change predictions to preds

Author: jacquesqiao

python/paddle/fluid/metrics.py

@@ -580,10 +580,10 @@ def __init__(self, name, curve='ROC', num_thresholds=200):
         self.tn_list = np.zeros((num_thresholds, ))
         self.fp_list = np.zeros((num_thresholds, ))
 
-    def update(self, predictions, labels):
+    def update(self, preds, labels):
         if not _is_numpy_(labels):
             raise ValueError("The 'labels' must be a numpy ndarray.")
-        if not _is_numpy_(predictions):
+        if not _is_numpy_(preds):
             raise ValueError("The 'predictions' must be a numpy ndarray.")
 
         kepsilon = 1e-7  # to account for floating point imprecisions
@@ -596,12 +596,12 @@ def update(self, predictions, labels):
             tp, fn, tn, fp = 0, 0, 0, 0
             for i, lbl in enumerate(labels):
                 if lbl:
-                    if predictions[i, 1] >= thresh:
+                    if preds[i, 1] >= thresh:
                         tp += 1
                     else:
                         fn += 1
                 else:
-                    if predictions[i, 1] >= thresh:
+                    if preds[i, 1] >= thresh:
                         fp += 1
                     else:
                         tn += 1