February 2019 - Boost - lists.preview.boost.org

[gsoc2019][astronomy]
by rittik verma 12 Feb '19

12 Feb '19

Hello everyone, I am Rittik Verma, a third year Computer Science student. I am looking forward to contributing to the Astronomy library for GSoC 2019. I have studied the repository and would like to add the expected features to the library. I was wondering if the potential mentor has already paired up with a student or the position is still available? My projects: https://github.com/codectile Thank you

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GSoC 2019
by Shourya IIT B 12 Feb '19

12 Feb '19

Respected Sir, I am Parashuram Shourya from India. Currently, I am doing my Master’s in Geoinformatics from Centre of Studies in Resources Engineering(CSRE), Indian Institute of Technology Bombay(IITB). I have a Bachelor's degree in Computer Science and Engineering. Currently, I am learning Machine Learning and High-Performance Computing. I have vast programming experience in C, C++, Python I would love to contribute to Boost C++ Libraries in the upcoming Google Summer of Code 2019. I would be very grateful to get any directions to start with so that I can pursue and participate in GSoC 2019 with your organization.

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[GSOC 19] Programming competency test for ublas
by Amit Singh 10 Feb '19

10 Feb '19

Hi, My name is Amit Singh and I’m interested in machine learning lib for ublas as already provided in my idea list in mailing list. I have completed my programming competency test for ublas and wanted to know where to submit it.

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An interest in a neural net library?
by Sergei Marchenko 09 Feb '19

09 Feb '19

Hi everyone. I would like to get your opinion if there is any interest for a library that implements simple neural networks trained via backpropagation. The main idea is to define the configuration of a feed-forward multi-layer network via template parameters, and also provide implementations for a couple of well-known variations of networks (i.e. convolutional, sampling, network ensemble etc). // Define a network ensemble with two networks with the same input and output size, // but different number of neuron layers and different number of neurons in each layer. typedef neural_network<100, 50, 10> network_1; typedef neural_network<100, 70, 20, 10> network_2; auto network = ensemble(network_1(), network_2()); // Train the network from a training set. // item.input is a 100-element input vector. // item.target is the 10-element desired output vector. for (auto item : training_set) network.train(item.input, item.target, learning_rate); // Feed some input data into the network to get the result. auto result = network.process(input); This code on github that my nephew and myself wrote a couple of years ago can be used as a more detailed illustration for the idea: https://github.com/nsokolnikov/mathlib/blob/master/src/neuralnet.h Also, this github repo has two sample projects that illustrate usage of the library. First sample trains a simple network with a simulated activity pattern and then uses the network to classify more simulated load as low, medium, or high: https://github.com/nsokolnikov/mathlib/tree/master/samples/NeuralNetwork Second sample trains a network on a part of MNIST data set of hand-written digits, and then uses the network to recognize the remaining part of the MNIST data set: https://github.com/nsokolnikov/mathlib/tree/master/samples/TextRecognition Thank you, Serguei Martchenko

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Sorting and Searching Algorithms Library
by Siddhartha Sen 09 Feb '19

09 Feb '19

Actually, I am interested equally in both searching and sorting algorithms. In sorting algorithms, I am actually trying recursive implementations of all the known algorithms myself, to see if somehow I can find any variations or maybe even an whole new algorithm which can give a better time complexity. As far as searching algorithm goes, my knowledge is unfortunately limited to only binary search and linear search and DFS and BFS if graphs are counted . However I am working on patterns in numbers to try and create a generic searching algorithm for integer arrays and strings. Apart from this, I am afraid I don't have a lot of idea and hence I am seeking guidance. Thanks On Sat, 9 Feb, 2019, 5:30 PM , <boost-request(a)lists.boost.org> wrote: > Send Boost mailing list submissions to > boost(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.boost.org/mailman/listinfo.cgi/boost > or, via email, send a message with subject or body 'help' to > boost-request(a)lists.boost.org > > You can reach the person managing the list at > boost-owner(a)lists.boost.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Boost digest..." > > > The boost archives may be found at: http://lists.boost.org/Archives/boost/ > > > Today's Topics: > > 1. building boost libraries with pdb files under windows > (Sean Farrow) > 2. Re: Boost Digest, Vol 5998, Issue 1 (Siddhartha Sen) > 3. Re: building boost libraries with pdb files under windows > (Daniela Engert) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 8 Feb 2019 12:05:58 +0000 > From: Sean Farrow <sean.farrow(a)seanfarrow.co.uk> > To: "boost(a)lists.boost.org" <boost(a)lists.boost.org> > Subject: [boost] building boost libraries with pdb files under windows > Message-ID: > < > DB6PR0501MB27593FBAC29B49059A752178C6690(a)DB6PR0501MB2759.eurprd05.prod.outlook.com > > > > Content-Type: text/plain; charset="us-ascii" > > Hi, > > Is there a way to build boost libraries with PDB files under visual C++ > 2017? > > Any help appreciated. > > Kind regards > Sean. > > > ------------------------------ > > Message: 2 > Date: Fri, 8 Feb 2019 22:32:18 +0530 > From: Siddhartha Sen <siddhartha99.sen(a)gmail.com> > To: boost(a)lists.boost.org, phdcluster(a)gmail.com > Subject: Re: [boost] Boost Digest, Vol 5998, Issue 1 > Message-ID: > < > CA+iicpFdnd67wpP25MVjXtBxW5TFEkGb78XL-SK5RPosw_nMHQ(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Actually, I am interested equally in both searching and sorting algorithms. > In sorting algorithms, I am actually trying recursive implementations of > all the known algorithms myself, to see if somehow I can find any > variations or maybe even an whole new algorithm which can give a better > time complexity. As far as searching algorithm goes, my knowledge is > unfortunately limited to only binary search and linear search and DFS and > BFS if graphs are counted . However I am working on patterns in numbers to > try and create a generic searching algorithm for integer arrays and > strings. Apart from this, I am afraid I don't have a lot of idea and hence > I am seeking guidance. > Thanks > > On Fri, 8 Feb, 2019, 5:30 PM , <boost-request(a)lists.boost.org> wrote: > > > Send Boost mailing list submissions to > > boost(a)lists.boost.org > > > > To subscribe or unsubscribe via the World Wide Web, visit > > https://lists.boost.org/mailman/listinfo.cgi/boost > > or, via email, send a message with subject or body 'help' to > > boost-request(a)lists.boost.org > > > > You can reach the person managing the list at > > boost-owner(a)lists.boost.org > > > > When replying, please edit your Subject line so it is more specific > > than "Re: Contents of Boost digest..." > > > > > > The boost archives may be found at: > http://lists.boost.org/Archives/boost/ > > > > > > Today's Topics: > > > > 1. qxcalc(GSoC2019) (Ggh) > > 2. qxcalc(GSoC2019)-2 (Ggh) > > 3. Sorting Algorithms Library (Siddhartha Sen) > > 4. Re: Sorting Algorithms Library (phdcluster) > > 5. Re: Feedback desired for reflective enum library (David Sankel) > > > > > > ---------------------------------------------------------------------- > > > > Message: 1 > > Date: Thu, 07 Feb 2019 10:07:10 +0200 > > From: Ggh <ggh(a)multi.fi> > > To: boost(a)lists.boost.org > > Subject: [boost] qxcalc(GSoC2019) > > Message-ID: > > <20190207100710.Horde.VkEf1bfe3uAO1wELKmHKrul(a)webmail.multi.fi> > > Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes > > > > > > Hi all, > > Not sure if there is interest, but some years ago I coded a > > parser/lexer with flex and yacc to do math. > > > > The project is online here > > "http://qxcalc.sourceforge.net/" > > > > Greg > > > > > > > > ------------------------------ > > > > Message: 2 > > Date: Thu, 07 Feb 2019 11:01:16 +0200 > > From: Ggh <ggh(a)multi.fi> > > To: boost(a)lists.boost.org > > Subject: [boost] qxcalc(GSoC2019)-2 > > Message-ID: > > <20190207110116.Horde.VeAEqWouVIYk0-9NMfOsi9P(a)webmail.multi.fi> > > Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes > > > > Some links on my page(these pages are not always online): > > > > http://www.multi.fi/~ghaga/qxcalcdocs/html/index.html > > http://www.multi.fi/~ghaga/qxcalc/ > > http://www.multi.fi/~ghaga/qxcalc/download.php > > > > Ty, > > Greg > > > > > > > > > > ------------------------------ > > > > Message: 3 > > Date: Fri, 8 Feb 2019 01:43:42 +0530 > > From: Siddhartha Sen <siddhartha99.sen(a)gmail.com> > > To: boost(a)lists.boost.org > > Subject: [boost] Sorting Algorithms Library > > Message-ID: > > <CA+iicpGMx+zroF= > > RhE7AtAqJiN4Rw6Fz3hvPnvKmKP6+htKQJg(a)mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > Hi, > > This is Siddhartha Sen, a student of Information Science and > > Engineering. I am proficient in C++ and am particularly interested in > > sorting algorithms. Being a GSOC aspirant, I was looking to pair up with > a > > potential mentor in this domain, who could give me some much needed > > guidance. > > Thank You > > > > > > ------------------------------ > > > > Message: 4 > > Date: Thu, 7 Feb 2019 17:30:36 -0500 > > From: phdcluster <phdcluster(a)gmail.com> > > To: boost(a)lists.boost.org > > Cc: Siddhartha Sen <siddhartha99.sen(a)gmail.com> > > Subject: Re: [boost] Sorting Algorithms Library > > Message-ID: > > < > > CAKYCxYFSbMoxJf4ycjgMxLQSQq9ddkuZUa1BF7bMfBOhntWO1Q(a)mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > What particular sorting algorithm you are interested in? Or what > algorithms > > you have in mind? > > > > Thanks, > > > > Wen > > > > On Thu, Feb 7, 2019 at 3:50 PM Siddhartha Sen via Boost < > > boost(a)lists.boost.org> wrote: > > > > > Hi, > > > This is Siddhartha Sen, a student of Information Science and > > > Engineering. I am proficient in C++ and am particularly interested in > > > sorting algorithms. Being a GSOC aspirant, I was looking to pair up > with > > a > > > potential mentor in this domain, who could give me some much needed > > > guidance. > > > Thank You > > > > > > _______________________________________________ > > > Unsubscribe & other changes: > > > <http://lists.boost.org/mailman/listinfo.cgi/boost> > > > http://lists.boost.org/mailman/listinfo.cgi/boost > > > > > > > > > ------------------------------ > > > > Message: 5 > > Date: Thu, 7 Feb 2019 19:39:11 -0500 > > From: David Sankel <camior(a)gmail.com> > > To: Nir Friedman <quicknir(a)gmail.com> > > Cc: Boost <boost(a)lists.boost.org> > > Subject: Re: [boost] Feedback desired for reflective enum library > > Message-ID: > > < > > CAFYdOOLxMqup9-0Vub+UNJGgpvaqTGL0mWr1d1txuq4mstMJGg(a)mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > On Tue, Feb 5, 2019, 2:00 PM Nir Friedman <quicknir(a)gmail.com> wrote: > > > > > Sure, I'm open to such a thing. Although, I feel like there may be > > caveats > > > to that (i.e. whether the reflection TS interface is easy to use, > whether > > > it's easy to emulate library-only, how likely it is to continue > changing, > > > etc). Do you have a link to a paper that shows what the latest in the > > > reflection TS for enums looks like? > > > > > > > http://cplusplus.github.io/reflection-ts/draft.pdf > > > > > > > > > > > ------------------------------ > > > > Subject: Digest Footer > > > > _______________________________________________ > > Unsubscribe & other changes: > > http://lists.boost.org/mailman/listinfo.cgi/boost > > > > > > ------------------------------ > > > > End of Boost Digest, Vol 5998, Issue 1 > > ************************************** > > > > > ------------------------------ > > Message: 3 > Date: Fri, 8 Feb 2019 19:16:44 +0100 > From: Daniela Engert <dani(a)ngrt.de> > To: boost(a)lists.boost.org > Subject: Re: [boost] building boost libraries with pdb files under > windows > Message-ID: <9a268d74-c868-f79b-2f2e-52f693482356(a)ngrt.de> > Content-Type: text/plain; charset=iso-8859-15 > > Hi Sean! > > Am 08.02.2019 um 13:05 schrieb Sean Farrow via Boost: > > > Is there a way to build boost libraries with PDB files under visual C++ > 2017? > > Well, I am generating PDBs for a couple of years now using a slightly > modified msvc.jam (see > https://github.com/DanielaE/boost.build/commits/vc). Unfortunatly, this > is just a hack that happens to work well enough for my use-case and > requires an additional step to collect the PDBs from the build tree to > the stage directory using some script. Putting more effort into this > isn't economical for at most three distribution build per year. > > Ciao, > Dani > > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost > > > ------------------------------ > > End of Boost Digest, Vol 5999, Issue 1 > ************************************** >

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building boost libraries with pdb files under windows
by Sean Farrow 08 Feb '19

08 Feb '19

Hi, Is there a way to build boost libraries with PDB files under visual C++ 2017? Any help appreciated. Kind regards Sean.

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Re: [boost] Boost Digest, Vol 5998, Issue 1
by Siddhartha Sen 08 Feb '19

08 Feb '19

Actually, I am interested equally in both searching and sorting algorithms. In sorting algorithms, I am actually trying recursive implementations of all the known algorithms myself, to see if somehow I can find any variations or maybe even an whole new algorithm which can give a better time complexity. As far as searching algorithm goes, my knowledge is unfortunately limited to only binary search and linear search and DFS and BFS if graphs are counted . However I am working on patterns in numbers to try and create a generic searching algorithm for integer arrays and strings. Apart from this, I am afraid I don't have a lot of idea and hence I am seeking guidance. Thanks On Fri, 8 Feb, 2019, 5:30 PM , <boost-request(a)lists.boost.org> wrote: > Send Boost mailing list submissions to > boost(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.boost.org/mailman/listinfo.cgi/boost > or, via email, send a message with subject or body 'help' to > boost-request(a)lists.boost.org > > You can reach the person managing the list at > boost-owner(a)lists.boost.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Boost digest..." > > > The boost archives may be found at: http://lists.boost.org/Archives/boost/ > > > Today's Topics: > > 1. qxcalc(GSoC2019) (Ggh) > 2. qxcalc(GSoC2019)-2 (Ggh) > 3. Sorting Algorithms Library (Siddhartha Sen) > 4. Re: Sorting Algorithms Library (phdcluster) > 5. Re: Feedback desired for reflective enum library (David Sankel) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 07 Feb 2019 10:07:10 +0200 > From: Ggh <ggh(a)multi.fi> > To: boost(a)lists.boost.org > Subject: [boost] qxcalc(GSoC2019) > Message-ID: > <20190207100710.Horde.VkEf1bfe3uAO1wELKmHKrul(a)webmail.multi.fi> > Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes > > > Hi all, > Not sure if there is interest, but some years ago I coded a > parser/lexer with flex and yacc to do math. > > The project is online here > "http://qxcalc.sourceforge.net/" > > Greg > > > > ------------------------------ > > Message: 2 > Date: Thu, 07 Feb 2019 11:01:16 +0200 > From: Ggh <ggh(a)multi.fi> > To: boost(a)lists.boost.org > Subject: [boost] qxcalc(GSoC2019)-2 > Message-ID: > <20190207110116.Horde.VeAEqWouVIYk0-9NMfOsi9P(a)webmail.multi.fi> > Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes > > Some links on my page(these pages are not always online): > > http://www.multi.fi/~ghaga/qxcalcdocs/html/index.html > http://www.multi.fi/~ghaga/qxcalc/ > http://www.multi.fi/~ghaga/qxcalc/download.php > > Ty, > Greg > > > > > ------------------------------ > > Message: 3 > Date: Fri, 8 Feb 2019 01:43:42 +0530 > From: Siddhartha Sen <siddhartha99.sen(a)gmail.com> > To: boost(a)lists.boost.org > Subject: [boost] Sorting Algorithms Library > Message-ID: > <CA+iicpGMx+zroF= > RhE7AtAqJiN4Rw6Fz3hvPnvKmKP6+htKQJg(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Hi, > This is Siddhartha Sen, a student of Information Science and > Engineering. I am proficient in C++ and am particularly interested in > sorting algorithms. Being a GSOC aspirant, I was looking to pair up with a > potential mentor in this domain, who could give me some much needed > guidance. > Thank You > > > ------------------------------ > > Message: 4 > Date: Thu, 7 Feb 2019 17:30:36 -0500 > From: phdcluster <phdcluster(a)gmail.com> > To: boost(a)lists.boost.org > Cc: Siddhartha Sen <siddhartha99.sen(a)gmail.com> > Subject: Re: [boost] Sorting Algorithms Library > Message-ID: > < > CAKYCxYFSbMoxJf4ycjgMxLQSQq9ddkuZUa1BF7bMfBOhntWO1Q(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > What particular sorting algorithm you are interested in? Or what algorithms > you have in mind? > > Thanks, > > Wen > > On Thu, Feb 7, 2019 at 3:50 PM Siddhartha Sen via Boost < > boost(a)lists.boost.org> wrote: > > > Hi, > > This is Siddhartha Sen, a student of Information Science and > > Engineering. I am proficient in C++ and am particularly interested in > > sorting algorithms. Being a GSOC aspirant, I was looking to pair up with > a > > potential mentor in this domain, who could give me some much needed > > guidance. > > Thank You > > > > _______________________________________________ > > Unsubscribe & other changes: > > <http://lists.boost.org/mailman/listinfo.cgi/boost> > > http://lists.boost.org/mailman/listinfo.cgi/boost > > > > > ------------------------------ > > Message: 5 > Date: Thu, 7 Feb 2019 19:39:11 -0500 > From: David Sankel <camior(a)gmail.com> > To: Nir Friedman <quicknir(a)gmail.com> > Cc: Boost <boost(a)lists.boost.org> > Subject: Re: [boost] Feedback desired for reflective enum library > Message-ID: > < > CAFYdOOLxMqup9-0Vub+UNJGgpvaqTGL0mWr1d1txuq4mstMJGg(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > On Tue, Feb 5, 2019, 2:00 PM Nir Friedman <quicknir(a)gmail.com> wrote: > > > Sure, I'm open to such a thing. Although, I feel like there may be > caveats > > to that (i.e. whether the reflection TS interface is easy to use, whether > > it's easy to emulate library-only, how likely it is to continue changing, > > etc). Do you have a link to a paper that shows what the latest in the > > reflection TS for enums looks like? > > > > http://cplusplus.github.io/reflection-ts/draft.pdf > > > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost > > > ------------------------------ > > End of Boost Digest, Vol 5998, Issue 1 > ************************************** >

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Feedback desired for reflective enum library
by Nir Friedman 08 Feb '19

08 Feb '19

Hey, I have a reflective enum library available here: https://github.com/quicknir/wise_enum. I've been working on this on and off for a couple of months. I've added features, dealt with various issues, added docs, expanded support through 11-17 and as idiomatically as possible. Overall I think the library is in nice shape (lacks unit tests though, though I do already have a boost license for the code). I feel like a reflective enum is just a very standard requirement in pretty much every codebase I've ever worked on. Simply to be able to reasonably log enums already makes it mandatory. It's also invaluable in configuration, error message alerting, and many other places. There is nothing for this in boost and actually there isn't really much of a standard, standalone solution anyway. The closest is Better Enums ( http://aantron.github.io/better-enums/), but this has some major issues (it doesn't actually create enums but rather enum-like classes, it targets 03). So I think a library like this is needed and my implementation ticks off the major requirements. Feedback on the overall design, any issues, any key features it fails to meet, would be very useful. The library itself is very small and simple so its easy to review. Once it seems like there's some consensus on the core design I'm willing to do the work involved getting it into boost (naming conventions/requirements, directory structure, tests, boost-style docs, etc). Note I'm not on the boost mailing list so please respond directly to this email so I can see! Cheers, Nir

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Sorting Algorithms Library
by Siddhartha Sen 07 Feb '19

07 Feb '19

Hi, This is Siddhartha Sen, a student of Information Science and Engineering. I am proficient in C++ and am particularly interested in sorting algorithms. Being a GSOC aspirant, I was looking to pair up with a potential mentor in this domain, who could give me some much needed guidance. Thank You

2 1

qxcalc(GSoC2019)-2
by Ggh 07 Feb '19

07 Feb '19

Some links on my page(these pages are not always online): http://www.multi.fi/~ghaga/qxcalcdocs/html/index.html http://www.multi.fi/~ghaga/qxcalc/ http://www.multi.fi/~ghaga/qxcalc/download.php Ty, Greg

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qxcalc(GSoC2019)
by Ggh 07 Feb '19

07 Feb '19

Hi all, Not sure if there is interest, but some years ago I coded a parser/lexer with flex and yacc to do math. The project is online here "http://qxcalc.sourceforge.net/" Greg

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GSoC 2019
by David Bellot 07 Feb '19

07 Feb '19

Hi Boost community, this year again we applied to the GSoC programm, Google Summer of Code. We hope to be as successfull as usual. I'm taking care of the admin work again this year. I completed an application for Boost on the Google website. It is somehow similar to our successfull applications from previous years. What we need from the community now is the following: 1) if you want to be a backup admin (I will need maybe one or two extra names at most), please let me know and I'll send you an invite. 2) if you wish to be a mentor, please let us know now and if possible on this mailing list so that students will be aware of it too. Don't forget to put the [gsoc2019] tag in the header of your email. You can write your proposals on this wiki: https://github.com/boostorg/boost/wiki/Google-Summer-of-Code:-2019 Ideally, we want to see many proposals before beginning of next week. 3) if you are a student and wants to participate, it's about time to speak loudly on the mailing list to pair with a potential mentor. The sooner the better. You can find ideas from previous years here: https://github.com/boostorg/boost/wiki/Google-Summer-of-Code%3A-Overview Happy coding. David

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find_package(Boost) support
by Peter Dimov 04 Feb '19

04 Feb '19

The current master and develop branches now install the necessary BoostConfig.cmake file (in $prefix/lib/cmake) such that f.ex. the CMake command find_package(Boost REQUIRED filesystem) will find Boost 1.70 using the config file, rather than via FindBoost.cmake (*) (if the Boost installation prefix is in CMake's prefix search path.) Interested parties are invited to test this support and share their experiences. Instead of a Git checkout, you can use the 1.70 release snapshots from https://dl.bintray.com/boostorg/master/ or https://dl.bintray.com/boostorg/develop/, as those better represent what the 1.70 release will contain. (*) Actually, the above command will invoke FindBoost.cmake, but FindBoost will look for a config file as a first step and use that, if found. To disable FindBoost completely, use find_package(Boost CONFIG REQUIRED filesystem) Or, on Windows, assuming the default C:\Boost installation, find_package(Boost REQUIRED filesystem PATHS C:/Boost)

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Coordinating Parameter 'master' merging for dependent libraries
by Edward Diener 03 Feb '19

03 Feb '19

I intend to merge Parameter 'develop' to 'master' for the next release of Boost. Cromwell Enage has done a great job of adding modern improvements to the Parameter library via PRs, while maintaining full backward compatibility with the Parameter public interface. I have reviewed and approved those changes and, where I have been lax, Peter Dimov has pointed out weaknesses in some of those changes, which Cromwell has corrected. The changes which Cromwell has made have also involved improvements in the Parameter private interface(s), which have entailed some updates to the 'develop' branch of some Boost libraries which unfortunately depended on some aspects of the Parameter private interface. These updates have already been made in those other library's 'develop' branch. At this point any further possible changes for Parameter for a while will very likely be in the Parameter documentation, which requires no syncing with other libraries, so this is an excellent time for merging. Since the merging for other libraries dependent on Parameter must be synced to the merging of Parameter from 'develop' to 'master' what is the best way to go about this ? Obviously I have first to merge Cromwell's changes from 'develop' to 'master', which is easily done. How should I inform other libraries that they need to merge their Parameter dependent 'develop' changes to 'master' ? Should I create PRs for doing this ? We do not normally create PRs for the 'master' branch of any Boost library. Should I create Issues for those other libraries and hope the maintainers of the other libraries will take the appropriate action ? Or should I inform the maintainers of the other libraries in this thread, and prompt them to review their changes here to get them to merge them from 'develop' to 'master' ? The other libraries involved are: Accumulators, Log, Convert, Lockfree, Signals2, and Graph. Cromwell knows more about the specific 'develop' changes in those libraries which need to be merged to 'master' than I do, since he was instrumental in creating the PRs that would allow these libraries to work with the updated Parameters' internals, so he may chime in here, but I would like to get this done so that Parameter and its dependent Boost libraries get properly updated for the next Boost release. Of course I will also plan with Cromwell update notes for Parameter to be part of the next release.

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[GSoC19] run-time Ratios
by Fenil Mehta 03 Feb '19

03 Feb '19

Hi everyone, It has been noticed that C++ provides a class to store ratios/fractions at compile-time. They provide very limited functionalities and are not modifiable during run-time. My *idea* is to have a *Ratio class* which provides all the necessary functionalities at run-time as well. I have already implemented this partially and I am willing to make it 100% ready for inclusion in Boost. Some guidance would be appreciated on how to proceed with this idea for GSoC19. Would anybody be interested in mentoring this idea for GSoC19 ? Regards, Fenil Mehta

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[interprocess] 32-bit offset_ptr
by Phil Endecott 03 Feb '19

03 Feb '19

Dear Experts, I have some old code that uses 32-bit offset_ptrs, i.e. typedef boost::interprocess::offset_ptr<void, int32_t, int32_t> ptr_t; This has stopped working on 64-bit systems at some point since 1.58. git blame suggests a commit on 14 Oct 2015. There is now a static assert that checks that OffsetType is at least as large as a raw pointer. In the current case, I'm using these pointers within memory-mapped files which will always be vastly smaller than the 32-bit limit. Using 32-bit offsets seemed like a worthwhile optimisation at the time, and now I am hoping to maintain binary compatibility with those files. In the past I've also used them to save memory on 64-bit systems with pointer-heavy data structures (using boost.intrusive) using an allocator that operates within a small memory region. Has something changed within the implementation that makes this restriction necessary? Was it never supposed to work as I was using it? There is also an assert that OffsetType is unsigned, which wasn't there before. Maybe I was doing that wrong. Thanks for any advice. Regards, Phil.

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[GSOC 19] Boost.ublas project Idea
by Amit Singh 02 Feb '19

02 Feb '19

Hi, My name is Amit Singh and I’m a 2nd year student. 1. I have studied last years ublas stats project and before that ublas lacked any statistics features, I would like to take boost.ublas stats further with 1. Linear Regression 2. Logistic Regression 3. Rigid Regression 4. Kernels ( Exponential Kernel, Gaussian Kernel, etc) 5. Correlation (Pearson product-moment correlation, Linear correlation, etc) 2. In ublas there is no expression solver which can solve a expression and assign the value to variable for ex:- A. matrix<double> m = “A^2 * (B * A^-1) + (det(A) * I)”; B. matrix<double> m = “A + 3” ; =>[ m = A + 3*I ] 3. In ublas to modify matrix you have to iterate using for loop. I’m hoping to create a function similar to transform in c++ or map in javascript 1. This is my small machine learning library that I implemented in c++ https://github.com/amitsingh19975/ML Would anybody be interested in mentoring my project for gsoc 19? or help me to improve my project ideas.

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[thread] Passing function with parameters to boost::barrier
by André Offringa 01 Feb '19

01 Feb '19

Hi Boost developers, I'm having a problem with passing a completion function to a boost::barrier, causing a segfault, and I suspect it is a bug in the barrier code. The following is a minimal example that shows the problem: #include <boost/thread/barrier.hpp> void func(int) { } int main() { boost::barrier b(1, std::bind(func, 42)); b.wait(); } Running inside gdb and doing a bt shows some infinite recursion happening, starting with: #0 0x000055555555e41a in boost::thread_detail::decay_copy<boost::detail::nullary_function<void ()>&>(boost::detail::nullary_function<void ()>&) ( t=<error reading variable: Cannot access memory at address 0x7fffff7feff0>) at /usr/include/boost/thread/detail/move.hpp:355 #1 0x000055555555d814 in boost::detail::nullary_function<void ()>::nullary_function<boost::detail::nullary_function<void ()>&>(boost::detail::nullary_function<void ()>&) ( this=0x7fffff7ff0c0, f=...) at /usr/include/boost/thread/detail/nullary_function.hpp:81 ... When I change "std::bind(func, 42)" to just "func" (and declare func without parameters), it does work and the program exits normally. Passing a lambda to barrier (e.g. barrier(1, [&]() { func(0); } ) ) causes the same segfault, and the same holds when I change std::bind to boost::bind. I'm using Boost 1.67 on Debian Linux, amd64, gcc 8.2.0. Is this a bug? Cheers, André

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