# HG changeset patch
# User Peter Kovacs <kpeter@inf.elte.hu>
# Date 2009-08-11 22:52:35
# Node ID 11c946fa8d13774d947c57e30f3f72cc7b0b3425
# Parent  97744b6dabf8d706434e30dc3caadb99db050c06

Simplify comparisons in min mean cycle classes (#179)
using extreme INF values instead of bool flags.

diff --git a/lemon/hartmann_orlin.h b/lemon/hartmann_orlin.h
--- a/lemon/hartmann_orlin.h
+++ b/lemon/hartmann_orlin.h
@@ -150,11 +150,10 @@
     // Data sturcture for path data
     struct PathData
     {
-      bool found;
       LargeValue dist;
       Arc pred;
-      PathData(bool f = false, LargeValue d = 0, Arc p = INVALID) :
-        found(f), dist(d), pred(p) {}
+      PathData(LargeValue d, Arc p = INVALID) :
+        dist(d), pred(p) {}
     };
 
     typedef typename Digraph::template NodeMap<std::vector<PathData> >
@@ -191,6 +190,9 @@
 
     Tolerance _tolerance;
 
+    // Infinite constant
+    const LargeValue INF;
+
   public:
 
     /// \name Named Template Parameters
@@ -245,7 +247,10 @@
                    const LengthMap &length ) :
       _gr(digraph), _length(length), _comp(digraph), _out_arcs(digraph),
       _best_found(false), _best_length(0), _best_size(1),
-      _cycle_path(NULL), _local_path(false), _data(digraph)
+      _cycle_path(NULL), _local_path(false), _data(digraph),
+      INF(std::numeric_limits<LargeValue>::has_infinity ?
+          std::numeric_limits<LargeValue>::infinity() :
+          std::numeric_limits<LargeValue>::max())
     {}
 
     /// Destructor.
@@ -472,7 +477,7 @@
         return false;
       }      
       for (int i = 0; i < n; ++i) {
-        _data[(*_nodes)[i]].resize(n + 1);
+        _data[(*_nodes)[i]].resize(n + 1, PathData(INF));
       }
       return true;
     }
@@ -482,7 +487,7 @@
     // node to node v containing exactly k arcs.
     void processRounds() {
       Node start = (*_nodes)[0];
-      _data[start][0] = PathData(true, 0);
+      _data[start][0] = PathData(0);
       _process.clear();
       _process.push_back(start);
 
@@ -517,12 +522,9 @@
           e = _out_arcs[u][j];
           v = _gr.target(e);
           d = _data[u][k-1].dist + _length[e];
-          if (!_data[v][k].found) {
-            next.push_back(v);
-            _data[v][k] = PathData(true, _data[u][k-1].dist + _length[e], e);
-          }
-          else if (_tolerance.less(d, _data[v][k].dist)) {
-            _data[v][k] = PathData(true, d, e);
+          if (_tolerance.less(d, _data[v][k].dist)) {
+            if (_data[v][k].dist == INF) next.push_back(v);
+            _data[v][k] = PathData(d, e);
           }
         }
       }
@@ -540,8 +542,8 @@
           e = _out_arcs[u][j];
           v = _gr.target(e);
           d = _data[u][k-1].dist + _length[e];
-          if (!_data[v][k].found || _tolerance.less(d, _data[v][k].dist)) {
-            _data[v][k] = PathData(true, d, e);
+          if (_tolerance.less(d, _data[v][k].dist)) {
+            _data[v][k] = PathData(d, e);
           }
         }
       }
@@ -561,7 +563,7 @@
       _curr_found = false;
       for (int i = 0; i < n; ++i) {
         u = (*_nodes)[i];
-        if (!_data[u][k].found) continue;
+        if (_data[u][k].dist == INF) continue;
         for (int j = k; j >= 0; --j) {
           if (level[u].first == i && level[u].second > 0) {
             // A cycle is found
@@ -586,11 +588,11 @@
         // Find node potentials
         for (int i = 0; i < n; ++i) {
           u = (*_nodes)[i];
-          pi[u] = std::numeric_limits<LargeValue>::max();
+          pi[u] = INF;
           for (int j = 0; j <= k; ++j) {
-            d = _data[u][j].dist * _curr_size - j * _curr_length;
-            if (_data[u][j].found && _tolerance.less(d, pi[u])) {
-              pi[u] = d;
+            if (_data[u][j].dist < INF) {
+              d = _data[u][j].dist * _curr_size - j * _curr_length;
+              if (_tolerance.less(d, pi[u])) pi[u] = d;
             }
           }
         }
diff --git a/lemon/howard.h b/lemon/howard.h
--- a/lemon/howard.h
+++ b/lemon/howard.h
@@ -178,6 +178,9 @@
 
     Tolerance _tolerance;
   
+    // Infinite constant
+    const LargeValue INF;
+
   public:
   
     /// \name Named Template Parameters
@@ -230,9 +233,13 @@
     /// \param length The lengths (costs) of the arcs.
     Howard( const Digraph &digraph,
             const LengthMap &length ) :
-      _gr(digraph), _length(length), _cycle_path(NULL), _local_path(false),
+      _gr(digraph), _length(length), _best_found(false),
+      _best_length(0), _best_size(1), _cycle_path(NULL), _local_path(false),
       _policy(digraph), _reached(digraph), _level(digraph), _dist(digraph),
-      _comp(digraph), _in_arcs(digraph)
+      _comp(digraph), _in_arcs(digraph),
+      INF(std::numeric_limits<LargeValue>::has_infinity ?
+          std::numeric_limits<LargeValue>::infinity() :
+          std::numeric_limits<LargeValue>::max())
     {}
 
     /// Destructor.
@@ -307,7 +314,7 @@
           if (!computeNodeDistances()) break;
         }
         // Update the best cycle (global minimum mean cycle)
-        if ( !_best_found || (_curr_found &&
+        if ( _curr_found && (!_best_found ||
              _curr_length * _best_size < _best_length * _curr_size) ) {
           _best_found = true;
           _best_length = _curr_length;
@@ -446,7 +453,7 @@
         return false;
       }
       for (int i = 0; i < int(_nodes->size()); ++i) {
-        _dist[(*_nodes)[i]] = std::numeric_limits<LargeValue>::max();
+        _dist[(*_nodes)[i]] = INF;
       }
       Node u, v;
       Arc e;
diff --git a/lemon/karp.h b/lemon/karp.h
--- a/lemon/karp.h
+++ b/lemon/karp.h
@@ -148,11 +148,10 @@
     // Data sturcture for path data
     struct PathData
     {
-      bool found;
       LargeValue dist;
       Arc pred;
-      PathData(bool f = false, LargeValue d = 0, Arc p = INVALID) :
-        found(f), dist(d), pred(p) {}
+      PathData(LargeValue d, Arc p = INVALID) :
+        dist(d), pred(p) {}
     };
 
     typedef typename Digraph::template NodeMap<std::vector<PathData> >
@@ -186,6 +185,9 @@
     std::vector<Node> _process;
 
     Tolerance _tolerance;
+    
+    // Infinite constant
+    const LargeValue INF;
 
   public:
 
@@ -241,7 +243,10 @@
           const LengthMap &length ) :
       _gr(digraph), _length(length), _comp(digraph), _out_arcs(digraph),
       _cycle_length(0), _cycle_size(1), _cycle_node(INVALID),
-      _cycle_path(NULL), _local_path(false), _data(digraph)
+      _cycle_path(NULL), _local_path(false), _data(digraph),
+      INF(std::numeric_limits<LargeValue>::has_infinity ?
+          std::numeric_limits<LargeValue>::infinity() :
+          std::numeric_limits<LargeValue>::max())
     {}
 
     /// Destructor.
@@ -458,7 +463,7 @@
         return false;
       }      
       for (int i = 0; i < n; ++i) {
-        _data[(*_nodes)[i]].resize(n + 1);
+        _data[(*_nodes)[i]].resize(n + 1, PathData(INF));
       }
       return true;
     }
@@ -468,7 +473,7 @@
     // node to node v containing exactly k arcs.
     void processRounds() {
       Node start = (*_nodes)[0];
-      _data[start][0] = PathData(true, 0);
+      _data[start][0] = PathData(0);
       _process.clear();
       _process.push_back(start);
 
@@ -493,12 +498,9 @@
           e = _out_arcs[u][j];
           v = _gr.target(e);
           d = _data[u][k-1].dist + _length[e];
-          if (!_data[v][k].found) {
-            next.push_back(v);
-            _data[v][k] = PathData(true, _data[u][k-1].dist + _length[e], e);
-          }
-          else if (_tolerance.less(d, _data[v][k].dist)) {
-            _data[v][k] = PathData(true, d, e);
+          if (_tolerance.less(d, _data[v][k].dist)) {
+            if (_data[v][k].dist == INF) next.push_back(v);
+            _data[v][k] = PathData(d, e);
           }
         }
       }
@@ -516,8 +518,8 @@
           e = _out_arcs[u][j];
           v = _gr.target(e);
           d = _data[u][k-1].dist + _length[e];
-          if (!_data[v][k].found || _tolerance.less(d, _data[v][k].dist)) {
-            _data[v][k] = PathData(true, d, e);
+          if (_tolerance.less(d, _data[v][k].dist)) {
+            _data[v][k] = PathData(d, e);
           }
         }
       }
@@ -528,12 +530,12 @@
       int n = _nodes->size();
       for (int i = 0; i < n; ++i) {
         Node u = (*_nodes)[i];
-        if (!_data[u][n].found) continue;
+        if (_data[u][n].dist == INF) continue;
         LargeValue length, max_length = 0;
         int size, max_size = 1;
         bool found_curr = false;
         for (int k = 0; k < n; ++k) {
-          if (!_data[u][k].found) continue;
+          if (_data[u][k].dist == INF) continue;
           length = _data[u][n].dist - _data[u][k].dist;
           size = n - k;
           if (!found_curr || length * max_size > max_length * size) {