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GSoC 2011
by mahbubul hasan 21 Apr '11

21 Apr '11

Hi, I am Mahbub. I am a CSE graduate. I just saw you had a proposal regarding queue and heap in GSoC 2010. In my undergraduate I did thesis on heaps. In that time I learned soft heap, it might be interesting to you. Here is the short description of soft heap<http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.85.3258&rep=rep1&t…>.( http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.85.3258&rep=rep1&t…) Soft heap is a heap like data structure but with some uncertainty. This data structure supports insert, delete, merge, findmin. It does every work in amortized constant time except insert operation which takes O( log 1/e ) where 0<e=<.5. Here e is error rate. The data structure will never contain more than en corrupted elements. There are two versions of soft heap. 1. By Binomial Tree 2. By forest of binary tree There is one more thing that might interesting to you. That is, in my undergraduate I improved the running time of heap sort by significant amount by applying pairing technique. The paper is submitted to International Journal of Computer Mathematics and it is under review now. It mainly improves Carlsson's variant of heapsort. It also improves the deletion method proposed by Gonnet and Munro (Heaps on Heaps). [The heap is inplace, that means no additional space is required] It also improves the Weak Heapsort. WeakHeapsort is a sorting method which requires O(n) additional bit to sort. However applying the pairing technique it can be reduced to O(n/2) additional bit. It is known that weakheap is the theoretically best known algorithm. [Best considering number of comparisons] So I am just curious if you are interested in these types of algorithms. I saw no possible proposal category where these fits in, but I thought you might be interested. Please let me know what do you think about this. Mahbub

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[locale] Formal review of Boost.Locale library EXTENDED
by Chad Nelson 21 Apr '11

21 Apr '11

(This message made it to the announcements list, but the copy intended for the developers list didn't make it and I hadn't noticed. I apologize if this inconvenienced anyone.) There have been only a handful of reviews of the proposed Boost.Locale library to date, and several people have requested more time to provide theirs, so the formal review of the Boost.Locale library has been extended. The deadline for reviews is now 11:59pm UTC on Friday, April 22nd. For those in the Western hemisphere, remember that that's earlier than it might seem -- 7:59pm in New York, 4:59 in Los Angeles. I'll accept late reviews until I complete the report on Saturday morning, but please try to get yours in earlier. You can find the "boost_locale_for_review" version here: https://sourceforge.net/projects/cppcms/files/boost_locale/ The HTML documentation can also be seen at: http://cppcms.sourceforge.net/boost_locale/html/index.html Writing a review ================ If you feel this is an interesting library, then please submit your review to the developer list (preferably), or to the review manager (me). Here are some questions you might want to answer in your review: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? And finally, every review should answer this question: - Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion. -- Chad Nelson Oak Circle Software, Inc. * * *

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review needed
by Xu Sun 20 Apr '11

20 Apr '11

Hi, I've posted my proposal on 04/05 but still didn't receive any reply including email or comment. I will be very appreciated if any one can give me any feedback about my proposal. The link is here: http://www.google-melange.com/gsoc/proposal/review/google/gsoc2011/sunbow/1 Sorry to bother others. Thanks, Xu Sun

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new operator traits: how to merge to the trunk?
by Frédéric Bron 20 Apr '11

20 Apr '11

Dear developpers, I am working on answering all comments of the review concerning the addition of operator traits. When this is finished, what will be the process to include the extension to the trunk? Is it something I will have to do my-self? If so, what is the way to do it? Thanks in advance, Frédéric

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[Fusion] Tentative of trasnform_if failed :(
by falcou 19 Apr '11

19 Apr '11

The following code http://ideone.com/xYk4X doesn't compile and i cant get the why of it. The goal is to have a fusion transform_if that takes a compile-time predicates For each element int he sequence, if the predicates its true, we apply some transform on it, if not we return the element unchanged. What am I missing ?

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Interest in doing project "concept Traits library"
by Rachit Kulshreshtha 19 Apr '11

19 Apr '11

I know that i am running late as i had my university exams but i have been following the projects entitled under Google Summer of Code 2011. I am a student of BITS-Pilani University, India doing my B.E. in Electronics and Instrumentation. I was going through the project "concept traits library" , trying to understand it. I was able to gather much information about what it is and how it works, with some details of the functions under operator traits, mpl_ext and even Concept traits. But since their is no well defined problem statement given on the website, i was wanting to know what functions \ templates already exist as parts of the library and what are we expected to create. Please reply soon... Thnx in advance -- its a bird, its a plane, its a rocket no its Rachit

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Re: [boost] [MSM] Interrupt anonymous transitions or blocking process_events?
by Christophe Henry 19 Apr '11

19 Apr '11

Hi Mathias, <snip> >By calling p.process_event(play()); the the player will start playing >Song1 and then change to the next song by itself. But now in single >threaded mode it blocks until it reaches "Song3". So it is not possible >to process any other events during this time. In other words, it cannot >process another process_event call. The "Playing" state has a "stop" >event but calling this will not help as it will not be processed until >the MSM has reached "Song3". The problem is that a state machine is based on run-to-completion. This means in your case that a transition must be "short". An event comes, a transition is executed, the state machine is in a new stable state and can process a new event. Until this happens, events are queued (in the case of MSM). >I start the same p.process_event(play()); in thread 1. And in thread 2 I >call p.process_event(stop()); The problem with this is that the stop() >event does not get processed until it reaches Song3 because of the >blocking call in p.process_event(play());. Actually I'd think because of the mutex. In any case, your design will be hard to get right I'm afraid. >Perhaps I am going about this the wrong here and please tell me if it >can be done in some other much better way! I want to be able to have >automatic transitions that I can interrupt. You have to use run-to-completion. Base your design on short-terms events fed to the state machine, which triggers work and reacts to changes in forms of other events. In your case, one possibility would be to have the state machine delegate (post) some work upon state entry or transition action to a thread, then posting a new task upon state exit, etc. Make your state machine be serviced by only one thread, triggering work and reacting to events. Trust me on that one, having a state machine serviced by 2 threads is a good receipt for headaches ;-) If you know boost::asio, it's a bit like the async_xxx methods, trigger some work and get ready for the next action (which would be a callback, to continue with this asio example). HTH, Christophe

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[preprocessor] seq/size.hpp BOOST_PP_SEQ_SIZE MSVC empty list warning
by damien benoist 19 Apr '11

19 Apr '11

Hello, It seems that BOOST_PP_SEQ_SIZE generates a warning with empty sequences under MSVC (vs 2010/boost 1.46.1). The same call works with gcc. The tests are available below. I've also put a patch but: - I'm really not sure of it (I have never been as far with preproceesor as in boost/preprocesor/) - I only tested it with BOOST_PP_CONFIG_MSVC (it should also be tested with BOOST_PP_CONFIG_EDG) And anyway this warning will likely appear with all macros manipulating sequences. Should this warning just be ignored or disabled with MSVC? More general question: I'm discovering boost. I'm really impressed by the macros in boost/preprocessor. It makes a lot of things possible. But it provides features the preprocessor was not meant for. For that, it uses a lot of tricks. How portable is it? How many architectures is it known to work/not work with? Can we be confident that it should work with any preprocessor? Thanks for your help. $ cat lstsz2.h #include "boost/preprocessor/seq/size.hpp" #define lst0 #define lst1 (a) #define lst2 (a)(b) #define lst3 (a)(b)(c) BOOST_PP_SEQ_SIZE(lst0) BOOST_PP_SEQ_SIZE(lst1) BOOST_PP_SEQ_SIZE(lst2) BOOST_PP_SEQ_SIZE(lst3) $ cpp -I ~/wh/softs/boost/1.46.1 < lstsz2.h ... 0 1 2 3 $ cl -I `cygpath -d "$HOME/wh/softs/boost/1.46.1"` /E lstsz2.h ... 0 1 2 3 lstsz2.h(8) : warning C4003: not enough actual parameters for macro 'BOOST_PP_SEQ_SIZE_I' $ diff -u 1.46.1/boost/preprocessor/seq/size.hpp.old 1.46.1/boost/preprocessor/seq/size.hpp --- 1.46.1/boost/preprocessor/seq/size.hpp.old 2005-06-21 09:55:15.000000000 +0200 +++ 1.46.1/boost/preprocessor/seq/size.hpp 2011-04-19 14:42:02.218750000 +0200 @@ -13,6 +13,7 @@ # define BOOST_PREPROCESSOR_SEQ_SIZE_HPP # # include <boost/preprocessor/cat.hpp> +# include <boost/preprocessor/empty.hpp> # include <boost/preprocessor/config/config.hpp> # include <boost/preprocessor/tuple/eat.hpp> # @@ -21,7 +22,7 @@ # define BOOST_PP_SEQ_SIZE_I(par) BOOST_PP_SEQ_SIZE_II ## par # define BOOST_PP_SEQ_SIZE_II(seq) BOOST_PP_CAT(BOOST_PP_SEQ_SIZE_, BOOST_PP_SEQ_SIZE_0 ## seq) # elif BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_EDG() || BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_MSVC() -# define BOOST_PP_SEQ_SIZE(seq) BOOST_PP_SEQ_SIZE_I(seq) +# define BOOST_PP_SEQ_SIZE(seq) BOOST_PP_SEQ_SIZE_I(seq BOOST_PP_EMPTY()) # define BOOST_PP_SEQ_SIZE_I(seq) BOOST_PP_CAT(BOOST_PP_SEQ_SIZE_, BOOST_PP_SEQ_SIZE_0 seq) # elif defined(__IBMC__) || defined(__IBMCPP__) # define BOOST_PP_SEQ_SIZE(seq) BOOST_PP_CAT(BOOST_PP_SEQ_SIZE_, BOOST_PP_CAT(BOOST_PP_SEQ_SIZE_0, seq))

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[TypeTraits] Are any of the new C++2011 traits implementable using SFINAE expressions?
by John Maddock 19 Apr '11

19 Apr '11

I'm quite sure the answer to this is no.... but are there any new language features in C++2011 that would allow the implementation of any of the following traits within the language? Thanks in advance, John. template <class T> struct is_trivial template <class T> struct is_trivially_copyable template <class T> struct is_standard_layout template <class T> struct is_literal_type template <class T, class... Args> struct is_constructible; template <class T> struct is_default_constructible; template <class T> struct is_copy_constructible; template <class T> struct is_move_constructible; template <class T, class U> struct is_assignable; template <class T> struct is_copy_assignable; template <class T> struct is_move_assignable; template <class T> struct is_destructible; template <class T, class... Args> struct is_trivially_constructible; template <class T> struct is_trivially_default_constructible; template <class T> struct is_trivially_copy_constructible; template <class T> struct is_trivially_move_constructible; template <class T, class U> struct is_trivially_assignable; template <class T> struct is_trivially_copy_assignable; template <class T> struct is_trivially_move_assignable; template <class T> struct is_trivially_destructible; template <class T, class... Args> struct is_nothrow_constructible; template <class T> struct is_nothrow_default_constructible; template <class T> struct is_nothrow_copy_constructible; template <class T> struct is_nothrow_move_constructible; template <class T, class U> struct is_nothrow_assignable; template <class T> struct is_nothrow_copy_assignable; template <class T> struct is_nothrow_move_assignable; template <class T> struct is_nothrow_destructible; template <class T> struct underlying_type;

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Re: [boost] [Filesystem] error including filesystem v3 with icpc -std=c++0x
by Galen Andrew 19 Apr '11

19 Apr '11

> > Hello, > > > > Including boost/filesystem.hpp is giving me errors using Intel > > compiler in Linux with -std=c++0x that look like > > > > > boost/filesystem/v3/operations.hpp(303): error: name followed by "::" > > must be a class or namespace name > > {detail::copy_file(from, to, > > copy_option::fail_if_exists);} > > ^ > > It compiles fine under g++ -std=c++0x. > > What happens with the Intel compiler if you don't specify -std=c++0x? Without -std=c++0x those errors are gone, but a similar error pops up in another boost library I'm using boost/random/variate_generator.hpp(209): error: name followed by "::" must be a class or namespace name typedef typename random::detail::engine_helper<have_int, want_int>::BOOST_NESTED_TEMPLATE impl<decorated_engine, typename Distribution::input_type>::type internal_engine_type; ^ > The regression tests are passing for Intel on Linux, but it doesn't > look like any of them specify -std=c++0x > > What version of the Intel compiler are you using? Version 12.0.2.137 Build 20110112 > > What version of Boost are you using? 1.46.1 Thanks!

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