Add softsign in numpy backend (keras-team#11879)

liushuaicare · Dec 17, 2018 · bf0f25f · bf0f25f
1 parent ca802e1
commit bf0f25f
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diff --git a/keras/backend/numpy_backend.py b/keras/backend/numpy_backend.py
@@ -285,6 +285,10 @@ def softplus(x):
     return np.log(1. + np.exp(x))
 
 
+def softsign(x):
+    return x / (1 + np.abs(x))
+
+
 def elu(x, alpha=1.):
     return x * (x > 0) + alpha * (np.exp(x) - 1.) * (x < 0)
 

diff --git a/keras/backend/tensorflow_backend.py b/keras/backend/tensorflow_backend.py
@@ -3447,6 +3447,8 @@ def softsign(x):
 
     # Returns
         A tensor.
+
+    {{np_implementation}}
     """
     return tf.nn.softsign(x)
 

diff --git a/tests/keras/backend/backend_test.py b/tests/keras/backend/backend_test.py
@@ -1077,6 +1077,7 @@ def test_relu(self, alpha, max_value, threshold):
                                       max_value=max_value, threshold=threshold)
 
     def test_nn_operations(self):
+        check_single_tensor_operation('softsign', (4, 10), WITH_NP)
         check_single_tensor_operation('softplus', (4, 10), WITH_NP)
         check_single_tensor_operation('elu', (4, 10), WITH_NP, alpha=0.5)