- Boost-users - lists.boost.org

trying to create a vector of histograms
by damien＠khubla.com 20 Jul '19

20 Jul '19

Hi all, As the subject says, I'm trying to create a vector of histograms. This needs to be a member variable of a class so I need to get the types right in the declaration. I keep getting type conversion errors when I pass the axis to the constructor, so I'm trying a non-vector example. Here's the base code: using UU = boost::histogram::unlimited_storage<std::allocator<double> >; using AA = std::tuple<boost::histogram::axis::variable<double> >; AA ax; boost::histogram::histogram<AA, UU> histo; histo = boost::histogram::histogram(ax); //this has a conversion problem The error on VS 2017 is: error C2440: '<function-style-cast>': cannot convert from 'boost::histogram::axis::variable<double,boost::use_default,boost::use_defau lt,std::allocator<_Ty>>' to 'boost::histogram::histogram<boost::histogram::axis::variable<double,boost:: use_default,boost::use_default,std::allocator<_Ty>>,boost::histogram::defaul t_storage>' with [ _Ty=double ] note: No constructor could take the source type, or constructor overload resolution was ambiguous I can see that the types are different, but no matter what I do with the template arguments of the axis type I still get that error. Can anyone help? Damien

1 1

[release] Boost 1.71.0 Beta 1
by Michael Caisse 19 Jul '19

19 Jul '19

Boost release 1.71.0 beta 1 is now available at: <https://dl.bintray.com/boostorg/beta/1.71.0.beta1.rc1/source/> The SHA256 checksums are as follows: 451adc4f199c73e995e541f38c4dbd51faf4ce0db15537136ffd5213a1be5e55 boost_1_71_0_b1_rc1.7z a93d7066fc1514995aec0e726532a219447dd39b0ffa7cb97ca5736f16b0488b boost_1_71_0_b1_rc1.tar.bz2 34743b80466463e0c1b7fc71b677f326bdc242fe0b87a9c1599b6f7ea6e5c0cb boost_1_71_0_b1_rc1.tar.gz 5cd448bddc8394469391306e0ccada0a8f88c5c6cf8ec775ddf8e56adef8bbc2 boost_1_71_0_b1_rc1.zip For details of what's in the release, see <http://www.boost.org/users/history/version_1_71_0.html>. Note: Having some trouble getting the web page updated... check back with it soon. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

2 4

boost::filtered_graph filtering on vertex color... if I only had a colormap
by Brian Davis 19 Jul '19

19 Jul '19

Lets say I have a graph g (of type graph_t) and a color map (boy I wish I had a colormap): typedef boost::property_map<graph_t, boost::vertex_color_t>::type color_map_t; or is it? auto indexmap = boost::get(boost::vertex_index, g); auto colors = boost::make_vector_property_map<boost::default_color_type>(indexmap); or maybe? auto indexmap = boost::get(boost::vertex_index, g); auto colors = boost::make_vector_property_map<boost::vertex_color_t>(indexmap); or possibly some goop found on the internet? boost::make_iterator_property_map(color_map.begin(), boost::get(boost::vertex_index, data_->g), color_map[0]) or other internet goop? typedef boost::property_map<GraphType, boost::vertex_color_t>::type color_map_t; color_map_t colorMap; boost::color_map(colorMap)) or other internet goop?? std::vector<int> colorMap(num_vertices(g), boost::white_color); so confused... (certainly not surprised why bgl is not a part of stl) Can someone help explain the various types and ways of specifying colormaps and the logic for each way and means? and a function (if I could get that far without VS syntax highlighter going bonkers and gobs of compiler errors.. you know the type): make_pretty(g, colormap ) which colors the graph colormap and a filter struct for boost::filtered_graph<Graph, EdgePredicate, VertexPredicate> (where I wonder why if I only want to filter vertices I have to set boost::keep_all for EdgePredicate... sigh... I know the answer... and also know how long it found me to find/figure out boost::keep_all - and if you are looking for boost::keep_all and found it here... your welcome ;-) ) and modifying (probably incorrectly) boost::filtered_graph example to: template <typename ColorMap> struct vertex_color_filter_eq { vertex_color_filter_eq() { } vertex_color_filter_eq(ColorMap colormap/*, boost::default_color_type c*/) : m_colormap(colormap)/*, m_c(c)*/ { } template <typename Vertex> bool operator()(const Vertex& v) const { return 0 < get(m_colormap, v); //return c < get(m_colormap, v); } ColorMap m_colormap; //boost::default_color_type m_c; }; auto indexmap = boost::get(boost::vertex_index, g); auto colors = boost::make_vector_property_map<boost::default_color_type>(indexmap); // some where here I would call make_pretty(g, colors) typedef property_map<graph_t, boost::vertex_color_t>::type ColorMap_t; vertex_color_filter<ColorMap_t> filter(colors); // boost::filtered_graph<graph_t, boost::keep_all, VertexPredicate> boost::filtered_graph<graph_t, boost::keep_all, vertex_color_filter> fg(g, filter); // Later say if I could get it compile and better if it compiled and worked I could move on and auto color = boost::red_color; typedef property_map<graph_t, boost::vertex_color_t>::type ColorMap_t; vertex_color_filter<ColorMap_t> filter(colors, color); boost::filtered_graph<graph_t, boost::keep_all, vertex_color_filter> fg(g, filter); Maybe if I color them yellow, I can then reach the wizard pull back the curtain and ask how to create a color map... If I only had a color map.

4 6

How can I create an internal and modifiable color_map for boost DFS?
by Juergen 19 Jul '19

19 Jul '19

Hello, everybody, at the moment I am really lost. The problem is to create the color map that can be used in Depth_First_Search. A special feature that I have is that I want to change the Vertex color of DFS to modify the DFS. For example like this: If I make the color map global and pass it to the visitor, everything works: If the color map is not global but external, I can write the map, but it is not the same as the DFS color map and therefore I cannot manipulate the DFS algorithm: I then tried to create an internal map and work with the get() and put() functions, but I didn't succeed: I'd be so grateful if you'd give me a hint. -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Users-f2553780.html

1 0

R: Support on Websoscket Plugin
by Clinco Fabrizio 17 Jul '19

17 Jul '19

Hello, for the Enterprise project I'm working on, we're looking for a library that implements the WebSocket Protocol (RFC 6455). As we consider your implementation very useful for our needs, we would like to know if you have a library compatible with the C ++ 98 standard on embedded emvironmant. Thank you in advance for your support, Fabrizio Fabrizio Clinco Delivery Manager Application Integration Digital Factory email: fabrizio.clinco(a)exprivia.com<mailto:fabrizio.clinco@exprivia.com> m.: +39 3427218158 [https://dbg.exprivia.it/exprivia-resources/images/Image/marchio-congiunto.j…] Exprivia S.p.A. Via Adriano Olivetti 11/a 70056 Molfetta (BA) T. +39 0803382070 F. +39 0803382077 www.exprivia.it<http://www.exprivia.it/> Exprivia Italtel Group Internet Email Confidentiality Footer ** La presente comunicazione, con le informazioni in essa contenute e ogni documento o file allegato, e' rivolta unicamente alla/e persona/e cui e' indirizzata ed alle altre da questa autorizzata/e a riceverla. Se non siete i destinatari/autorizzati siete avvisati che qualsiasi azione, copia, comunicazione, divulgazione o simili basate sul contenuto di tali informazioni e' vietata e potrebbe essere contro la legge (art. 616 C.P., D.Lgs n. 196/2003 Codice in materia di protezione dei dati personali). Se avete ricevuto questa comunicazione per errore, vi preghiamo di darne immediata notizia al mittente e di distruggere il messaggio originale e ogni file allegato senza farne copia alcuna o riprodurne in alcun modo il contenuto. Al link seguente e' disponibile l'informativa Privacy: https://www.exprivia.it/it/132/cookie-and-privacy-policy.php ** This e-mail and its attachments are intended for the addressee(s) only and are confidential and/or may contain legally privileged information. If you have received this message by mistake or are not one of the addressees above, you may take no action based on it, and you may not copy or show it to anyone; please reply to this e-mail and point out the error which has occurred. Click here to read your privacy notice: https://www.exprivia.it/it/132/cookie-and-privacy-policy.php

1 0

boost::asio::steady_timer only firing once
by Christopher Pisz 16 Jul '19

16 Jul '19

I am trying to perform a task on an interval and I made a POC using boost::asio::steady_timer. When I debug it, it only performs the callback once and does not fire again. I am not sure what I am doing wrong. Any suggestions? // DoMouseEvents.cpp : This file contains the 'main' function. Program execution begins and ends there. // #include <boost/asio.hpp> #include "boost/asio/deadline_timer.hpp" #include<boost/bind.hpp> #include <chrono> #include <iostream> class Pooper { boost::asio::io_context & m_ioContext; boost::asio::steady_timer m_timer; public: Pooper(boost::asio::io_context & ioContext) : m_ioContext(ioContext) , m_timer(boost::asio::steady_timer(ioContext)) { } void Run() { m_timer.expires_from_now(std::chrono::seconds(5)); m_timer.async_wait(boost::bind(&Pooper::OnTimerExpired, this, boost::asio::placeholders::error)); } void OnTimerExpired(const boost::system::error_code & error) { if (error.failed()) { std::cerr << "boost error: Failed" << std::endl; } std::cout << "Poop" << std::endl; try { // Move the mouse int x = 500; int y = 500; if (!::SetCursorPos(x, y)) { int errorCode = GetLastError(); std::cerr << "SetCursorPos error: " << errorCode << std::endl; } // Left button down x = 65536 * 500; y = 65536 * 500; ::mouse_event(MOUSEEVENTF_ABSOLUTE | MOUSEEVENTF_LEFTDOWN, x, y, NULL, NULL); // Left button up x = 65536 * 500; y = 65536 * 500; ::mouse_event(MOUSEEVENTF_ABSOLUTE | MOUSEEVENTF_LEFTUP, x, y, NULL, NULL); m_timer.expires_from_now(std::chrono::seconds(5)); m_timer.async_wait(boost::bind(&Pooper::OnTimerExpired, this, boost::asio::placeholders::error)); } catch (std::exception &) { std::cerr << "An exception occured." << std::endl; } } }; int main() { boost::asio::io_context ioContext; auto pooper = Pooper(ioContext); pooper.Run(); ioContext.run(); std::cerr << "Exited..." << std::endl; }

6 10

[multiprecision] Getting the best performance on windows for uint128_t etc
by Neill Clift 14 Jul '19

14 Jul '19

Hi, I develop a program for generating optimal addition chains. I normally use 64 bit integers but in order to attack some conjectures I compile up my program with boost using uint128_t. In order to get some functionality I need I used the backend access to limbs. For example I need population count/hamming weight/binary digit count. I did this like this: static LPTYPER bits(NTYPE n) /*++ Calculates the number of 1 bits in a number. --*/ { LPTYPER b = 0; std::size_t size = n.backend().size(); boost::multiprecision::limb_type* p = n.backend().limbs(); for (std::size_t i = 0; i < size; i++) { b += (LPTYPER)__popcnt64(p[i]); } return b; } I use the same sort of logic to calculate Floor(Log2(n)) (number of largest bit set), to clear the bottom say b bits of an integer. Is this a reasonable (though probably not idea) way to go? I noted that the limbs are 32 bits on Windows and this leads me to my second question. How can I get the internals of boost using bigger chunks like 64 bit? It seems I need a compiler supporting __int64. I have access to the intel compiler (19) and MSVC but neither seem to change this. I tried LLVM but that seemed quite slow. I may not have put enough effort into investigating LLVM up to this point. Various bit operations seem overly slow in boost. For example I use sequences like this: Control &= Control + 1; Mask = ((Control - 1) ^ Control) >> 1; Control |= Mask; These seem to be bottlenecks under boost. That sequence above is meant to generate masks that straddle the first run of zero bits in control so 1010100000111111_2 produces a mask of 11111111111_2. Thanks. Neill. Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10

4 7

A question regarding gregorian week_iterator
by Bill Moo 12 Jul '19

12 Jul '19

I can’t understand what, if indeed anything, I am doing wrong here. Using boost 1.69 on Arch Linux I am trying to use a gregorian::week_iterator to iterate a gregorian date_period that has a length of 365 which produces this output: Starts 2018-07-10 Ends 2019-07-10 true false true 365 >From this code: boost::gregorian::date_period dp{ m_Start, m_Ends } ; BOOST_LOG(lg) << "Starts " << boost::gregorian::to_iso_extended_string(dp.begin()) << " Ends " << boost::gregorian::to_iso_extended_string(dp.end()) << " " << isYear << " " << isMonth << " " << isWeek << " " << dp.length() ; The following is the code I am using to iterate the date_period: for(boost::gregorian::week_iterator wi = dp.begin(); wi != dp.end(); ++wi) { items.push_back(formatParams(pi, (*wi))) ; } However, when this code executes it eventually fails with the following error: Year is out of valid range: 1400..9999 In my formatParams method the code generates the correct strings, but it doesn’t stop at Jun 2019 as I’d expect but continues to run out to 2375! I would appreciate some feedback on this as I have identical code that uses a gregorian::month_iterator and this generates the 12 items from the same date_period range as I’d expect. -- Bill

3 5

The out_ptr review is now over
by Zach Laine 11 Jul '19

11 Jul '19

Thanks to all that participated. A review result with be posted sometime in the next couple of weeks (the upcoming C++ standards meeting next week will delay it a bit). Zach

1 0

boost interprocess data structure operating when process killed
by 吴昊 09 Jul '19

09 Jul '19

Hello, as I haven’t read the source code deeply, I doubt about what will happen when boost interprocess is handling data structure such as map (e.g. rbtree rotating) while the process is killed (whether or not -9) or the machine is shutdown. Will the inner structure like the rbtree be broken ? Or will interprocess library detect this and fix it ?

2 1