/* -*- mode: C++; indent-tabs-mode: nil; -*-

 *

 * This file is a part of LEMON, a generic C++ optimization library.

 *

 * Copyright (C) 2003-2010

 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

 * (Egervary Research Group on Combinatorial Optimization, EGRES).

 *

 * Permission to use, modify and distribute this software is granted

 * provided that this copyright notice appears in all copies. For

 * precise terms see the accompanying LICENSE file.

 *

 * This software is provided "AS IS" with no warranty of any kind,

 * express or implied, and with no claim as to its suitability for any

 * purpose.

 *

 */

#include <iostream>

#include "test_tools.h"

#include <lemon/smart_graph.h>

#include <lemon/preflow.h>

#include <lemon/edmonds_karp.h>

#include <lemon/concepts/digraph.h>

#include <lemon/concepts/maps.h>

#include <lemon/lgf_reader.h>

#include <lemon/elevator.h>

using namespace lemon;

char test_lgf[] =

  "@nodes\n"

  "label\n"

  "0\n"

  "1\n"

  "2\n"

  "3\n"

  "4\n"

  "5\n"

  "6\n"

  "7\n"

  "8\n"

  "9\n"

  "@arcs\n"

  "    label capacity\n"

  "0 1 0     20\n"

  "0 2 1     0\n"

  "1 1 2     3\n"

  "1 2 3     8\n"

  "1 3 4     8\n"

  "2 5 5     5\n"

  "3 2 6     5\n"

  "3 5 7     5\n"

  "3 6 8     5\n"

  "4 3 9     3\n"

  "5 7 10    3\n"

  "5 6 11    10\n"

  "5 8 12    10\n"

  "6 8 13    8\n"

  "8 9 14    20\n"

  "8 1 15    5\n"

  "9 5 16    5\n"

  "@attributes\n"

  "source 1\n"

  "target 8\n";

// Checks the general interface of a max flow algorithm

template <typename GR, typename CAP>

struct MaxFlowClassConcept

{

  template <typename MF>

  struct Constraints {

    typedef typename GR::Node Node;

    typedef typename GR::Arc Arc;

    typedef typename CAP::Value Value;

    typedef concepts::ReadWriteMap<Arc, Value> FlowMap;

    typedef concepts::WriteMap<Node, bool> CutMap;

    GR g;

    Node n;

    Arc e;

    CAP cap;

    FlowMap flow;

    CutMap cut;

    Value v;

    bool b;

    void constraints() {

      checkConcept<concepts::Digraph, GR>();

      const Constraints& me = *this;

      typedef typename MF

          ::template SetFlowMap<FlowMap>

          ::Create MaxFlowType;

      typedef typename MF::Create MaxFlowType2;

      MaxFlowType max_flow(me.g, me.cap, me.n, me.n);

      const MaxFlowType& const_max_flow = max_flow;

      max_flow

          .capacityMap(cap)

          .flowMap(flow)

          .source(n)

          .target(n);

      typename MaxFlowType::Tolerance tol = const_max_flow.tolerance();

      max_flow.tolerance(tol);

      max_flow.init();

      max_flow.init(cap);

      max_flow.run();

      v = const_max_flow.flowValue();

      v = const_max_flow.flow(e);

      const FlowMap& fm = const_max_flow.flowMap();

      b = const_max_flow.minCut(n);

      const_max_flow.minCutMap(cut);

      ignore_unused_variable_warning(fm);

    }

  };

};

// Checks the specific parts of Preflow's interface

void checkPreflowCompile()

{

  typedef int Value;

  typedef concepts::Digraph Digraph;

  typedef concepts::ReadMap<Digraph::Arc, Value> CapMap;

  typedef Elevator<Digraph, Digraph::Node> Elev;

  typedef LinkedElevator<Digraph, Digraph::Node> LinkedElev;

  Digraph g;

  Digraph::Node n;

  CapMap cap;

  typedef Preflow<Digraph, CapMap>

      ::SetElevator<Elev>

      ::SetStandardElevator<LinkedElev>

      ::Create PreflowType;

  PreflowType preflow_test(g, cap, n, n);

  const PreflowType& const_preflow_test = preflow_test;

  const PreflowType::Elevator& elev = const_preflow_test.elevator();

  preflow_test.elevator(const_cast<PreflowType::Elevator&>(elev));

  bool b = preflow_test.init(cap);

  preflow_test.startFirstPhase();

  preflow_test.startSecondPhase();

  preflow_test.runMinCut();

  ignore_unused_variable_warning(b);

}

// Checks the specific parts of EdmondsKarp's interface

void checkEdmondsKarpCompile()

{

  typedef int Value;

  typedef concepts::Digraph Digraph;

  typedef concepts::ReadMap<Digraph::Arc, Value> CapMap;

  typedef Elevator<Digraph, Digraph::Node> Elev;

  typedef LinkedElevator<Digraph, Digraph::Node> LinkedElev;

  Digraph g;

  Digraph::Node n;

  CapMap cap;

  EdmondsKarp<Digraph, CapMap> ek_test(g, cap, n, n);

  ek_test.init(cap);

  bool b = ek_test.checkedInit(cap);

  b = ek_test.augment();

  ek_test.start();

  ignore_unused_variable_warning(b);

}

template <typename T>

T cutValue (const SmartDigraph& g,

              const SmartDigraph::NodeMap<bool>& cut,

              const SmartDigraph::ArcMap<T>& cap) {

  T c=0;

  for(SmartDigraph::ArcIt e(g); e!=INVALID; ++e) {

    if (cut[g.source(e)] && !cut[g.target(e)]) c+=cap[e];

  }

  return c;

}

template <typename T>

bool checkFlow(const SmartDigraph& g,

               const SmartDigraph::ArcMap<T>& flow,

               const SmartDigraph::ArcMap<T>& cap,

               SmartDigraph::Node s, SmartDigraph::Node t) {

  for (SmartDigraph::ArcIt e(g); e != INVALID; ++e) {

    if (flow[e] < 0 || flow[e] > cap[e]) return false;

  }

  for (SmartDigraph::NodeIt n(g); n != INVALID; ++n) {

    if (n == s || n == t) continue;

    T sum = 0;

    for (SmartDigraph::OutArcIt e(g, n); e != INVALID; ++e) {

      sum += flow[e];

    }

    for (SmartDigraph::InArcIt e(g, n); e != INVALID; ++e) {

      sum -= flow[e];

    }

    if (sum != 0) return false;

  }

  return true;

}

void initFlowTest()

{

  DIGRAPH_TYPEDEFS(SmartDigraph);

  SmartDigraph g;

  SmartDigraph::ArcMap<int> cap(g),iflow(g);

  Node s=g.addNode(); Node t=g.addNode();

  Node n1=g.addNode(); Node n2=g.addNode();

  Arc a;

  a=g.addArc(s,n1); cap[a]=20; iflow[a]=20;

  a=g.addArc(n1,n2); cap[a]=10; iflow[a]=0;

  a=g.addArc(n2,t); cap[a]=20; iflow[a]=0;

  Preflow<SmartDigraph> pre(g,cap,s,t);

  pre.init(iflow);

  pre.startFirstPhase();

  check(pre.flowValue() == 10, "The incorrect max flow value.");

  check(pre.minCut(s), "Wrong min cut (Node s).");

  check(pre.minCut(n1), "Wrong min cut (Node n1).");

  check(!pre.minCut(n2), "Wrong min cut (Node n2).");

  check(!pre.minCut(t), "Wrong min cut (Node t).");

}

template <typename MF, typename SF>

void checkMaxFlowAlg() {

  typedef SmartDigraph Digraph;

  DIGRAPH_TYPEDEFS(Digraph);

  typedef typename MF::Value Value;

  typedef Digraph::ArcMap<Value> CapMap;

  typedef CapMap FlowMap;

  typedef BoolNodeMap CutMap;

  Digraph g;

  Node s, t;

  CapMap cap(g);

  std::istringstream input(test_lgf);

  DigraphReader<Digraph>(g,input)

      .arcMap("capacity", cap)

      .node("source",s)

      .node("target",t)

      .run();

  MF max_flow(g, cap, s, t);

  max_flow.run();

  check(checkFlow(g, max_flow.flowMap(), cap, s, t),

        "The flow is not feasible.");

  CutMap min_cut(g);

  max_flow.minCutMap(min_cut);

  Value min_cut_value = cutValue(g, min_cut, cap);

  check(max_flow.flowValue() == min_cut_value,

        "The max flow value is not equal to the min cut value.");

  FlowMap flow(g);

  for (ArcIt e(g); e != INVALID; ++e) flow[e] = max_flow.flowMap()[e];

  Value flow_value = max_flow.flowValue();

  for (ArcIt e(g); e != INVALID; ++e) cap[e] = 2 * cap[e];

  max_flow.init(flow);

  SF::startFirstPhase(max_flow);       // start first phase of the algorithm

  CutMap min_cut1(g);

  max_flow.minCutMap(min_cut1);

  min_cut_value = cutValue(g, min_cut1, cap);

  check(max_flow.flowValue() == min_cut_value &&

        min_cut_value == 2 * flow_value,

        "The max flow value or the min cut value is wrong.");

  SF::startSecondPhase(max_flow);       // start second phase of the algorithm

  check(checkFlow(g, max_flow.flowMap(), cap, s, t),

        "The flow is not feasible.");

  CutMap min_cut2(g);

  max_flow.minCutMap(min_cut2);

  min_cut_value = cutValue(g, min_cut2, cap);

  check(max_flow.flowValue() == min_cut_value &&

        min_cut_value == 2 * flow_value,

        "The max flow value or the min cut value was not doubled");

  max_flow.flowMap(flow);

  NodeIt tmp1(g, s);

  ++tmp1;

  if (tmp1 != INVALID) s = tmp1;

  NodeIt tmp2(g, t);

  ++tmp2;

  if (tmp2 != INVALID) t = tmp2;

  max_flow.source(s);

  max_flow.target(t);

  max_flow.run();

  CutMap min_cut3(g);

  max_flow.minCutMap(min_cut3);

  min_cut_value=cutValue(g, min_cut3, cap);

  check(max_flow.flowValue() == min_cut_value,

        "The max flow value or the min cut value is wrong.");

}

// Struct for calling start functions of a general max flow algorithm

template <typename MF>

struct GeneralStartFunctions {

  static void startFirstPhase(MF& mf) {

    mf.start();

  }

  static void startSecondPhase(MF& mf) {

    ignore_unused_variable_warning(mf);

  }

};

// Struct for calling start functions of Preflow

template <typename MF>

struct PreflowStartFunctions {

  static void startFirstPhase(MF& mf) {

    mf.startFirstPhase();

  }

  static void startSecondPhase(MF& mf) {

    mf.startSecondPhase();

  }

};

int main() {

  typedef concepts::Digraph GR;

  typedef concepts::ReadMap<GR::Arc, int> CM1;

  typedef concepts::ReadMap<GR::Arc, double> CM2;

  // Check the interface of Preflow

  checkConcept< MaxFlowClassConcept<GR, CM1>,

                Preflow<GR, CM1> >();

  checkConcept< MaxFlowClassConcept<GR, CM2>,

                Preflow<GR, CM2> >();

  // Check the interface of EdmondsKarp

  checkConcept< MaxFlowClassConcept<GR, CM1>,

                EdmondsKarp<GR, CM1> >();

  checkConcept< MaxFlowClassConcept<GR, CM2>,

                EdmondsKarp<GR, CM2> >();

  // Check Preflow

  typedef Preflow<SmartDigraph, SmartDigraph::ArcMap<int> > PType1;

  typedef Preflow<SmartDigraph, SmartDigraph::ArcMap<float> > PType2;

  checkMaxFlowAlg<PType1, PreflowStartFunctions<PType1> >();

  checkMaxFlowAlg<PType2, PreflowStartFunctions<PType2> >();

  initFlowTest();

  // Check EdmondsKarp

  typedef EdmondsKarp<SmartDigraph, SmartDigraph::ArcMap<int> > EKType1;

  typedef EdmondsKarp<SmartDigraph, SmartDigraph::ArcMap<float> > EKType2;

  checkMaxFlowAlg<EKType1, GeneralStartFunctions<EKType1> >();

  checkMaxFlowAlg<EKType2, GeneralStartFunctions<EKType2> >();

  initFlowTest();

  return 0;

}