demo/lgf_demo.cc
author Peter Kovacs <kpeter@inf.elte.hu>
Tue, 24 Mar 2009 00:18:25 +0100
changeset 596 8c3112a66878
parent 294 cbe3ec2d59d2
permissions -rw-r--r--
Use XTI implementation instead of ATI in NetworkSimplex (#234)

XTI (eXtended Threaded Index) is an imporved version of the widely
known ATI (Augmented Threaded Index) method for storing and updating
the spanning tree structure in Network Simplex algorithms.

In the ATI data structure three indices are stored for each node:
predecessor, thread and depth. In the XTI data structure depth is
replaced by the number of successors and the last successor
(according to the thread index).
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/* -*- mode: C++; indent-tabs-mode: nil; -*-
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 *
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 * This file is a part of LEMON, a generic C++ optimization library.
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 *
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 * Copyright (C) 2003-2009
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 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
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 * (Egervary Research Group on Combinatorial Optimization, EGRES).
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 *
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 * Permission to use, modify and distribute this software is granted
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 * provided that this copyright notice appears in all copies. For
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 * precise terms see the accompanying LICENSE file.
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 *
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 * This software is provided "AS IS" with no warranty of any kind,
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 * express or implied, and with no claim as to its suitability for any
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 * purpose.
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 *
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 */
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///\ingroup demos
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///\file
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///\brief Demonstrating graph input and output
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///
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/// This program gives an example of how to read and write a digraph
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/// and additional maps from/to a stream or a file using the
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/// \ref lgf-format "LGF" format.
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///
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/// The \c "digraph.lgf" file:
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/// \include digraph.lgf
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///
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/// And the program which reads it and prints the digraph to the
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/// standard output:
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/// \include lgf_demo.cc
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#include <iostream>
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#include <lemon/smart_graph.h>
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#include <lemon/lgf_reader.h>
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#include <lemon/lgf_writer.h>
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using namespace lemon;
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int main() {
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  SmartDigraph g;
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  SmartDigraph::ArcMap<int> cap(g);
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  SmartDigraph::Node s, t;
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  try {
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    digraphReader(g, "digraph.lgf"). // read the directed graph into g
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      arcMap("capacity", cap).       // read the 'capacity' arc map into cap
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      node("source", s).             // read 'source' node to s
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      node("target", t).             // read 'target' node to t
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      run();
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  } catch (Exception& error) { // check if there was any error
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    std::cerr << "Error: " << error.what() << std::endl;
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    return -1;
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  }
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  std::cout << "A digraph is read from 'digraph.lgf'." << std::endl;
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  std::cout << "Number of nodes: " << countNodes(g) << std::endl;
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  std::cout << "Number of arcs: " << countArcs(g) << std::endl;
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  std::cout << "We can write it to the standard output:" << std::endl;
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  digraphWriter(g).                // write g to the standard output
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    arcMap("capacity", cap).       // write cap into 'capacity'
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    node("source", s).             // write s to 'source'
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    node("target", t).             // write t to 'target'
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    run();
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  return 0;
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}