Ticket #620: fp-nagamochi-ibaraki-89dd204d3d12.patch

lemon/nagamochi_ibaraki.h

@@ -30 +30 @@
 #include <lemon/maps.h>
 #include <lemon/radix_sort.h>
 #include <lemon/unionfind.h>
+#include <lemon/tolerance.h>
 
 #include <cassert>
 
@@ -98 +99 @@
     static Heap *createHeap(HeapCrossRef& r) {
       return new Heap(r);
     }
+
+    /// \brief The tolerance used by the algorithm
+    ///
+    /// The tolerance used by the algorithm to handle inexact computation.
+    typedef lemon::Tolerance<Value> Tolerance;
   };
 
   /// \ingroup min_cut
@@ -275 +281 @@
 
     typedef typename Graph::template NodeMap<bool> MinCutMap;
     MinCutMap *_cut_map;
+    
+    typedef typename Traits::Tolerance Tolerance;
+    Tolerance _tolerance;
 
     void createStructures() {
       if (!_nodes) {
@@ -560 +569 @@
            n != INVALID; n = (*_nodes)[n].next) {
         bool merged = false;
         for (int a = (*_nodes)[n].first_arc; a != -1; a = _arcs[a].next) {
-          if (!(_edges[a >> 1].cut < pmc)) {
+          if (!_tolerance.less(_edges[a >> 1].cut, pmc)) {
             if (!merged) {
               for (int b = (*_nodes)[n].first_arc; b != -1; b = _arcs[b].next) {
                 (*_nodes)[_arcs[b].target].curr_arc = b;

test/nagamochi_ibaraki_test.cc

@@ -40 +40 @@
   "4\n"
   "5\n"
   "@edges\n"
-  "     cap1 cap2 cap3\n"
-  "0 1  1    1    1   \n"
-  "0 2  2    2    4   \n"
-  "1 2  4    4    4   \n"
-  "3 4  1    1    1   \n"
-  "3 5  2    2    4   \n"
-  "4 5  4    4    4   \n"
-  "2 3  1    6    6   \n";
+  "     cap1 cap2 cap3 cap4\n"
+  "0 1  1    1    1    1   \n"
+  "0 2  2    2    4    1   \n"
+  "1 2  4    4    4    1   \n"
+  "3 4  1    1    1    1e-4\n"
+  "3 5  2    2    4    1e-5\n"
+  "4 5  4    4    4    1   \n"
+  "2 3  1    6    6    1   \n";
 
 void checkNagamochiIbarakiCompile()
 {
@@ -95 +95 @@
 int main() {
   SmartGraph graph;
   SmartGraph::EdgeMap<int> cap1(graph), cap2(graph), cap3(graph);
+  SmartGraph::EdgeMap<double> cap4(graph);
   SmartGraph::NodeMap<bool> cut(graph);
 
   istringstream input(lgf);
@@ -102 +103 @@
     .edgeMap("cap1", cap1)
     .edgeMap("cap2", cap2)
     .edgeMap("cap3", cap3)
+    .edgeMap("cap4", cap4)
     .run();
 
   {
@@ -133 +135 @@
     ni.run();
     ni.minCutMap(cut);
 
-    ConstMap<SmartGraph::Edge, int> cap4(1);
+    ConstMap<SmartGraph::Edge, int> cap5(1);
     check(ni.minCutValue() == 1, "Wrong cut value");
-    check(ni.minCutValue() == cutValue(graph, cap4, cut), "Wrong cut value");
+    check(ni.minCutValue() == cutValue(graph, cap5, cut), "Wrong cut value");
+  }
+  {
+    NagamochiIbaraki<SmartGraph, SmartGraph::EdgeMap<double>> ni(graph, cap4);
+    ni.run();
+    ni.minCutMap(cut);
+
+    Tolerance<double> tolerance;
+    check(!tolerance.different(ni.minCutValue(), 1.1e-4), "Wrong cut value");
+    check(!tolerance.different(ni.minCutValue(), cutValue(graph, cap4, cut)), "Wrong cut value");
   }
 
   return 0;