- Boost-users - lists.boost.org

boost bindings
by e r 06 Oct '07

06 Oct '07

i, i looked at previous posts on this topic. did not help, a suggestion would be appreciated: installed atlas version 3.6.0-20.6 /usr/lib/atlas3-test runs just fine. header cblas.h and clapack.h are in /usr/include/ which is by default in my include path. Configuration: -I/usr/local/include/boost_1_34_1 -I/usr/local/include/boost-bindings -L/usr/lib/atlas -llapack -lblas i'm trying to run the program: #include <boost/numeric/bindings/atlas/clapack.hpp> #include <boost/numeric/bindings/traits/ublas_matrix.hpp> #include <boost/numeric/bindings/traits/std_vector.hpp> // #include <atlas/cblas.h> namespace ublas = boost::numeric::ublas; namespace atlas = boost::numeric::bindings::atlas; int main() { std::size_t n = 5; ublas::matrix<double> a(n, n); // fill matrix a std::vector<int> ipiv (n); // pivot vector atlas::lu_factor (a, ipiv); // alias for getrf() atlas::lu_invert (a, ipiv); // alias for getri() return 0; }; i get the error Building target: testing_numeric_bindings Invoking: GCC C++ Linker g++ -L/usr/lib/atlas -o"testing_numeric_bindings" ./main.o -llapack -lblas ./main.o: In function `boost::numeric::bindings::atlas::detail::getrf(CBLAS_ORDER, int, int, double*, int, int*)': /usr/local/include/boost-bindings/boost/numeric/bindings/atlas/clapack_overloads.hpp:87: undefined reference to `clapack_dgetrf' ./main.o: In function `boost::numeric::bindings::atlas::detail::getri(CBLAS_ORDER, int, double*, int, int const*)': /usr/local/include/boost-bindings/boost/numeric/bindings/atlas/clapack_overloads.hpp:163: undefined reference to `clapack_dgetri' collect2: ld returned 1 exit status make: *** [testing_numeric_bindings] Error 1 make: Target `all' not remade because of errors. Build complete for project testing_numeric_bindings

2 3

ublas/matrix product/efficiently compute A * B * C
by e r 05 Oct '07

05 Oct '07

currently i do: boost_auxiliary::matrix_double D; boost::numeric::ublas::axpy_prod(A, B, D, true); boost::numeric::ublas::axpy_prod(D, C, D, true); there must be a better way? A * B * C generates an ambiguous overloaded operator* message (ambiguous with element-wise product, i read). pls help.

1 0

[interprocess] - Usage of boost::interprocess::open_or_create mode
by Srinivas Gardas 05 Oct '07

05 Oct '07

Hi, I am quite new to boost. Are there any code examples around usage of 'open_or_create' mode for ceating the shared_memory_object? My problem is, after we create a 'shared_memory_object' using 'open_or_create' there is no way to know whether it created 'created' a file or 'opened' an already existing file. We need this apparently, because if we are creating a new file, we have to '*construct<container>("MySharedMemory") *' the file with the desired container, otherwise we have to '* find<container>("MySharedMemory")*'. All the usage examples I could get were only around 'create_only' and then 'open_only' modes.. My idea is to write one single method, that'd use the 'open_or_create' mode so that we don't have to bother.. a sequence of creation and then usage.. I am not sure if I was clear enough in putting my problem across, please feel free to respond with questions. Really appreciate any help around this. Thanks & Regards, Srinivas Gardas

2 1

[random] getting a 50% probability generator
by Jeffrey Holle 05 Oct '07

05 Oct '07

I am at the point in my application where I must introduce randomness to a sort routine. Basically when 2 elements are equal, I need to create a 50% probability that they will be swapped. What is the correct boost::random library resource to code this? I've attempted to use uniform_01, by creating an instance of it with this type: typedef boost::uniform_01<boost::minstd_rand, double> rand_gen_t; However, after getting it constructed as a class attribute, I find accessing it with: cout << (*pRand_gen++) << endl; It produces numbers like 1 134784888 134784288 2 134784845 134784224 134785176 5 0 134784376 134785328 0. What I want is a sequence like 0 1 0 1 0 1 0 0 0 1 1 1 1 0 1 0 1 that is sort of random.

4 5

[boost-users] enable_if on boost::operators compile error on visual c++.
by chun ping wang 05 Oct '07

05 Oct '07

Given this code which is suggested by David Abraham.... template <class T, class U> char (& is_op_test(boost::operators<T,U> const&) )[2]; template <class T> char is_op_test(T const&); template<class T> T const& make(); template <class T> struct is_operators : boost::mpl::bool_<(sizeof(is_op_test(make<T>())) == 2)> {}; and this function declaration. template <typename T, template <typename ELEM, typename = std::allocator<ELEM> > class CONT > typename boost::enable_if<boost::mpl::or_<boost::is_integral<T>, boost::is_operators<T> >, CONT<T> >::type primelist(const T& MAX_BOUND, const T& K, boost::function<bool(const T&, const T&)> f); I compile with T = int and it works. When i compile with T = BigInteger I get the following errors. ./cs512/c++/primeMain.cpp(78) : error C2770: invalid explicit template argument(s) for 'boost::enable_if<boost::mpl::or_<boost::is_integral<T>,boost::is_operators<T> >,CONT<T>>::type primelist(const T &,const T &,boost::function<bool(const T &,const T &)>)' ./cs512/c++/primeMain.cpp(24) : see declaration of 'primelist'" BigInteger class declaration looks like this.. class BigInteger : public BigUnsigned, boost::operators<BigInteger>, boost::operators<BigInteger, int> { }; thanks for the help.

1 0

lexical_cast
by Peter Sliepenbeek 05 Oct '07

05 Oct '07

Hi all, The test below fails: #include <iostream> #include <boost/lexical_cast.hpp> int main(int argc, char* argv[]) { std::string s; try { double d = std::numeric_limits <double> ::max(); s = boost::lexical_cast <std::string> (d); } catch (const boost::bad_lexical_cast&) { std::cout << "double to std::string fails" << std::endl; } try { double dd = boost::lexical_cast <double> (s); } catch (const boost::bad_lexical_cast&) { std::cout << "std::string to double fails" << std::endl; } return 0; } To solve this issue I propose to alter the line "stream.precision(std::numeric_limits<Target>::digits10 + 1" in the constructor for lexical_stream into "stream.precision(std::numeric_limits<Target>::digits10 - 1". Regards, P. Sliepenbeek --------------------------------- Be a better Heartthrob. Get better relationship answers from someone who knows. Yahoo! Answers - Check it out.

2 1

[Boost.FileSystem] File or Wildcards in Path? How-to do this?
by Lawrence Spector 05 Oct '07

05 Oct '07

Here's a simple example. Is there a way to do achieve this effect? std::string folderName = "C:\\*.sys"; boost::filesystem::path fsDirectoryPath = boost::filesystem::system_complete( boost::filesystem::path(folderName, boost::filesystem::native)); boost::filesystem::directory_iterator end_iter; for (boost::filesystem::directory_iterator dir_itr(fsDirectoryPath); dir_itr != end_iter; ++dir_itr) // throws exception { std::cout << "Contains the following file: " << dir_itr->string() << std::endl; } // end for When I do this, I get the following exception: boost::filesystem::basic_directory_iterator constructor I don't see any documentation for how to narrow your searches with wildcards or how to only find files that match a particular file name. Am I missing something? Obviously you can refine your search later in the loop, but that is inefficient. Please let me know. Thanks, Lawrence

3 6

A tuple performance question
by Peng Yu 05 Oct '07

05 Oct '07

Hi, It is mentioned at http://www.boost.org/libs/tuple/doc/tuple_users_guide.html#performance that the following two ways would be different in term of performance. ////////////// void f1(int&, double&); tuple<int, double> f2(); //Then, the call #1 may be slightly faster than #2 in the code below: int i; double d; ... f1(i,d); // #1 tie(i,d) = f2(); // #2 /////////////////// What about the current commonly used compiler, such as GCC? Are #1 and #2 different in GCC? Does the compiler always have some way to optimize #2 to make it as good as #1? Is it just a matter of fact whether the optimization method is implemented? Or #2 can never be made as good as #1? Thanks, Peng

7 15

Any way to work around missing <locale> under Windows CE ?
by luper rouch 05 Oct '07

05 Oct '07

The standard <locale> include file is not shipped with the windows CE/mobile sdks, and therefore lots of boost parts are unusable. Is there a way to work around this problem in boost ? Luper Rouch

4 3

[interprocess]failed to build doc
by Sean Huang 05 Oct '07

05 Oct '07

Has anybody had any success in building doc for interprocess (trunk version). Doxygen 1.5.3 crashed and I switched to 1.4.7 but I'm still getting the following errors: xslt-xsltproc .\..\..\bin.v2\libs\interprocess\doc\msvc-8.0\debug\threading-multi\autodoc -xml.boostbook warning: failed to load external entity "Reference" cannot parse Reference set XML_CATALOG_FILES=..\..\..\bin.v2/boostbook_catalog.xml "xsltproc.exe" --stringparam boost.doxygen.refid " "reference"" --stringparam boost.doxygen.reftitle ""Boost.Interprocess Reference"" --xinclude -o "..\..\..\bin.v2\libs\interprocess\doc\msvc-8.0\debug\threading-multi\autodo c-xml.boostbook" "boost\boost\tools\boostbook\xsl\doxygen\doxygen2boostbook.xsl" "..\..\..\bin.v2\libs\interprocess\doc\msvc-8.0\debug\threading-multi\autodo c-xml.doxygen" ..failed xslt-xsltproc .\..\..\bin.v2\libs\interprocess\doc\msvc-8.0\debug\threading-multi\autodoc -xml.boostbook... ..skipped <p.>autodoc.xml for lack of <p..\..\..\bin.v2\libs\interprocess\doc\msvc-8.0\debug\threading-multi>autod oc-xml.boostbook... ..skipped <p..\..\..\bin.v2\libs\interprocess\doc\msvc-8.0\debug\threading-multi>inter process.docbook for lack of <p.>a utodoc.xml... ..skipped <phtml>standalone_HTML.manifest for lack of <p..\..\..\bin.v2\libs\interprocess\doc\msvc-8.0\debug\threading- multi>interprocess.docbook... ..failed updating 1 target... ..skipped 3 targets... Thanks, Sean

2 2