June 2006 - Boost - lists.preview.boost.org

Interest in a small array count facility?
by Gennaro Prota 14 Jul '06

14 Jul '06

Hi guys, a while ago there was some discussion about incorporating a compile-time array count facility in boost. I also provided an implementation for multidimensional arrays. Is there still interest for this? The benefits over the classical sizeof(array)/sizeof(array[0]) idiom are not overwhelming but at least there's a fair syntactical convenience and, of course, the advantage of unit test integration. If there's interest I can add it, to the utility subdirectory I guess (better suggestions are welcome; I really don't like using utility/ as a sort of repository for anything we have no better place for). --Gennaro.

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[config] Macro proposal
by Gennaro Prota 13 Jul '06

13 Jul '06

Hi guys, could we please add something like this to the config system? #if defined(__GNUC_PATCHLEVEL__) # define <choose_a_name> ( __GNUC__ * 10000 \ + __GNUC_MINOR__ * 100 \ + __GNUC_PATCHLEVEL__ ) #else # define <choose_a_name> ( __GNUC__ * 10000 \ + __GNUC_MINOR__ * 100) #endif PS: of course it's possible to "share" the common part of the replacement-lists: ( __GNUC__ * 10000 + __GNUC_MINOR__ * 100) or (100 * ( __GNUC__ * 100 + __GNUC_MINOR__)) The decision is up to John :) --Gennaro.

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Random Access to Files (RAF) - any interest ?
by Slava, Alex 13 Jul '06

13 Jul '06

Dear Boost Community, Is there any interest in submission of a Random Access to Files (RAF) Library to Boost? Please see http://www.trukhanov.kiev.ua/RAF/ for documentation and an initial implementation. Thank you, -- Svyatoslav Trukhanov, Oleksii Ursulenko

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Is there interest in parallel versions of <algorithm> functions?
by Clint Levijoki 12 Jul '06

12 Jul '06

Hey all, This is actually a 2 part interest inquiry: 1. I think there could be some usefulness in parallel versions of the algorithm functions, like for_each and find and unique_copy. 2. In the couple days of r&d I have come up with a class named parallel_task_master which runs a thread function many times over and manages them so you keep your thread counts low and working as hard as possible. So if you have a quad-core cpu it can be specified so you never go over a 4 thread limit. It's also setup so you can keep adding tasks recursively and it will keep the thread count fixed and never deadlock. Because the tasks in parallel_task_master run relatively in order, I think some sort of queue could be made to parallelize functions that needed to return output in a serial form. So it could be used to decode video stream packets for example. This parallel_task_master in itself may have some value alone, but it was written to assist in creating parallel version of the functions in <algorithm>. Some of them are not so parallelizable, some are embarrassingly so. -Clint Levijoki

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[system] - system_error
by Oliver.Kowalke＠qimonda.com 11 Jul '06

11 Jul '06

Hi, shouldn't system_error::const char * what() const contain throw ()? regards, Oliver

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Re: [boost] [Review][PQS] Review deadline
by Michael Fawcett 11 Jul '06

11 Jul '06

On 6/8/06, Andy Little <andy(a)servocomm.freeserve.co.uk> wrote: > Hi Michael, > > > -----Original Message----- > > From: Michael Fawcett [mailto:michael.fawcett@gmail.com] > > Sent: 08 June 2006 15:49 > > To: andy(a)servocomm.freeserve.co.uk > > Subject: Re: [boost] [Review][PQS] Review deadline > > > > A goal of pqs is to be useable in that sort of situation. To be > > really effective > > > it will need a lot of supporting classes ( matrix, vector, quat) though. > > > > Did you plan on using Boost::uBLAS for this, along with > > Boost::quaternion? This seemed tangential enough to the PQS > > discussions that I didn't want to clutter up the mailing list, but I > > am defeinitely curious. > > FWIW Its extremely important. I think it would be worth asking on the list. > I dont think many people realise! I have discussed it in various replies but > no one has asked me the direct question: > > Neither of those libraries above will work with other than numeric types > AFAIK. IOW where T is a type (simplifying and ignoring e.g floating point > promotion etc), it must satisfy: > > T result = T() + T(); > T result = T() * T(); > > (among others) > > If T is a physical quantity, the second requirement never can be true. > Quantity Compatible library must be written something like: > > Where Op is +,-,*,/, ==, etc ... > > typeof( T1() Op T1() ) result = T1() Op T2(); This was a private e-mail discussion but Andy thought it important to be bruoght up on the list. FWIW, my own current matrix/vector/quaternion code does what you are asking for (with boost's help), but I had been looking at changing all my stuff over to uBLAS/quaternion for some time. As an example: blas::vec3<float> a(1, 0, 0); blas::vec3<double> b(0, 1, 0); blas::vec3<double> result = cross_product(a, b); // returns vec3<double>! I accomplished this using what I think never became a boost library (from the sandbox maybe? Did MPL::transform consume this functionality?) result_of which was used something like: template <typename LHS, typename RHS> typename boost::result_of_plus<LHS, RHS>::type operator +(const LHS &lhs, const RHS &rhs) { typename boost::result_of_plus<LHS, RHS>::type nrv(lhs); nrv += rhs; return nrv; } I would hope some solution could be found where you didn't have to implement all new matrix/vector/quaternion classes and their corresponding functionality, rather, just ensure the return type from the operation follows normal promotion rules (this is actually what I thought the promotion traits library was going to do). --Michael Fawcett

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Thanks Bjam!
by Andy Little 08 Jul '06

08 Jul '06

Whenever I invoke bjam I get this first: warning: Python location is not configured warning: the Boost.Python library won't be built Building Boost.Regex with the optional Unicode/ICU support disabled. Please refer to the Boost.Regex documentation for more information (and if you don't know what ICU is then you probably don't need it). Thanks Bjam. You know what? I really don't care! ;-) regards Andy Little

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[system] remarks and feedback
by Gennaro Prota 04 Jul '06

04 Jul '06

Hi Beman, one thing I forgot in my last post about the system library: wouldn't boost/cstdlib.hpp fit nicely into it? PS: this thread's subject has been purposedly "generalized" so that, unless there are objections, we can group all our comments on the system library here. --Gennaro.

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[Review Request] Message Passing Interface (MPI) Library
by Doug Gregor 03 Jul '06

03 Jul '06

I am requesting a formal review for a Boost library that provides modern C++ bindings for the Message Passing Interface (MPI). The Message Passing Interface (MPI) is a standard interface for message passing in high-performance parallel applications. It defines a library interface, available from C, Fortran, and C++, for which there are many MPI implementations. Although there exist C++ bindings for MPI, they offer little functionality over the C bindings. The Boost.MPI library provides an alternative C++ interface to MPI that better supports modern C++ development styles, including complete support for user-defined data types and C++ Standard Library types and using arbitrary function objects for collective algorithms. Boost.MPI is built for efficiency, avoiding unnecessary overhead and translating high-level operations into the most specialized MPI call possible. Boost.MPI currently covers the majority of the MPI 1.1specification, including blocking and non-blocking point-to-point communication, collective operations, communicators, MPI datatypes, and environment management. The library documentation is available in HTML and PDF: http://www.osl.iu.edu/~dgregor/boost.mpi/libs/parallel/doc/html/ http://www.osl.iu.edu/~dgregor/boost.mpi/libs/parallel/doc/mpi.pdf You can browse the library source code here: http://www.osl.iu.edu/~dgregor/boost.mpi/ Or download the source code and documentation as a tarball here: http://www.osl.iu.edu/~dgregor/boost.mpi/boost-mpi-20060628.tgz The library is also available in the Boost Sandbox, in the subdirectories boost/parallel and libs/parallel. Note that you will need the latest Boost from CVS HEAD. Cheers, Doug Gregor

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Convert "60%" to 0.6
by Boris 03 Jul '06

03 Jul '06

I'm using boost::lexical_cast to convert strings to double. However I just run into a string with a percent sign where boost::lexical_cast throws boost::bad_lexical_cast. As far as I can see there is no way to configure boost::lexical_cast to convert eg. "60%" to 0.6. I also checked out boost::numeric_cast but from what I read I think it doesn't help either. Is there anything in Boost which I can use to convert a more descriptive string like "60%" to a double? Boris

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