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mpi all_reduce
by Kraus Philipp 03 Dec '10

03 Dec '10

Hello, how can I use the mpi::all_reduce with std::accumulate? I would reduce the values of each process with a sum function Thanks Phil

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boost-1.45.0 / MSVC 9.0: bjam --layout=system fails
by Roman Neuhauser 03 Dec '10

03 Dec '10

hello, i'm trying to build 1.45.0 on Windows 7 with MSVC 9.0. I'm using the Windows SDK shell. "bootstrap; bjam" passes. "bootstrap; bjam --layout=system" fails: c:/MinGW/msys/1.0/home/roman/wc/boost_1_45_0/tools/build/v2/build\virtual-target.jam:1066: in virtual-target.register-actual-name from module virtual-target error: Duplicate name of actual target: <pstage\lib>libboost_date_time.lib error: previous virtual target { common%common.copy-libboost_date_time.lib.STATIC_LIB { msvc%msvc.archive-libboost_date_time.lib.STATIC_LIB { msvc%msvc.compile.c++-gregorian\greg_month.obj.OBJ { gregorian/greg_month.cpp.CPP } } { msvc%msvc.compile.c++-gregorian\greg_weekday.obj.OBJ { gregorian/greg_weekday.cpp.CPP } } { msvc%msvc.compile.c++-gregorian\date_generators.obj.OBJ { gregorian/date_generators.cpp.CPP } } } } error: created from ./stage-proper error: another virtual target { common%common.copy-libboost_date_time.lib.STATIC_LIB { msvc%msvc.archive-libboost_date_time.lib.STATIC_LIB { msvc%msvc.compile.c++-gregorian\greg_month.obj.OBJ { gregorian/greg_month.cpp.CPP } } { msvc%msvc.compile.c++-gregorian\greg_weekday.obj.OBJ { gregorian/greg_weekday.cpp.CPP } } { msvc%msvc.compile.c++-gregorian\date_generators.obj.OBJ { gregorian/date_generators.cpp.CPP } } } } error: created from ./stage-proper error: added properties: <debug-symbols>off <define>NDEBUG <inlining>full <optimization>speed <runtime-debugging>off <variant>release error: removed properties: <debug-symbols>on <inlining>off <optimization>off <runtime-debugging>on <variant>debug c:/MinGW/msys/1.0/home/roman/wc/boost_1_45_0/tools/build/v2/build\virtual-target.jam:490: in actualize-no-scanner from module object(file-target)@3863 c:/MinGW/msys/1.0/home/roman/wc/boost_1_45_0/tools/build/v2/build\virtual-target.jam:135: in object(file-target)(a)3863.actualize from module object(file-target)@3863 c:/MinGW/msys/1.0/home/roman/wc/boost_1_45_0/tools/build/v2\build-system.jam:748: in load from module build-system c:\MinGW\msys\1.0\home\roman\wc\boost_1_45_0\tools\build\v2/kernel\modules.jam:283: in import from module modules c:\MinGW\msys\1.0\home\roman\wc\boost_1_45_0\tools\build\v2\kernel\bootstrap.jam:142: in boost-build from module c:\MinGW\msys\1.0\home\roman\wc\boost_1_45_0\boost-build.jam:17: in module scopefrom module i need the system layout build. how can i get around the error? -- roman

3 4

Nested If in boost:mpl::if_
by Leon Sit 02 Dec '10

02 Dec '10

hi all I am trying to use mpl to do some simple type computation that involves nest if statements The logic is somewhat like if(T is Libor) return LiborType if( or( or(T = Euribor, T = EURLibor), is_base_of(T, Libor) ), ConstrType2, if( or(is_base_of(T, Euribor), is_base_of(T, EURLibor)), ConstrType1, ConstrType ) ) When I first coded it and instantiate T with some derived class of Libor, the final type is always a generic type. Few more testing shows that the inner if_ in the code below typedef typename boost::mpl::if_ < boost::is_same<InType, QuantLib::Libor>, QuantLib::Libor, boost::mpl::if_ < boost::mpl::or_ < boost::is_same<InType, QuantLib::Euribor>, boost::is_same<InType, QuantLib::EURLibor>, boost::is_base_of<QuantLib::Libor, InType> > ConstrType2, boost::mpl::if_ < boost::mpl::or_ < boost::is_base_of<QuantLib::Euribor, InType>, boost::is_base_of<QuantLib::EURLibor, InType> >, ConstrType1, ConstrType > > >::type Type; does not reduce to ConstrType1/ConstrType2/ConstrType but the whole is used as a type. So the final Type is just a type with 3 nested if_ class inside. I tried linearising the logic but this introduces other problem. Is this a bug or a limitation of mpl::if_? Thanks

2 1

[Boost.Test] does not always include checkpoint information
by Peter Soetens 02 Dec '10

02 Dec '10

I'm using boost 1.40. When parsing the output of a Boost.Test xml file, I sometimes get this error: "test-result.xml:cvc-complex-type.2.4.b: The content of element 'Exception' is not complete. One of '{LastCheckpoint}' is expected." (output from Hudson Test plugin). It appears that It does not consider the entry point of the unit test function as a checkpoint, while the documentation says it does. I can 'fix' this by inserting check/pass points at the beginning of every function, but shouldn't Boost.Test do this automatically ? Peter

2 1

mpi non-blocking communication
by Kraus Philipp 02 Dec '10

02 Dec '10

Hello, I have some problems with the MPI non-blocking communication, but I can be a thinking error. The CPU 0 (rank 0) creates a loop with this: while (true) { std::string l_str; p_com.irecv( mpi::any_source, LOGGER_MPI_TAG, l_str ); } p_com is the commuicator object. All other CPUs (!= 0) can send a message to CPU 0, which should be received. The CPUs (!=0) can send a message, but they need not, so I would create this with non-blocking communication. At this time my l_str is alway empty, so it seems that the message, that are send, not transmittet, received or not inserted into l_str. I hope the problems is described in a clear way. I would like that the CPU 0 can receive message of there are some and all other CPUs can send messages. Thanks Phil

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Writing an inline nullary function object?
by Robert Jones 02 Dec '10

02 Dec '10

How can I write an inline nullary function object, returning a fixed value? The equivalent of this... int x = 4; int f( ) { return x; } boost::function<int()> g = f; but without defining the intermediate f()? I thought this might work... boost::function<int()> g = bind(bind(apply<int>(), _1 ), x ); but maybe I've not got it quite right? Thx - Rob.

3 4

[Units] Converting from angular_velocity to degrees_per_second
by Andrew Hundt 01 Dec '10

01 Dec '10

I need to make a conversion from a general angular_velocity to degrees/second. For example: boost::units::quantity< boost::units::si::angular_velocity> m_speed((30.0*boost::units::si::radians_per_second)); uint32_t result = static_cast<uint32_t>(boost::units::quantity<boost::units::si::angular_velocity,uint32_t>(m_speed*boost::units::degree::degrees/boost::units::si::seconds).value()); However it fails to compile in gcc 4.4, reporting: error:incomplete type '[type removed]' used in nested name specifier Could someone explain the proper syntax to achieve the desired type specification and subsequent conversion? Do I need to specify a degrees_per_second unit, and if so, how? Thank you in advance for your help. Cheers! Andrew Hundt

2 3

[interprocess] Named mutex
by Chard 01 Dec '10

01 Dec '10

Ion, anyone, I'm trying to use a named mutex to control access to a file. The example given here: http://www.boost.org/doc/libs/1_45_0/doc/html/interprocess/synchronization_… seems to be a starting point. However, I'm not exactly sure what this example is demonstrating. For example: - it appears to be attempting to control access to a file called "file_name". However, streams are opened on the file so, AFAICT, if interleaving calls from two processes stream out to it, the outcome will be unpredictable (even under controlled lock, due to the file-pointer position) ? - the file is thrown away at process exit; what would this mean if the other process is accessing it? - the 'mutex_remove' object causes removal of the named mutex on construction. I presume this is to demonstrate a clean up of a residual named mutex if a previous execution did not exit cleanly. However, if process 1 starts up and executes until just after the mutex creation, then process 2 starts up and executes the mutex_remove, the mutex appears to be in an invalid state, and the scoped_lock calls have no effect - this is certainly the case on Windows. This would defeat the whole point. Any clarification appreciated...

1 0

[spirit] This parser hang
by Kamil Zubair 01 Dec '10

01 Dec '10

This code: std::string s("blablabla"); std::string::iterator start = s.begin(); std::string::iterator finish = s.end(); bool result = phrase_parse(start, finish, +(!char_(':')), space); It's just a simple parser that match string which doesn't have ':' character in it right ? But when I run it, function phrase_parse is hang, it never return anything. I'm using boost 1.44 with VC 2008

3 4

[range] Tuple initialization?
by Marcin Zalewski 01 Dec '10

01 Dec '10

I have a following fragment of code: local = boost::begin(f(*current)); local_end = boost::end(f(*current)); local and local_end are two iterators, f is a function that returns a range, and current is some iterator I have around. I would like to initialize two iterators from the range returned by f, but it seems that I only have two choices: create a local range variable or call f twice and have two temporary ranges. Am I missing something, or are these indeed the only choices? Would it be reasonable to have a begin_end (or such) function that returns a tuple of iterators from a range for tuple initialization of two iterators? Currently, the range concepts do not require anything of the sort. Thanks, Marcin

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