, then it will fail doing further sends and recvs. My code look like this: # Echo server program import socket from threading import Thread import time class ClientThread(Thread): def __init__(self, clientSocket): Thread.__init__(self) self.clientSocket = clientSocket def run(self): while 1: try: # It will hang here, even if I do close on the socket data = self.clientSocket.recv(1024) print "Got data: ", data self.clientSocket.send(data) except: break self.clientSocket.close() HOST = '' PORT = 6000 serverSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) serverSocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) serverSocket.bind((HOST, PORT)) serverSocket.listen(1) clientSocket, addr = serverSocket.accept() print 'Got a new connection from: ', addr clientThread = ClientThread(clientSocket) clientThread.start() time.sleep(1) # This won't make the recv in the clientThread to stop immediately, # nor will it generate an exception clientSocket.close()

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  • can these templates be made unambiguous

    - by R Samuel Klatchko
    I'm trying to create a set of overloaded templates for arrays/pointers where one template will be used when the compiler knows the size of the array and the other template will be used when it doesn't: template <typename T, size_t SZ> void moo(T (&arr)[SZ]) { ... } template <typename T> void moo(T *ptr) { ... } The problem is that when the compiler knows the size of the array, the overloads are ambiguous and the compile fails. Is there some way to resolve the ambiguity (perhaps via SFINAE) or is this just not possible.

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  • Detect if objects are loaded [Javascript]

    - by Samuel
    I was wondering, is there a way to detect if a certain image / div is loaded? For example when i am loading two heavy images and showing a loading sign at the two places the images will later occupy, is there a way to already display the first image when it's loaded while still loading the second one?

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  • Python 4 step setup with progressBars

    - by Samuel Taylor
    I'm having a problem with the code below. When I run it the progress bar will pulse for around 10 secs as meant to and then move on to downloading and will show the progress but when finished it will not move on to the next step it just locks up. import sys import time import pygtk import gtk import gobject import threading import urllib import urlparse class WorkerThread(threading.Thread): def __init__ (self, function, parent, arg = None): threading.Thread.__init__(self) self.function = function self.parent = parent self.arg = arg self.parent.still_working = True def run(self): # when does "run" get executed? self.parent.still_working = True if self.arg == None: self.function() else: self.function(self.arg) self.parent.still_working = False def stop(self): self = None class MainWindow: def __init__(self): gtk.gdk.threads_init() self.wTree = gtk.Builder() self.wTree.add_from_file("gui.glade") self.mainWindows() def mainWindows(self): self.mainWindow = self.wTree.get_object("frmMain") dic = { "on_btnNext_clicked" : self.mainWindowNext, } self.wTree.connect_signals(dic) self.mainWindow.show() self.installerStep = 0 # 0 = none, 1 = preinstall, 2 = download, 3 = install info, 4 = install #gtk.main() self.mainWindowNext() def pulse(self): self.wTree.get_object("progress").pulse() if self.still_working == False: self.mainWindowNext() return self.still_working def preinstallStep(self): self.wTree.get_object("progress").set_fraction(0) self.wTree.get_object("btnNext").set_sensitive(0) self.wTree.get_object("notebook1").set_current_page(0) self.installerStep = 1 WT = WorkerThread(self.heavyWork, self) #Would do a heavy function here like setup some thing WT.start() gobject.timeout_add(75, self.pulse) def downloadStep(self): self.wTree.get_object("progress").set_fraction(0) self.wTree.get_object("btnNext").set_sensitive(0) self.wTree.get_object("notebook1").set_current_page(0) self.installerStep = 2 urllib.urlretrieve('http://mozilla.mirrors.evolva.ro//firefox/releases/3.6.3/win32/en-US/Firefox%20Setup%203.6.3.exe', '/tmp/firefox.exe', self.updateHook) self.mainWindowNext() def updateHook(self, blocks, blockSize, totalSize): percentage = float ( blocks * blockSize ) / totalSize if percentage > 1: percentage = 1 self.wTree.get_object("progress").set_fraction(percentage) while gtk.events_pending(): gtk.main_iteration() def installInfoStep(self): self.wTree.get_object("btnNext").set_sensitive(1) self.wTree.get_object("notebook1").set_current_page(1) self.installerStep = 3 def installStep(self): self.wTree.get_object("progress").set_fraction(0) self.wTree.get_object("btnNext").set_sensitive(0) self.wTree.get_object("notebook1").set_current_page(0) self.installerStep = 4 WT = WorkerThread(self.heavyWork, self) #Would do a heavy function here like setup some thing WT.start() gobject.timeout_add(75, self.pulse) def mainWindowNext(self, widget = None): if self.installerStep == 0: self.preinstallStep() elif self.installerStep == 1: self.downloadStep() elif self.installerStep == 2: self.installInfoStep() elif self.installerStep == 3: self.installStep() elif self.installerStep == 4: sys.exit(0) def heavyWork(self): time.sleep(10) if __name__ == '__main__': MainWindow() gtk.main()

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  • How to diganose an unlogged Error 500 on Apache?

    - by samuel morhaim
    We are running a very simple Symfony script, that randomly returns an Error 500. The system administrator says he can't find any trace of an Error 500 on the error logs, however using Curl or Firebug, it is obvious that an Error 500 is being returned. The script simply parses a POST request submitted to an URL on our server. We already checked for performance, memory etc but nothing seems to be the problem. How is this possible? We already enabled all debugging, logging, on Apache, PHP, etc and nothing.

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  • capturing user identity for an online application

    - by Samuel
    We are designing an online application (college admission form) which mandates the user to upload a scanned copy of his photo along with his signature, so that this information can be used to cross verify the applicant when he appears for a exam + personal interview at a later point in time. This entire process requires a scanner for the applicant to scan his photo / signature into an appropriate size. Is there a better way to capture user identity for such purposes as usage of scanner for capturing signature, photo is a painful process.

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  • javascript: execute a bunch of asynchronous method with one callback

    - by Samuel Michelot
    I need to execute a bunch of asynchronous methods (client SQLite database), and call only one final callback. Of course, the ugly way is: execAll : function(callBack) { asynch1(function() { asynch2(function() { ... asynchN(function() { callBack(); }) }) }); } But I know there are better ways to do it. Intuitively I would detect when all call back has been called with a counter to call the final callback. I think this is a common design-pattern, so if someone could point me in the right direction... Thanks in advance !

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  • Image storage as a service

    - by Samuel
    Google App Engine provides a image API for storing / retrieving images. We are currently not in a position to deploy our application on top of App Engine because of limitations in the java frameworks (jboss seam 2.2.0) we are using to build our j2ee application. We would eventually want to deploy our production application on top of Google App Engine, but what are the short term options (java based open source products) which provides comparable functionality to Google App Engine's Image API and will have an easier migration path at a later point in time.

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  • AudioConverterConvertBuffer problem with insz error

    - by Samuel
    Hi Codegurus, I have a problem with the this function AudioConverterConvertBuffer. Basically I want to convert from this format _ streamFormat.mFormatFlags = kLinearPCMFormatFlagIsSignedInteger | kLinearPCMFormatFlagIsPacked |0 ; _streamFormat.mBitsPerChannel = 16; _streamFormat.mChannelsPerFrame = 2; _streamFormat.mBytesPerPacket = 4; _streamFormat.mBytesPerFrame = 4; _streamFormat.mFramesPerPacket = 1; _streamFormat.mSampleRate = 44100; _streamFormat.mReserved = 0; to this format _streamFormatOutput.mFormatFlags = kLinearPCMFormatFlagIsSignedInteger | kLinearPCMFormatFlagIsPacked|0 ;//| kAudioFormatFlagIsNonInterleaved |0; _streamFormatOutput.mBitsPerChannel = 16; _streamFormatOutput.mChannelsPerFrame = 1; _streamFormatOutput.mBytesPerPacket = 2; _streamFormatOutput.mBytesPerFrame = 2; _streamFormatOutput.mFramesPerPacket = 1; _streamFormatOutput.mSampleRate = 44100; _streamFormatOutput.mReserved = 0; and what i want to do is to extract an audio channel(Left channel or right channel) from an LPCM buffer based on the input format to make it mono in the output format. Some logic code to convert is as follows This is to set the channel map for PCM output file SInt32 channelMap[1] = {0}; status = AudioConverterSetProperty(converter, kAudioConverterChannelMap, sizeof(channelMap), channelMap); and this is to convert the buffer in a while loop AudioBufferList audioBufferList; CMBlockBufferRef blockBuffer; CMSampleBufferGetAudioBufferListWithRetainedBlockBuffer(sampBuffer, NULL, &audioBufferList, sizeof(audioBufferList), NULL, NULL, 0, &blockBuffer); for (int y=0; y<audioBufferList.mNumberBuffers; y++) { AudioBuffer audioBuffer = audioBufferList.mBuffers[y]; //frames = audioBuffer.mData; NSLog(@"the number of channel for buffer number %d is %d",y,audioBuffer.mNumberChannels); NSLog(@"The buffer size is %d",audioBuffer.mDataByteSize); numBytesIO = audioBuffer.mDataByteSize; convertedBuf = malloc(sizeof(char)*numBytesIO); status = AudioConverterConvertBuffer(converter, audioBuffer.mDataByteSize, audioBuffer.mData, &numBytesIO, convertedBuf); char errchar[10]; NSLog(@"status audio converter convert %d",status); if (status != 0) { NSLog(@"Fail conversion"); assert(0); } NSLog(@"Bytes converted %d",numBytesIO); status = AudioFileWriteBytes(mRecordFile, YES, countByteBuf, &numBytesIO, convertedBuf); NSLog(@"status for writebyte %d, bytes written %d",status,numBytesIO); free(convertedBuf); if (numBytesIO != audioBuffer.mDataByteSize) { NSLog(@"Something wrong in writing"); assert(0); } countByteBuf = countByteBuf + numBytesIO; But the insz problem is there... so it cant convert. I would appreciate any input Thanks in advance

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  • date representation in user interface

    - by Samuel
    Most of the sites capture the date (e.g. birth date) information as either a single entity (i.e via a calendar control) or instead as separate fields (date, month, year). Are there any benefits in showing them as separate fields? Are they represented in the database as DATE data type or as separate fields. I am just trying to understand the pros & cons of representing the date field.

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  • c99 goto past initialization

    - by R Samuel Klatchko
    While debugging a crash, I came across this issue in some code: int func() { char *p1 = malloc(...); if (p1 == NULL) goto err_exit; char *p2 = malloc(...); if (p2 == NULL) goto err_exit; ... err_exit: free(p2); free(p1); return -1; } The problem occurs when the first malloc fails. Because we jump across the initialization of p2, it contains random data and the call to free(p2) can crash. I would expect/hope that this would be treated the same way as in C++ where the compiler does not allow a goto to jump across an initialization. My question: is jumping across an initialization allowed by the standard or is this a bug in gcc's implementation of c99?

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  • Inserting rows while fetching(from another table) in SQLite

    - by Samuel
    I'm getting this error no matter what with python and sqlite. File "addbooks.py", line 77, in saveBook conn.commit() sqlite3.OperationalError: cannot commit transaction - SQL statements in progress The code looks like this: conn = sqlite3.connect(fname) cread = conn.cursor() cread.execute('''select book_text from table''') while True: row = cread.fetchone() if row is None: break .... for entry in getEntries(doc): saveBook(entry, conn) Can't do a fetchall() because table and column size are big, and the memory is scarce. What can be done without resorting to dirty tricks(as getting the rowids in memory, which would probably fit, and then selecting the rows one by one)?.

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  • Pseudo Transparant images

    - by Samuel
    Hello World! For an assignment at university we program in a pretty unknown language Modula 2, which lacks major graphic support. I was wondering how to achieve a 'transparency' effect on images, i figured it would work like this: Create a 2D array for the background area of the image filled with the colours of the different pixels in that area, create another 2D array of the image with again the colours of every picture and than merge the pixel colours and draw the different "new colours" on their appropriate place. What i was wondering about: how do i merge the colours (hexadecimals) just: ( colour1 + colour2 ) / 2 ? Thanks for your help!!

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  • Multiple Post Requests Occuring in Quick Succession

    - by Samuel
    This is a bit of an open ended question but we have a problem with a web application that on the final step of completing an order, multiple post requests are being made, sometimes up to 10 and all within a couple of seconds to the page. Theirs nothing unusual about the page, the user fills out a form which is then validated using the jQuery form validation plugin. We've seen this behavior exhibited over a couple of different browser types, notably IE6 but also IE8. We've also managed to trigger the bug ourselves but nothing out of the ordinary seems to occur on the browsers end, everything progresses as normal. Apache logs show that multiple post requests where made at the same time and the Rails logs show that multiple posts requests were also received by the application, leading me to think it's a problem with the browser. I've exhausted all avenues that I can think of for debugging so I'm throwing this out there to see if anyone has some ideas of what we could try or look for next.

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