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[release] 1.66.0 fully closed for beta
by Daniel James 15 Nov '17

15 Nov '17

I've stopped updating the master branch of the super project, and will try to get the beta release out tomorrow, so there's only a little delay. You can still add your release notes at: <https://github.com/boostorg/website/blob/master/feed/history/boost_1_66_0.q…> Thanks, -- The Boost Release Team

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Re: [boost] seeking endorsement for histogram library
by Hans Dembinski 15 Nov '17

15 Nov '17

Dear Fabian, I am CCing boost, because maybe some others want to read this as well and/or correct me. > On 15. Nov 2017, at 14:21, Fabian Bösch <boeschf(a)student.ethz.ch> wrote: > > Thanks for clarifying. While it is true that Boost.Accumulators does > this, it is for the uni-variate case only, afaik. Please correct me, if > I'm wrong. I believe you can compute a multi-dimensional mean, if you feed an appropriate Boost.Accumulator with std::valarrays. Maybe there is an easier way. > Now you have multi-variate histograms for which one would probably also > like to know the Covariance (rank-2 tensor), for example. Maybe this is > out of scope but a general solution for this would be nice. But perhaps > this would rather be addressed in another generalized accumulator > library. What do you think? I think you are right. You can compute the covariance of two variables with Boost.Accumulators: http://www.boost.org/doc/libs/1_65_0/doc/html/accumulators/user_s_guide.htm… but it does not give you a full matrix for N covariates. Maybe you could contact the maintainer of Accumulators, Eric Niebler. It is a reasonable request that would fit better into Accumulators than in Histogram. Best regards, Hans

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Re: [boost] seeking endorsement for histogram library
by Hans Dembinski 15 Nov '17

15 Nov '17

Dear Francesco, > On 13. Nov 2017, at 19:09, Francesco Guerrieri <f.guerrieri(a)gmail.com> wrote: > > Hi this proposal is of great interest to me, thanks for sharing your work with us. Which compilers/OSs are supported? I tested the code on OSX with Apple clang, and via TravisCI on several versions of gcc on Linux. The CMake build works on both OSX and Linux. I wanted to also test Windows via Appveyor, but couldn't get my CMake build script to work with msvc. I am passing compiler flags directly, which works for clang and gcc, but naturally not for msvc. Debugging this non-interactively, by committing a change to github, letting Appveyor run, seeing it breaking again..., was a pain and I stopped at some point. If an expert for Windows had a look at my CMakeLists.txt, it is probably something that could be easily fixed. Best regards, Hans

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seeking endorsement for histogram library
by Hans Dembinski 14 Nov '17

14 Nov '17

Dear Boost developers, I believe the histogram library is now ready to be presented here and I am looking for endorsement. Histogram is a C++11 header-only library that provides a safe, convenient, and fast multi-dimensional histogram for statistical analysis and visualisation. The library has a unique feature set, among it a safety guarantee that the counts in the histogram cannot overflow. It is easily customisable for power users, while providing defaults that just work for the occasional user. Meta-programming is used to provide an especially fast histogram implementation that can be used when the histogram configuration is known at compile-time. A dynamic implementation is also provided for the other case when the configuration is only known at run-time. The two implementations share a common interface, so it is easy to switch between them. Python bindings are included for the dynamic implementation. The Python interface supports Numpy arrays to greatly speed up the exchange of data between the Python and C++ side. I tested the performance of the library in benchmarks against other libraries, which have fewer features, and this library beats them in almost all cases. I am stealing the style of the rest of the email from Antony Polukhin. Library: https://github.com/HDembinski/histogram <https://github.com/HDembinski/histogram> Docs: https://htmlpreview.github.io/?https://raw.githubusercontent.com/HDembinski… <https://htmlpreview.github.io/?https://raw.githubusercontent.com/HDembinski…> Boost Library Incubator: http://blincubator.com/bi_library/histogram-2/?gform_post_id=1582 <http://blincubator.com/bi_library/histogram-2/?gform_post_id=1582> Library changes since last mail: * Support for efficient adding of multiple histograms and scaling * Support for reduce transformation * Re-design of category axis as a general mapping between unique values and bins * Re-design of the bin description an axis returns upon element access * Regular axis can accepted bijective (user-provided) transformations * Interface cleanup, refactoring, and simplification * Finished documentation Best regards, Hans

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[test] [build] best practices for looking up data files from test executables
by Stefan Seefeld 14 Nov '17

14 Nov '17

Hi there, I'm trying to write a test that needs to access a data file. As I'm surely not the first wanting to use external data in my tests, I wonder whether there are established "best practices" or idioms when using Boost.Build and Boost.Test. My first attempt was to compute the relative path using the test source's `__FILE__`, until I realized the path was invalid due to the build logic moving executables before running them. Then I considered using a command-line option to point at the data directory, but that seems quite involved when using boost::test (and BOOST_TEST_MODULE)... Any suggestions for how to approach this ? Thanks, Stefan -- ...ich hab' noch einen Koffer in Berlin...

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Exceptions vs Assertion for library API?
by Jonathan Biggar 13 Nov '17

13 Nov '17

Any advice in choosing between throwing an exception vs asserting for invalid uses of a library API? I'm building a small "transactional" library I'd like to contribute to boost where certain API calls are constrained to only be valid if the transaction is still "in-progress". Such calls will never succeed, and are easy for the implementation to diagnose. I'd like to have the library fail an assertion, which is far clearer to the user that the code logic is incorrect, but it bothers me that assertions are much more difficult to write unit tests for. (Is there even a concept of a test that passes if if fails to compile or fails with an assertion in the boost testing framework?) I suppose I could mangle the interface to ensure that the user has nothing to invoke the API calls in question unless the transaction is in-progress, but that generally requires a custom "lock" interface for my RAII implementation that makes the API more complex to grasp. -- Jon Biggar jon(a)biggar.org

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[release] 1.66.0 closing for beta tomorrow
by Daniel James 13 Nov '17

13 Nov '17

Hi, I'll close the master branch for the beta release tomorrow. Sorry we've been quiet about the release and that this is a bit short notice. If you haven't written your release notes yet, you can add them to: https://github.com/boostorg/website/blob/master/feed/history/boost_1_66_0.q… Use the pencil icon at the top right of the code to edit it, or you can mail your notes to me, and I'll add them. thanks, Daniel

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[release][1.66.0] Permission to merge Hana
by Louis Dionne 12 Nov '17

12 Nov '17

Hi, Being at a C++ meeting all week, I did not see the release coming and the email in time. None of the changes to Hana have been merged to master, and I'd like to get them in for the release. Can I merge them, or should I wait until after the beta? Thanks and apologies for the untimeliness, Louis -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Dev-f2600599.html

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[release][1.66.0] Permission to merge Predef.
by Rene Rivera 10 Nov '17

10 Nov '17

Some late fixes for Predef came in over the past two days: < https://github.com/boostorg/predef/commit/4a230ebe853980e27e7fb7cb36605fd6c… > < https://github.com/boostorg/predef/commit/74f88005cc2227b4f8fd4d640daae18c2… > < https://github.com/boostorg/predef/commit/5e8f5d5a4b9df640ffaeaf51e89c83e28… > Can I merge those to master for the beta? -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net

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Seeking endorsement for the reflection library (PFR)
by Antony Polukhin 10 Nov '17

10 Nov '17

Hello, PFR is a C++14 library that provides tuple-like methods for aggregate initializables. Library has a set of predefined operators and useful functions for everyday use. Works with user-defined types without any macro or boilerplate code. Library: https://github.com/apolukhin/magic_get Docs: http://apolukhin.github.io/magic_get/ Boost Library Incubator: http://blincubator.com/bi_library/pfr-pod-flat-reflection/?gform_post_id=16… Seeking for some endorsement, as per http://www.boost.org/development/submissions.html Library changes since last mail: * Now works on latest MSVC in C++17 mode * C++14 limitations in reflection were significantly relaxed * Removed UB (no more reinterpret casting of unrelated types!) * Thaler Benedek was approved as a review manager for the library. Boost libraries that may benefit from PFR: * Convert - for out-of-the-box conversions of user types * Hana - for using user types instead of tuples * Intrusive - for reusing unused bits in user provided types * Serialization - for out-of-the-box serialization of user types * Spirit - for putting rule results into user provided types without Phoenix or Fusion macro * Test - for outputting content of user provided types * TypeTraits - for traits like has_unique_object_representations in C++14 -- Best regards, Antony Polukhin

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