Add epsilon for numerical stability.

climax/core/loss.py

@@ -65,6 +65,9 @@ class BernoulliGammaLoss(NaNLoss):
         mask = ~torch.isnan(y_true)
         y_true = y_true[mask]
 
+        # mask values less than 0
+        y_true[y_true < 0] = 0
+
         # calculate true probability of precipitation:
         # 1 if y_true > min_amount else 0
         p_true = (y_true > self.min_amount).type(torch.float32)