April 2006 - Boost-users - lists.boost.org

Shortest Path City map
by Jeroen Vanattenhoven 10 Apr '06

10 Apr '06

Hello, I'm just learning and reading about the graph theory and shortest path algorithms. For graph representation there are 3 possibilities: adjacency matrix for dense graphs, adjacency lists for sparse graphs and edge lists. The road network of a city map belongs to which category? I've also been reading that Dijkstra is applied to a directed graph. Calculating the shortest route in a city map implies an undirected graph (am I wrong?). So how can I do shortest path calculation of a city map the best way? Jeroen

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[Graph] Very minor typo/doc-bug in bellman-ford example
by Greg Link 10 Apr '06

10 Apr '06

I'm not quite sure where to submit this, but the main boost.org site noted that bug reports are often best reported to mailing lists, so here goes. In the documentation for the Bellman-Ford algorithm, there is an example program (bellman-example.cpp) that contains the following 'main' function (snippet): main() { enum { u, v, x, y, z, N }; char name[] = { 'u', 'v', 'x', 'y', 'z' }; typedef std::pair < int, int >E; const int n_edges = 10; E edge_array[] = { E(u, y), E(u, x), E(u, v), E(v, u), E(x, y), E(x, v), E(y, v), E(y, z), E(z, u), E(z,x) }; ... Note that edge_array[] is of type "E", which of course, should be "Edge". The example doesn't work as listed, as such. - Greg Link

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Using raph algorithm
by David Zweigenhaft 10 Apr '06

10 Apr '06

Does anyone know how to achieve the following: * find all the paths between 2 nodes ? Or, find the first N shortest paths between 2 nodes ? * find the shortest path using include/exclude constraints (passing through list of nodes) * BWY - am I using the correct mailing list ?

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cvs activity
by Serge Skorokhodov 10 Apr '06

10 Apr '06

Hi, Whenever I try to update boost source tree from sf.net, I see no changes. Is it just a low activity period or I missed the change of the settings? TIA -- Serge

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(no subject)
by Karim Bakir 10 Apr '06

10 Apr '06

Hi , I have a problem, I can' use boost multi array as private member, I have the mistake: "unexpected extents" I can only return a boost multi array in my function Thanks // KOKO.h: interface for the KOKO class. // ////////////////////////////////////////////////////////////////////// #if !defined(AFX_KOKO_H__3E4A2230_0446_43C2_BD69_6FF9C2614C02__INCLUDED_) #define AFX_KOKO_H__3E4A2230_0446_43C2_BD69_6FF9C2614C02__INCLUDED_ #if _MSC_VER > 1000 #pragma once #endif // _MSC_VER > 1000 #include "boost/multi_array.hpp" #include <cassert> using namespace std; using namespace boost; class KOKO { typedef boost::multi_array<double,3> array_type_3dd; public: KOKO(); virtual ~KOKO(); boost::multi_array<double,3>MiseEnFormeMatrice3D(vector<double>data,int nbJourSimule, int na, int nbEnergie); private: int d1; int d2; int d3; array_type_3d myvector(boost::extents[d1][d2][d3]); }; #endif // !defined(AFX_KOKO_H__3E4A2230_0446_43C2_BD69_6FF9C2614C02__INCLUDED_) --------------------------------- Nouveau : téléphonez moins cher avec Yahoo! Messenger ! Découvez les tarifs exceptionnels pour appeler la France et l'international.Téléchargez la version beta.

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[BGL] Survivability Network Design Problem
by Alejandro Aragón 10 Apr '06

10 Apr '06

Hello everybody, I was wondering if anybody had to implement the SNDP problem using graphs. Is there anything in the boost library that deals with this problem? In the SNDP we have to design a graph having certain degree of redundancy (cycles in the graph) so if you remove one edge, then you can still reach every part in the graph. Stated in a different way, you should be able to have different paths between two vertices in the graph. So far I have seen only algorithms to deal with minimum spanning trees. I appreciate anything related to this problem. Alejandro Aragon

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Selective depth-first search in a graph
by Anatoli Sakhnik 10 Apr '06

10 Apr '06

Hello, boost users! Is there a simple way to perform a selective depth-first search in a graph, so that I could choose edges to traverse the graph? For example, let's assume I can walk through an edge, only if its weight is greater than 0. How could I reveal all reachable vertices? It worth pointing out that the real availability condition is a little bit more complicated, but easity can be revealed from edge's inner properties. Thank you in advance! -- Anatoli Sakhnik

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Boost and CPAN and CodeProject
by Lynn Allan 10 Apr '06

10 Apr '06

From: "Eric Niebler" <eric(a)boost-consulting.com> > evening, and he asked why C++ didn't have the equivalent of Perl's CPAN > -- that is, a huge repository of useful code to which anybody can > submit. No releases. No quality assurance. No reviews. Survival of the > fittest. Here's a wacky thought: can we turn boost-sandbox into CBAN > (the Comprehensive Boost Archive Network), and cherry-pick the best > libraries from CBAN for inclusion in boost? If anybody could make > something like this fly, it's boost. We'd need to look closely at the > CPAN model to find out why it's successful. Something this boost newbie would find valuable would be the equivalent of codeproject.com (or a Boost section within codeproject ... there is a section for STL). http://www.codeproject.com/vcpp/stl/ This might be yet another repository for code examples and "best practices" that are "peer reviewed" ... and there is certainly as element of "survival of the fittest".

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embedded platform setup help, please
by Garrett Weinberg 10 Apr '06

10 Apr '06

Hi all, I'm trying to use a few header-only Boost libraries in an embedded environment -- to be specific, an SH4 platform that runs Windows CE.NET 4.2. My IDE is Embedded Visual C++ 4.0. My minimal "hello world" does nothing interesting but instantiating a simple boost::shared_array of chars. I get the following unresolved external when linking: minimal.obj : error LNK2019: unresolved external symbol __InterlockedDecrement referenced in function "public: void __cdecl boost::detail::sp_counted_base::release(void)" (?release@sp_counted_base@detail@boost@@QAAXXZ) SH4Rel/minimal.exe : fatal error LNK1120: 1 unresolved externals Further information: My compiler /? output is: "Microsoft (R) C/C++ Optimizing Compiler Vers. 12.20.9518 for Hitachi SH" This compiler does support Exceptions and RTTI when you turn on the right switches (/GX and /GR, respectively), provided that you link against a library that has also been custom-built (using WinCE Platform Builder) to support these features (the default CE 4.2 SDK's lib does not). I have tried the WinCE 4.2's (limited) native C++/STL as well as STLPort -only and Dinkumware-only implementations. I get the same unresolved external in each case. Any help would be greatly appreciated. Thanks in advance, Garrett

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Re: [Boost-users] Delayed write file handling
by Andrew Holden 10 Apr '06

10 Apr '06

> -----Original Message----- > From: James Hughes [mailto:JHughes@Linx.co.uk] > Sent: Monday, April 10, 2006 11:59 AM > For example, if our machine power fails, we have very limited amount of > battery backup to store everything cached to flash before we run out of > watts, so whatever scheme I implement needs to be able to be told to flush > immediately - can I do that with streambufs? I think you can force a stream to flush immediatly with something similar to the following: outputStream << std::flush;

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