August 2006 - Boost-users - lists.preview.boost.org

[BGL] Maps as vectors x parameterized maps
by Leandro Melo 18 Aug '06

18 Aug '06

Hi! Some of boost algorithms require a vertex_index_map. Since I'm not very familiar with bgl, I don't know if there're any which also require an edge_index_map. If the algorithms were parametrized by the above maps, we could use vectors indexed by the the values in this maps to create capacity_maps, distance_maps, weight_maps and any other maps required by the algorithm (however, to maintain the same level of flexibility we would have to allow the users to parameterize the value types of this vectors). And we would still have constant time access to the maps (like the default boost map implementations in the algorithms). Just for a matter of curiosity, what are advantages between using boost's strategy and the one I described above (in which all maps would be vectors)? The major benefit I can see on boost's current strategy is flexibility. The user can use any map implementation he/she wants (maybe this maps comes from legacy applications). There's also the possibility of implementing readable and writable maps. What are others advantages? And what could be the drawbacks of using this vector aproach? Thanks. -- Leandro Terra C. Melo

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[BGL]container traits
by Louis Lavery 18 Aug '06

18 Aug '06

Would it be much easier to implement the boost graph lib if C++ containers could reference themselves? I mean if something like std::list_traits<T> was available so that the iterator class could be got without instantiating the actual list. Simplistically, some thing like... struct vertex; struct edge; typedef std::list_traits<vertex>::iterator Vit; typedef std::list_traits<edge>::iterator Eit; struct edge { Vit source; Vit target; }; struct vertex { std::list<Eit> edges; }; I'm asking because container traits seem to be useful in the work I do, so I'm trying to garner support for them. Thanks, Louis.

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matrix<double> initialization
by Minkoo Seo 18 Aug '06

18 Aug '06

Hi list. I got a problem of matrix initialization. Please see the following code: #include <iostream> #include <iterator> #include <boost/numeric/ublas/matrix.hpp> #include <boost/numeric/ublas/io.hpp> using namespace std; using namespace boost::numeric::ublas; int main () { matrix<double> m(3, 3); for (unsigned i = 0; i < 3; i++) m(i, i) = -i; cout << m << endl; return EXIT_SUCCESS; } In this code, I'm trying to initialize the diagonal with -1, -2, -3. But, the result is obviously different from what I expected: [3,3]((0,0,0),(0,4.29497e+09,0),(0,0,4.29497e+09)) This must be due to type conversion from unsigned from double that occurs at 'm(i, i) = -i'. IMHO, the code must works as follows i // unsigned -i // (-1) * i = int * unsigned = int m(i, i) = -i // lhs is double, so int on rhs should be converted // into double. But the result implies that I'm wrong. Anybody knows what I'm missing here? How would you correct the above code? Sincerely, Minkoo Seo

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Re: [Boost-users] matrix<double> initialization
by james.jones＠firstinvestors.com 18 Aug '06

18 Aug '06

From: Minkoo Seo <minkoo.seo(a)gmail.com> [code snipped] > for (unsigned i = 0; i < 3; i++) > m(i, i) = -i; > > In this code, I'm trying to initialize the diagonal with > -1, -2, -3. But, the result is obviously different from > what I expected: > > [3,3]((0,0,0),(0,4.29497e+09,0),(0,0,4.29497e+09)) If you must use unsigned, then change to: m(i, i) = -1.0 * static_cast<double>(i); What it's doing now is this: i = 1; -i = 4294967295; // it's unsigned, after all double(-i) = 4.295e+9 Probably clearer to use int instead of unsigned, though. - James Jones Administrative Data Mgmt. Webmaster 375 Raritan Center Pkwy, Suite A Data Architect Edison, NJ 08837

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[Asio]How to solve the link wrongs in Mingw ?
by SP Z 18 Aug '06

18 Aug '06

Sorry,this is a beginner question, Maybe waste your time here :) When I build the examples of tutorial asio 0.37 in Mingw , the compiler tell me " undefined reference to `WinMain@16'" at the last step. I try google anywhere ,but still can't the right way. the wrong messages $ bjam -sTOOLS=mingw ...found 1176 targets... ...updating 12 targets... gcc-Link-action ..\..\..\..\bin\boost\libs\asio\example\tutorial\timer1.exe\mingw\debug\threading-multi\timer1.exe F:/job/environment/mingw/mingw/bin/../lib/gcc/i686-pc-mingw32/3.4.2/../../../libmingw32.a(main.o):main.c:(.text+0x106): undefined reference to `WinMain@16' collect2: ld returned 1 exit status "g++" "-Wl,--enable-auto-image-base" -g -mthreads -Wl,--allow-multiple-definition -mno-cygwin -o "..\..\..\..\bin\boost\libs\asio\example\tutorial\timer1.exe\mingw\debug\threading-multi\timer1.exe" -L"../../../../bin/boost/libs/thread/build/libboost_thread.lib/mingw/debug/threading-multi" -L"" "..\..\..\..\bin\boost\libs\asio\example\tutorial\timer1.exe\mingw\debug\threading-multi\timer.obj" "..\..\..\..\bin\boost\libs\thread\build\libboost_thread.lib\mingw\debug\threading-multi\libboost_thread-mgw-mt-d-1_33_1.lib" "..\..\..\..\bin\boost\libs\thread\build\libboost_thread.lib\mingw\debug\threading-multi\libboost_thread-mgw-mt-d-1_33_1.lib" -lws2_32 -lmswsock and so on........ --

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[Boost.Test] How to handle std::valarray<> w/ BOOST_CHECK or BOOST_CHECK_EQUAL
by Marc Viala 18 Aug '06

18 Aug '06

Hello, I am using the Boost.Test framework, but I not able to use std::valarray<> with BOOST_CHECK or BOOST_CHECK_EQUAL macro. For example: <\code> static void print_valarray(std::ostream& os, std::valarray<double> const& v) { // TODO } namespace std { std::ostream& operator<< (std::ostream& os, std::valarray<double> const& v) { print_valarray(os, v) ; return os ; } } ; std::valarray<double> v(10) ; BOOST_CHECK_EQUAL(v, v); <\code> Failed with the following compilation error: c:\Dev\MViala\ADV\Library\boost-1_33_1\boost\test\predicate_result.hpp(51): error C2664: 'boost::test_tools::predicate_result::readonly_property57::readonly_property57(const boost::test_tools::predicate_result::readonly_property57::write_param_t)' : impossible de convertir le paramètre 1 de 'std::_Boolarray' en 'const boost::test_tools::predicate_result::readonly_property57::write_param_t' Configuration: Platform: Win32 Compiler: Microsoft Visual C++ version 7.1 STL : Dinkumware standard library version 313 Boost : 1.33.1 Any help will be appreciated... Marc Viala

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Vacation Days
by Clarke, Carus V 17 Aug '06

17 Aug '06

Matt, My son has an audition with the Tacoma Youth Symphony tomorrow and needs me to provide transportation. Therefore, I will need to take one day of vacation to do this. Also, he has a college visit scheduled in Portland next Wednesday, August 23, and I will have to take another day of vacation to take him. Thanks, Carus V. (Bud) Clarke carus.v.clarke(a)boeing.com

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Building boost for 64-bit on AIX
by Patrik Jonsson 17 Aug '06

17 Aug '06

Hi, I'm trying to build boost (1.32.0) on an IBM SP2 under AIX5, using the 64-bit ABI. This is troublesome. I do: bjam "-sTOOLS=gcc" "-sGXX=g++ -maix64 -pthread" --prefix=$HOME --libdir=$HOME/lib64-gcc --includedir=$HOME/include-gcc install But it doesn't work. I get loads of errors like: gcc-Link-action bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/libboost_date_time-gcc-d-1_32.so ld: 0711-738 ERROR: Input file bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/greg_month.o: XCOFF32 object files are not allowed in 64-bit mode. collect2: ld returned 8 exit status set -e LIBPATH=bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true:$LIBPATH export LIBPATH "g++" -maix64 -pthread -g -fPIC -shared -o "bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/libboost_date_time-gcc-d-1_32.so" "bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/greg_month.o" "bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/greg_weekday.o" "bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/date_generators.o" ...failed gcc-Link-action bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/libboost_date_time-gcc-d-1_32.so... ...skipped <@boost!lib64-gcc>libboost_date_time-gcc-d-1_32.so for lack of <@boost!libs!date_time!build/libboost_date_time.so/gcc/debug/shared-linkable-true>libboost_date_time-gcc-d-1_32.so... It seems it's using -maix64 ok when trying to build the library, but not when compiling... Can anyone tell me what the proper way of building boost under these conditions are? Thanks, /Patrik Jonsson

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Boost Stride/Extent useage in multi array.
by james osburn 17 Aug '06

17 Aug '06

given the following: multi_array< double, 3 > y( extents[dim3][dim2][dim1] ); what is: y.shape()[0] y.strides()[0] thanks black_13

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Re: [Boost-users] [Graph] kamada_kawai_spring_layout runs forever
by Sebi 17 Aug '06

17 Aug '06

hi chris, > I think your problem is that all your verticies are at the same > location. >> From the documentation: > > " Prior to invoking this algorithm, it is recommended that the > vertices be > placed along the vertices of a regular n-sided polygon via > circle_layout<http://www.boost.org/libs/graph/doc/circle_layout.html>. > " thank you so much, that was it. i actually read the docs, but since it says "recommended" i thought i'd rather leave it away to make things not even more complicated. i think i will suggest to have the documentation changed to "...it is required that...". lots of regards, sebastian mecklenburg

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