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serialization, pickling, and mersenne_twister
by Neal D. Becker 02 Sep '04

02 Sep '04

I propose to add the following to mersenne_twister, which will support both the [proposed] boost::serialization as well as any other use: Index: mersenne_twister.hpp =================================================================== RCS file: /cvsroot/boost/boost/boost/random/mersenne_twister.hpp,v retrieving revision 1.16 diff -c -r1.16 mersenne_twister.hpp *** mersenne_twister.hpp 27 Jul 2004 03:43:32 -0000 1.16 --- mersenne_twister.hpp 2 Sep 2004 16:44:07 -0000 *************** *** 133,138 **** --- 133,145 ---- return os; } + template<class Archive> + void serialize(Archive & ar, const unsigned int version) + { + ar & x; + ar & i; + } + template<class CharT, class Traits> friend std::basic_istream<CharT,Traits>& operator>>(std::basic_istream<CharT,Traits>& is, mersenne_twister& mt) For use with boost::python pickling, I considered 2 approaches. 1) Use boost::serialization. This would require providing an archive format that would archive via pickling. 2) Use an independent technique, but share the same interface "serialize". I believe #2 is the best choice. Layering pickling on top of serialization would result in duplication and inefficiency. Although #2 is a bit awkward, it is feasible. Here is an example of how to serialize mersenne_twister via the above interface, using boost::python pickle. Perhaps this technique could be made more generic. struct mt_pickle_suite : python::pickle_suite { struct Archive { struct Save { python::list result; void operator & (rng_t::result_type x[]) { python::list l; for (int i = 0; i < 2*rng_t::state_size; i++) l.append (x[i]); result.append (l); } template<typename T> void operator & (const T& x) { result.append (x); } }; struct Load { python::object entries; Load (const python::object& _entries) : entries (_entries) {} void operator & (rng_t::result_type x[]) { python::list l = python::extract<python::list> (entries[0]); for (int i = 0; i < 2*rng_t::state_size; i++) x[i] = python::extract<rng_t::result_type> (l[i]); } template<typename T> void operator & (T& x) { x = (python::extract<T>(entries[1])); } }; }; static python::object getstate (rng_t& rng) { Archive::Save ar; rng.serialize (ar, 0); return ar.result; } static void setstate(rng_t& rng, python::object entries) { Archive::Load ar (entries); rng.serialize (ar, 0); } };

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Changes to numeric/ublas/vector.hpp break ublas bindings
by Matthias Troyer 02 Sep '04

02 Sep '04

Yesterday's change in numeric/ublas/vector.hp in the Boost CVS (making the pointer typedefs private) breaks the ublas LAPACK and BLAS bindings which need access to this type. Is it possible to make these types public again? Matthias

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RE: [boost] Re: New design proposal for boost::filesystem
by Ben Hutchings 02 Sep '04

02 Sep '04

Beman Dawes <bdawes(a)acm.org> wrote: > At 01:53 PM 8/30/2004, Carlo Wood wrote: > > >My idea on this was (and still is) that it is possible to convert > >a relative path to an absolute path (automatically) by adding an > >absolute path object reference to the relative path object. > > Yes, as long as you know the absolute path reference. Is the absolute > path reference known for all operating systems? I'm not sure about > that. For example, there have been multi-rooted systems that didn't > have a concept of "current drive". How would that work? <snip> Further, I know of one OS that supports directories but not a current directory: Windows CE. All paths passed to its filesystem functions must be absolute.

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RE: [boost] Re: IOStream mmap too restrictive?
by Ben Hutchings 02 Sep '04

02 Sep '04

Jonathan Graehl <jonathan(a)graehl.org> wrote: <snip> > I don't see how, in Windows, to atomically keep the file open before > it's mmapped, because chsize takes an int fh and the (equivalent of) > mmap takes a HANDLE (maybe there is some Win32 call to get the HANDLE > from the int fh?). <snip> You mean file descriptor, not "int fh". "File handle" usually means a FILE or FILE pointer. Anyway, file descriptors are a Unix feature emulated by many C libraries and not by Win32. The VC++ library provides the function _get_osfhandle which returns the underlying Win32 file handle for a file descriptor. Other C/C++ libraries for Windows may provide similar functions.

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lambda: missing result deduction
by David Abrahams 02 Sep '04

02 Sep '04

I had to add this to get some tests for the TMP book to pass: namespace boost { namespace lambda { template<int N> struct plain_return_type_2<arithmetic_action<plus_action>, char[N], std::string> { typedef std::string type; }; }} // namespace boost::lambda Obviously this could be generalized for basic_string and for the reversed arguments. I assume it's not in the library because it forces you to #include <string>? Maybe there should be a special lambda header for each std:: type that needs deduction help? -- Dave Abrahams Boost Consulting http://www.boost-consulting.com

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Get/set state in Mersenne Twister
by Neal D. Becker 02 Sep '04

02 Sep '04

In order to serialize, it would be helpful to add an interface to mersenne_twister to get/set the state. I don't think there is any I/F to get the state.

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Fw: Boost in Software 2.0 Extra! magazine
by John Maddock 02 Sep '04

02 Sep '04

This one may be of interest to a some our continental developers: > Hello, > > We are currently working on an issue of our Software 2.0 Extra! magazine > devoted exclusively to C/C++ programming using crossplatform libraries. > The Boost project is widely known and its constituent libraries are used > by many programmers all over the world, so it would be great if we had > something about it in our magazine. > > Would you or anyone else from the Boost development team be interested > in writing an article on C/C++ programming with Boost for our magazine? > We can agree on a specific subject later on. > > Our magazine appears in four language versions: Polish (Poland), French > (France, Belgium, Canada), German (Germany, Austria, Switzerland) and > Spanish (Spain, Portugal) with a total circulation of about 30000. Each > issue is devoted to a different area of IT. > > Please let me know if you are interested in cooperating with us on this > issue. > > Best regards, > > Zbigniew Banach > > -- > Software-Wydawnictwo Sp. z o.o. > ul. Lewartowskiego 6, 00-190 Warszawa > tel.: +48 22 860-17-60 > fax.: +48 22 860-17-71 > www: http://www.software20.org > e-mail: zbyszek(a)software.com.pl > >

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another bjam question
by Robert Ramey 02 Sep '04

02 Sep '04

When I build and run config_info using msvc-stlport I get the output below which doesn't seem correct. I get no reference to stlport. When I investigate the bjam output I find (for another test) I find that the following is being used for the command line: "cl" /Zm800 -nologo /EHsc -c -D_STLP_DEBUG=1 -D_STLP_DEBUG_UNINITIALIZED=1 -D_STLP_USE_DYNAMIC_LIB=1 /Z7 /Od /Ob0 /EHsc /GR /MDd -I"C:\BoostMainCVS" -I"c:/Program Files/microsoft visual studio\vc98\include" -I"c:\STLport-4.5.3\stlport" -Fo"..\..\..\bin\boost\libs\config\test\no_ded_typename_fail.test\msvc-stlpo rt\debug\threading-multi\no_ded_typename_fail.obj" -Tp"..\..\..\libs\config\test\no_ded_typename_fail.cpp" This indicates that the Microsoft native include is specified BEFORE the STLPort one. This would explain why the config_info doesn't reflect the STLPort usage. Can someone tell me what I should be doing differently? Robert Ramey Microsoft Visual C++ version 6.0 _CPPUNWIND =1 __cplusplus =1 _M_IX86 =500 _WIN32 =1 _WCHAR_T_DEFINED [no value] _CPPRTTI =1 _DLL =1 _MSC_EXTENSIONS =1 _MSC_VER =1200 _MT =1 __BOOL_DEFINED =1 ********************************************************************* Dinkumware standard library version 1.x ********************************************************************* Detected Platform: Win32 Type char is signed Type wchar_t is unsigned byte order for type short =0 8 byte order for type int =0 8 16 24 byte order for type long =0 8 16 24 sizeof(wchar_t) =2 sizeof(short) =2 sizeof(int) =4 sizeof(long) =4 sizeof(size_t) =4 sizeof(ptrdiff_t) =4 sizeof(void*) =4 sizeof(void(*)(void)) =4 sizeof(float) =4 sizeof(double) =8 sizeof(long double) =8 CHAR_BIT =8 CHAR_MAX =127 WCHAR_MAX =((wchar_t)-1) SHRT_MAX =32767 INT_MAX =2147483647 LONG_MAX =2147483647L ********************************************************************* Boost version 103100 BOOST_USER_CONFIG =<boost/config/user.hpp> BOOST_COMPILER_CONFIG ="boost/config/compiler/visualc.hpp" BOOST_STDLIB_CONFIG ="boost/config/stdlib/dinkumware.hpp" BOOST_PLATFORM_CONFIG ="boost/config/platform/win32.hpp" BOOST_BCB_PARTIAL_SPECIALIZATION_BUG [no value] BOOST_DEDUCED_TYPENAME [no value] BOOST_FUNCTION_SCOPE_USING_DECLARATION_BREAKS_ADL [no value] BOOST_HAS_DECLSPEC [no value] BOOST_HAS_FTIME [no value] BOOST_HAS_MACRO_USE_FACET [no value] BOOST_HAS_MS_INT64 [no value] BOOST_HAS_THREADS [no value] BOOST_HAS_WINTHREADS [no value] BOOST_MSVC =1200 BOOST_MSVC_STD_ITERATOR =1 BOOST_MSVC6_MEMBER_TEMPLATES [no value] BOOST_NESTED_TEMPLATE =template BOOST_NO_ARGUMENT_DEPENDENT_LOOKUP [no value] BOOST_NO_ARRAY_TYPE_SPECIALIZATIONS [no value] BOOST_NO_CV_VOID_SPECIALIZATIONS [no value] BOOST_NO_DEDUCED_TYPENAME [no value] BOOST_NO_DEPENDENT_TYPES_IN_TEMPLATE_VALUE_PARAMETERS [no value] BOOST_NO_EXPLICIT_FUNCTION_TEMPLATE_ARGUMENTS [no value] BOOST_NO_FUNCTION_TEMPLATE_ORDERING [no value] BOOST_NO_HASH [no value] BOOST_NO_INCLASS_MEMBER_INITIALIZATION [no value] BOOST_NO_INTEGRAL_INT64_T [no value] BOOST_NO_INTRINSIC_WCHAR_T [no value] BOOST_NO_LONG_LONG_NUMERIC_LIMITS [no value] BOOST_NO_MEMBER_TEMPLATE_FRIENDS [no value] BOOST_NO_MEMBER_TEMPLATES [no value] BOOST_NO_MS_INT64_NUMERIC_LIMITS [no value] BOOST_NO_PRIVATE_IN_AGGREGATE [no value] BOOST_NO_SFINAE [no value] BOOST_NO_SLIST [no value] BOOST_NO_STD_ALLOCATOR [no value] BOOST_NO_STD_ITERATOR [no value] BOOST_NO_STD_ITERATOR_TRAITS [no value] BOOST_NO_STD_MIN_MAX [no value] BOOST_NO_STD_OUTPUT_ITERATOR_ASSIGN [no value] BOOST_NO_STD_USE_FACET [no value] BOOST_NO_STDC_NAMESPACE [no value] BOOST_NO_SWPRINTF [no value] BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION [no value] BOOST_NO_TEMPLATE_TEMPLATES [no value] BOOST_NO_TEMPLATED_ITERATOR_CONSTRUCTORS [no value] BOOST_NO_USING_TEMPLATE [no value] BOOST_NO_VOID_RETURNS [no value] BOOST_STD_EXTENSION_NAMESPACE =std BOOST_UNREACHABLE_RETURN(0) [no value] EXIT STATUS: 0

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Compilation problem of ublas
by Matthias Troyer 02 Sep '04

02 Sep '04

Hi, Doing a cvs update of the Boost CVS I encountered a compiler bug in ublas: ...boost/boost/numeric/ublas/matrix_sparse.hpp:2556: error: no matching function for call to `boost::numeric::ublas::unbounded_array<size_t, std::allocator<size_t> >::unbounded_array() Is there a problem in the constructor of matrix_sparse, or is the missing default constructor of unbounded_array the problem? Could one of the ublas developers look into this problem? Matthias

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name mangling scheme for tru64cxx65
by Markus Schöpflin 02 Sep '04

02 Sep '04

Hello! Currently, the name mangling scheme used on this platform is the default one selected by the compiler. It turns out that this is a bad choice when compiling boost. The problem is illustrated by the following example: ---%<--- #include <iostream> using namespace std; template <typename T> void foo(T const &x) { cout << "1" << endl; } template <typename T> void foo(T * const &x) { cout << "2" << endl; } int main() { foo("abc"); return 0; } --->%--- This prints out "2" with the default name mangling scheme. When manually selecting "ansi" as the name mangling scheme, the correct result "1" is printed. Therefore I propose to explicitely set the name mangling to ansi in the tools file for this compiler. Does anyone have any strong feelings or arguments against such a change? Markus

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