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Search found 1973 results on 79 pages for 'boost spirit qi'.

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  • how to instantiate template of template

    - by aaa
    hello I have template that looks like this: 100 template<size_t A0, size_t A1, size_t A2, size_t A3> 101 struct mask { 103 template<size_t B0, size_t B1, size_t B2, size_t B3> 104 struct compare { 105 static const bool value = (A0 == B0 && A1 == B1 && A2 == B2 && A3 == B3); 106 }; 107 }; ... 120 const typename boost::enable_if_c< 121 mask<a,b,c,d>::compare<2,3,0,1>::value || ...>::type I am trying to instantiate compare structure. How do I do get value in line 121?

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  • how to handle delete by illegal address

    - by Davit Siradeghyan
    Suppose we have a situation like this. How to handle this problem? How to protect code from crashes? I know about and use boost smart pointers. But what to do if we have this situation. struct Test { int a; int b; int c; }; Test global; int main() { Test *p = new Test; p->a = 1; p->b = 2; p->c = 3; p = &global; delete p; return 0; }

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  • Java Concurrency: CAS vs Locking

    - by Hugo Walker
    Im currently reading the Book Java Concurrency in Practice. In the Chapter 15 they are speaking about the Nonblocking algorithms and the compare-and-swap (CAS) Method. It is written that the CAS perform much better than the Locking Methods. I want to ask the people which already worked with both of this concepts and would like to hear when you are preferring which of these concept? Is it really so much faster? Personally for me the usage of Locks is much clearer and easier to understand and maybe even better to maintain. (Please correct me if I am wrong). Should we really focus creating our concurrent code related on CAS than Locks to get a better performance boost or is sustainability a higher thing? I know there is maybe not a strict rule, when to use what. But I just would like to hear some opinions, experiences with the new concept of CAS.

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  • Gap after table in LaTex

    - by Tim
    Hi, I notice that there is some gap after my table. See the following snapshot: http://i42.tinypic.com/23rkdn6.jpg My Latex code is: \begin{table}[htb] \caption{Error rates VS training size in AdaBoosted stump, SVM and kNN. \label{tab:examplecount8000errerrplot}} \begin{center} \begin{tabular}{c c} \includegraphics[scale=0.4]{../boost.eps} & \includegraphics[scale=0.4]{../svm.eps} \\ \includegraphics[scale=0.4]{../knn.eps} & \\ \end{tabular} \end{center} \end{table} % \subsection{Feature Numbers} Is the gap normal or How can I reduce the gap to be normal? Thanks and regards!

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  • What's the next big thing after LINQ?

    - by Leniel Macaferi
    I started using LINQ (Language Integrated Query) when it was still in beta, more specifically Microsoft .NET LINQ Preview (May 2006). Almost 4 years have passed and here we are using LINQ in a lot of projects for the most diverse tasks. I even wrote my final college project based on LINQ. You see how I like it. LINQ and more recently PLINQ (Parallel LINQ) give our jobs a great boost when it comes to more programming power and less lines of code leading us to more expressive and readable code. I keep thinking what could be the next big language improvement for C# after LINQ. I know there are some promissing language features coming as Code Contracts, etc, but nothing having the impact that LINQ had. What do you think could be the next big thing?

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  • Umbraco or ASP.NET MVC

    - by StupidBoy
    I'm about to create a site that will act as public front site of company that sells furniture, but after user log in, he'll see much more options. Internal news, files to download, customized pricings, newsletters, etc. - stuff for wholesale clients. I want to make it quickly and maintain/extend it easily. I'm asp.net developer and while I could write it in python, php, whatever else (I know these too), I still prefer asp.net. I was thinking about umbraco, since it gives a real productivity boost and that I familiar with it ( and extending it). I've had a short romance with ASP.NET MVC, so I know what it's all about, but I would still spend some time learning it (but what a fun!). Of course, there's also webforms, but that's my last choice here. Last but not least to mention is the SEO. The question is, have anyone of you had similiar dilemma and what was your final choice?

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  • Intersections of 3D polygons in python

    - by Andrew Walker
    Are there any open source tools or libraries (ideally in python) that are available for performing lots of intersections with 3D geometry read from an ESRI shapefile? Most of the tests will be simple line segments vs polygons. I've looked into OGR 1.7.1 / GEOS 3.2.0, and whilst it loads the data correctly, the resulting intersections aren't correct, and most of the other tools available seem to build on this work. Whilst CGAL would have been an alternative, it's license isn't suitable. The Boost generic geometry library looks fantastic, but the api is huge, and doesn't seem to support wkt or wkb readers out of the box.

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  • C++: posix regex error reporting?

    - by Helltone
    I'm writing a small C++ program that parses some strings. I chose to use C's regex.h because I only need POSIX Extended Syntax and I'm concerned with portability. However, I've just noticed that when regexec fails to match, it returns != 0 and I have no idea of what was wrong :-(. I expected to be able to display at least a small message like: line:col: Syntax error or giig sdoigosdigo* sodfg ^ Syntax error Is there a way to know which character did not match? Should I use boost:regex instead? For reference, my regex is: "^" "[ ;\t\n]*" "(" // (1) identifier "[a-zA-Z_][a-zA-Z0-9_]*" ")" "[ \t]*" "(" // (2) non-marking "\[" "(" // (3) non-marking "[ \t]*" "(" // (4..n-1) argument "[a-zA-Z0-9_]+" ")" "[ \t]*" "," ")*" "[ \t]*" "(" // (n) last argument "[a-zA-Z0-9_]+" ")" "]" ")?" "[ \t\n]*" ";" Which matches for instance blablabla[arg1, arg2];

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  • Memory leak using shared_ptr

    - by nabulke
    Both code examples compile and run without problems. Using the second variant results in a memory leak. Any ideas why? Thanks in advance for any help. Variant 1: typedef boost::shared_ptr<ParameterTabelle> SpParameterTabelle; struct ParTabSpalteData { ParTabSpalteData(const SpParameterTabelle& tabelle, const string& id) :Tabelle(tabelle), Id(id) { } const SpParameterTabelle& Tabelle; string Id; }; Variant 2: struct ParTabSpalteData { ParTabSpalteData(const SpParameterTabelle& tabelle, const string& id) :Id(id) { // causes memory leak Tabelle2 = tabelle; } SpParameterTabelle Tabelle2; string Id; };

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  • QPluginLoader with PyQt modules as plugins: possible?

    - by Thorfin
    Hi! I have a C++ application that loads externals plugins thanks to QPluginloader. QPluginLoader provides access to a Qt plugin. A Qt plugin is stored in a shared library (a DLL). The plugins have to inherit from a pure virtual class ( and Q_DECLARE_INTERFACE ) and QObject. I would like to create plugins by using python and PyQt. Is this possible without too much work? For instance if I have to convert the modules to C++ with boost::python, this could be nonsense, as PyQt is already a conversion from C++ to Python... Thanks!

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  • Laws of Computer Science and Programming

    - by Jonas
    We have Amdahl's law that basically states that if your program is 10% sequential you can get a maximum 10x performance boost by parallelizing your application. Another one is Wadler's law which states that In any language design, the total time spent discussing a feature in this list is proportional to two raised to the power of its position. 0. Semantics 1. Syntax 2. Lexical syntax 3. Lexical syntax of comments My question is this: What are the most important (or at least significant / funny but true / sad but true) laws of Computer Science and programming? I want named laws, and not random theorems, So an answer should look something like Surname's (law|theorem|conjecture|corollary...) Please state the law in your answer, and not only a link. Edit: The name of the law does not need to contain it's inventors surname. But I do want to know who stated (and perhaps proved) the law

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  • Virtual Earth Shape Rendering Performance

    - by Mike
    I am overlaying a transparent image on my VEMap control by rendering it as a single VEShape. The shape changes sizes dynamically depeding on the zoom level of my map and can be as large as 4000*4000px. In older browsers such as IE6 and early versions of Firefox 2.x, map control performance degrades rapidly when my shape gets larger than 1500*1500px. The mouse pointer moves slowly and the map responds very slowly to events. I don't see this issue at all in newer browsers (IE7+). Are there any workarounds to boost performance of rendering a large shape for IE6 users?

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  • Is this a good code (came across while reading code of a colleague)

    - by eriks
    // file a.hpp class a; typedef boost::shared_ptr<a> aPtr class a{ public: static aPtr CreateImp(); virtual void Foo() = 0 ; .... }; //file aImp.hpp class aImp : public a{ virtual void Foo(); }; //file aImp.cpp aPtr a::CreateImp() { return aPtr(new aImp()); } void aImp::Foo(){} The client must use CreateImp to get ptr to 'a', and can't use 'a' other ways. What do you think about this implementation? what do you think about this king of implementation?

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  • What are the pro and cons of statically linking a library?

    - by Mathieu Pagé
    Hi, I want to release an application I developed as a hobby both for Linux and Windows. This application depends on boost (and possibly other libraries). The norm for this kind of application (a chess engine) is to provide only an executable file and possibly some helper files. I tough it would be a good idea to statically link the libraries so the executable would not have any dependencies. So the end user can just put the executable in a directory and start using it. However, while doing some research online I found some negative comments about statically linking libraries, some even arguing that an application with statically linked libraries would be hardly portable, meaning that it would only run on my system of highly similar systems. So what are the pros and cons of statically linking library? I already know that the executable will be bigger. But I can't see why it would make my application less portable.

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  • Custom iterator for a class based on two sets

    - by Dan Hook
    I have a class that contains two sets. They both contain the same key type but have different compare operations. I would like to provide an iterator for the class that iterates through the elements of both sets. I want to start with one set, then when I increment an iterator pointing to the last element of the first set, I want to go to the first element of the second set. How do I do this? I would like to preserve the bidirectional iterator semantics of std::set, but if it turns out that implementing a forward iterator is much easier, so be it. I'm willing to use the Boost Iterator library if that would help.

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  • OpenCV, Python (ctypes), and OS X 10.5: dylib errors/confusion

    - by Jeff
    I have tried two brands of ctypes (ctypes-opencv and another) wrappers for OpenCV (2.0 from svn head), can use Python and OpenCV in the Python console, but whenever I try to import the packages (from ctypes_opencv import *) from another Python file, I get the following error message: OSError: dlopen(/usr/local/lib/libcv.dylib, 6): Symbol not found: __ZN2cv10fastMallocEm Referenced from: /usr/local/lib/libcv.dylib Expected in: flat namespace And some more Python errors: module body in __init__.py at line 18 from ctypes_opencv.cxcore import * module body in cxcore.py at line 80 _cxDLL, _cvDLL, _hgDLL = detect_opencv() function detect_opencv in cxcore.py at line 59 cvDLL = cdll.LoadLibrary(find_lib('cv')) function LoadLibrary in __init__.py at line 431 return self._dlltype(name) function __init__ in __init__.py at line 353 self._handle = _dlopen(self._name, mode) I most recently built OpenCV using flags the ctypes_opencv wiki recommended: ENABLE_SSE(2) OFF and BUILD_NEW_PYTHON_SUPPORT OFF. I've tried a number of flag combinations though. I also tried using the MacPorts install of OpenCV, got the same messages, uninstalled it, and now it errors out as well. :P And if that wasn't enough, I tried using the latest ctypes wrapper, but get boost-jam errors. Any help would be very much appreciated.

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  • console windows not close after stopping program

    - by robUK
    Hello, Visual Studio 2005 C++ Windows XP Pro I have a sample application that I am testing, that links with boost libraries. However, the program runs ok. However, when I try and stop the program by clicking the 'Stop Debugging' button. The program ends, but the console window remains open. So I have many of them, as during my testing I am starting and stopping the application. Even when I try and close it by clicking the close button it has no affect. And it doesn't seem to appear under task manager when the program ends. The only way I can close them if I reboot windows. I am thinking it might be a thread that has not closed, and maybe that is keeping the console windows open. Many thanks for any advice,

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  • Expression Tree

    - by nettguy
    My understanding of expression tree is : Expression trees are in-memory representation of expression like arithmetic or boolean expression.The expressions are stored into the parsed tree.so we can easily transalate into any other language. Linq to SQL uses expression tree.Normally in LINQ to SQL query the compiler translates it into parsed expression trees.These are passed to Sql Server as T-SQL Statements.The Sql server executes the T-SQL query and sends down the result back.That is why when you execute LINQ to SQL you gets IQueryable<T> not IEnumetrable<T>.Because IQuerybale contains public IQueryable:IEnumerable { Type Element {get;} Expression Expression {get;} IQueryaleProvider Provider {get;} } Questions : Microsoft uses Expression trees to play with LINQ-to-Sql.What are the different ways can i use expression trees to boost my code. Apart from LINQ to SQL,Linq to amazon ,who used expression trees in their applications? Linq to Object return IEnumerable,Linq to SQL return IQueryable ,What does LINQ to XML return?

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  • Inverted index in a search engine

    - by Ayman
    Hello there, I'm trying to write some code to make a small application for searching text from files. Files should be crawled, and I need to put an inverted index to boost searches. My problem is that I kind of have ideas about how the parser would be, I'm willing to implement the AND, NOT, OR in the query. Whereas, I couldn't figure out how my index should be... I have never created an inverted index so if any body could suggest a feasable way to do it I would be very grateful... I do know in theory how it works but my problem is I absolutely have no idea to make happen in MySql I need to give keywords being indexed a weight too... Thank you so much.

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  • How can I refactor this to use an inline function or template instead of a macro?

    - by BillyONeal
    Hello, everyone :) I have a useful macro here: #define PATH_PREFIX_RESOLVE(path, prefix, environment) \ if (boost::algorithm::istarts_with(path, prefix)) { \ ExpandEnvironmentStringsW(environment, buffer, MAX_PATH); \ path.replace(0, (sizeof(prefix)/sizeof(wchar_t)) - 1, buffer); \ if (Exists(path)) return path; \ } It's used about 6 times within the scope of a single function (that's it), but macros seem to have "bad karma" :P Anyway, the problem here is the sizeof(prefix) part of the macro. If I just replace this with a function taking a const wchar_t[], then the sizeof() will fail to deliver expected results. Simply adding a size member doesn't really solve the problem either. Making the user supply the size of the constant literal also results in a mess of duplicated constants at the call site. Any ideas on this one?

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  • FOX toolkit, file concatentation

    - by Robb
    I'm using the FOX Toolkit and C++ to develop a GUI. I'm Having an issue with the FXFile::concat(...) command. The method looks like: FXFile::concat(const FXString & srcfile1, const FXString & srcfile2, const FXString & dstfile, FXbool overwrite = false And when I call it with the srcfile1 and dstfile being the same thing (because I need to simply add to srcfile1), the method does not work. dstfile is empty. Anyone have experience with FOX and this concatentation problem? I'm open to other suggestions as well, including boost.

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  • Algorithm - Pick the best combination of Armor (for a game)

    - by Chu
    I'm designing a piece of a game where the AI needs to determine which combination of armor will give the best overall stat bonus to the character. Each character will have about 10 stats, of which only 3-4 are important, and of those important ones, a few will be more important than the others. Armor will also give a boost to 1 or all stats. For example, a shirt might give +4 to the character's int and +2 stamina while at the same time, a pair of pants may have +7 strength and nothing else. So let's say that a character has a healthy choice of armor to use (5 pairs of pants, 5 pairs of gloves, etc.) We've designated that Int and Perception are the most important stats for this character. How could I write an algorithm that would determine which combination of armor and items would result in the highest of any given stat (say in this example Int and Perception)?

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  • Random noise in Solr score

    - by Andrea Campi
    I am looking for a way of introducing random noise into my scoring function, and I'm at a loss on how to best proceed. Some background: We use Solr for a web application that manages large-ish sets of photos for agencies. One customer has an interesting requirement for scoring: 'quality' field, maintained by editors, from 1 (highest) to 3 (lowest); 'date' field, boosting more recent photos; I would probably use a logarithmic function; However, due to how the stock photo market works, this will likely result in many similar photos appearing together. Their request is to give 'quality' a large boost, but introduce some randomness so that photos will not appear in a strict date order. Any idea? EDITED: a key requirement is to have "stable" query results: if I search twice for "tropical island" I can get a slightly different result set, but if I ask for the first page, then the second, then the first, I'd better get the same results :)

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  • C++ 'mutable' keyword

    - by Rob
    A while ago I came across some code that marked a member variable of a class with the 'mutable' keyword. As far as I can see it simply allows you to modify a variable in a 'const' method: class Foo { private: mutable bool done_; public: void doSomething() const { ...; done_ = true; } }; Is this the only use of this keyword or is there more to it than meets the eye? I have since used this technique in a class, marking a boost::mutex as mutable allowing const functions to lock it for thread-safety reasons, but, to be honest, it feels like a bit of a hack.

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  • Toubleshooting mapkit performance

    - by brettr
    I'm plotting over 500 points on a map using mapkit. Zooming is a little jittery compared to the native google map app. I've discovered what is causing the slowness. I'm adding custom annotations so that I can later add different pin colors and buttons for detail views: - (MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(AddressNote *) annotation { MKPinAnnotationView *annView=[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"currentlocation"]; annView.pinColor = MKPinAnnotationColorGreen; annView.animatesDrop=TRUE; annView.canShowCallout = YES; annView.calloutOffset = CGPointMake(-5, 5); return annView; } If I comment out the above code, everything works fine. Very smooth with zooming in/out. Should I be adding annotations differently to boost performance?

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