Investigating why second name in distillation.py is incorrect when se…

…lf.update() is called in addVariable

examples/chip.py

@@ -13,8 +13,8 @@
 varNames.append('Tables')
 varNames.append('Sets of chairs')
 
-x1 = h.addVar(obj = 10, name = varNames[0])
-x2 = h.addVar(obj = 25, name = varNames[1])
+x1 = h.addVariable(obj = 10, name = varNames[0])
+x2 = h.addVariable(obj = 25, name = varNames[1])
 
 vars = list()
 vars.append(x1)

examples/distillation.py

@@ -15,13 +15,36 @@
 varNames.append('TypeA')
 varNames.append('TypeB')
 
-useTypeA = h.addVar(obj =  8, name = varNames[0])
-useTypeB = h.addVar(obj = 10, name = varNames[1])
+print("DEBUG ", varNames)
+
+update_in_addVariable = True
+if update_in_addVariable:
+    print("DEBUG update_in_addVariable is True")
+else:
+    print("DEBUG update_in_addVariable is False")
+
+useTypeA = h.addVariable(obj =  8, name = varNames[0], update = update_in_addVariable)
+useTypeB = h.addVariable(obj = 10, name = varNames[1], update = update_in_addVariable)
+
+# With update_in_addVariable = False (so runs as originally written,
+# with self.update() being called only in addConstr) useTypeB.name is
+# "TypeB"
+#
+# With update_in_addVariable = True (so self.update() is called in addVariable) useTypeB.name is
+# "TypeA"
+#
+# Looks as if the internal stack of names isn't being cleared, so
+# TypeA is still on top when useTypeB is being defined
+
+print('\nDEBUG Names: useTypeA', useTypeA.name, "; varNames[0]", varNames[0])
+print('DEBUG Names: useTypeB', useTypeB.name, "; varNames[0]", varNames[1])
 
 vars = list()
 vars.append(useTypeA)
 vars.append(useTypeB)
 
+print("\nDEBUG vars: ", vars)
+
 constrNames = list()
 constrNames.append('Product1')
 constrNames.append('Product2')
@@ -44,12 +67,12 @@
 print('Solved as LP')
 
 for var in vars:
-    print('Use', h.varValue(var), h.varName(var), ': Reduced cost', h.varDual(var))
+    print('Use {0:6f} of {1:6s}: reduced cost {2:6f}'.format(h.varValue(var), h.varName(var), h.varDual(var)))
 print('Use', h.varValues(vars), 'of', h.varNames(vars))
 print('Use', h.allVarValues(), 'of', h.allVarNames())
 
 for name in constrNames:
-    print('Constraint', name, 'has value', h.constrValue(name), 'and dual', h.constrDual(name))
+    print('Constraint {0:6s} has value {1:6f} and dual {2:6f}'.format(name, h.constrValue(name), h.constrDual(name)))
 
 print('Constraints have values', h.constrValues(constrNames), 'and duals', h.constrDuals(constrNames))
 
@@ -66,6 +89,6 @@
 print('Solved as MIP')
 
 for var in vars:
-    print('Use', h.varValue(var), h.varName(var))
+    print('Use {0:6f} of {1:6s}'.format(h.varValue(var), h.varName(var)))
 
 print('Optimal objective value is', h.getObjectiveValue())

examples/minimal.py

@@ -2,8 +2,8 @@
 
 h = highspy.Highs()
 
-x1 = h.addVar(lb=-h.inf)
-x2 = h.addVar(lb=-h.inf)
+x1 = h.addVariable(lb = -h.inf)
+x2 = h.addVariable(lb = -h.inf)
 
 h.addConstr(x2 - x1 >= 2)
 h.addConstr(x1 + x2 >= 0)

src/highspy/highs.py

@@ -104,9 +104,10 @@ def maximize(self, obj=None):
     # update variables
     def update(self):
         current_batch_size = len(self._batch.obj)
-
+        print("\nDEBUG update(self): On entry - current_batch_size = ", current_batch_size)
         if current_batch_size > 0:
             names = [self._vars[i].name for i in range(current_batch_size)]
+            print("DEBUG update(self): names = [", names, "] costs = ", self._batch.obj)
 
             super().addVars(int(current_batch_size), self._batch.lb, self._batch.ub)
             super().changeColsCost(current_batch_size, self._batch.idx, self._batch.obj)
@@ -119,6 +120,7 @@ def update(self):
                 super().passColName(int(self._batch.idx[i]), str(names[i]))
 
         self._batch = highs_batch(self)
+        print("DEBUG update(self): On  exit - current_batch_size = ", len(self._batch.obj))
 
     def val(self, var):
         return super().getSolution().col_value[var.index]
@@ -214,13 +216,17 @@ def allConstrDuals(self):
     #
     # Change the name of addVar to addVariable to prevent shadowing of
     # highspy binding to Highs::addVar
-    def addVariable(self, lb = 0, ub = kHighsInf, obj = 0, type=HighsVarType.kContinuous, name = None):
+    def addVariable(self, lb = 0, ub = kHighsInf, obj = 0, type=HighsVarType.kContinuous, name = None, update = False):
+        print("\nDEBUG addVariable: name = ", name, "; obj = ", obj, "; lb = ", lb, "; ub = ", ub, " with update = ", update)
         var = self._batch.add(obj, lb, ub, type, name, self)
         self._vars.append(var)
         # No longer acumulate a batch of variables so that addVariable
         # behaves like Highs::addVar and highspy bindings modifying
         # column data and adding rows can be used
-        self.update()
+        if update:
+            self.update()
+            print("\nDEBUG ")
+        print("DEBUG addVariable: On exit - current_batch_size = ", len(self._batch.obj))
         return var
 
     def addIntegral(self, lb = 0, ub = kHighsInf, obj = 0, name = None):
@@ -554,5 +560,6 @@ def add(self, obj, lb, ub, type,name,solver):
         self.type.append(type)
 
         newIndex = self.highs.numVars + len(self.obj)-1
+        print("\nDEBUG add: newIndex = ", newIndex)
         self.idx.append(newIndex)
         return highs_var(newIndex, solver, name)