Mailman 3 May 2002 - Cplusplus-sig

RE: Cygwin Boost.Python Build
by Raoul Gough Aug. 3, 2002

Aug. 3, 2002

If it's any help, here's my set-up script for building Boost with the Cygwin Python: export PYTHON='f:\cygwin\bin\python.exe' export PYTHON_ROOT='f:\cygwin\lib\python2.1' export PYTHON_VERSION='2.1' export PYTHON_INCLUDES='f:\cygwin\usr\include\python2.1' export PYTHON_LIB_PATH='f:\cygwin\lib\python2.1\config' export PYTHON_STDLIB_PATH='f:\cygwin\lib\python2.1' export GCC_PYTHON_ROOT='f:\cygwin\usr' I remember it taking some time to arrive at this - maybe it will help Scott get his set-up working (with appropriate replacements). Regards, Raoul Gough. _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

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Profiling object instantiation... a preliminary report
by Greg Landrum June 26, 2002

June 26, 2002

Re-establishing context: I have an extension class that I've wrapped using both Boost and Cxx. I need to be able to pickle and depickle large numbers (1e5-1e6) of these objects quickly for my target application (storing them in a ZODB and querying the resulting database). I discovered that simple instantiation of 1e5 objects took dramatically longer in Boost than in Cxx (6.7 seconds vs 0.9 seconds). I pulled down a copy of Intel's vtune profiler[1] and profiled my Boost and Cxx wrapped libraries to find the origin of the huge performance difference. After fiddling around for a while figuring out the appropriate magic to make vtune actually work, I found something surprising. I had exposed 4 different constructors for my Mol class. What I failed to realize is that when you overload functions (at least constructors) in BPL, this is handled using exceptions. This was at least partially responsible for the tremendous slow down in the Boost wrapper of my code. When I commented out some constructors, rebuilt, and reprofiled my code I got a run time of 1.9 seconds, only twice the Cxx run time. I'm a lot happier with this, but I'll continue to do a bit of exploration to see if I can bring that down more. I'm rather enjoying vtune now that I've figure out what can be done with it. If anyone wants more detailed information, I'd be happy to provide it. -greg [1] The beta of vtune is available as a free download for linux and windows. These results are under Win2K using MSVC++ v6. ---- greg Landrum (greglandrum(a)earthlink.net) Software Carpenter/Computational Chemist

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Link trouble on OS X
by Scott Smith June 13, 2002

June 13, 2002

Hello, In trying to educate myself on Boost I decided to try and build Boost.Python on a fresh Mac OS X. I installed Python 2.2.1-1 and downloaded Boost 1.28.0. I then built Jam with seemingly no problems, set my environment variables, and tried to build Boost.Python. It seemed fine (just the same warning about long doubles) until it hit the linking step: gcc-Link-action ../../../libs/python/build/bin/libboost_python.so/gcc/release/inlining-on/ runtime-link-dynamic/shared-linkable-true/libboost_python.so /usr/bin/ld: can't locate file for: -lutil I don't know where the util library is supposed to come from, but if I can find it I think the build will complete. Anyone know what this is? Thanks, Scott

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Re: [jamboost] Re: 1_28_0 python2.2.1 gcc3.0.4 build on sparc-solaris-2.7 problem report
by David Abrahams June 12, 2002

June 12, 2002

Moving this to the C++-sig, where it belongs... ----- Original Message ----- From: "Mike Rovner" <gclbb-jamboost(a)m.gmane.org> > > "David Abrahams" wrote... > > Sounds like you're right. What's the proposed fix? > > Modify boost[.python] to use 64-bit file operations [in that case]. Boost.Python doesn't use any file operations. > I.e. include wrap_python.hpp first, huh? "huh", Huh? Which file should #include wrap_python first? > Or exclude <cstddef> from config.hpp - I see no use of it in that file. It's needed for offsetof()... though it appears BOOST_OFFSETOF is not used anywhere anymore, so we could just dispense with that. What happens if you comment out the #include <cstddef> from config.hpp? -Dave

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constructor wrappers?
by Ralf W. Grosse-Kunstleve June 3, 2002

June 3, 2002

Would something like the following be possible/desirable? struct any { any(int a=0, int b=0, int c=0) { ... } }; any any_from_python_list_or_tuple(PyObject* list_or_tuple) { // extract between 0 and 3 int from a list or tuple and use to construct // an object any_instance. return any_instance; } BOOST_PYTHON_MODULE_INIT(any) { boost::python::module this_module("any"); this_module.add( boost::python::class_<any>("any") .def_init(any_from_python_list_or_tuple) ); } I guess what I am after is an equivalent of the thin wrappers for member functions, some easy-to-use flexible mechanism for "customizing" constructors when they are exposed to Python. Thanks, Ralf __________________________________________________ Do You Yahoo!? Yahoo! - Official partner of 2002 FIFA World Cup http://fifaworldcup.yahoo.com

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error C2904: 'from_python' : template-name already defined
by Achim Domma June 1, 2002

June 1, 2002

Hi, still trying to wrap ImageMagick with boost.python I get the following error: e:\cvsroot\boost\boost/python/converter/from_python.hpp(24) : error C2904: 'from_python' : template-name already defined as '__restrict volatile const signed __fastcall boost::python::from_python' e:\cvsroot\boost\boost/mpl/aux_/count_if_not.hpp(61) : fatal error C1506: unrecoverable block scoping error Here is the file I try to compile: ----> #include <boost/python/module.hpp> #include <boost/python/class.hpp> #include <string> #include <Magick++.h> using namespace boost::python; void add_class_Image_to_module(module& m) { m.add(class_<Magick::Image>("Image") .def_init() ); } <---- I have such a file for each class, due to internal compiler errors if I put all classes in one file. The module definition looks like this: ----> void add_class_Image_to_module(boost::python::module& m); BOOST_PYTHON_MODULE_INIT(ImageMagick) { using namespace boost::python; module m("ImageMagick"); add_class_Image_to_module(m); } <---- Is there something wrong with this code? I have no idea where the error comes from. greetings Achim

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cannot return boost::python::tuple
by Ralf W. Grosse-Kunstleve June 1, 2002

June 1, 2002

I am having trouble returning a boost::python::tuple. This works (reports None when called from Python): void//boost::python::tuple UnitCell_getinitargs(const UnitCell& uc) { boost::python::tuple initargs; //return initargs; } This is what I really want: boost::python::tuple UnitCell_getinitargs(const UnitCell& uc) { boost::python::tuple initargs; return initargs; } But I get: Traceback (most recent call last): File "dbg.py", line 6, in ? print u.__getinitargs__() TypeError: bad argument type for built-in operation What am I doing wrong? Thanks, Ralf __________________________________________________ Do You Yahoo!? Yahoo! - Official partner of 2002 FIFA World Cup http://fifaworldcup.yahoo.com

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V2: isinstance(obj,cls) equivalent
by Pearu Peterson June 1, 2002

June 1, 2002

Hi, What would be the best way to determine if PyObject *obj is an instance of a Boost.Python V2 wrapped class, say A? Hints where to look are most appreciated. Thanks, Pearu

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custom from_python
by Ralf W. Grosse-Kunstleve May 31, 2002

May 31, 2002

I am really impressed by the nice mechanism for registering a custom to_python conversion. What is the best way to define and register an equivalent custom from_python converter? I am looking at the code in src/converter/from_python.cpp. Most built-in types seem to go through slot_rvalue_from_python. Should I use this, too? Thanks, Ralf __________________________________________________ Do You Yahoo!? Yahoo! - Official partner of 2002 FIFA World Cup http://fifaworldcup.yahoo.com

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same to_python_converter in multiple modules?
by Ralf W. Grosse-Kunstleve May 30, 2002

May 30, 2002

Here is less contrived example for doc/v2/to_python_converter.html: template <typename ElementType, std::size_t N> struct boost_array_to_tuple { static PyObject* convert(boost::array<ElementType, N> const& a) { boost::python::tuple result(a.size()); for(std::size_t i=0;i<a.size();i++) { result.set_item(i, boost::python::make_ref(a[i])); } return result.reference().release(); } }; boost::python::to_python_converter< boost::array<int, 3>, boost_array_to_tuple<int, 3> >(); If I have two independent modules that both need this converter, where would I put the last statement. In both modules? What happens if both modules are loaded at the same time? What if I have 30 modules that need this converter (this will happen in our application)? Thanks, Ralf __________________________________________________ Do You Yahoo!? Yahoo! - Official partner of 2002 FIFA World Cup http://fifaworldcup.yahoo.com

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