test/min_cost_flow_test.cc
author Peter Kovacs <kpeter@inf.elte.hu>
Sat, 25 Apr 2009 02:12:41 +0200
changeset 623 7c1324b35d89
parent 609 e6927fe719e6
child 640 6c408d864fa1
permissions -rw-r--r--
Modify the interface of Suurballe (#266, #181)

- Move the parameters s and t from the constructor to the run()
function. It makes the interface capable for multiple run(s,t,k)
calls (possible improvement in the future) and it is more similar
to Dijkstra.
- Simliarly init() and findFlow(k) were replaced by init(s) and
findFlow(t,k). The separation of parameters s and t is for the
future plans of supporting multiple targets with one source node.
For more information see #181.
- LEMON_ASSERT for the Length type (check if it is integer).
- Doc improvements.
- Rearrange query functions.
- Extend test file.
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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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#include <iostream>
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#include <fstream>
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#include <lemon/list_graph.h>
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#include <lemon/lgf_reader.h>
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#include <lemon/network_simplex.h>
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#include <lemon/concepts/digraph.h>
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#include <lemon/concept_check.h>
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#include "test_tools.h"
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using namespace lemon;
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char test_lgf[] =
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  "@nodes\n"
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  "label  sup1 sup2 sup3 sup4 sup5\n"
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  "    1    20   27    0   20   30\n"
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  "    2    -4    0    0   -8   -3\n"
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  "    3     0    0    0    0    0\n"
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  "    4     0    0    0    0    0\n"
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  "    5     9    0    0    6   11\n"
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  "    6    -6    0    0   -5   -6\n"
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  "    7     0    0    0    0    0\n"
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  "    8     0    0    0    0    3\n"
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  "    9     3    0    0    0    0\n"
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  "   10    -2    0    0   -7   -2\n"
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  "   11     0    0    0  -10    0\n"
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  "   12   -20  -27    0  -30  -20\n"
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  "\n"
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  "@arcs\n"
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  "       cost  cap low1 low2\n"
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  " 1  2    70   11    0    8\n"
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  " 1  3   150    3    0    1\n"
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  " 1  4    80   15    0    2\n"
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  " 2  8    80   12    0    0\n"
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  " 3  5   140    5    0    3\n"
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  " 4  6    60   10    0    1\n"
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  " 4  7    80    2    0    0\n"
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  " 4  8   110    3    0    0\n"
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  " 5  7    60   14    0    0\n"
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  " 5 11   120   12    0    0\n"
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  " 6  3     0    3    0    0\n"
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  " 6  9   140    4    0    0\n"
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  " 6 10    90    8    0    0\n"
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  " 7  1    30    5    0    0\n"
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  " 8 12    60   16    0    4\n"
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  " 9 12    50    6    0    0\n"
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  "10 12    70   13    0    5\n"
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  "10  2   100    7    0    0\n"
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  "10  7    60   10    0    0\n"
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  "11 10    20   14    0    6\n"
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  "12 11    30   10    0    0\n"
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  "\n"
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  "@attributes\n"
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  "source 1\n"
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  "target 12\n";
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enum ProblemType {
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  EQ,
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  GEQ,
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  LEQ
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};
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// Check the interface of an MCF algorithm
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template <typename GR, typename Flow, typename Cost>
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class McfClassConcept
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{
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public:
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  template <typename MCF>
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  struct Constraints {
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    void constraints() {
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      checkConcept<concepts::Digraph, GR>();
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      MCF mcf(g);
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      b = mcf.reset()
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             .lowerMap(lower)
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             .upperMap(upper)
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             .capacityMap(upper)
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             .boundMaps(lower, upper)
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             .costMap(cost)
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             .supplyMap(sup)
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             .stSupply(n, n, k)
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             .flowMap(flow)
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             .potentialMap(pot)
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             .run();
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      const MCF& const_mcf = mcf;
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      const typename MCF::FlowMap &fm = const_mcf.flowMap();
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      const typename MCF::PotentialMap &pm = const_mcf.potentialMap();
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      v = const_mcf.totalCost();
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      double x = const_mcf.template totalCost<double>();
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      v = const_mcf.flow(a);
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      v = const_mcf.potential(n);
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      ignore_unused_variable_warning(fm);
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      ignore_unused_variable_warning(pm);
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      ignore_unused_variable_warning(x);
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    }
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    typedef typename GR::Node Node;
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    typedef typename GR::Arc Arc;
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    typedef concepts::ReadMap<Node, Flow> NM;
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    typedef concepts::ReadMap<Arc, Flow> FAM;
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    typedef concepts::ReadMap<Arc, Cost> CAM;
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    const GR &g;
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    const FAM &lower;
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    const FAM &upper;
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    const CAM &cost;
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    const NM &sup;
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    const Node &n;
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    const Arc &a;
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    const Flow &k;
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    Flow v;
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    bool b;
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    typename MCF::FlowMap &flow;
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    typename MCF::PotentialMap &pot;
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  };
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};
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// Check the feasibility of the given flow (primal soluiton)
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template < typename GR, typename LM, typename UM,
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           typename SM, typename FM >
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bool checkFlow( const GR& gr, const LM& lower, const UM& upper,
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                const SM& supply, const FM& flow,
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                ProblemType type = EQ )
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{
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  TEMPLATE_DIGRAPH_TYPEDEFS(GR);
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  for (ArcIt e(gr); e != INVALID; ++e) {
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    if (flow[e] < lower[e] || flow[e] > upper[e]) return false;
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  }
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  for (NodeIt n(gr); n != INVALID; ++n) {
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    typename SM::Value sum = 0;
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    for (OutArcIt e(gr, n); e != INVALID; ++e)
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      sum += flow[e];
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    for (InArcIt e(gr, n); e != INVALID; ++e)
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      sum -= flow[e];
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    bool b = (type ==  EQ && sum == supply[n]) ||
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             (type == GEQ && sum >= supply[n]) ||
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             (type == LEQ && sum <= supply[n]);
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    if (!b) return false;
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  }
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  return true;
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}
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// Check the feasibility of the given potentials (dual soluiton)
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// using the "Complementary Slackness" optimality condition
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template < typename GR, typename LM, typename UM,
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           typename CM, typename SM, typename FM, typename PM >
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bool checkPotential( const GR& gr, const LM& lower, const UM& upper,
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                     const CM& cost, const SM& supply, const FM& flow, 
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                     const PM& pi )
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{
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  TEMPLATE_DIGRAPH_TYPEDEFS(GR);
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  bool opt = true;
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  for (ArcIt e(gr); opt && e != INVALID; ++e) {
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    typename CM::Value red_cost =
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      cost[e] + pi[gr.source(e)] - pi[gr.target(e)];
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    opt = red_cost == 0 ||
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          (red_cost > 0 && flow[e] == lower[e]) ||
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          (red_cost < 0 && flow[e] == upper[e]);
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  }
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  for (NodeIt n(gr); opt && n != INVALID; ++n) {
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    typename SM::Value sum = 0;
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    for (OutArcIt e(gr, n); e != INVALID; ++e)
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      sum += flow[e];
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    for (InArcIt e(gr, n); e != INVALID; ++e)
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      sum -= flow[e];
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    opt = (sum == supply[n]) || (pi[n] == 0);
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  }
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  return opt;
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}
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// Run a minimum cost flow algorithm and check the results
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template < typename MCF, typename GR,
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           typename LM, typename UM,
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           typename CM, typename SM >
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void checkMcf( const MCF& mcf, bool mcf_result,
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               const GR& gr, const LM& lower, const UM& upper,
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               const CM& cost, const SM& supply,
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               bool result, typename CM::Value total,
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               const std::string &test_id = "",
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               ProblemType type = EQ )
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{
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  check(mcf_result == result, "Wrong result " + test_id);
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  if (result) {
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    check(checkFlow(gr, lower, upper, supply, mcf.flowMap(), type),
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          "The flow is not feasible " + test_id);
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    check(mcf.totalCost() == total, "The flow is not optimal " + test_id);
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    check(checkPotential(gr, lower, upper, cost, supply, mcf.flowMap(),
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                         mcf.potentialMap()),
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          "Wrong potentials " + test_id);
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  }
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}
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int main()
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{
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  // Check the interfaces
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  {
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    typedef int Flow;
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    typedef int Cost;
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    typedef concepts::Digraph GR;
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    checkConcept< McfClassConcept<GR, Flow, Cost>,
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                  NetworkSimplex<GR, Flow, Cost> >();
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  }
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  // Run various MCF tests
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  typedef ListDigraph Digraph;
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  DIGRAPH_TYPEDEFS(ListDigraph);
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  // Read the test digraph
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  Digraph gr;
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  Digraph::ArcMap<int> c(gr), l1(gr), l2(gr), u(gr);
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  Digraph::NodeMap<int> s1(gr), s2(gr), s3(gr), s4(gr), s5(gr);
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  ConstMap<Arc, int> cc(1), cu(std::numeric_limits<int>::max());
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  Node v, w;
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  std::istringstream input(test_lgf);
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  DigraphReader<Digraph>(gr, input)
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    .arcMap("cost", c)
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    .arcMap("cap", u)
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    .arcMap("low1", l1)
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    .arcMap("low2", l2)
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    .nodeMap("sup1", s1)
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    .nodeMap("sup2", s2)
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    .nodeMap("sup3", s3)
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    .nodeMap("sup4", s4)
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    .nodeMap("sup5", s5)
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    .node("source", v)
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    .node("target", w)
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    .run();
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  // A. Test NetworkSimplex with the default pivot rule
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  {
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    NetworkSimplex<Digraph> mcf(gr);
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    // Check the equality form
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    mcf.upperMap(u).costMap(c);
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    checkMcf(mcf, mcf.supplyMap(s1).run(),
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             gr, l1, u, c, s1, true,  5240, "#A1");
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    checkMcf(mcf, mcf.stSupply(v, w, 27).run(),
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             gr, l1, u, c, s2, true,  7620, "#A2");
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    mcf.lowerMap(l2);
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    checkMcf(mcf, mcf.supplyMap(s1).run(),
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             gr, l2, u, c, s1, true,  5970, "#A3");
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    checkMcf(mcf, mcf.stSupply(v, w, 27).run(),
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             gr, l2, u, c, s2, true,  8010, "#A4");
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    mcf.reset();
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    checkMcf(mcf, mcf.supplyMap(s1).run(),
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             gr, l1, cu, cc, s1, true,  74, "#A5");
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    checkMcf(mcf, mcf.lowerMap(l2).stSupply(v, w, 27).run(),
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             gr, l2, cu, cc, s2, true,  94, "#A6");
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    mcf.reset();
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    checkMcf(mcf, mcf.run(),
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             gr, l1, cu, cc, s3, true,   0, "#A7");
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    checkMcf(mcf, mcf.boundMaps(l2, u).run(),
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             gr, l2, u, cc, s3, false,   0, "#A8");
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    // Check the GEQ form
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    mcf.reset().upperMap(u).costMap(c).supplyMap(s4);
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    checkMcf(mcf, mcf.run(),
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             gr, l1, u, c, s4, true,  3530, "#A9", GEQ);
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    mcf.problemType(mcf.GEQ);
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    checkMcf(mcf, mcf.lowerMap(l2).run(),
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             gr, l2, u, c, s4, true,  4540, "#A10", GEQ);
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    mcf.problemType(mcf.CARRY_SUPPLIES).supplyMap(s5);
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    checkMcf(mcf, mcf.run(),
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             gr, l2, u, c, s5, false,    0, "#A11", GEQ);
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    // Check the LEQ form
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    mcf.reset().problemType(mcf.LEQ);
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    mcf.upperMap(u).costMap(c).supplyMap(s5);
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    checkMcf(mcf, mcf.run(),
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             gr, l1, u, c, s5, true,  5080, "#A12", LEQ);
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    checkMcf(mcf, mcf.lowerMap(l2).run(),
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             gr, l2, u, c, s5, true,  5930, "#A13", LEQ);
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    mcf.problemType(mcf.SATISFY_DEMANDS).supplyMap(s4);
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    checkMcf(mcf, mcf.run(),
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             gr, l2, u, c, s4, false,    0, "#A14", LEQ);
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  }
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  // B. Test NetworkSimplex with each pivot rule
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  {
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    NetworkSimplex<Digraph> mcf(gr);
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    mcf.supplyMap(s1).costMap(c).capacityMap(u).lowerMap(l2);
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    checkMcf(mcf, mcf.run(NetworkSimplex<Digraph>::FIRST_ELIGIBLE),
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             gr, l2, u, c, s1, true,  5970, "#B1");
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    checkMcf(mcf, mcf.run(NetworkSimplex<Digraph>::BEST_ELIGIBLE),
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             gr, l2, u, c, s1, true,  5970, "#B2");
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    checkMcf(mcf, mcf.run(NetworkSimplex<Digraph>::BLOCK_SEARCH),
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             gr, l2, u, c, s1, true,  5970, "#B3");
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    checkMcf(mcf, mcf.run(NetworkSimplex<Digraph>::CANDIDATE_LIST),
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             gr, l2, u, c, s1, true,  5970, "#B4");
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    checkMcf(mcf, mcf.run(NetworkSimplex<Digraph>::ALTERING_LIST),
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             gr, l2, u, c, s1, true,  5970, "#B5");
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  }
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  return 0;
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}