October 2002 - Boost-users - lists.boost.org

are examples on maual page ready to run?
by J-S Lin 25 Oct '02

25 Oct '02

I just download boost and tried to get a hang of it by running examples out of the doc page. But I am not sure if these examples are ready to run or simply like a pseudo-code? A point in the case: This simple matrix example int main () { using namespace boost::numeric::ublas; matrix<double> m (3, 3); for (int i = 0; i < m.size1 (); ++ i) for (int j = 0; j < m.size2 (); ++ j) m (i, j) = 3 * i + j; std::cout << m << std::endl; } I copied it and added the following includes: #include <boost/numeric/ublas/matrix.hpp> #include <iostream> But the compiler (VC7) flag an error on cout. So is this line " std::cout << m << std::endl;" supposed to work, or it is a pseudo-code. Thanks. J-S Lin

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How do I use boost::multi_array with a templated argument?
by Björn Lindberg 25 Oct '02

25 Oct '02

I cannot get the code below to compile with g++-3.2 on GNU/Linux. The error message is: exempel.cpp: In member function `void functor<T>::operator()() [with T = P]': exempel.cpp:26: instantiated from here exempel.cpp:18: `nodetab' has incomplete type exempel.cpp:18: confused by earlier errors, bailing out Since everything is visible at compile time, I can't understand why I'm getting this error message, or what to do about it. ------------- #include <boost/multi_array.hpp> struct P {}; template<typename T> struct functor { typedef boost::multi_array<T, 3> table_t; typedef typename table_t::array_view<2>::type nodetab_t; typedef typename table_t::index_range range; void operator()() { table_t table(boost::extents[5][6][7]); nodetab_t nodetab = table[boost::indices[1][range()][range()]]; } }; int main() { functor<P> vis; vis(); return 0; } ------------- Björn

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Borland 6 Graph example 1
by chongwhite001 25 Oct '02

25 Oct '02

Hi All, I am attempting to run the 1st example (file dependancy) of Boost Graph library with Borland C++Builder 6. It compiles ok but crashes when run in exception.hpp with a call, or rather THROW to negative_edge exception. If anyone can provide any light into this I would be most grateful. (details below) Thanks Christian _________________________________________________________ Fault occurs in: dijkstra_shortest_paths.hpp: void examine_edge(Edge e, Graph& g) { if (m_compare(get(m_weight, e), m_zero)) throw negative_edge(); m_vis.examine_edge(e, g); } The actual fault is in exception.hpp at the point: struct negative_edge : public bad_graph { negative_edge() : bad_graph("The graph may not contain an edge with negative weight."){ } }; The error is: --------------------------- Debugger Exception Notification --------------------------- Project Boost_Ex1_Console.exe raised exception class boost::negative_edge with message 'Exception Object Address: 0x896912'. Process stopped. Use Step or Run to continue. --------------------------- OK Help ---------------------------

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Fwd: uBLAS vs MTL for sparse matrices
by Paul C. Leopardi 25 Oct '02

25 Oct '02

Hi, I posted the following message to boost and have so far had no response. Maybe boost-users is the correct mailing list? Hi, Thanks to Joerg Walter's original conversion of GluCat ( http://glucat.sf.net ) to uBLAS, I have fairly painlessly been able to get GluCat going with the version of uBLAS now promoted to Boost. I'm using sparse matrices: boost::numeric::ublas::sparse_matrix< Scalar_T, boost::numeric::ublas::row_major> and comparing performance to MTL: mtl::matrix< Scalar_T, mtl::rectangle<>, mtl::compressed<>, mtl::row_major >::type The operation I'm performing is quite complicated. Basically, I am generating a large number of sparse matrices, and computing the inner product of a given matrix with each of these matrices in turn. ( If you have a copy of GluCat, see basis_element() in matrix_multi_imp.h ) Because these sparse matrices have only one non-zero per row, operations on an n x n matrix are typically O(n), and seem to be so using MTL: Size vs speed for MTL: Size Time (ms) 32 10 64 20 128 80 256 160 512 700 But with uBLAS, essentially the same operations seem to be O(n^2): Size Time (ms) Slowdown 32 30 3 64 70 3.5 128 830 10.4 256 1940 12.1 512 31770 45.4 o Is there a more appropriate data type in uBLAS? o Do you have any tips on where to tweak uBLAS to get better (ie. O(n) ) performance? o What is BOOST_UBLAS_USE_CANONICAL_ITERATOR and what effect should it have on performance? Thanks

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assign a scalar to boost::numeric::ublas::matrix?
by Michael Na Li 24 Oct '02

24 Oct '02

Hi, having tried various matrix classes, I was excited to see boost finally includes a "standard" matrix class. Thanks for the good work. I have one question, though. How do I initialize a matrix to a scalar value? There is no constructor of the form 'matrix (nr, nc, value)' nor 'matrix::operator=( T value )'. I think both would be nice to have. Michael -- ---------------------------------------------------------------------------- Michael Na Li Email: lina(a)u.washington.edu Department of Biostatistics, Box 357232 University of Washington, Seattle, WA 98195 ---------------------------------------------------------------------------

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[BUG] Macos.hpp configuration woes
by Bobby Thomale 24 Oct '02

24 Oct '02

Yesterday I was trying to help my wife get the Boost libraries to compile in her application. It reminded me of an issue I thought I brought up a while ago (maybe I forgot) that still exists in the boost Macos.hpp config file. In the MacOS.hpp file, it checks to see if you are compiling a Mach-O target. If you are, it reasons, you must be using the Apple BSD headers as well. This logic is even documented in a comment: // If __MACH__, we're using the BSD standard C library, not the MSL: #if __MACH__ The problem with this is that, starting with CW Pro 8, it is actually possible to build a Mach-O target and use the MSL in place of the BSD libraries. Lots of people are apparently doing this, including my wife. (I am still on CFM and have not made the transition to Mach-o yet, but I will eventually and I will potentially be in the same boat. The newer Carbon APIs are Mach-o only so that is where all the carbon programmers will eventually go, and as long as Codewarrior is around, MSL will be there as an option for people.) There are also people who use other STL implementations, such as STLPORT. When it defines all of the stuff it does in there, for the BSD libraries, the mach-o MSL code does not compile. Instead, I get hundreds of compile errors. The only way I could get this to compile for her was to force it to use the TARGET_CARBON stuff at the bottom, after the #else (meaning "not mach-o"), by commenting the __MACH__ stuff out. Obviously, that was a "see if this is really her problem" solution, also to get her up and running, and not a long-term fix. :-) It worked by the way. The config.hpp stuff seperates out your platform settings from your standard library settings. Is there a reason that standard library implementation-specific settings are being set by platform and binary format? If there is magic that needs to happen that is specific to Apple's BSD headers, shouldn't there maybe be a "BSD.hpp" or even "AppleBSD.hpp" for BOOST_STDLIB_CONFIG instead? Or am I missing something? Anyway. That is just a question/suggestion, take it or leave it. It makes sense that the TARGET_CARBON stuff at the bottom is platform specific, but the stuff above it seems like it should go somewhere else. In any case, whether that stuff is moved or not, something needs to change to alleviate the pain for those using Mach-o and MSL together, because right now boost is broken for those users. (Am I reporting this to the right list by the way?) -- Bobby --------------------------------------------------------------------- Bobby Thomale Senior Software Developer Inoveon Corporation http://www.inoveon.com/ ---------------------------------------------------------------------

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VC++ 6.0 ,SGI STL and Boost
by Joshua 23 Oct '02

23 Oct '02

I'm just trying to include the files for the shared_ptr class and keep having problems. I was able to fix a problem with a duplicate definition of 'max' and 'min' (in suffix.hpp, it was conflicting with a file from the SGI STL implementation) I mainly just commented it out, if someone has a better plan on how to fix it I would love to know how to fix it. I have tried Boost 1.28 and 1.29 and still got the same set of errors. In addition to the 'max' and 'min' conflict I am getting these errors : e:\programming projects\c++ projects\boost_1_28_0\boost\checked_delete.hpp(24) : error C2061: syntax error : identifier 'T' e:\programming projects\c++ projects\boost_1_28_0\boost\checked_delete.hpp(24) : error C2061: syntax error : identifier 'T' e:\programming projects\c++ projects\boost_1_28_0\boost\checked_delete.hpp(30) : error C2061: syntax error : identifier 'T' e:\programming projects\c++ projects\boost_1_28_0\boost\checked_delete.hpp(30) : error C2061: syntax error : identifier 'T' e:\programming projects\c++ projects\boost_1_28_0\boost\detail\shared_count.hpp(184) : error C2504: 'counted_base' : base class undefined e:\programming projects\c++ projects\boost_1_28_0\boost\detail\shared_count.hpp(206) : see reference to class template instantiation 'detail::counted_base_impl<P,D>' being compiled e:\programming projects\c++ projects\boost_1_28_0\boost\detail\shared_count.hpp(253) : error C2061: syntax error : identifier 'Y' e:\programming projects\c++ projects\boost_1_28_0\boost\detail\shared_count.hpp(254) : error C2065: 'Y' : undeclared identifier e:\programming projects\c++ projects\boost_1_28_0\boost\detail\shared_count.hpp(390) : fatal error C1506: unrecoverable block scoping error So I'm not sure if I'm doing something wrong (like not setting up the include order correctly) or if Microsoft is once again making my life hell. I am being bad and using the __int64 data type but I may need to rethink it and convert it to standard C++ (well sorta standard, I think gcc supports a longlong to get a 64bit int.. if not I may change it around to a bit_vector or something). But if anyone can shed some light on why I'm getting these errors listed above I'd really appreciate it. thanks. Joshua.

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VC++ 6.0 with SGI STL and Boost
by Joshua 23 Oct '02

23 Oct '02

I'm using VC++ 6.0 with the SGI implementation of the STL. I'm trying to use the shared_ptr but when I try to include the <boost/shared_ptr.hpp> file I get about 40 errors. Most are related to errors redefining template functions. Its conflicting with the SGI STL header files but I'm not sure how to fix it. I keep thinking that I need to adjust the include order (Currently the Boost files are first, the the STL, then Microsofts includes. It doesn't matter where the Boost include directory is though I still get the same errors : this is a small sample --------------------Configuration: DryDock - Win32 Debug-------------------- Compiling... AbstractComponent.cpp e:\programming projects\c++ projects\boost_1_29_0\boost\config\suffix.hpp(256) : error C2995: 'min' : template function has already been defined e:\programming projects\c++ projects\drydock\drydock\stl\stl_algobase.h(106) : see declaration of 'min' e:\programming projects\c++ projects\boost_1_29_0\boost\config\suffix.hpp(260) : error C2995: 'max' : template function has already been defined e:\programming projects\c++ projects\drydock\drydock\stl\stl_algobase.h(112) : see declaration of 'max' e:\programming projects\c++ projects\boost_1_29_0\boost\checked_delete.hpp(24) : error C2061: syntax error : identifier 'T' e:\programming projects\c++ projects\boost_1_29_0\boost\checked_delete.hpp(24) : error C2061: syntax error : identifier 'T' e:\programming projects\c++ projects\boost_1_29_0\boost\checked_delete.hpp(30) : error C2061: syntax error : identifier 'T' e:\programming projects\c++ projects\boost_1_29_0\boost\checked_delete.hpp(30) : error C2061: syntax error : identifier 'T' e:\programming projects\c++ projects\boost_1_29_0\boost\detail\shared_count.hpp(213) : error C2504: 'counted_base' : base class undefined e:\programming projects\c++ projects\boost_1_29_0\boost\detail\shared_count.hpp(235) : see reference to class template instantiation 'detail::counted_base_impl<P,D>' being compiled And it goes on like that to a grand total of 40 errors. I know its probably just something like the order of the includes or I need to add something to specify the namespace correctly. Has any tried using this combination of libraries (VC++, SGI STL, Boost) and gotten it to work? Thanks.

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Newbie trying to use multi_array ...
by Jon Pendergrass 23 Oct '02

23 Oct '02

I'm new to Boost, so please excuse my lack of knowledge. I'm trying to use the multi_array class and have hit a small snag. I'd like to have a class with a 4-D array. Initially it won't contain any data. However, Microsoft Visual C++ v6.0 complains about not finding a constructor. I want to do something like this: #include "boost/multi_array.hpp" typedef boost::multi_array<std::complex<double>, 4> t_Array4D; class foobar { t_Array4D ar; }; void foobar::SetValue() { // set extents code // set value this->ar[0][0][0][0] = 2.0; }

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Error in date_time example -- exp-time_periods.html
by David Clark 22 Oct '02

22 Oct '02

date_time/doc/exp-time_periods.html class day_period : public { should be class day_period : public time_period {

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