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[MPI] Efficient way to have views on arrays
by Matthieu Brucher 22 Dec '08

22 Dec '08

Hi, I've started to use the MPI Boost library in conjunction with the usual C library. I'lm trying to get as much as possible done with Boost directly. I'd like to use it in a parallel finite difference loop. This means that before each iteration I have to send a strip of my computed data to each neighbor (getting the neighbors is done through a C MPI function). This can be done with MPI_Type_vector (constant-stride data) in C. Does someone know how it can be done with Boost.MPI ? Matthieu -- Information System Engineer, Ph.D. Website: http://matthieu-brucher.developpez.com/ Blogs: http://matt.eifelle.com and http://blog.developpez.com/?blog=92 LinkedIn: http://www.linkedin.com/in/matthieubrucher

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[format] format in boost 1_37_0 cause VS 2003SP1 ICE?
by Max 22 Dec '08

22 Dec '08

Hello, I have a project that makes use of some boost components, including regex, format, function, and so on. The things are well with boost of version 1.36. But after I installed boost 1.37.0 and switched the searching paths of the IDE to the ones that relate to the new boost version, I have several ICE's - internal compiler error. The IDE told me the error occured at line 203 of format\feed_args.hpp: oss2 << ' '; I've attemped to prepare a small test program that uses boost::format only to see if boost::format(1.37.0) doesn't support VS2003SP1. But it got compiled well. Anybody has similar experience or any hints of where I should go? Thanks in advance. B/Rgds Max ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ )

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boost::serialization does not compile when archiving to xml
by Daniel Roberts 22 Dec '08

22 Dec '08

Building a Win32 console app, the following code compiles just fine: #include "stdafx.h" #include <boost/archive/text_oarchive.hpp> #include <fstream> class SomeClass { public: SomeClass() : m_foo(666), m_bar(777.f) {} private: friend class boost::serialization::access; template<class Archive> void serialize(Archive& archive, const unsigned int version) { archive & m_foo; archive & m_bar; } int m_foo; float m_bar; }; int _tmain(int argc, _TCHAR* argv[]) { SomeClass someClass; std::ofstream fileStream("TestFile.object"); boost::archive::text_oarchive oa(fileStream); oa << someClass; return 0; } but if I include xml_oarchive.hpp and create an xml_oarchive object, just changing the include statement and the type of oa, I get the following error: >c:\program files (x86)\boost\boost_1_36_0\boost\archive\basic_xml_oarchive.hpp(88) : error C2664: 'boost::mpl::assertion_failed' : cannot convert parameter 1 from 'boost::mpl::failed ************boost::serialization::is_wrapper<T>::* ***********' to 'boost::mpl::assert<false>::type' 1> with 1> [ 1> T=SomeClass 1> ] 1> No constructor could take the source type, or constructor overload resolution was ambiguous 1> c:\program files (x86)\boost\boost_1_36_0\boost\archive\detail\interface_oarchive.hpp(64) : see reference to function template instantiation 'void boost::archive::basic_xml_oarchive<Archive>::save_override<T>(T &,int)' being compiled 1> with 1> [ 1> Archive=boost::archive::xml_oarchive, 1> T=SomeClass 1> ] 1> c:\users\daniel\documents\visual studio 2008\projects\testdata\testdata.cpp(31) : see reference to function template instantiation 'Archive &boost::archive::detail::interface_oarchive<Archive>::operator <<<SomeClass>(T &)' being compiled 1> with 1> [ 1> Archive=boost::archive::xml_oarchive, 1> T=SomeClass 1> ] Basically, I can't archive into XML. Can someone please explain what I am doing wrong? I am using Windows Vista, Visual Studio 2008 and boost v36, Thanks

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Re: [Boost-users] [MultiArray] Bounds Guarding in array_view for (stride>1)
by Max 22 Dec '08

22 Dec '08

Perhaps I've not described the question quite clear. :-( What I mean is in the cases the specified stride > 1, will it cause undefined bahavior if I define the range of one dimention as range_t(first, last+stride-1, stride) (I know the correct form is range_t(first, last+stride, stride)) Thanks for any explanation. Max ----- Original Message ----- From: loadcom To: boost-users Subject: [Boost-users] [MultiArray] Bound Guarding Date: 2008-12-21 09:29:55 Hello, I'm using boost::multi_array for a while and find it very powerful except one point that I cannot specify an array_view's number of dimentions at runtime. But this pity is not the topic of this post. You know one can create an array_view with arbirary given start/bound indices as well as the stride as follows: typedef boost::multi_array array_t; array_t myarray; //... typedef array_t::index_range range_t; typename array_t::array_view::view myview = myarrray[boost::indices[range_t(0, 8, 2)][rang_t()][1]]; As I don't know in the internal of the lib how the dound guarding of iteration is done, either - in the 'standard' STL manner as i!=bound; or - in the 'conventional' C stale as ihttp://space.sina.com.cn/ ) ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ )

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date_time question
by Amadeus W.M. 21 Dec '08

21 Dec '08

I want to read from stdin files that contain dates and data. The files come from various sources so the dates are in different formats. Of course, the problem is reading the dates. Based on the date_time examples I put together a few lines of code using facets that I thought should work, but it doesn't seem to. Can't tell if I'm way off, or I'm missing something small. #include <boost/date_time/posix_time/posix_time.hpp> using namespace boost::posix_time; using namespace std; int main(int argc, char * argv[]) { // Create a facet with the expected format. time_input_facet * tfacet=new time_input_facet("%Y/%m/%d %H:%M:%S"); ptime pt(not_a_date_time); cin.imbue(locale(cin.getloc(),tfacet)); cin >> pt; cout << pt << endl; // pt still not_a_date_time. return 0; } Compilation: g++ -g -Wall -o facets -I/usr/local/include/boost-1_35 -L/usr/local/lib/ facets.C -lboost_date_time-gcc43-mt-1_35 Run: echo "12/20/2008 09:56:00" | ./facets not-a-date-time # pt unchanged Once I sort out how to read dates from stdin (initially with the format hard-coded) I have to figure out how to parse the date and guess the format internally in the program. Please help! Thanks!

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[bind] code sample crashing MS compiler
by Christian Henning 21 Dec '08

21 Dec '08

This following code sample will crash the MS compiler version 8. I hope there are some MS folks reading this mailing list, since I have no idea where else to post this. #include <boost/bind.hpp> struct A { void operator() () { boost::bind( &A::lookup, *this, unsigned char() )(); } void lookup( unsigned char& c ) {} }; int main(int argc, char* argv[]) { A()(); return 0; } I know the code is not suppose to compile. Uncommenting the this pointer in the bind construct will make the code compile fine. Regards, Christian

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[test framework] one testsuite over multiple translation units
by Georg Sauthoff 21 Dec '08

21 Dec '08

Hi, I am using the unittest framework from boost 1.34 and it is really usefull (starting with the BOOST_CHECK_EQ style macros are great, since they print out the values of the arguments, etc.). Currently I am using a set of testsuites, i.e. one testsuite consistst of one translation unit, and each translation unit is linked to the main from the boost test framework (utf). Thus I get n test executables for n testsuites. Is it possible (and/or intended) to link a set of different testsuites in different translation together to one test executable? I looked at different versions of utf documentation, but couldn't find something specific about this use case. Currently I am using utf for the single translation unit case like this: //testsuite_foo.cc #define BOOST_TEST_DYN_LINK #define BOOST_TEST_MAIN #define BOOST_TEST_MODULE foo #include <boost/test/unit_test.hpp> BOOST_AUTO_TEST_CASE( foo_bar ) { } And to compile it: $ g++ testsuite_foo.cc -lboost_unit_test_framework How do you use the utf regarding to this aspect? Best regards Georg Sauthoff

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Re: [Boost-users] [boost] [review][constrained_value] Review of Constrained Value Library begins today
by Mika Heiskanen 21 Dec '08

21 Dec '08

Sebastian Redl wrote: > Mika Heiskanen wrote: >> Thank you for your explanation Peter. However, I do not see why an assert >> should be the first choice when a programming error can be detected by >> the program itself. For example, I would prefer my word processor >> to announce a programming error instead of producing a core dump. > And then what? The best thing it can do is do an emergency dump of the > currently open document and then abort. This is something a smart assert > can do as well. I thought we were comparing plain assert with exception handling. I would count a smart assert closer to the latter. > If you detect a programming error through violation of an invariant, > what can you do? If you know exactly what damage the error has caused > and you have enough information to fix all that damage, then you should > know the error well enough that you could have fixed it in the first > place. If you can't fix all the damage, anything except aborting the > program is a major data corruption waiting to happen. Precisely. The fact that an invariant is broken does not mean everything else is broken too, and that all the damage cannot be fixed. If it cannot, of course aborting is the best choice. We're probably comparing apples and oranges here. Perhaps it is pointless to continue this thread on how broken invariants should be handled, it will most likely always depend on the details of the case. What matters is that the reviewed library should enable exceptions as an error mechanism, which I think we all agree on, and I do not see why it wouldn't be the most common use case and hence the default action, which we may not agree on. I can live with that. Kind regards, --> Mika Heiskanen

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[C++] Boost::Regex beginner question
by P.C. 21 Dec '08

21 Dec '08

salutations, I'm a complete beginner in Regex++; I've downloaded it and installed it in Visual C++ 6.0, and it's functioning properly. the problem is that I searched all over the internet and I only discovered how to do basic matching operations and basic replacing. my doubt is the following: I want to know how to do search and replace regexp operations, like it can be done in Perl by using groups (expressions surrounded by parentheses), which allow to select the substrings, matched by the regexp, in the form of $1, $2, and so on. basically, the parentheses mark the matched expression for future reference (for example, for use in the replace operation). for example (Perl example): s/X(.*?)Y/XY$1/g; I'm not sure if this explanation of what I want is very clear. I would appreciate a straightforward example code. thank you in advance. -- View this message in context: http://www.nabble.com/-C%2B%2B--Boost%3A%3ARegex-beginner-question-tp210817… Sent from the Boost - Users mailing list archive at Nabble.com.

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Re: [Boost-users] [bind] Need Help - Function Composition
by loadcom 21 Dec '08

21 Dec '08

Hello Watanabe, I'm not sure if what you mean is that in your use case: boost::function f = make_less_by_func(boost::bind(...)); the temporarily constructed bind obj will go out of its lifetime before we use it via a refence to it? But if I cannot declare const F& func_; instead of F func_; then why bother using another ref lib? or, in other words, is there a way to save this 'unneeded' copy construction and allow us to use make_less_by_func(boost::bind(...)) ? btw, I'm not using ref lib frequently, but should boost::unwrap_ref be boost::unwrap_reference? Thank you so much for your continuous help and patience to my probable stupid questions. Best regards Max ----- Original Message ----- From: Steven Watanabe To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] [bind] Need Help - Function Composition Date: 2008-12-21 02:39:38 AMDG loadcom wrote: > One step further, will the following version save one copy construction > in make_less_by_func()? > > template struct less_by_func > { > typedef bool result_type; > > const F & func_; > less_by_func(const F & func) : func_(func) {} > > template > bool operator()(const T& lhs, const T& rhs) const > { return func_(lhs) }; > > // helper function > template less_by_func make_less_by_func(const F& func) > { return less_by_func(func); } > I don't advise this in general because it requires the argument of make_less_by_func to survive for a while. boost::function f = make_less_by_func(boost::bind(...)); f(1, 2); // undefined behavior because of the dangling reference. If you really want this capability #include template struct less_by_func { typedef bool result_type; F func_; less_by_func(const F & func) : func_(func) {} template bool operator()(const T& lhs, const T& rhs) const { return boost::unwrap_ref(func_)(lhs) http://lists.boost.org/mailman/listinfo.cgi/boost-users ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ )

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