April 2013 - Boost - lists.preview.boost.org

[preprocessor] BOOST_PP_OVERLOAD not defined if variadic macros not supported.
by Mostafa 14 Apr '13

14 Apr '13

I just found out the hard way that BOOST_PP_OVERLOAD is "silently" not defined if variadic macros are not supported , ie in c++03. This led to quite a frustrating session of debugging on the premise that there's something wrong with my include paths/environment variables. It would be very nice if BOOST_PP_OVERLOAD errored explicitly if variadic macros were not supported by the compiler, or at lease have a gentle reminder to the reader in BOOST_PP_OVERLOAD documentation (and, where appropriate, in other places) that variadic macros are only standard in c++11 and may not be supported on all compilers, hence one might get a BOOST_PP_OVERLOAD undeclared error. Mostafa

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GSOC 2013 . BOOST GLB
by Niranjan Singh 14 Apr '13

14 Apr '13

@antoshk Hello sir, As I go through the graph library of boost, everything seems to be done like all major algorithms for graphs. That's pretty good however we can use it to implement a structure of methods which deals with problems like Chinese postman problem, Decision making poblem , Project management.,Graph partitioning and clustering , Distribution of Eigen values and compression e.t.c With graph we can solve friend-of-friend problems and also implement a simple command line social network based on c++ with the help of graphs. This would be really interesting. However shortest path algorithms can be implemented from one cutting plane algorithm , and Ant algorithm. It would be better if we can change the input and output display by using graphics so that user gets an interactive output of graph. With these graph techniques and algorithms can be use for calculating polynomials time verification via hamiltonian cycles and NP problems. May be useful in Boost uBLabs. with many thanks and regards Niranjan Singh

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GSOC 2013
by Niranjan Singh 14 Apr '13

14 Apr '13

@antoshk Hello sir, As I go through the graph library of boost, everything seems to be done like all major algorithms for graphs. That's pretty good however we can use it to implement a structure of methods which deals with problems like Chinese postman problem, Decision making poblem , Project management.,Graph partitioning and clustering , Distribution of Eigen values and compression e.t.c With graph we can solve friend-of-friend problems and also implement a simple command line social network based on c++ with the help of graphs. This would be really interesting. However shortest path algorithms can be implemented from one cutting plane algorithm , and Ant algorithm. It would be better if we can change the input and output display by using graphics so that user gets an interactive output of graph. With these graph techniques and algorithms can be use for calculating polynomials time verification via hamiltonian cycles and NP problems. May be useful in Boost uBLabs.

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GSOC 2013
by Niranjan Singh 13 Apr '13

13 Apr '13

Hello, My name is Niranjan , It was really a pleasure seeing a poject like this, and the ideas were also very good. I like to contribute to the vector ,making new matrix class. I would like to propose you my idea as below As *Graph theory* as a subject also and is becoming increasingly significant as it is applied to other areas of mathematics, science and technology. It is being actively used in fields as varied as *biochemistry (genomics), electrical engineering (communication networks and coding theory), computer science (algorithms and computation) and operations research (scheduling).* The powerful *combinatorial methods* found in graph theory have also been used to prove fundamental results in other areas of pure mathematics. And so is becoming an important subject in mathematics and algorithms also. So I was thinking to make a library to implement all the graph functions and its various properties and applications in it so that it can be used by student to understand the concept and it can also be used to solve problems like *Travelling Salesman problem, finding chromatic number, edge colouring. * Finding *shortest path , face colouring* e.t.c. With the help of small functions user can create a program which tackles the big problem. Lots of data-structures can also be implemented. Thanks. P.S. Sir, As my end semester are exams are on .. so its possible that i couldn't reply you fast but I do want to do this project. Exams will over on 30 april.. Thanks for you concern.

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Niranjan Singh has invited you to open a Google mail account
by Niranjan Singh 13 Apr '13

13 Apr '13

I've been using Gmail and thought you might like to try it out. Here's an invitation to create an account. You're Invited to Google Mail! Niranjan Singh has invited you to open a Google Mail account. Google Mail is Google's free email service, built on the idea that email can be intuitive, efficient and fun. Google Mail has: *Less spam* Keep unwanted messages out of your inbox with Google's innovative technology. *Lots of space* Enough storage so that you'll never have to delete another message. *Built-in chat* Text or video chat with Niranjan Singh and other friends in real time. *Mobile access* Get your email anywhere with Google Mail on your mobile phone. You can even import your contacts and email from Yahoo!, Hotmail, AOL or any other web mail or POP accounts. Once you create your account, Niranjan Singh will be notified of your new Google Mail address so you can stay in touch. Learn more<http://mail.google.com/mail/help/intl/en/about.html>or get started<http://mail.google.com/mail/a-b2df9a7699-186fc6feff-CUGUbjU3pJUkhZ0HbL1w6xE…> ! Sign up<http://mail.google.com/mail/a-b2df9a7699-186fc6feff-CUGUbjU3pJUkhZ0HbL1w6xE…> Google Inc. | 1600 Amphitheatre Parkway | Mountain View, California 94043

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JSON Parser GSoC 2013
by Stephan Bourgeois 13 Apr '13

13 Apr '13

Hi everybody, I am studying for an MSc in Computer Science at Oxford Brookes University. I have taken a compiler construction course this year and I am therefore interested in the JSON Parser idea for the Boost library. Open Source JSON parsers have already been implemented in C++ and in Java. Examples of Java libraries are: Gson, quick-json. Even if other libraries already exist, developers who are using Boost for their project will appreciate having a JSON parser within Boost. >From a compiler construction background, writing a JSON parser is not difficult. The JSON grammar is simple and the specification is easy to find. Potential difficulties can exist with robustness of error handling and recovery. The question is what data structure we should use to represent JSON objects, and how the user can access key/value pairs in those objects. (examples: Boost.PropertyTree, pre-existing C++ object, ...) Ideally we should offer validating and non-validating implementations. We should also offer JSON generation as well as parsing. Let me know what you think. Kind regards, Stephan.

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Regarding proposal for GSOC
by Niranjan Singh 12 Apr '13

12 Apr '13

If I have to send my proposal for the poject in GSOC then whom should I mail. This link only or is there some other email. Thanks

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JSON Parser GSoC 2013 (part 2)
by Stephan Bourgeois 12 Apr '13

12 Apr '13

Hi everybody, thank you for all your replies. I will try to summarize my impressions so far: 1. Although there is a solution in Boost.PropertyTree, a majority of users consider it to be incomplete, and quite a few developers are using external libraries at present. 2. As Bjorn Reese pointed out, a solution should offer several different interfaces. Some being already implemented in the protoc library. Michael Marcin suggested that something similar to JsonFX in C# be added to Bjorn's list. 3. There is already a Lexer implementation as part of the tokenizer API in protoc. This is how I imagine I could contribute to the project: 1. Collect requirements for functionality and interfaces. 2. review existing Java, C++, C#, Android library solutions. 3. Write a Parser with error recovery using the Lexer from the protoc library. Or adapt an existing parser if there is a good reason for doing so. 4. review JSON specific issues like type casting and how to deserialize arrays with multiple types. (see posts by Arindam Mukherjee and Michael Marcin on deserialization) 5. With the help of my mentor, implement the different interfaces, preferably in a modular way. (I know an example of this in compiler design using the visitor pattern for code generation) Please don't be offended as I only had the time to have a quick look at a single library. I understand that I need to look at a wider code base from other libraries and familiarize myself with general issues related to JSON and serialization. Bjorn Reese offered to mentor this project, please let us know if someone more "officially involved" with Boost needs to approve this. Please let me know what you think. Stephan

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[gsoc-2013] Physics Library Abstraction Layer
by Preston Hamlin 12 Apr '13

12 Apr '13

Hello, my name is Preston Hamlin and I am a current CS undergraduate at the Florida State University. I was reading over the list of ideas provided and then referenced the source code libraries to get a feel for what was being asked for. I found the prospect of writing an abstraction layer for PhysX or related libraries to be interesting. I am somewhat familiar with THREE.js which is an abstraction of WebGL. In THREE.js there is a heavy amount of abstraction to the degree of providing geometric primitives, particles effect presets, simple materials and basic data structures (matrices, vectors, etc...). Given the platform that THREE.js operates on, such a degree is understandable. How much of the physics library is to be abstracted away in generic structures and functions? I would think that having a few simple primitives (cube, low-poly sphere, etc...) would be required since they are commonly used. However more advanced meshes like a torus might be better produced through using modifiers on said primitives rather than a built-in preset. I think the degree of abstraction is most important for modifiers, and I desire to get a feel for what is being looked for. I assume the end goal is to be able to produce Blender/Unity/3dsMax usable code as well as standalone utilities. Many thanks, -Preston

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Re: [boost] JSON Parser GSoC 2013
by John Venarchick 12 Apr '13

12 Apr '13

> 2013/4/12 Michael Marcin <mike.marcin(a)gmail.com> > >> Arindam Mukherjee wrote: >> >>> In JSON we typically deal with maps and arrays. The arrays themselves >>> could >>> have arbitrary types (string, object, array, numeric, boolean, null) as >>> elements. The key types in the maps are always strings and the value types >>> in the maps could be anything that can appear in an array, including >>> another map or array. >>> >>> Due to this, I'd imagine being able to use Boost.Variant or Boost.Any in a >>> list and as a value_type in a map would help. >>> >>> I have been doing some work with JSON and boost by modifying the current 1.53 ptree. I created a type for use as the data_type of the ptree that represents the various options for JSON data (no value, null value, bool, integer, float, string). It uses boost::variant and visitors. I have it working for my purposes, but would want to make it a little nicer before submitting a patch. I also implemented property_tree::translator_ between to make it work with the spirit classic parser in json_parser_read and json_parser_write. I can post more if anyone is interested. I'm also working a generic way to load arbitrary structures from the created ptree. -John V

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