test/min_cost_arborescence_test.cc
author Peter Kovacs <kpeter@inf.elte.hu>
Tue, 24 Mar 2009 00:18:25 +0100
changeset 604 8c3112a66878
child 625 029a48052c67
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) 2003-2008
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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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#include <iostream>
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#include <set>
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#include <vector>
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#include <iterator>
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#include <lemon/smart_graph.h>
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#include <lemon/min_cost_arborescence.h>
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#include <lemon/lgf_reader.h>
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#include "test_tools.h"
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using namespace lemon;
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using namespace std;
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const char test_lgf[] =
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  "@nodes\n"
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  "label\n"
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  "0\n"
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  "1\n"
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  "2\n"
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  "3\n"
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  "4\n"
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  "5\n"
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  "6\n"
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  "7\n"
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  "8\n"
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  "9\n"
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  "@arcs\n"
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  "     label  cost\n"
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  "1 8  0      107\n"
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  "0 3  1      70\n"
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  "2 1  2      46\n"
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  "4 1  3      28\n"
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  "4 4  4      91\n"
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  "3 9  5      76\n"
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  "9 8  6      61\n"
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  "8 1  7      39\n"
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  "9 8  8      74\n"
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  "8 0  9      39\n"
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  "4 3  10     45\n"
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  "2 2  11     34\n"
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  "0 1  12     100\n"
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  "6 3  13     95\n"
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  "4 1  14     22\n"
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  "1 1  15     31\n"
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  "7 2  16     51\n"
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  "2 6  17     29\n"
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  "8 3  18     115\n"
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  "6 9  19     32\n"
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  "1 1  20     60\n"
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  "0 3  21     40\n"
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  "@attributes\n"
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  "source 0\n";
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int main() {
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  typedef SmartDigraph Digraph;
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  DIGRAPH_TYPEDEFS(Digraph);
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  typedef Digraph::ArcMap<double> CostMap;
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  Digraph digraph;
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  CostMap cost(digraph);
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  Node source;
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  std::istringstream is(test_lgf);
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  digraphReader(digraph, is).
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    arcMap("cost", cost).
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    node("source", source).run();
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  MinCostArborescence<Digraph, CostMap> mca(digraph, cost);
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  mca.run(source);
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  vector<pair<double, set<Node> > > dualSolution(mca.dualNum());
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  for (int i = 0; i < mca.dualNum(); ++i) {
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    dualSolution[i].first = mca.dualValue(i);
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    for (MinCostArborescence<Digraph, CostMap>::DualIt it(mca, i);
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         it != INVALID; ++it) {
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      dualSolution[i].second.insert(it);
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    }
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  }
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  for (ArcIt it(digraph); it != INVALID; ++it) {
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    if (mca.reached(digraph.source(it))) {
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      double sum = 0.0;
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      for (int i = 0; i < int(dualSolution.size()); ++i) {
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        if (dualSolution[i].second.find(digraph.target(it))
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            != dualSolution[i].second.end() &&
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            dualSolution[i].second.find(digraph.source(it))
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            == dualSolution[i].second.end()) {
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          sum += dualSolution[i].first;
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        }
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      }
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      if (mca.arborescence(it)) {
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        check(sum == cost[it], "INVALID DUAL");
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      }
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      check(sum <= cost[it], "INVALID DUAL");
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    }
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  }
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  check(mca.dualValue() == mca.arborescenceValue(), "INVALID DUAL");
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  check(mca.reached(source), "INVALID ARBORESCENCE");
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  for (ArcIt a(digraph); a != INVALID; ++a) {
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    check(!mca.reached(digraph.source(a)) ||
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          mca.reached(digraph.target(a)), "INVALID ARBORESCENCE");
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  }
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  for (NodeIt n(digraph); n != INVALID; ++n) {
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    if (!mca.reached(n)) continue;
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    int cnt = 0;
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    for (InArcIt a(digraph, n); a != INVALID; ++a) {
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      if (mca.arborescence(a)) {
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        check(mca.pred(n) == a, "INVALID ARBORESCENCE");
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        ++cnt;
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      }
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    }
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    check((n == source ? cnt == 0 : cnt == 1), "INVALID ARBORESCENCE");
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  }
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  Digraph::ArcMap<bool> arborescence(digraph);
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  check(mca.arborescenceValue() ==
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        minCostArborescence(digraph, cost, source, arborescence),
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        "WRONG FUNCTION");
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  return 0;
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}