Replaced hardshrink implementation by a pure python one.

tensorflow_addons/activations/hardshrink.py

@@ -14,9 +14,6 @@
 # ==============================================================================
 
 import tensorflow as tf
-from tensorflow_addons.utils.resource_loader import LazySO
-
-_activation_so = LazySO("custom_ops/activations/_activation_ops.so")
 
 
 @tf.keras.utils.register_keras_serializable(package='Addons')
@@ -34,12 +31,13 @@ def hardshrink(x, lower=-0.5, upper=0.5):
     Returns:
         A `Tensor`. Has the same type as `x`.
     """
+    if lower > upper:
+        raise ValueError("The value of lower is {} and should"
+                         " not be higher than the value "
+                         "variable upper, which is {} .".format(lower, upper))
     x = tf.convert_to_tensor(x)
-    return _activation_so.ops.addons_hardshrink(x, lower, upper)
-
-
-@tf.RegisterGradient("Addons>Hardshrink")
-def _hardshrink_grad(op, grad):
-    return _activation_so.ops.addons_hardshrink_grad(grad, op.inputs[0],
-                                                     op.get_attr("lower"),
-                                                     op.get_attr("upper"))
+    mask_lower = x < lower
+    mask_upper = upper < x
+    mask = tf.logical_or(mask_lower, mask_upper)
+    mask = tf.cast(mask, x.dtype)
+    return x * mask

tensorflow_addons/activations/hardshrink_test.py

@@ -24,8 +24,7 @@
 @test_utils.run_all_in_graph_and_eager_modes
 class HardshrinkTest(tf.test.TestCase, parameterized.TestCase):
     def test_invalid(self):
-        with self.assertRaisesOpError(
-                "lower must be less than or equal to upper."):  # pylint: disable=bad-continuation
+        with self.assertRaises(ValueError):
             y = hardshrink(tf.ones(shape=(1, 2, 3)), lower=2.0, upper=-2.0)
             self.evaluate(y)
 

tensorflow_addons/custom_ops/activations/BUILD

@@ -9,8 +9,6 @@ custom_op_library(
     srcs = [
         "cc/kernels/gelu_op.cc",
         "cc/kernels/gelu_op.h",
-        "cc/kernels/hardshrink_op.cc",
-        "cc/kernels/hardshrink_op.h",
         "cc/kernels/lisht_op.cc",
         "cc/kernels/lisht_op.h",
         "cc/kernels/mish_op.cc",
@@ -20,7 +18,6 @@ custom_op_library(
         "cc/kernels/tanhshrink_op.cc",
         "cc/kernels/tanhshrink_op.h",
         "cc/ops/gelu_op.cc",
-        "cc/ops/hardshrink_op.cc",
         "cc/ops/lisht_op.cc",
         "cc/ops/mish_op.cc",
         "cc/ops/softshrink_op.cc",
@@ -29,8 +26,6 @@ custom_op_library(
     cuda_srcs = [
         "cc/kernels/gelu_op.h",
         "cc/kernels/gelu_op_gpu.cu.cc",
-        "cc/kernels/hardshrink_op.h",
-        "cc/kernels/hardshrink_op_gpu.cu.cc",
         "cc/kernels/lisht_op.h",
         "cc/kernels/lisht_op_gpu.cu.cc",
         "cc/kernels/mish_op.h",