lib/rumale/pairwise_metric.rb in rumale-0.17.3 vs lib/rumale/pairwise_metric.rb in rumale-0.18.0

@@ -40,18 +40,19 @@
       #
       # @param x [Numo::DFloat] (shape: [n_samples_x, n_features])
       # @param y [Numo::DFloat] (shape: [n_samples_y, n_features])
       # @return [Numo::DFloat] (shape: [n_samples_x, n_samples_x] or [n_samples_x, n_samples_y] if y is given)
       def squared_error(x, y = nil)
-        y = x if y.nil?
+        y_not_given = y.nil?
+        y = x if y_not_given
         x = Rumale::Validation.check_convert_sample_array(x)
-        y = Rumale::Validation.check_convert_sample_array(y)
-        n_features = x.shape[1]
-        one_vec = Numo::DFloat.ones(n_features).expand_dims(1)
-        sum_x_vec = (x**2).dot(one_vec)
-        sum_y_vec = (y**2).dot(one_vec).transpose
-        dot_xy_mat = x.dot(y.transpose)
-        dot_xy_mat * -2.0 + sum_x_vec + sum_y_vec
+        y = Rumale::Validation.check_convert_sample_array(y) unless y_not_given
+        sum_x_vec = (x**2).sum(1).expand_dims(1)
+        sum_y_vec = y_not_given ? sum_x_vec.transpose : (y**2).sum(1).expand_dims(1).transpose
+        err_mat = -2 * x.dot(y.transpose)
+        err_mat += sum_x_vec
+        err_mat += sum_y_vec
+        err_mat.class.maximum(err_mat, 0)
       end
 
       # Calculate the rbf kernel between x and y.
       #
       # @param x [Numo::DFloat] (shape: [n_samples_x, n_features])