December 2011 - Boost - lists.preview.boost.org

Re: [boost] Proposal for a Differential Evolution C++ library
by Adrian Michel 26 Dec '11

26 Dec '11

Hi everybody, I released a new version of the DE library based on feedback I received on the initial release - see the doc at http://www.amichel.com/de/doc/html. First of all, I updated the documentation to describe in more detail what DE is, its use in one specific case, and links to descriptions of several other use cases - see the Overview page at the link above. I hope this will help make the case why a DE library would be worth being included in boost. BTW, there are already implementations in several languages and for several free or commercial products: Java, C, Matlab, Scilab, Fortran90, Python, Labview, Pascal, C#, etc. As far as the library itself, Thomas Heller noted that requiring the objective functions to be derived from the de::objective_function abstract class limited the user options by not allowing arbitrary unnamed or plain functions to be passed as objective functions. I followed his suggestion and reimplemented parts of the library as template classes, in particular the de::processor class. It is now possible to pass objective functions as: named functions, unnamed functions, functors (all with the right prototype) or objective function factories which create local copies of the objective function. All of these can be passed as either references, plain pointers or boost::shared_ptr. This change should make it easier to integrate the library within existing code. Your comments will be appreciated. Adrian

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[string_algo] New Maintainer
by Pavol Droba 26 Dec '11

26 Dec '11

Dear Boosters, After a careful consideration I finally realized that I can no long act as a maintainer for String Algorithms Library. I simply don't have the required time and I thinks that the library deserves at least development. Therefore I would like to call for a volunteer(s) who would like to take String Algorithm library further. I will still be available for consultations or any such assistance if required. Hopefully I will be also able to contribute a bit if my situation changes. Now, I don't really know if there is an official process for this kind of shift. I would be nice if potential volunteers would send a few words about the future direction they would take. A community can make a decision then. Best Regards, Pavol

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[config, c++11] emplace_back check?
by Tim Blechmann 26 Dec '11

26 Dec '11

hi all, i wonder, is there a way to determine, if std::vector provides emplace_back? this currently causes a compile failure for boost.heap on gcc-4.3 with c++0x enabled: it does not implement emplace_back, although it has rvalue references and variadic templates. thanks, tim

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boost releases on microblogs
by Pedro Larroy 25 Dec '11

25 Dec '11

Hi Wouldn't it be nice to have twitter and identi.ca anouncements of boost releases? Regards. Pedro.

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Re: [boost] FW: Proposal for a Differential Evolution C++ library
by Adrian Michel 24 Dec '11

24 Dec '11

Hi Philip, On 12/09/2011 4:35 PM, Philip Bennefall wrote: >> The full documentation is at http://www.amichel.com/de/doc/html but I'd >> suggest these pages for a first read >> http://www.amichel.com/de/doc/html/dd/d53/overview.html and >> http://www.amichel.com/de/doc/html/db/d4e/tutorial.html . >> >> The zip containing the DE C++ library and helper files is at >> http://www.amichel.com/de/de.zip. >> >> The DE main page is at http://www.icsi.berkeley.edu/~storn/code.html . > I took a peak at the overview and some of the other pages and from what I > can see initially, it looks like a very useful library for artificial > intelligence. I have very limited knowledge in the field but this is > something that grabs my interest, so if it's made public I'll definitely use > Thanks for your interest. DE and this library can be certainly used for AI, but many different problems in various areas can be optimized efficiently using DE (references to some of those can be found here: http://www.icsi.berkeley.edu/~storn/code.html) Best, Adrian

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[geometry] MSVC needs namespace even if it is hoisted
by Barend Gehrels 24 Dec '11

24 Dec '11

Hi, We got a strange MSVC compilation problem in a Unit Test for Boost.Geometry. Attached a miminal reproduction. The essention is that we have stated: using strategy::distance::services::returning_type; and somewhere after that: typedef typename returning_type<strategy_type>::type the_return_type; but this is not accepted, in this case, by MSVC. It is well accepted by gcc, clang and comeau. If the namespace is specified, it is accepted by MSVC. The error message is: reproduce_msvc_using_bug.cpp(257): error C2059: syntax error : '<' And that is the same message as if the returning_type would not be a template. If we state: std::cout << typeid(returning_type).name() << std::endl; It compiles in MSVC, but it should not compile, because it is a template. So somehow it picks up this "returning_type" as if it is not a template. But of course it is. I've tried another (much smaller) minimal reproduction to mimic this problem but that is compiled normally by MSVC. So attached this one with (reworked) pieces from Boost.Geometry and even Boost, but still all contained in one file. We've discussed this internally and the current thought is that it is a compiler problem. If so, is this issue known to anyone on this list, or Microsoft? Otherwise I will report it. If not so, what is the problem here? It is of course easy to work around: giving the full namespace is OK for any compiler. So this is more out of curiosity: what is wrong here? Regards, Barend

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TRAC hit hard last night
by Marshall Clow 23 Dec '11

23 Dec '11

We got a major infusion of garbage; strictly speaking, it doesn't appear to be spam, because it's not advertising anything, and the text doesn't contain any links. However, it doesn't have anything to do with boost. I've deleted about 40 tickets this morning. Any suggestions on how to prevent this in the future? -- Marshall Marshall Clow Idio Software <mailto:mclow.lists@gmail.com> A.D. 1517: Martin Luther nails his 95 Theses to the church door and is promptly moderated down to (-1, Flamebait). -- Yu Suzuki

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C++11 challenge: ASSERT_INVALID_EXPR
by Dave Abrahams 23 Dec '11

23 Dec '11

I don't know whether this is actually possible, but I was thinking today that there might be a way to use the new SFINAE to detect errors in a large class of invalid expressions without actually causing a hard error, and thereby build an assertion that fails compilation when passed a valid expression and passes for any invalid expression in the large class mentioned above. Any takers? -- Dave Abrahams BoostPro Computing http://www.boostpro.com

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[concept_check] Some issues
by Robert Kawulak 23 Dec '11

23 Dec '11

Hi, I've spotted some problems when playing with BCCL: - The implementation of assignable_archetype defines private default and copy constructors, so for example assignable_archetype<copy_constructible_archetype<>> will not actually be copy constructible. The same for convertible_to_archetype and convertible_from_archetype, but additionally with copy assignment. Is this by purpose? - copy_constructible_archetype defines public default constructor - again, am I overlooking something or it should not be there? - Function and predicate archetypes also seem to provide too wide interface (they are copy constructible and assignable). Additionally, they don't allow for archetypes chaining since they lack the Base parameter (with the only exception of binary_predicate_archetype - why the inconsistency?) - Apart from the provided function object concepts and archetypes it seems it would be useful to have a general Callable concept and the corresponding callable_archetype, parameterised with the types of arguments and return value. Wouldn't it be valuable to add them? - There's boost/concept_check directory in the trunk - are the files in it actually used anywhere? I've found no reference to them in Boost headers, documentation doesn't mention them too. Best regards, Robert

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boost and google search
by Edward Rankin 23 Dec '11

23 Dec '11

Hi, I am sure it is pretty common for users of boost to use google to search for documentation/tutorials on their favorite library in boost. I have found that the top hits are typically not the latest documents. For example I just searched for boost,foreach and a documentation from 1.35 was the first hit. It would be great if there is a way to tell google to update their links to the latest version. Anyone knows whether this is possible, and how to make it happen? This problem probably applies to any search engine but I can only comment on google search. Thanks, Edward

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