Add the LEMON graph library source to the repo

I'll likely be using it, so this just makes it easier to get to from
elsewhere. If I end up not using it then I can just delete it.

1 files changed, 285 insertions, 0 deletions

diff --git a/lemon/test/bellman_ford_test.cc b/lemon/test/bellman_ford_test.cc
new file mode 100644
index 0000000..2f6c7dd
--- /dev/null
+++ b/lemon/test/bellman_ford_test.cc
@@ -0,0 +1,285 @@
+/* -*- 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 <lemon/concepts/digraph.h>
+#include <lemon/smart_graph.h>
+#include <lemon/list_graph.h>
+#include <lemon/lgf_reader.h>
+#include <lemon/bellman_ford.h>
+#include <lemon/path.h>
+
+#include "graph_test.h"
+#include "test_tools.h"
+
+using namespace lemon;
+
+char test_lgf[] =
+  "@nodes\n"
+  "label\n"
+  "0\n"
+  "1\n"
+  "2\n"
+  "3\n"
+  "4\n"
+  "@arcs\n"
+  "    length\n"
+  "0 1 3\n"
+  "1 2 -3\n"
+  "1 2 -5\n"
+  "1 3 -2\n"
+  "0 2 -1\n"
+  "1 2 -4\n"
+  "0 3 2\n"
+  "4 2 -5\n"
+  "2 3 1\n"
+  "@attributes\n"
+  "source 0\n"
+  "target 3\n";
+
+
+void checkBellmanFordCompile()
+{
+  typedef int Value;
+  typedef concepts::Digraph Digraph;
+  typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap;
+  typedef BellmanFord<Digraph, LengthMap> BF;
+  typedef Digraph::Node Node;
+  typedef Digraph::Arc Arc;
+
+  Digraph gr;
+  Node s, t, n;
+  Arc e;
+  Value l;
+  int k=3;
+  bool b;
+  BF::DistMap d(gr);
+  BF::PredMap p(gr);
+  LengthMap length;
+  concepts::Path<Digraph> pp;
+
+  {
+    BF bf_test(gr,length);
+    const BF& const_bf_test = bf_test;
+
+    bf_test.run(s);
+    bf_test.run(s,k);
+
+    bf_test.init();
+    bf_test.addSource(s);
+    bf_test.addSource(s, 1);
+    b = bf_test.processNextRound();
+    b = bf_test.processNextWeakRound();
+
+    bf_test.start();
+    bf_test.checkedStart();
+    bf_test.limitedStart(k);
+
+    l  = const_bf_test.dist(t);
+    e  = const_bf_test.predArc(t);
+    s  = const_bf_test.predNode(t);
+    b  = const_bf_test.reached(t);
+    d  = const_bf_test.distMap();
+    p  = const_bf_test.predMap();
+    pp = const_bf_test.path(t);
+    pp = const_bf_test.negativeCycle();
+
+    for (BF::ActiveIt it(const_bf_test); it != INVALID; ++it) {}
+  }
+  {
+    BF::SetPredMap<concepts::ReadWriteMap<Node,Arc> >
+      ::SetDistMap<concepts::ReadWriteMap<Node,Value> >
+      ::SetOperationTraits<BellmanFordDefaultOperationTraits<Value> >
+      ::Create bf_test(gr,length);
+
+    LengthMap length_map;
+    concepts::ReadWriteMap<Node,Arc> pred_map;
+    concepts::ReadWriteMap<Node,Value> dist_map;
+
+    bf_test
+      .lengthMap(length_map)
+      .predMap(pred_map)
+      .distMap(dist_map);
+
+    bf_test.run(s);
+    bf_test.run(s,k);
+
+    bf_test.init();
+    bf_test.addSource(s);
+    bf_test.addSource(s, 1);
+    b = bf_test.processNextRound();
+    b = bf_test.processNextWeakRound();
+
+    bf_test.start();
+    bf_test.checkedStart();
+    bf_test.limitedStart(k);
+
+    l  = bf_test.dist(t);
+    e  = bf_test.predArc(t);
+    s  = bf_test.predNode(t);
+    b  = bf_test.reached(t);
+    pp = bf_test.path(t);
+    pp = bf_test.negativeCycle();
+  }
+}
+
+void checkBellmanFordFunctionCompile()
+{
+  typedef int Value;
+  typedef concepts::Digraph Digraph;
+  typedef Digraph::Arc Arc;
+  typedef Digraph::Node Node;
+  typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap;
+
+  Digraph g;
+  bool b;
+  bellmanFord(g,LengthMap()).run(Node());
+  b = bellmanFord(g,LengthMap()).run(Node(),Node());
+  bellmanFord(g,LengthMap())
+    .predMap(concepts::ReadWriteMap<Node,Arc>())
+    .distMap(concepts::ReadWriteMap<Node,Value>())
+    .run(Node());
+  b=bellmanFord(g,LengthMap())
+    .predMap(concepts::ReadWriteMap<Node,Arc>())
+    .distMap(concepts::ReadWriteMap<Node,Value>())
+    .path(concepts::Path<Digraph>())
+    .dist(Value())
+    .run(Node(),Node());
+}
+
+
+template <typename Digraph, typename Value>
+void checkBellmanFord() {
+  TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
+  typedef typename Digraph::template ArcMap<Value> LengthMap;
+
+  Digraph gr;
+  Node s, t;
+  LengthMap length(gr);
+
+  std::istringstream input(test_lgf);
+  digraphReader(gr, input).
+    arcMap("length", length).
+    node("source", s).
+    node("target", t).
+    run();
+
+  BellmanFord<Digraph, LengthMap>
+    bf(gr, length);
+  bf.run(s);
+  Path<Digraph> p = bf.path(t);
+
+  check(bf.reached(t) && bf.dist(t) == -1, "Bellman-Ford found a wrong path.");
+  check(p.length() == 3, "path() found a wrong path.");
+  check(checkPath(gr, p), "path() found a wrong path.");
+  check(pathSource(gr, p) == s, "path() found a wrong path.");
+  check(pathTarget(gr, p) == t, "path() found a wrong path.");
+
+  ListPath<Digraph> path;
+  Value dist;
+  bool reached = bellmanFord(gr,length).path(path).dist(dist).run(s,t);
+
+  check(reached && dist == -1, "Bellman-Ford found a wrong path.");
+  check(path.length() == 3, "path() found a wrong path.");
+  check(checkPath(gr, path), "path() found a wrong path.");
+  check(pathSource(gr, path) == s, "path() found a wrong path.");
+  check(pathTarget(gr, path) == t, "path() found a wrong path.");
+
+  for(ArcIt e(gr); e!=INVALID; ++e) {
+    Node u=gr.source(e);
+    Node v=gr.target(e);
+    check(!bf.reached(u) || (bf.dist(v) - bf.dist(u) <= length[e]),
+          "Wrong output. dist(target)-dist(source)-arc_length=" <<
+          bf.dist(v) - bf.dist(u) - length[e]);
+  }
+
+  for(NodeIt v(gr); v!=INVALID; ++v) {
+    if (bf.reached(v)) {
+      check(v==s || bf.predArc(v)!=INVALID, "Wrong tree.");
+      if (bf.predArc(v)!=INVALID ) {
+        Arc e=bf.predArc(v);
+        Node u=gr.source(e);
+        check(u==bf.predNode(v),"Wrong tree.");
+        check(bf.dist(v) - bf.dist(u) == length[e],
+              "Wrong distance! Difference: " <<
+              bf.dist(v) - bf.dist(u) - length[e]);
+      }
+    }
+  }
+}
+
+void checkBellmanFordNegativeCycle() {
+  DIGRAPH_TYPEDEFS(SmartDigraph);
+
+  SmartDigraph gr;
+  IntArcMap length(gr);
+
+  Node n1 = gr.addNode();
+  Node n2 = gr.addNode();
+  Node n3 = gr.addNode();
+  Node n4 = gr.addNode();
+
+  Arc a1 = gr.addArc(n1, n2);
+  Arc a2 = gr.addArc(n2, n2);
+
+  length[a1] = 2;
+  length[a2] = -1;
+
+  {
+    BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
+    bf.run(n1);
+    StaticPath<SmartDigraph> p = bf.negativeCycle();
+    check(p.length() == 1 && p.front() == p.back() && p.front() == a2,
+          "Wrong negative cycle.");
+  }
+
+  length[a2] = 0;
+
+  {
+    BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
+    bf.run(n1);
+    check(bf.negativeCycle().empty(),
+          "Negative cycle should not be found.");
+  }
+
+  length[gr.addArc(n1, n3)] = 5;
+  length[gr.addArc(n4, n3)] = 1;
+  length[gr.addArc(n2, n4)] = 2;
+  length[gr.addArc(n3, n2)] = -4;
+
+  {
+    BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
+    bf.init();
+    bf.addSource(n1);
+    for (int i = 0; i < 4; ++i) {
+      check(bf.negativeCycle().empty(),
+            "Negative cycle should not be found.");
+      bf.processNextRound();
+    }
+    StaticPath<SmartDigraph> p = bf.negativeCycle();
+    check(p.length() == 3, "Wrong negative cycle.");
+    check(length[p.nth(0)] + length[p.nth(1)] + length[p.nth(2)] == -1,
+          "Wrong negative cycle.");
+  }
+}
+
+int main() {
+  checkBellmanFord<ListDigraph, int>();
+  checkBellmanFord<SmartDigraph, double>();
+  checkBellmanFordNegativeCycle();
+  return 0;
+}