Fix/skew symmetric constraints

PEPit/function.py

@@ -386,7 +386,7 @@ def add_constraints_from_two_lists_of_points(self, list_of_points_1, list_of_poi
             constraint_name (str): generic name for this constraint.
             set_class_constraint_i_j (Callable): a function that takes two points in input
                                                  and returns a :class:`Constraint`.
-            symmetry (bool or int, optional): A boolean specifying if the constraint function is symmetric or not. If equals -1, means a skew symmetric constraint.
+            symmetry (bool, optional): A boolean specifying if the constraint function is symmetric or not.
                                        If so, the number of constraints is divided by 2.
                                        Set to False by default.
 
@@ -418,7 +418,7 @@ def add_constraints_from_two_lists_of_points(self, list_of_points_1, list_of_poi
                 if xj_id is None:
                     xj_id = "Point_{}".format(j)
 
-                if (i == j and symmetry != -1) or (i > j and symmetry):
+                if i == j or (i > j and symmetry):
                     row_of_constraints.append(0)
 
                 else:

PEPit/operators/skew_symmetric_linear.py

@@ -78,6 +78,17 @@ def set_antisymmetric_linear_constraint_i_j(xi, gi, fi,
 
         return constraint
 
+    @staticmethod
+    def set_diagonal_linear_constraint_i(xi, gi, fi,
+                                         ):
+        """
+        Formulates the list of interpolation constraints for self (Skew-symmetric linear operator).
+        """
+        # Interpolation conditions of symmetric linear operators class
+        constraint = (xi * gi == 0)
+
+        return constraint
+
     def add_class_constraints(self):
         """
         Formulates the list of necessary and sufficient conditions for interpolation of self
@@ -90,8 +101,13 @@ def add_class_constraints(self):
                                                       constraint_name="antisymmetric_linearity",
                                                       set_class_constraint_i_j=
                                                       self.set_antisymmetric_linear_constraint_i_j,
-                                                      symmetry=-1,
+                                                      symmetry=True,
                                                       )
+        self.add_constraints_from_one_list_of_points(list_of_points=self.list_of_points,
+                                                     constraint_name="diagonal_linearity",
+                                                     set_class_constraint_i=
+                                                     self.set_diagonal_linear_constraint_i,
+                                                     )
 
         # Create a PSD matrix to enforce the singular values to be smaller than L
         N = len(self.list_of_points)

docs/source/whatsnew/0.4.0.rst

@@ -16,3 +16,5 @@ What's new in PEPit 0.4.0
 - Corrected example: SGD's closed-form solution has been updated.
 
 - The support of functions of the class :class:`ConvexIndicatorFunction` can be constrained through a radius in addition to a diameter.
+
+- Fix: The :class:`SkewSymmetricLinearOperator` constraints have been completed with the formerly missing "xi * gi == 0".

tests/test_functions_and_operators.py

@@ -227,7 +227,7 @@ def test_add_constraints(self):
         self.assertEqual(len(self.operator8.list_of_class_constraints), num_points_eval * (num_points_eval - 1) / 2)
         self.assertEqual(len(self.operator9.list_of_class_constraints), num_points_eval)
         self.assertEqual(len(self.operator10.list_of_class_constraints), num_points_eval * (num_points_eval - 1) / 2)
-        self.assertEqual(len(self.operator11.list_of_class_constraints), num_points_eval * (num_points_eval - 1) / 2)
+        self.assertEqual(len(self.operator11.list_of_class_constraints), num_points_eval * (num_points_eval + 1) / 2)
         self.assertEqual(len(self.new_operator.list_of_class_constraints), 0)
 
     def test_name(self):