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[interval][units] interval operators not working when inteval elements are quantities
by alfC 26 Jan '12

26 Jan '12

Hi, Does anybody know what is missing in the boost.interval (or in the boost.units) to allow these operation. It seems that there is no other way than to make "interval/arith.hpp:operator/" more generic. -- Thanks, Alfredo #include<boost/units/systems/si.hpp> #include "alf/boost/units/interval.hpp" int main(){ boost::numeric::interval<double> iv(1.,10.); clog << iv << " " << 1./iv << endl; // ok, gives [1., 10] and [0.1,1.] boost::numeric::interval<quantity<si::length> > iv2(1.*si::meter, 10.*si::meter); clog << iv2 << " " << 1./iv2 << endl; // error: no match for ‘operator/’ in ‘1.0e+0 / iv2’ return 0; }

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FW: adjacency lists
by Neiderer, Andrew M CIV (US) 26 Jan '12

26 Jan '12

tried with https://svn.boost.org/svn/boost/trunk/boost/graph/adjacency_list_io.hpp but getting during translation. Thank you for your time. __________________________________________________________________________________________________________________________________________________________________________ > From: boost-users-bounces(a)lists.boost.org [boost-users-bounces(a)lists.boost.org] on behalf of Jeremiah Willcock [jewillco(a)osl.iu.edu] > Sent: Thursday, January 19, 2012 10:36 AM > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] adjacency lists > > On Thu, 19 Jan 2012, Neiderer, Andrew M CIV (US) wrote: > > > > > This is about 1/4 of error message. I think if this is addressed then rest of errors will go away. > > > > > > > > Result of > > > > $g++ -I home/neiderer/src/C++/boost_1_48_0 -c adjacency_list_io.cpp > > > > > > > > (I do think you need src since already exists in .../libs/graph/example) > > Please try your code again with the change I just committed to the Boost > trunk (r76588). > > -- Jeremiah Willcock > > > > > > > > > Thank you > > > > ____________________________________________________________________________________________________________________ > > From: boost-users-bounces(a)lists.boost.org [boost-users-bounces(a)lists.boost.org] on behalf of Jeremiah Willcock > > [jewillco(a)osl.iu.edu] > > Sent: Thursday, January 19, 2012 9:27 AM > > To: boost-users(a)lists.boost.org > > Subject: Re: [Boost-users] adjacency lists > > > > On Thu, 19 Jan 2012, Neiderer, Andrew M CIV (US) wrote: > > > > > > > > I am still learning graphs, BGL 1.48.0 so beginner questions: > > > > > > > > > > > > 1. not sure what adjacency list/matrix are used for other than building a graph > > > > > > for traversal. Or maybe this is it? > > > > That is what they are used for -- to build and represent graphs. > > > > > > > > > > > > > > 2. I need to build a sparse network. So I am using adjacency_list_io.cpp by Francois Faure (2001). > > > > > > In this example I can read(g2), but when outputting > > > > > > > > > > > > std::cout << write(g2) > > > > > > > > > > > > I get lots of translation errors :-( > > > > > > > > > > > > I know I do not give details here but maybe someone could guess a -D??? to make > > > > > > adjacency_list_io.hpp happy. > > > > > > (The read(g2) works fine) > > > > > > > > > > > > Or I can certainly provide some of the error message. > > > > Could you please provide that? I am not familiar with that code. > > > > > > > > > > > > > > Also has Dr. Nick Edmonds completed (or near completion) of "active-message" based release (MPI)? > > > > We are still working on the paper based on that code. A release is likely > > to be within the next couple of months, but nothing is certain yet. > > > > -- Jeremiah Willcock > > > > > >

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[BGL] question about connected_components()
by Andriy Gapon 25 Jan '12

25 Jan '12

This page: http://www.boost.org/doc/libs/1_48_0/libs/graph/doc/connected_components.ht… says "The connected_components() functions compute the connected components of an _undirected_ graph using a DFS-based approach." [emphasis mine] Looking here: http://www.boost.org/doc/libs/1_48_0/boost/graph/connected_components.hpp I see somewhat some unexpected things. o Only the first variant asserts that the graph is undirected, in the second variant the assert is commented out - why is that? o Both variants use depth_first_search() and not undirected_dfs(), which would seem to be more logical for the undirected case - why? Despite the above questions I actually want to use connected_components() [and not strong_components()] for a directed graph. Should that be possible? Does it make sense? Thank you! -- Andriy Gapon

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d_ary_heap_indirect problem
by David Doria 25 Jan '12

25 Jan '12

I am trying to use d_ary_heap_indirect. I was able to create an object of the queue, but I can't push a vertex into it. Here is what I tried: http://programmingexamples.net/wiki/CPP/Boost/BGL/d_ary_heap_indirect I get a "no match for operator[]" error on the last line (the push()). Can anyone see what is wrong with that example? Thanks, David

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~optional<int> generates unnessesary code
by Hite, Christopher 25 Jan '12

25 Jan '12

The problem is that m_initialized is checked and set during deconstruction. This generates a bunch of useless code for types with trivial deconstruction: if(m_initialized){ // do nothing m_initialized = false; } The code is more than useless since it contains a branch. In my case I've got a big object I would expect to die without peep, branching and writing to memory for no reason. The steps below show what gcc 4.6.0 generates. You'd expect the function to do nothing. Boost optional has no obligation to maintain state during deconstruction (otherwise you'd need states for deconstructing,constructing). It's not responsible for the bytes left behind after deconstruction. By the way boost::variant does do this correctly. Chris ------------------ #include <boost/optional.hpp> typedef boost::optional<int> optional_int; void deconstruct_boost_optional(optional_int& o){ o.~optional_int(); } ------------------ objdump -f -d -C -l boost_optional_deconstruction.o |c++filt 00000000 <deconstruct_boost_optional(boost::optional<int>&)>: deconstruct_boost_optional(boost::optional<int>&)(): /home/eh2hite/chris/src_root/src/test/boost_optional_deconstruction.cpp:5 0: 8b 44 24 04 mov 0x4(%esp),%eax boost::optional_detail::optional_base<int>::destroy()(): /usr/local/include/boost/optional/optional.hpp:407 4: 80 38 00 cmpb $0x0,(%eax) 7: 74 03 je c <deconstruct_boost_optional(boost::optional<int>&)+0xc> boost::optional_detail::optional_base<int>::destroy_impl(mpl_::bool_<false>)(): /usr/local/include/boost/optional/optional.hpp:434 9: c6 00 00 movb $0x0,(%eax) c: f3 c3 repz ret

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BGL defining my own iterator?
by Anders Wallin 24 Jan '12

24 Jan '12

Hi all, For traversing the faces of a planar BGL graph I store 'next' pointers in a bundled property for each edge. I can go round a face of the graph like this: BGLGraph g; edge_descriptor current,start; // initialize these! do { // do something with current current=g[current].next; } while(current!=start); Now I was thinking that a lot of 'boilerplate' code would be eliminated if I could do these loops with BOOST_FOREACH. Following the tutorial for iterator_facade I am trying something like this: https://github.com/aewallin/sandbox/blob/master/bgl_iterator/main.cpp However as commented in the code it doesn't quite work. I get either no iterations, one iteration, or all but one edge. Also, holding a pointer to an edge_descriptor in the iterator class doesn't strike me as very elegant, could I store an edge_descriptor directly? suggestions? thanks, AW

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Boost MSM: No transition from submachine to external state
by stetkas 24 Jan '12

24 Jan '12

Using the following example as a template: http://svn.boost.org/svn/boost/trunk/libs/msm/doc/HTML/examples/CompositeTu… http://svn.boost.org/svn/boost/trunk/libs/msm/doc/HTML/examples/CompositeTu… I am trying to create a state machine that consists of an alarm state and a composite state (submachine). When an alarm event is posted while in the composite state, the state machine is supposed to transition to the Alarm state; however, the machine complains that no transition from the composite state on the alarm event exists. This is similar to the example where the player is in playing and a stop event is received. Below is a dumbed-down version of my state machine: http://boost.2283326.n4.nabble.com/file/n4300991/StateMachine.gif Here is the implementation: Here is the output: See anything that could be causing my problem? -- View this message in context: http://boost.2283326.n4.nabble.com/Boost-MSM-No-transition-from-submachine-… Sent from the Boost - Users mailing list archive at Nabble.com.

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Simple example program builds but hangs when I run it. (Ubuntu).
by vincegata 24 Jan '12

24 Jan '12

Hello, I run Ubuntu 11.04. I downloaded Boost 1.48.0, then I followed the instructions from Getting Started on Unix variants to build the libraries into /usr/local/include and /usr/local/lib. Now, I build the Simple example program without any errors, however when I run the program it just hangs indefinitely on std::for_each() line. Could someone help me with this please? $: g++ -g -lboost_filesystem main.cpp #include <boost/lambda/lambda.hpp> #include <iostream> #include <iterator> #include <algorithm> int main() { using namespace boost::lambda; typedef std::istream_iterator<int> in; std::for_each(in(std::cin), in(), std::cout << (_1 * 3) << " " ); int stop = 1; }

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Re: [Boost-users] Need help with Errors in boost MPL, tutorials
by Linh Ha 24 Jan '12

24 Jan '12

> Just on a first glance, looks like you're mistaking ::_1 (placeholder from > Boost.Bind) for boost::mpl::_1 (placeholder from Boost.MPL). They're > incompatible; try using the latter...? > > - Jeff Thanks, Jeff ! It works. But then my next question is why they are different and somehow incompatible even-though are both placeholders. Why we keep two different place holder if they do exactly a same functionality.

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license
by Kraus Philipp 24 Jan '12

24 Jan '12

Hello, I would like to create a PHP plugin that uses the Boost UBlas datatypes. The plugin will be use the GPLv3 license. Can I use the bcp utility to extract the UBlas structures and can I include them into my plugin without any license problems? The plugin should store all needed parts into its own directory. Thanks Phil

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