Fix score_pairs

Author: mvargas33

metric_learn/base_metric.py

@@ -180,7 +180,8 @@ def score_pairs(self, pairs):
       pairs = check_input(pairs, type_of_inputs='tuples',
                           preprocessor=self.preprocessor_,
                           estimator=self, tuple_size=2)
-      return np.dot(np.dot(pairs[:, 1, :], self.components_), pairs[:, 0, :].T)
+
+      return [np.dot(np.dot(u, self.components_), v.T) for u,v in zip(pairs[:, 1, :], pairs[:, 0, :])]
 
   def get_metric(self):
       check_is_fitted(self, 'components_')

test_bilinear.py

@@ -9,7 +9,7 @@ def test_toy_distance():
     mixin.fit([u, v], [0, 0])
     #mixin.components_ = np.array([[1, 0, 0],[0, 1, 0],[0, 0, 1]])
 
-    dist = mixin.score_pairs([[u, v]])
+    dist = mixin.score_pairs([[u, v],[v, u]])
     print(dist)
 
 test_toy_distance()