- Boost-users - lists.preview.boost.org

multi_array iterator question
by James N. Knight 02 Apr '04

02 Apr '04

I am trying to sort a multi_array along a dimension that is not the last. In other words, I can sort the rows of a 2D multi_array like so: typedef boost::multi_array<double, 2> array_type; typedef array_type::iterator iterator2; typedef array_type::template subarray<1>::type::iterator iterator1; array_type A(boost::extents[10][10]); for (iterator2 i = A.begin(); i!=A.end(); ++i){ sort((*i).begin(),(*i).end()); What I can't seem to do is sort the columns. Is there a way I can create a view with the dimensions reordered? Or, can I somehow create a strided iterator that will do the job (select the values in a column)? I would like to avoid transposing the array. Pointers to the relevant documentation or suggestions are appreciated. James

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Boost.Test support address
by Gennadiy Rozental 02 Apr '04

02 Apr '04

For anyone interrested, direct support address for Boost.Test issues is now rogeeff(a)patmedia.com. Old one is not free anymore and not supported accordingly. Regards, Gennadiy.

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linker error creating simple unit_test (boost 1.31.0 + win32 + vc 71)
by Langston, Matthew David 02 Apr '04

02 Apr '04

I'm trying to create a simple unit test (using the Unit Test Framework) using boost 1.31.0 + win32 + vc71, but I get the following linker error due to the undefined symbol __imp___CrtSetReportHook: tests error LNK2019: unresolved external symbol __imp___CrtSetReportHook referenced in function "public: int __thiscall boost::execution_monitor::execute(bool,int)" (?execute@execution_monitor@boost@@QAEH_NH@Z) There was mention of this undefined symbol (__imp___CrtSetReportHook) in this thread: http://lists.boost.org/MailArchives/boost/msg43787.php. However, that post was concerning the Metrowerks compiler, but I am using Microsoft's vc71 compiler. Can someone help me resolve this undefined symbol (__imp___CrtSetReportHook) problem? Here is my simple "unit test suite" that I am trying to build: #include <boost/test/unit_test.hpp> #include <boost/test/included/unit_test_framework.hpp> using boost::unit_test_framework::test_suite; void test_GleamData() { BOOST_CHECK(2 == 1); // non-critical test => continue after failure } test_suite* init_unit_test_suite( int, char* [] ) { test_suite* test = BOOST_TEST_SUITE( "GleamAnalysis Test Suite" ); test -> add( BOOST_TEST_CASE( &test_GleamData ), 1 /* expected one error */ ); return test; } Warmest regards, Matt

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RE: [Boost-users] Re: License compatibility issues.
by Jim.Hyslop 01 Apr '04

01 Apr '04

David Abrahams wrote: > It seems to me that we can't ask > our volunteer lawyers to draw up a list of answers to all the possible > licensing questions along these lines, nor can we reasonably make them > available as an on-demand resource for answering boost users' legal > questions. No, but I think that the interaction between the LGPL or GPL and the Boost License is probably going to be a very frequently encountered scenario. Basically, what it boils down to is: what is the compatibility between LGPL or GPL, and the Boost license? Can we draw up a list of the most common free-software licenses, say the top three, and ask the volunteer lawyers to determine whether Boost is compatible with each of the three? I don't mean to determine the various combinations and permutations, e.g. Boost and GPL and Mozilla Artistic, but the simple ones: Boost and "x", Boost and "y", etc. Until and unless such a comparison is done, though, I would echo your advice about seeking a competent legal opinion. -- Jim Hyslop Senior Software Designer Leitch Technology International Inc. (http://www.leitch.com) Columnist, C/C++ Users Journal (http://www.cuj.com/experts)

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Re: License compatibility
by Cromwell Enage 01 Apr '04

01 Apr '04

Thanks, David Abrahams and Jim Hyslop! I'll heed your advice on seeking legal counsel and contacting the Free Software Foundation. Cromwell __________________________________ Do you Yahoo!? Yahoo! Small Business $15K Web Design Giveaway http://promotions.yahoo.com/design_giveaway/

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RE: [Boost-users] Re: about license
by Jim.Hyslop 01 Apr '04

01 Apr '04

David Abrahams wrote: > Only the Boost code must use the Boost license; you can put any > license terms you wish on your own code. Why would you think > otherwise? Maybe he's used to the GPL, which forces its license model to be applied to the entire package? -- Jim Hyslop Senior Software Designer Leitch Technology International Inc. (http://www.leitch.com) Columnist, C/C++ Users Journal (http://www.cuj.com/experts)

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about license
by Marleny Rafferty 01 Apr '04

01 Apr '04

Hi- I am considering using boost in my applications, but I have a question about the boost license at http://www.boost.org/LICENSE_1_0.txt . It says (edited) "Permission is hereby granted, free of charge, to ... use [and] reproduce ... the Software". It also says that any derivative works must also have the same license grant. If my application uses boost libraries unchanged, is it considered a derivative work? If so, does that mean that if I distribute my compiled software, I must allow free of charge use and distribution? Thanks. -- Marleny

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License compatibility issues.
by Cromwell Enage 01 Apr '04

01 Apr '04

Good morning. >From previous posts regarding the License, I'm assuming the Legal Team is on this mailing list; if not, please direct me to them. Scenario I: I'm building a library that uses the Boost libraries (the ones covered by the current Boost Software License) and the Simple DirectMedia Layer, which is distributed under the terms of the GNU "Lesser" Public License <http://www.gnu.org/copyleft/lgpl.html>. Can I release my library under the Boost Software License? Can I release it under the GNU LGPL? Or can I not release it at all? Scenario II: I plan on building an application that uses the Boost libraries (the ones covered by the current Boost Software License) and the FOX GUI Toolkit, which is distributed under the terms of the GNU General Public License. According to <http://www.gnu.org/licenses/gpl-faq.html#IfLibraryIsGPL>, if I publicly distribute my application (e.g. via SourceForge.net) I must do so using the GNU GPL, since the FOX Toolkit is distributed under that license. Will the Boost Software License allow me to do this? Kind regards, Cromwell Enage __________________________________ Do you Yahoo!? Yahoo! Small Business $15K Web Design Giveaway http://promotions.yahoo.com/design_giveaway/

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removing parallel edges in the Boost Graph Library?
by Nicholas Burlett 01 Apr '04

01 Apr '04

I am trying to use BGL to model a directed multigraph, but every time I try to remove just one of the edges (u,v), it removes all of the edges from u to v. My graph definition is: typedef adjacency_list<listS, listS, bidirectionalS, VertexProperty, EdgeProperty> graphdata; where VertexProperty and EdgeProperty are properties I've defined. Everything else seems to work: I have can add parallel edges, find the edge I want to remove based on the EdgeProperty, filter the graph for topological sorting, check for existing edges, etc. In the following, e is of type graph_traits<graphdata>::edge_descriptor, and g is the graph of type graphdata (defined above): std::cout << "about to remove edge\n"; DumpInfo(); remove_edge(e, g); std::cout << "removed edge\n"; DumpInfo(); Here is some sample output: about to remove edge vertex: 0 out-edges: in-edges: (1,0) (1,0) adjacent vertices: vertex: 1 out-edges: (1,0) (1,0) in-edges: adjacent vertices: 0 0 removed edge vertex: 0 out-edges: in-edges: adjacent vertices: vertex: 1 out-edges: in-edges: adjacent vertices: Note that there were two edges present before the call to remove_edge, but only one after. What am I doing wrong? I'm using version 1.31, if that helps. Thanks, Nicholas Burlett nrb23(a)cornell.edu

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Re: [boost] [BGL] forced client complexity
by Cromwell Enage 31 Mar '04

31 Mar '04

prs, On reflection, I've decided to cross-list my reply. > If one accepts the axiom that "a picture is worth a > thousand words," then it naturally follows that > discussion of graphs is always overly prolix. I recently had a chat with a fellow programmer and attempted to summarize, in semi-layman terms, how the core algorithms of my multi-state-mazes library work. They're pretty simple, but I couldn't do it without paper and pencil. > Sadly, the same reasoning is also applicable to > the code of graph libraries. If a "code-visualizing compiler IDE" existed that would give us "code pictures" (plus conform to the new C++ standard, not ICE, and so on), I'm pretty sure more of us would be using it for all programming projects, not just graph applications. :) But seriously, with graph theory containing several different problem domains (search, network, AI, etc.), a graph library attempting to be generic enough for use in all of them is necessarily complex. > Boost.Graph seems to expose and require an > unnecessarily large amount of complexity, > though. If by "exposure" you mean lots of source code, I'll take that complexity any day of the week and twice on Sundays. :) The library does have a rather steep learning curve, especially if you're somewhat unfamiliar with graph theory and/or template programming. > Whereas libraries like Spirit go to great lengths > to make hard things easy, BGL seems to try only to > make hard things possible. I haven't looked at the Spirit library yet, so I can't tell you how easy it may be to use it. Perhaps getting your hands on a copy of the Boost Graph Library book will help (I don't have one, so I'm not certain). > The amount of scaffolding required > to use BGL for even the simplest of projects > often dwarfs the code size of a naive, > yet functional, special-purpose implementation. Special-purpose implementation of a graph library? Or the project? BGL aims to be as generic as the STL, but whereas each STL container deals with essentially one type of element, a graph needs to contain two types: a vertex type and an edge type. Furthermore, while most STL algorithms confine themselves to handling just those STL container elements, most graph algorithms also need the properties of vertices and/or edges as input. BGL delegates some of the responsibility of property storage to the Boost Property Map Library. I'm just glad the developers kept the complexity down to its current level. > While I understand that the BGL is deeply entrenched > in boost culture, certain academic circles, and even > publications, I nonetheless suggest that BGL lacks > the ease of use necessary for widespread adoption. Having dwelt in the academic circle known as the University of Central Florida, and thus familiar with the theoretical uses of a graph library (plus I've studied some game development apps on the side), I'd like to learn more about how the Real World would want to use BGL. > Even knowing that ease-of-use is not a criterion > for acceptance into boost, looking at what is > required of the client to use the BGL always leaves > me feeling perplexed. Is there any particular reason > that a simplified interface is not made available? Again, I don't know a simple graph problem that requires a simplified graph interface. > Perhaps a container adapter could be packaged with > the library allowing a compromise of functionality > and flexibility for simplicity? I thought the boost::vector_as_graph class template served that purpose. Wrap it around a std::vector<EdgeList>, with EdgeList = std::list<unsigned int> (or an edge list container of your choice, so long as the value type is usable as an index in the vector), and you should be good to go. > If a graphing problem is trivial, shouldn't BGL > provide a trivial solution? Why are the simplest > useful examples several hundred lines of code? The examples don't seem that big and hard to understand. Of course, quite a few of them have #ifdefs that I could do without since I don't use the compilers in question, but I can live with them. > I apologize for all of my vague criticisms - my > intention is not to flame but rather to test the > waters. Your criticisms seem healthy, and I hope my responses are helpful. > It is difficult for me to assess whether the > simplicity I yearn for isn't present for stylistic > reasons or whether it would rather necessitate a > sacrifice of flexibility, functionality or > implementation clarity. Nor is it clear to me to > what extent these criteria can be compromised to > promote clarity of client code. For what it is > worth, the kind of ease-of-use I'm imagining might > look like: #include <less_than_10_graph_headers> ... digraph<some_node_type,some_edge_context_type> g; g << "vertex" << make_pair("vertex", "implicit_vertex"); g.add_edge("brother", "sister", "sibling"); if(g.find(make_pair("brother", "sister"))) related = true; > Could someone please elucidate on why it is > impossible/impractical/unnecessary/whatever for a > graph library to have such an interface? I believe the potential for ambiguity would hinder this syntax the most. In this case, you'd have to overload operator<< to input both edges and vertices, and what if some_node_type turned out to be std::pair? You couldn't pass in make_pair(vertex,vertex) as an edge then. The same goes for g.find(); is it supposed to find a vertex, an edge, or both? Also, it seems you want to be able to use non-built-in or custom types as vertex IDs. You'll have to build your own custom-type-to-vertex map and bind it to the graph; BGL won't do it for you, to retain its genericity. Incidentally, BGL favors free functions over member functions. The rationale for that can be found in the FAQ <http://www.boost.org/libs/graph/doc/faq.html>. > Should I accept that the BGL is not the magic bullet > graph library and move on, or can this kind of > simplicity be somehow found within? Yeah, no magic bullets here. It depends on the problem you are trying to solve. Cromwell Enage __________________________________ Do you Yahoo!? Yahoo! Finance Tax Center - File online. 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