add cross entropy loss to BCR

Author: mjd3

autolab_core/learning_analysis.py

@@ -353,6 +353,10 @@ def __init__(self, pred_probs, labels, threshold=0.5):
         self.threshold = threshold
         ClassificationResult.__init__(self, pred_probs, labels)
 
+    @property
+    def cross_entropy_loss(self):
+        return np.mean((-1 * self.labels * np.log(self.pred_probs)) + (-1 * (1 - self.labels) * np.log(1 - self.pred_probs)))
+
     @property
     def num_categories(self):
         return 2