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

Is there interest in e_float: Multiple-precision float and special functions?
by Christopher Kormanyos 24 Jun '11

24 Jun '11

Is there interest in my e_float library for potential inclusion in boost? e_float is a portable C++ system for multiple-precision floating-point calculations and calculations of special functions. The e_float library supports 30 to 300 decimal digits of precision. It has an extendable architecture featuring a uniform C++ mathematical layer which can be used with any suitably prepared big-number back end such as GMP, MPFR, etc. The e_float system implements many high precision special functions and extends some of these to very large parameter ranges not available from other systems. Interoperability with Microsoft's CLR, Python (via Boost.Python) and Mathematica are supported. The e_float library is well-tested and has high performance. Further details can be found in my original work published in the ACM: Christopher Kormanyos, "Algorithm 910: A Portable C++ Multiple-Precision System for Special-Function Calculations", ACM Trans. Math. Soft. 37, 4, 2010, article 45. http://portal.acm.org/citation.cfm?id=1916469 e_float is potentially suited for boost because: * It provides a uniform, standardization-capable interface to multiple precision mathematics. * It has a sound mathematical foundation (published in the ACM). * It has been programmed from the ground up using modern C++ programming idioms. * It uses a layered architecture that hosts any number of big-number back ends. * It is highly portable, robust and durable. * It has a broad test suite developed in conjunction with code coverage analyses. * It is extendable. Additional functions, parameter ranges and test cases can be added. * It provides interfaces to very high level languages. Thank you for your feedback. Sincerely, Chris.

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[Review] The 'Type Traits Introspection' library Review starst next friday, july 1st
by Joel falcou 24 Jun '11

24 Jun '11

According to the schedule, review for the Type Traits Introspection library by Edward Diener will run from friday, July 1st to monday, july 10 2011. =========== What is it? =========== The TTI library, which is an abbreviation for the 'Type Traits Introspection' library, allows a programmer to introspect at compile time the inner elements of a C++ type. The introspection process depends on specifying the name of the inner element by different macros for different types of elements, and then using a generated metafunction to determine whether that element exists within the enclosing type. The inner elements which can be introspected are type, class template, member data, member function, static member data, and static member function. The TTI library is based on the type_traits_ext portion of the Concept Traits Library, with improvements and additions, and also reproduces functionality ( without changing existing code ), for the purposes of completeness, from Boost.MPL regarding introspection of types and templates. The purpose of the library is to provide a consistent set of interfaces for doing compile-time introspection of a type, which other template metaprogrammers can use in their code. If you are at all interested in compile-time introspection of types, please take a look at the functionality of this library. =================== Getting the library =================== The library is available at http://svn.boost.org/svn/boost/sandbox/tti/ Note that this repository will be updated up to next thursday by Edward. =================== Writing a Review =================== The reviews and all comments should be submitted to the developers list, and the email should have "[TTI] Review" at the beginning of the subject line to make sure it's not missed. Please explicitly state in your review whether the library should be accepted. The general review checklist: - 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.

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Re: [boost] Is there interest in an alternative to the Singleton anti-pattern?
by Ben Robinson 24 Jun '11

24 Jun '11

Antony, Thank you for your interest. The Singularity Pattern (as I am calling it) is policy based, and allows you to supply the threading model as a template parameter. If you choose the default policy of single_threaded, there is no thread safety, but there is also no overhead in using a mutex and using a volatile pointer. If you choose the multi_threaded policy, you get thread safety. The user of Singularity can also create a multi threaded policy of their own, implemented using the mutex of their choice, should their platform not support the boost::mutex. I am currently working as a real-time, embedded C++ developer, and therefore I often need to disable exceptions on small microcontrollers, and don't need/can't afford thread safety. That is why in addition to using a policy to control the threading model, I have implemented Singularity to use assert instead of exceptions, if BOOST_NO_EXCEPTIONS is defined. I look forward to your feedback on the Singularity Pattern. The unittests in Vault/Singularity/singularity_unittest.cpp are great to study first to see how Singularity is meant to be used. Thank you, Ben Robinson, Ph.D. My interest is piqued. Is your solution thread safe? Best regards, Antony Polukhin

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Re: [boost] Is there interest in an alternative to the Singleton anti-pattern?
by Ben Robinson 24 Jun '11

24 Jun '11

Matt, I am glad your interest is piqued (and I learned it is not spelled peaked). I have posted the source file, and a Boost Test unittest file in the Vault in the folder Singularity. Commenting on your first and second point, the Singularity Pattern (as I am calling it) is flexible enough to allow constructing the class with any supplied constructor. It is true you can construct a Singleton using the default constructor, and pass in dependencies via member functions, but you cannot pass in references this way. Singularity provides this flexibility which Singleton does not. I agree with you that the lifetime of Singleton is difficult to manage. The lifetime of a Singularity is bracketed by the calls to create() and destroy(), just like any other object created with new() and delete(). The difference being that new() can create any number of a objects, and Singularity::create() will only allow one. I look forward to your feedback on the pattern. I recommend looking at the usage in the Singularity/singularity_unittest.cpp file before studying the implementation. Thank you, Ben Robinson, Ph.D. On 6/23/2011 1:08 AM, Ben Robinson wrote: > The Singleton pattern does have its uses because it guarantees a single > instance of a class. However, it suffers from three weaknesses: > > 1) Encapsulation: Singleton provides global access to the class. Some may > view this as a feature, but advocates of unit testing, and dependency > injection would disagree. > 2) Initialization: Singleton restricts the class to the default constructor. > This makes Singleton unusable for classes which require non-default > constructors. > 3) Lifetime: Singleton introduces lifetime management complexities (for a > detailed discussion, see Chapter 6 of Modern C++ Design by Andrei * > Alexandrescu*). > > I have formalized what I believe is a novel design pattern, which guarantees > a single instance of a class, but which does not suffer 1-3 above. And > unlike Monostate, this pattern I propose does instantiate a genuine instance > of any class, using any one of its available constructors. I hope this > inquiry peaks your interest. I've often wondered about singleton's bad rap (other than the difficulty of making them reliable in C++). I use a singleton from the boost vault for hiding implementation details of globally accessible interfaces (e.g. an interface to access information about elements of the periodic table when I don't hard-code all the constants). This usage is unit testable as long as the implementation details can be thoroughly tested through the interface. It could support DI too if the dependencies are given to the singleton's methods instead of at construction. I don't understand weakness #2. My usage of singletons makes initialization an implementation detail. Construction is not part of the singleton's interface because constructing it different ways from different parts of the program would mean having more than a single instance. #3 is a indeed a bitch with C++. The boost vault solution I use makes it quite easy to chain singletons though. Nevertheless, my interest is piqued. Thanks, -Matt

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[1.47.0][range] boost::irange break change
by Akira Takahashi 24 Jun '11

24 Jun '11

Hi. https://svn.boost.org/trac/boost/ticket/5544 This ticket is break change. Please write history document, and release note. example: #include <iostream> #include <boost/range/irange.hpp> #include <boost/range/algorithm/for_each.hpp> void disp(int x) { std::cout << x << std::endl; } int main() { boost::for_each(boost::irange(0, 9, 2), disp); } 1.46.1 result: 0 2 4 6 1.47.0 result: 0 2 4 6 8 >>======================== Akira Takahashi mail : faithandbrave(a)gmail.com blog : http://d.hatena.ne.jp/faith_and_brave/

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[1.47] permission to merge doc change
by Eric Niebler 23 Jun '11

23 Jun '11

A minor and trivial doc-only change. Can I get another release manager's approval, please? https://svn.boost.org/trac/boost/changeset/72722 -- Eric Niebler BoostPro Computing http://www.boostpro.com

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[1.47] Beta build of PDF docs available
by John Maddock 23 Jun '11

23 Jun '11

A beta build of the PDF documentation for Boost-1.47 is available from http://sourceforge.net/projects/boost/files/boost-docs/1.47.0/boost_1_47_pd… As ever, only that subset of libraries that uses Quickbook/Boostbook/Docbook for documentation is included in the build. If library authors can take a look at let me know of any SNAFU's that would be great. New libraries added this time around are chrono, ratio, phoenix and geometry. Regards, John.

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[1.47.0] Beta 1 Release Notice
by Beman Dawes 23 Jun '11

23 Jun '11

Boost release 1.47.0 beta 1 is now available from SourceForge See http://sourceforge.net/projects/boost/files/ New Libraries: Chrono, Geometry, Phoenix and Ratio. Updated Libraries: Accumulators, Asio, Config, DateTime, Dynamic Bitset, Foreach, Function, Function Types, Graph, Iterator, Lexical Cast, Logic, Math, Meta State Machine, MultiIndex, Proto, Spirit, Tokenizer, Utility, Wave For details of what's in the release, see http://beta.boost.org/users/news/version_1_47_0. Note that the links to files on this web page are for the final release - use the SourceForge link above to get the beta files. There have been reports of build issues with MinGW/CGG and 64-bit Windows/VC++. These are being investigated and hopefully should be cleared up before the final release Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team Beman Dawes Daniel James Eric Niebler Rene Rivera Vladimir Prus

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Is there interest in an alternative to the Singleton anti-pattern?
by Ben Robinson 23 Jun '11

23 Jun '11

The Singleton pattern does have its uses because it guarantees a single instance of a class. However, it suffers from three weaknesses: 1) Encapsulation: Singleton provides global access to the class. Some may view this as a feature, but advocates of unit testing, and dependency injection would disagree. 2) Initialization: Singleton restricts the class to the default constructor. This makes Singleton unusable for classes which require non-default constructors. 3) Lifetime: Singleton introduces lifetime management complexities (for a detailed discussion, see Chapter 6 of Modern C++ Design by Andrei * Alexandrescu*). I have formalized what I believe is a novel design pattern, which guarantees a single instance of a class, but which does not suffer 1-3 above. And unlike Monostate, this pattern I propose does instantiate a genuine instance of any class, using any one of its available constructors. I hope this inquiry peaks your interest. Thank you, Ben Robinson, Ph.D.

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[typeof] deducing type at class level
by lcaminiti 23 Jun '11

23 Jun '11

Hello all, Is there any way to use BOOST_TYPEOF at class level? For example: struct vect { size_t size(); typedef BOOST_TYPEOF(size()) size_type; // can I make this work somehow? }; If not with Boost.Typeof, can I do this with C++0x? Thanks! --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/boost-typeof-deducing-type-at-class-leve… Sent from the Boost - Dev mailing list archive at Nabble.com.

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