Ticket #8892: trac_8892.patch

sage/graphs/generic_graph.py

@@ -2058 +2058 @@
                                  "Please convert it to a Graph if you really mean it.")
 
         if use_edge_labels:
-            weight = lambda u,v : self.edge_label(u,v) if self.edge_label(u,v)!=None else 1
+            from sage.rings.real_mpfr import RR
+            weight = lambda u,v : self.edge_label(u,v) if self.edge_label(u,v) in RR else 1
         else:
             weight = lambda u,v : 1
 
@@ -3108 +3109 @@
         The edge cut between the two ends is the edge of minimum weight::
 
            sage: minimum = min([l for u,v,l in g.edge_iterator()])
-           sage: minimum == g.edge_cut(0, 14, use_edge_labels=True) # optional - requires GLPK or COIN-OR/CBC
+           sage: abs(minimum - g.edge_cut(0, 14, use_edge_labels=True)) < 10**(-5) # optional - requires GLPK or COIN-OR/CBC or CPLEX
            True
            sage: [value,[[u,v]]] = g.edge_cut(0, 14, use_edge_labels=True, value_only=False) # optional - requires GLPK or COIN-OR/CBC
            sage: g.edge_label(u, v) == minimum # optional - requires GLPK or COIN-OR/CBC
@@ -3133 +3134 @@
         if vertices:
             value_only = False
         if use_edge_labels:
-            weight = lambda x: 1 if x == None else x
+            from sage.rings.real_mpfr import RR
+            weight = lambda x: x if x in RR else 1
         else:
             weight = lambda x: 1
 
@@ -3653 +3655 @@
             sage: [ value, edges, [ setA, setB ]] = g.max_cut(vertices=True)                  # optional - requires Glpk or COIN-OR/CBC
             sage: value == 5*6                                                                # optional - requires Glpk or COIN-OR/CBC
             True
-            sage: bsetA, bsetB  = g.bipartite_sets()
+            sage: bsetA, bsetB  = map(list,g.bipartite_sets())
             sage: (bsetA == setA and bsetB == setB ) or ((bsetA == setB and bsetB == setA ))  # optional - requires Glpk or COIN-OR/CBC
             True
 
@@ -3670 +3672 @@
             value_only=False
         
         if use_edge_labels: 
-            weight=lambda x: 1 if x==None else x 
+            from sage.rings.real_mpfr import RR
+            weight = lambda x: x if x in RR else 1
         else: 
-            weight=lambda x: 1 
+            weight = lambda x: 1 
 
         if g.is_directed():
             reorder_edge = lambda x,y : (x,y)
@@ -3834 +3837 @@
         flow=p.new_variable(dim=2)
 
         if use_edge_labels:
-            capacity=lambda x: x if x!=None else 1
+            from sage.rings.real_mpfr import RR
+            capacity=lambda x: x if x in RR else 1
         else:
             capacity=lambda x: 1
 
@@ -4054 +4058 @@
 
         # returns the weight of an edge considering it may not be
         # weighted ...
-        weight=lambda x: 1 if x==None else x
+
+        from sage.rings.real_mpfr import RR
+        weight=lambda x: x if x in RR else 1
 
         p=MixedIntegerLinearProgram(maximization=True)
 
@@ -4263 +4269 @@
             value_only=False
         
         if use_edge_labels: 
-            weight=lambda x: 1 if x==None else x 
+            from sage.rings.real_mpfr import RR
+            weight=lambda x: x if x in RR else 1
         else: 
             weight=lambda x: 1 
 

sage/graphs/graph.py

@@ -1428 +1428 @@
 
             sage: g = graphs.CycleGraph(6)
             sage: bounds = lambda x: [1,1]
-            sage: m = g.degree_constrained_subgraph(bounds=bounds) # optional - requires GLPK or CBC
-            sage: m.size() #optional
+            sage: m = g.degree_constrained_subgraph(bounds=bounds) # optional - requires GLPK or CBC or CPLEX
+            sage: m.size() # optional - requires GLPK CBC or CPLEX
             3
         """
 
@@ -1438 +1438 @@
         p = MixedIntegerLinearProgram(maximization=False)
         b = p.new_variable()
 
-        reorder = lambda x: (min(x[0],x[1]),max(x[0],x[1]),x[2])
+        reorder = lambda x,y: (x,y) if x<y else (y,x)
 
         if bounds is None:
             raise ValueError,"The `bounds` keyword can not be equal to None"
@@ -1449 +1449 @@
             
 
         if self.weighted():
-            weight = lambda x: x[2] if x[2] is not None else 1
+            from sage.rings.real_mpfr import RR
+            weight = lambda x: x if x in RR else 1
         else:
             weight = lambda x: 1
 
         for v in self:
             minimum,maximum = f_bounds(v)
-            p.add_constraint(sum([ b[reorder(e)]*weight(e) for e in self.edges_incident(v)]),min=minimum, max=maximum)
+            p.add_constraint(sum([ b[reorder(x,y)]*weight(l) for x,y,l in self.edges_incident(v)]),min=minimum, max=maximum)
         
-        p.set_objective(sum([ b[reorder(e)]*weight(e) for e in self.edge_iterator()]))
+        p.set_objective(sum([ b[reorder(x,y)]*weight(l) for x,y,l in self.edge_iterator()]))
         p.set_binary(b)
 
         try:
             p.solve()
             g = self.copy()
             b = p.get_values(b)
-            g.delete_edges([e for e in g.edge_iterator() if b[reorder(e)] == 0])
+            g.delete_edges([(x,y) for x,y,_ in g.edge_iterator() if b[reorder(x,y)] < 0.5])
             return g
             
         
@@ -1472 +1473 @@
             return False
             
 
-        
-        
-
     ### Orientations
 
     def strong_orientation(self):
@@ -2913 +2911 @@
         from sage.sets.set import Set
         
         # The default capacity of an arc is 1
-        capacity = lambda label: label if label is not None else 1
+        from sage.rings.real_mpfr import RR
+        capacity = lambda label: label if label in RR else 1
 
         # Keeping the graph's embedding
         pos = False

sage/graphs/graph_coloring.py

@@ -543 +543 @@
     obj = {}
     k = max(g.degree())
     # reorders the edge if necessary...
-    R = lambda x: x if (x[0] <= x[1]) else (x[1], x[0], x[2])
+    R = lambda x: x if (x[0] <= x[1]) else (x[1], x[0])
     # Vizing's coloring uses Delta + 1 colors
     if vizing:
         value_only = False
         k += 1
     #  A vertex can not have two incident edges with the same color.
     [p.add_constraint(
-            sum([color[R(e)][i] for e in g.edges_incident(v)]), max=1)
+            sum([color[R(e)][i] for e in g.edges_incident(v, labels=False)]), max=1)
                 for v in g.vertex_iterator()
                     for i in xrange(k)]
     # an edge must have a color
     [p.add_constraint(sum([color[R(e)][i] for i in xrange(k)]), max=1, min=1)
-         for e in g.edge_iterator()]
+         for e in g.edge_iterator(labels=False)]
     # anything is good as an objective value as long as it is satisfiable
-    e = g.edge_iterator().next()
+    e = g.edge_iterator(labels=False).next()
     p.set_objective(color[R(e)][0])
     p.set_binary(color)
     try:
@@ -577 +577 @@
     color = p.get_values(color)
     classes = [[] for i in xrange(k)]
     [classes[i].append(e)
-         for e in g.edge_iterator()
+         for e in g.edge_iterator(labels = False)
              for i in xrange(k)
                  if color[R(e)][i] == 1]
     # if needed, builds a dictionary from the color classes adding colors