API: addMatrixCons supports ExprCons (#1036)

* API: `addMatrixCons` supports `ExprCons`

* test error

* test accepting `ExprCons`

* Update CHANGELOG.md

* Update CHANGELOG.md

* Update scip.pxi

* Add comments to clarify error tests in matrix variable tests

Added comments to the test_catching_errors function in test_matrix_variable.py to clarify the purpose of each exception test case.

* Move addCons testcase to top

* Add test for shape mismatch in addMatrixCons

Added a test case to ensure addMatrixCons raises a ValueError when provided with an initial array of incorrect shape.

* Apply suggestions from code review

* Update test_matrix_variable.py

* Update scip.pxi

* tabs spaces

* tabs and spaces finally?

---------

Co-authored-by: João Dionísio <57299939+Joao-Dionisio@users.noreply.github.com>

Author: Zeroto521

CHANGELOG.md

@@ -18,7 +18,8 @@
 - Raised an error when an expression is used when a variable is required
 - Fixed some compile warnings
 ### Changed
-- MatrixExpr.sum() now supports axis arguments and can return either a scalar or MatrixExpr depending on the result dimensions
+- MatrixExpr.sum() now supports axis arguments and can return either a scalar or MatrixExpr, depending on the result dimensions.
+- AddMatrixCons() also accepts ExprCons.
 ### Removed
 
 ## 5.5.0 - 2025.05.06

src/pyscipopt/scip.pxi

@@ -5775,7 +5775,7 @@ cdef class Model:
         return constraints
 
     def addMatrixCons(self,
-                      cons: MatrixExprCons,
+                      cons: Union[ExprCons, MatrixExprCons],
                       name: Union[str, np.ndarray] ='',
                       initial: Union[bool, np.ndarray] = True,
                       separate: Union[bool, np.ndarray] = True,
@@ -5792,8 +5792,8 @@ cdef class Model:
 
         Parameters
         ----------
-        cons : MatrixExprCons
-            The matrix expression constraint that is not yet an actual constraint
+        cons : ExprCons or MatrixExprCons
+            The matrix expression constraint or expression constraint, that are not yet an actual constraint
         name : str or np.ndarray, optional
             the name of the matrix constraint, generic name if empty (Default value = "")
         initial : bool or np.ndarray, optional
@@ -5820,12 +5820,17 @@ cdef class Model:
 
         Returns
         -------
-        MatrixConstraint
-            The created and added MatrixConstraint object.
-
+        Constraint or MatrixConstraint
+            The created and added Constraint or MatrixConstraint.
         """
-        assert isinstance(cons, MatrixExprCons), (
-                "given constraint is not MatrixExprCons but %s" % cons.__class__.__name__)
+        if not isinstance(cons, (ExprCons, MatrixExprCons)):
+            raise TypeError("given constraint is not MatrixExprCons nor ExprCons but %s" % cons.__class__.__name__)
+
+        if isinstance(cons, ExprCons):
+            return self.addCons(cons, name=name, initial=initial, separate=separate,
+                        enforce=enforce, check=check, propagate=propagate,
+                        local=local, modifiable=modifiable, dynamic=dynamic,
+                        removable=removable, stickingatnode=stickingatnode)
 
         shape = cons.shape
 

tests/test_matrix_variable.py

@@ -15,12 +15,15 @@ def test_catching_errors():
     y = m.addMatrixVar(shape=(3, 3))
     rhs = np.ones((2, 1))
 
+    # require ExprCons
     with pytest.raises(Exception):
-        m.addMatrixCons(x <= 1)
+        m.addCons(y <= 3)
 
+    # require MatrixExprCons or ExprCons
     with pytest.raises(Exception):
-        m.addCons(y <= 3)
+        m.addMatrixCons(x)
 
+    # test shape mismatch
     with pytest.raises(Exception):
         m.addMatrixCons(y <= rhs)
 
@@ -169,7 +172,7 @@ def test_matrix_sum_argument():
 
     # compare the result of summing 2d array to a scalar with a scalar
     x = m.addMatrixVar((2, 3), "x", "I", ub=4)
-    m.addCons(x.sum() == 24)
+    m.addMatrixCons(x.sum() == 24)
 
     # compare the result of summing 2d array to 1d array
     y = m.addMatrixVar((2, 4), "y", "I", ub=4)