lib/rumale/pairwise_metric.rb in rumale-0.18.2 vs lib/rumale/pairwise_metric.rb in rumale-0.18.3

@@ -59,15 +59,16 @@
       # @param x [Numo::DFloat] (shape: [n_samples_x, n_features])
       # @param y [Numo::DFloat] (shape: [n_samples_y, n_features])
       # @param gamma [Float] The parameter of rbf kernel, if nil it is 1 / n_features.
       # @return [Numo::DFloat] (shape: [n_samples_x, n_samples_x] or [n_samples_x, n_samples_y] if y is given)
       def rbf_kernel(x, y = nil, gamma = nil)
-        y = x if y.nil?
-        gamma ||= 1.0 / x.shape[1]
+        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)
+        y = Rumale::Validation.check_convert_sample_array(y) unless y_not_given
+        gamma ||= 1.0 / x.shape[1]
         Rumale::Validation.check_params_numeric(gamma: gamma)
-        Numo::NMath.exp(-gamma * squared_error(x, y).abs)
+        Numo::NMath.exp(-gamma * squared_error(x, y))
       end
 
       # Calculate the linear kernel between x and y.
       #
       # @param x [Numo::DFloat] (shape: [n_samples_x, n_features])