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ialexei
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 Posted: Sat Sep 27, 2003 10:18 am Post subject: Problem using Boost Graph Library |
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Hi,
I am posting this here because, I saw that the author of this
library(Boost Graph Library) had replied to questions reg its usage
here in the past.
I am doing a topological sort on a graph with vertices
V = {0,1,2,3,4,5}
and edges
E = {(0,1), (2,4), (2,5), (0,3), (1,4), (4,3), (2,3) }
On running the sample I get the result as
6 2 5 0 1 4 3
I am not able to fifgure out, where this 6 came from ??????
-Alexei
//---------------------------------------------------------------------------
// TopoTest.cpp : Defines the entry point for the console application.
//---------------------------------------------------------------------------
// Platform Win32, MSVC++ 7.1 (VS.NET 2003)
#include "stdafx.h"
#include <iostream> // for std::cout
#include <utility> // for std::pair
#include <algorithm> // for std::for_each
#include <boost/graph/graph_traits.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/topological_sort.hpp>
using namespace boost;
using namespace std;
typedef int vertex_type;
typedef pair<vertex_type, vertex_type> Pair;
int _tmain(int argc, _TCHAR* argv[])
{
typedef adjacency_list< vecS, vecS, directedS>/*, color_property<>
| Quote: | */ Graph;
typedef boost::graph_traits<Graph>::vertex_descriptor Vertex; |
typedef std::vector< Vertex > container;
Pair edges[] = { Pair(0,1), Pair(2,4),
Pair(2,5),
Pair(0,3), Pair(1,4),
Pair(4,3), Pair(2,3) };
int nCount = sizeof(edges)/sizeof(Pair);
Graph G(edges, edges + nCount, nCount);
container c;
try {
topological_sort(G, std::back_inserter(c));
}catch(not_a_dag e)
{
cout << "Cycle found" <
}
cout << "A topological ordering: ";
for ( container::reverse_iterator itr=c.rbegin(); itr!=c.rend();
itr++)
cout << (*itr) << " ";
cout << endl;
return 0;
}
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David Abrahams
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| Posted: Sat Sep 27, 2003 2:51 pm Post subject: Re: Problem using Boost Graph Library |
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[email]ialexei (AT) hotmail (DOT) com[/email] (ialexei) writes:
| Quote: | Hi,
I am posting this here because, I saw that the author of this
library(Boost Graph Library) had replied to questions reg its usage
here in the past.
|
Didn't he also tell you that the boost developers' list
(http://www.boost.org/more/mailing_lists.htm) was a better place to
get help with the graph library? If not, he should have. The Boost
developers don't always read this newsgroup; I think you'll have
better luck there.
--
Dave Abrahams
Boost Consulting
www.boost-consulting.com
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
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Derek Ledbetter
Guest
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| Posted: Wed Oct 01, 2003 8:22 am Post subject: Re: Problem using Boost Graph Library |
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On Sat, 27 Sep 2003 3:18:23 -0700, ialexei wrote
(in message <6ef50842.0309260641.257dbbe (AT) posting (DOT) google.com>):
| Quote: | I am doing a topological sort on a graph with vertices
V = {0,1,2,3,4,5}
and edges
E = {(0,1), (2,4), (2,5), (0,3), (1,4), (4,3), (2,3) }
On running the sample I get the result as
6 2 5 0 1 4 3
I am not able to fifgure out, where this 6 came from ??????
.....
Pair edges[] = { Pair(0,1), Pair(2,4),
Pair(2,5),
Pair(0,3), Pair(1,4),
Pair(4,3), Pair(2,3) };
int nCount = sizeof(edges)/sizeof(Pair);
Graph G(edges, edges + nCount, nCount);
|
The third parameter to this constructor is the number of vertices, so
G has a vertex "6" that is not connected to any other vertex.
Replace nCount with 6.
--
Derek Ledbetter
[email]derekledbetter (AT) attbi (DOT) com[/email]
"Life's short and hard like a body-building elf."
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
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