Ticket #270: circ-inf-547e6b876ee1.patch

lemon/circulation.h

@@ -119 +119 @@
      at the nodes.
 
      The exact formulation of this problem is the following.
-     Let \f$G=(V,A)\f$ be a digraph,
-     \f$lower, upper: A\rightarrow\mathbf{R}^+_0\f$ denote the lower and
-     upper bounds on the arcs, for which \f$0 \leq lower(uv) \leq upper(uv)\f$
+     Let \f$G=(V,A)\f$ be a digraph, \f$lower: A\rightarrow\mathbf{R}\f$
+     \f$upper: A\rightarrow\mathbf{R}\cup\{\infty\}\f$ denote the lower and
+     upper bounds on the arcs, for which \f$lower(uv) \leq upper(uv)\f$
      holds for all \f$uv\in A\f$, and \f$sup: V\rightarrow\mathbf{R}\f$
      denotes the signed supply values of the nodes.
      If \f$sup(u)>0\f$, then \f$u\f$ is a supply node with \f$sup(u)\f$
      supply, if \f$sup(u)<0\f$, then \f$u\f$ is a demand node with
      \f$-sup(u)\f$ demand.
-     A feasible circulation is an \f$f: A\rightarrow\mathbf{R}^+_0\f$
+     A feasible circulation is an \f$f: A\rightarrow\mathbf{R}\f$
      solution of the following problem.
 
      \f[ \sum_{uv\in A} f(uv) - \sum_{vu\in A} f(vu)
@@ -503 +503 @@
       }
 
       for (ArcIt e(_g);e!=INVALID;++e) {
-        if (!_tol.positive((*_excess)[_g.target(e)] + (*_up)[e])) {
+        if (!_tol.less(-(*_excess)[_g.target(e)], (*_up)[e])) {
           _flow->set(e, (*_up)[e]);
           (*_excess)[_g.target(e)] += (*_up)[e];
           (*_excess)[_g.source(e)] -= (*_up)[e];
-        } else if (_tol.positive((*_excess)[_g.target(e)] + (*_lo)[e])) {
+        } else if (_tol.less(-(*_excess)[_g.target(e)], (*_lo)[e])) {
           _flow->set(e, (*_lo)[e]);
           (*_excess)[_g.target(e)] += (*_lo)[e];
           (*_excess)[_g.source(e)] -= (*_lo)[e];
@@ -748 +748 @@
     bool checkBarrier() const
     {
       Flow delta=0;
+      Flow inf_cap = std::numeric_limits<Flow>::has_infinity ?
+        std::numeric_limits<Flow>::infinity() :
+        std::numeric_limits<Flow>::max();
       for(NodeIt n(_g);n!=INVALID;++n)
         if(barrier(n))
           delta-=(*_supply)[n];
@@ -755 +758 @@
         {
           Node s=_g.source(e);
           Node t=_g.target(e);
-          if(barrier(s)&&!barrier(t)) delta+=(*_up)[e];
+          if(barrier(s)&&!barrier(t)) {
+            if (_tol.less(inf_cap - (*_up)[e], delta)) return false;
+            delta+=(*_up)[e];
+          }
           else if(barrier(t)&&!barrier(s)) delta-=(*_lo)[e];
         }
       return _tol.negative(delta);