add numpy functions

adnc/utils/np_functions.py

@@ -0,0 +1,25 @@
+# Copyright 2018 Jörg Franke
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+import numpy as np
+
+
+def softmax(x):
+    e = np.exp(x)
+    return e / np.sum(e, axis=-1, keepdims=True)
+
+
+def weighted_softmax(x, s):
+    e_x = np.exp(x * s)
+    return e_x / e_x.sum(axis=-1, keepdims=True)