Merge pull request #1335 from arcondello/fix/CQM.from_dqm

Fix ConstrainedQuadraticModel.from_discrete_quadratic_model()

dimod/constrained/cyconstrained.pyx

@@ -415,18 +415,19 @@ cdef class cyConstrainedQuadraticModel:
         cqm.cppcqm.set_objective(cydqm.cppbqm)
         cqm.variables._extend(relabel_func(v, case) for v in dqm.variables for case in dqm.get_cases(v))
 
-        cqm.cppcqm.add_constraints(cydqm.num_variables())
-        cqm.constraint_labels._extend(dqm.variables)
-
         cdef Py_ssize_t vi, ci
         for vi in range(cydqm.num_variables()):
-            constraint = cqm.cppcqm.constraint_ref(vi)
+            constraint = cqm.cppcqm.new_constraint()
             for ci in range(cydqm.case_starts_[vi], cydqm.case_starts_[vi+1]):
                 constraint.add_linear(ci, 1)
             constraint.set_sense(cppSense.EQ)
             constraint.set_rhs(1)
             constraint.mark_discrete()
 
+            cqm.cppcqm.add_constraint(move(constraint))
+
+        cqm.constraint_labels._extend(dqm.variables)  # adjust the labels to match
+
         assert(cqm.cppcqm.num_variables() == cqm.variables.size())
         assert(cqm.cppcqm.num_constraints() == cqm.constraint_labels.size())
 

releasenotes/notes/fix-CQM.from_dqm-f9b7b35c91118d0a.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - Fix ``ConstrainedQuadraticModel.from_discrete_quadratic_model()`` incorrectly
+    formulating the discrete constraints. This bug was introcued in version 0.12.7.

tests/test_constrained.py

@@ -877,6 +877,13 @@ def test_case_label(self):
 
         self.assertEqual(set(cqm.constraints), set(dqm.variables))
 
+        for v in dqm.variables:
+            self.assertEqual(cqm.constraints[v].lhs.num_variables, dqm.num_cases(v))
+            self.assertTrue(cqm.constraints[v].lhs.is_discrete())
+
+        self.assertEqual(cqm.constraints["v"].lhs.variables,
+                         [('v', 'blue'), ('v', 'yellow'), ('v', 'brown')])
+
     def test_empty(self):
         dqm = dimod.DiscreteQuadraticModel()
 
@@ -914,6 +921,10 @@ def test_typical(self):
         # keys of constraints are the variables of DQM
         self.assertEqual(set(cqm.constraints), set(dqm.variables))
 
+        for v in dqm.variables:
+            self.assertEqual(cqm.constraints[v].lhs.num_variables, dqm.num_cases(v))
+            self.assertTrue(cqm.constraints[v].lhs.is_discrete())
+
 
 class TestNumBiases(unittest.TestCase):
     def test_simple(self):