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Re: [boost] [GSOC] XML library of Boost
by Amos Ji 28 Apr '13

28 Apr '13

On Apr 28, 2013, at 12:11 PM, Andrey Semashev <andrey.semashev(a)gmail.com> wrote: > On Monday 29 April 2013 02:08:01 Amos Ji wrote: >> Hi All, >> >> I'm a graduate student from Fudan University in China. And I hope to >> contribute some code to Boost during the GSOC. >> >> I've scanned the idea page. The ideas in the page are all very interesting >> and challenging. But what I'm interested in most is XML library, which is >> at the bottom of page. I think the XML format is the most popular standard >> for storing information so it's important for Boost to have a good XML >> library. > > Agreed, a good and fast XML library would be most useful. >> In my opinion, an XML parser must be able to do these things: >> >> 1. To Iterate over DOM nodes tree; >> 2. To access the values of nodes and their attributes quickly; >> 3. To insert or delete nodes or attribute of an exact node easily; >> 4. To generate new XML from the structure which stores XML in the >> library. > > IMHO, support for SAX is also mandatory. I would even say that SAX should be > the first and the primary thing to be implemented in Boost.XML, as DOM can be > added later on top of it if the time for GSOC allows. > I agree. SAX parser will use less memory than DOM parser. I'll add it into my proposal. > You also listed support for encodings in the optional features. I agree with > it being optional with exception for Unicode. At least UTF-8 should be > supported from the very start. But that should not be a problem now that we > have Boost.Locale. I know little about Boost.Locale. I'll see how it can help support other encodings when I need. Thanks a lot for your suggestions. _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

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Google Summer of Code 2013
by sskytyba＠gmail.com 28 Apr '13

28 Apr '13

I’m student from Ukraine. My name is Skytyba Sergij. I want to get some information. I’m interested in such projects as Boost.uBLAS, Boost.Math Bernoulli Numbers and Applications to Special Functions (very) , Boost.Multiprecision (very) , Boost.Thread/SyncQueue, Moving Boost to Boost.Move. To whom can I send my proposal and how can I contact with mentors of these projects?

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[GSoC] Boost.Multiprecision project
by Віталій Мельник 28 Apr '13

28 Apr '13

Hi! I am a second year student in Computer Science and I`m very interested in Boost.Multiprecision project on GSoC. What can I do to be invited to this project? I have some achievements in sport programming, so I can tell you that I know algorithms and I like to solve algorithmic problems. -- Vitalii Melnyk

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Re: [boost] GSoC Boost.Multiprecision project
by Jyotesh Choudhari 28 Apr '13

28 Apr '13

> 2013/4/21 Jyotesh Choudhari <jyoteshrc_at_[hidden]>: > <...> >> Looking at the project description, I think I have understood what needs to >> be implemented in this project. I have also gone through the current code >> cpp_bin_float.hpp and I have understood some part of it. I want to know how >> detailed should my proposal be? What details should I include in my >> proposal? What should be the deliverables for the project? > Hi, and welcome! > Start from writing a proposal according to this link > https://svn.boost.org/trac/boost/wiki/SoCSubmissionTemplate<https://svn.boost.org/trac/boost/wiki/SoCSubmissionTemplate>. > This link may also help https://svn.boost.org/trac/boost/wiki/SoCHints I have attached my proposal with this mail. Please have a look at it and let me know your feedback. Thanks and regards, Jyotesh Choudhari > After it is done, mail it ti this mailing list with title starting > from [boost] GSOC. > I also recommend to read this mailing list first, because there is a > lot of interesting discussions and useful information about GSOC and > some comments about Boost.Multiprecision. > One more advice: there are already two or three students that want to > work on Boost.Multiprecision. Try to describe in your proposal why do > you suit for that task better than others. > -- > Best regards, > Antony Polukhin

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[GSOC-2013]-boost.odeint implicit routines
by preethamsreenivas 28 Apr '13

28 Apr '13

Hi all, I am preetham sreenivas, a sophomore at computer science and engineering, IIT Bombay(Indian Institute of Technology, Bombay). I am very much interested in the project of adding support to implicit routines to the boost.odeint library. I have recently completed a course on numerical analysis and i've used all the common numerical methods as part of the course including euler methods , runge-kutta routines etc. I've also used the boost.odeint for algorithmic analysis assignments for this course. I've gone through the articles linked from the project description and also snippets of odeint code at codeproject.com I would like to get through to mario mulansky or Karsten Ahnert , the mentors for this project to provide me with further pointers and any assignments they would like to give me. I am sorry that i couldn't start on it earlier as i've just completed my exams for the spring semester. please reply as soon as possible. kindly oblige, regards, preetham sreenivas, sophomore, CSE IIT Bombay -- View this message in context: http://boost.2283326.n4.nabble.com/GSOC-2013-boost-odeint-implicit-routines… Sent from the Boost - Dev mailing list archive at Nabble.com.

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GSoC uBLAS algorithms for derterminants, inversion and decomposition
by Ganesh Prasad 28 Apr '13

28 Apr '13

As inversion involves steps that use the determinant of the matrix, it's better to develop an algorithm that evaluates the determinant of the matrix faster than the conventional recursive way. I think extending the rule of Sarrus does the trick. So far we have used rule of sarrus as a light weight formula for evaluating determinants of 2x2 and 3x3 matrices. But extending it in the following way makes it applicable for higher order matrices too. And this algorithm has a time complexity O(2*n^2) for nxn matrices. // a is a n x n matrix Det_a=0 Sum1=0 Sum2=0 For count=0 to n-1 do For i=1 to n do J=i+count Val=(j>n)?n:0 j-=val product*=a[i][j] sum1+=product For count=0 to n-1 do For i=1 to n do J=n-count-(i+1) Val=(j<1)?n:0 J+=val product*=a[i][j] sum2+=product det_a=sum1-sum2 return det_a I want to use this algorithm in my GSoC project to evaluate determinants, and based on this implementation I'll develop algorithms for inversion and decomposition. But I think if we can make some changes to this algorithm, this may run faster. As you can see, this thing traverses the matrix twice. If we can achieve the goal in only one traversal calculating sum1 and sum2 simultaneously, then it'd be a bit faster, but here I lack ideas. So please provide me with some help in this regard. ~Ganesh Prasad

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[Boost][GSOC] proposal for Trie
by Hardy Huang 28 Apr '13

28 Apr '13

Hi, this is my proposal for GSOC 2013, please read it and give me some useful information on it, thanks == Personal Details == * Name: Zhe(Hardy) Huang * College/University: Peking University * Course/Major: Computer Science * Degree Program: M.Sc. * Email: hzithlony(a)gmail.com * Homepage: not yet * Availability: * How much time do you plan to spend on your GSoC? I will spend the most part time of the semester(till late June), and then the whole summer on my GSoC project. * What are your intended start and end dates? I basically will obey the rules of GSoC, and I will also listen to mentor’s advice on it. * What other factors affect your availability (exams, courses, moving, work, etc.)? I am having my courses now, and I will have my final exams in June. Since I am not having many courses, I have enough time to do something for the project before exams. And in summer I could almost work full time on it. == Background Information == Please summarize your educational background (degrees earned, courses taken, etc.). I majored in Computer Science in Zhongshan University from 2008 to 2012, by which I earned my bachelor’s degree. During the four years, I learned many basic courses on Computer Science, like algebra, logic, data structure, algorithms, operating system, Compilers, databases, networks. >From 2012 till now, I am studying Computer Science in Peking University pursuing my master’s degree. My research field is information retrieval. Please summarize your programming background (OSS projects, internships, jobs, etc.). GSoC is the first time that I get involved with a real and large OSS project. Besides, I’ve developed many things in C and C++. I developed a simplified B-tree data structure in C during my intership for a small company. Later a system in C to extract and evaluate the content of webpages for my research, and I am still on it. An implementation of a search system in C++. A webpage template system in C for my lab to generating webpages in order to do some research on them. Please tell us a little about your programming interests. I like to write codes for the basic and general use. I am pursuing well-framework of design and code, and high reusability when I think of develop the project. Please tell us why you are interested in contributing to the Boost C++ Libraries. Boost is widely used by programmers and famous for its powerful and efficient. It is an honor to contribute to such a lib, and have my codes used and reviewed by so many programmers. I like the reusability of well-designed lib, so it also will be a good chance for me to improve my skill of design and programming. And a good chance to communicate with good guys as well. I want to be a good programmer with many good programmers as my friends. What is your interest in the project you are proposing? Because I have participated in many competitions of algorithm, I have a good knowledge of algorithms and data structures. I have also implement many, but for the sake of winning, the codes usually can not be well-reused. Meanwhile the STL in C++, which I’ve used many times during the competitions, such as set, map, priority_queue, sort are good examples of well-reused algorithms and data structures. So I’ve been expecting to develop some general libraries of algorithms and data structures. Boost is a well-formed organization, and Boost lib is a widely-used lib, so I also want to learn some skills to develop a good lib from developing the project with mentors in Boost. Have you done any previous work in this area before or on similar projects? I am good at data structure and algorithm, and I wrote codes of various algorithms and data structures for many times. I am very familiar with the Trie data structure, and as I list above, I've develop a simplified general B-tree data structure in C, which is a good experience when I develop Trie for Boost. What are your plans beyond this Summer of Code time frame for your proposed work?. I will dedicate my summer to my work. And taking the experience as a good beginning, I will be feeling happy to contribute more to Boost, and other OSS projects. Please rate, from 0 to 5 (0 being no experience, 5 being expert), your knowledge of the following languages, technologies, or tools: - C++ 3 - C++ Standard Library 3 - Boost C++ Libraries 2 - Subversion 3 What software development environments are you most familiar with (Visual Studio, Eclipse, KDevelop, etc.)? I use Visual Studio in my lab, and vim + gcc for myself. What software documentation tool are you most familiar with (Doxygen, !DocBook, Quickbook, etc.)? I’ve used Doxygen before, it is simple and efficient. == Project Proposal == Please provide a description of your proposed work. Trie(Radix Tree) is an efficient in memory data structure to deal with string storing and searching. It can be used in many applications, and in comparison to hashtables, it has better expandability and stability. It will be an data structure of great importance and wide usage. == Proposed Milestones and Schedule == Please provide estimated milestones and schedule for completing the proposed work. Before May 27: To familiarize with the Boost lib, with reading the codes and discussing about it in mailing list. To have a better knowledge of lib, with reading some books of STL and Boost, and comparing Boost with STL. To setup us a proper environment for development. Study deep into Trie, reading some others’ good implementations. May 27 – June 17: Keep in touch with the Boost organization and have good communications with my mentor. Get involved with the development of boost. Try some toys about Boost, and discuss them with mentor, in order to know better about mentor and how the development goes on. June 17 – July 15(Coding period begins): Discuss the detail of the design with mento, develop an alpha version of Trie, and have it tested in small scale. July 15 – July 29(To mid-term evaluation): Refine my alpha codes, analyze the performance, and try to improve it. Write an initial report of the project and document of Trie. July 29 – September 23: Refine my codes, and have some thorough tests on it, make it robust. Reorganize codes and improve documents.

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[result_of] Allow result_of to work with C++11 lambdas
by Nathan Crookston 27 Apr '13

27 Apr '13

Hi all, Using C++11 lambda functions with several boost components. For example, the following code snippet will not work with VC10, nor with g++ up to 4.8: #include <boost/assign.hpp> #include <boost/range/adaptors.hpp> #include <boost/range/algorithm.hpp> #include <iostream> int main() { std::vector<int> v; for(int i = 0; i < 10; ++i) v.push_back(i); boost::for_each(v | boost::adaptors::transformed([](int i) { return i * 2; }), [](int i) { std::cout << i << std::endl; }); } g++4.5 gives around 34k of error messages, while VC10 has a mere 22k. The root of these problems is that lambda functions don't conform to the tr1::result_of protocol -- there is no nested result_type member, nor nested result struct. The standard doesn't mandate this case since decltype may be used to deduce the return type on C++11-conforming compilers. boost::result_of disables the use of decltype on many compilers in favor of tr1-style deduction due to weaknesses in the implementation of decltype. While it is important to use tr1-protocol result_of to allow code involving incomplete types to compile, it would be very convenient to fall back to a decltype approach when it's detected that the tr1 protocol is not being followed. Jeff Hellrung suggested[1] a fallback to decltype *only* for compilers which had nonconforming decltype operators. Thus the only behavioral change would be that some code which before would produce an error would now compile and run correctly. A ticket[1] with a patch (including tests and docs) was created. Daniel Walker suggested further discussion on the list, which this attempts to provoke. I think this would be a nice improvement for a set of often-used compilers -- the list of boost-users questions whose problems could be addressed by this patch is extensive (and can be provided, if desired). Thanks, Nate [1] http://boost.2283326.n4.nabble.com/Range-amp-c-0x-Lambdas-Can-this-be-done-…<http://boost.2283326.n4.nabble.com/Range-amp-c-0x-Lambdas-Can-this-be-done-…> [2] https://svn.boost.org/trac/boost/ticket/7753

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[type_erasure] Using any with iterator Concept.
by Adam Wulkiewicz 27 Apr '13

27 Apr '13

Hi, I'm trying to use type-erased iterator in STL algorithms, e.g. copy but get errors like this one: error C2039: 'iterator_category' : is not a member of 'boost::type_erasure::any<Concept>' c:\program files (x86)\microsoft visual studio 10.0\vc\include\xutility 373 of course any doesn't define iterator_category. I'm using MSVC2010 and doing something like this: typedef boost::type_erasure::any< boost::type_erasure::iterator< boost::single_pass_traversal_tag > > iterator; // ... iterator first = return_some_iterator(...); iterator last = return_some_iterator(...); // BAM! std::copy(first, last, std::back_inserter(result)); // BAM! typedef iterator::iterator_category C; I simply tried to add it to the iterator<> Concept defined in iterator.hpp but this didn't help: template<...> struct iterator< ::boost::single_pass_traversal_tag, ...> : iterator< ::boost::incrementable_traversal_tag, ...> { typedef ValueType value_type; typedef typename iterator_reference< Reference, ValueType >::type reference; typedef DifferenceType difference_type; typedef std::input_iterator_tag iterator_category; }; Am I doing something wrong or is it an error in Boost.TypeErasure? Regards, Adam Wulkiewicz

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Bernoulli Numbers Implementation With More Precision and Boost.Test
by Gaurav Deshmukh 27 Apr '13

27 Apr '13

I have further improved the implementation of 'bernoulli' function for Math.Bernoulli project idea of GSoC-2013. In my previous update, I made the return type generic. But, there was lack of precision as I had mentioned. For achieving greater accuracy, I implemented the Akiyama-Tanigawa algorithm using 'cpp_rational' data type. As there is no approximation in intermediate steps, it gives best accuracy. It can be casted to the data types of 'cpp_dec_float'. But, I think this implementation may be slower than the previous implementations. So, there is trade-off between running time and precision. We may implement 'bernoulli' function in two ways. If priority is running time than the accuracy of precision, then we can use previous implementation. If priority is the precision, then we can use this implementation. I have attached the 3 files. 1) bernoulli.hpp : It contains the function fr calculating bernoulli number. 2) example.cpp : It contains the program to test bernoulli.hpp 3) test.cpp : This is the Boost.Test comparing the values calculated by benoulli.hpp with some of the published values.

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