fix lp_test.py in debug

Author: lperron

ortools/linear_solver/python/linear_solver.i

@@ -359,6 +359,7 @@ PY_CONVERT(MPVariable);
 %unignore operations_research::MPSolver::NumVariables;
 %unignore operations_research::MPSolver::EnableOutput;  // No unit test
 %unignore operations_research::MPSolver::SuppressOutput;  // No unit test
+%rename (IsMip) operations_research::MPSolver::IsMIP;
 %rename (LookupConstraint)
     operations_research::MPSolver::LookupConstraintOrNull;
 %rename (LookupVariable) operations_research::MPSolver::LookupVariableOrNull;

ortools/linear_solver/python/lp_test.py

@@ -158,15 +158,16 @@ def SolveAndPrint(self, solver, variable_list, constraint_list, is_precise):
 
         print('Advanced usage:')
         print(('Problem solved in %d iterations' % solver.iterations()))
-        for variable in variable_list:
-            print(('%s: reduced cost = %f' % (variable.name(),
+        if not solver.IsMip():
+            for variable in variable_list:
+                print(('%s: reduced cost = %f' % (variable.name(),
                                               variable.reduced_cost())))
-        activities = solver.ComputeConstraintActivities()
-        for i, constraint in enumerate(constraint_list):
-            print(
-                ('constraint %d: dual value = %f\n'
-                 '               activity = %f' %
-                 (i, constraint.dual_value(), activities[constraint.index()])))
+            activities = solver.ComputeConstraintActivities()
+            for i, constraint in enumerate(constraint_list):
+                print(
+                    ('constraint %d: dual value = %f\n'
+                     '               activity = %f' %
+                     (i, constraint.dual_value(), activities[constraint.index()])))
 
     def testApi(self):
         print('testApi', flush=True)