bugfix: force WeightNormalization to execute in order (#458)

* BUG: force code to execute in order

* CLN: clean codes

* TST: clean

Author: facaiy

tensorflow_addons/layers/wrappers.py

@@ -92,32 +92,39 @@ def build(self, input_shape):
             trainable=False)
 
         if self.data_init:
-            self._naked_layer = tf.keras.layers.deserialize(
-                tf.keras.layers.serialize(self.layer))
-            self._naked_layer.build(input_shape)
-            self._naked_layer.set_weights(self.layer.get_weights())
-            self._naked_layer.activation = None
+            # Used for data initialization in self._data_dep_init.
+            layer_config = tf.keras.layers.serialize(self.layer)
+            layer_config['config']['trainable'] = False
+            self._naked_clone_layer = tf.keras.layers.deserialize(layer_config)
+            self._naked_clone_layer.build(input_shape)
+            self._naked_clone_layer.set_weights(self.layer.get_weights())
+            self._naked_clone_layer.activation = None
 
         self.built = True
 
     def call(self, inputs):
         """Call `Layer`"""
 
         def _do_nothing():
-            return inputs
+            return tf.identity(self.g)
 
         def _update_weights():
-            self._initialize_weights(inputs)
-            return inputs
+            # Ensure we read `self.g` after _update_weights.
+            with tf.control_dependencies(self._initialize_weights(inputs)):
+                return tf.identity(self.g)
 
-        inputs = tf.cond(self._initialized, _do_nothing, _update_weights)
+        g = tf.cond(self._initialized, _do_nothing, _update_weights)
 
         with tf.name_scope('compute_weights'):
             # Replace kernel by normalized weight variable.
             self.layer.kernel = tf.nn.l2_normalize(
-                self.v, axis=self.kernel_norm_axes) * self.g
+                self.v, axis=self.kernel_norm_axes) * g
 
-        return self.layer(inputs)
+            # Ensure we calculate result after updating kernel.
+            update_kernel = tf.identity(self.layer.kernel)
+            with tf.control_dependencies([update_kernel]):
+                outputs = self.layer(inputs)
+                return outputs
 
     def compute_output_shape(self, input_shape):
         return tf.TensorShape(
@@ -136,31 +143,36 @@ def _initialize_weights(self, inputs):
                     message='The layer has been initialized.')
         ]):
             if self.data_init:
-                self._data_dep_init(inputs)
+                assign_tensors = self._data_dep_init(inputs)
             else:
-                self._init_norm()
-            self._initialized.assign(True)
+                assign_tensors = self._init_norm()
+            assign_tensors.append(self._initialized.assign(True))
+            return assign_tensors
 
     def _init_norm(self):
         """Set the weight g with the norm of the weight vector."""
         with tf.name_scope('init_norm'):
             v_flat = tf.reshape(self.v, [-1, self.layer_depth])
             v_norm = tf.linalg.norm(v_flat, axis=0)
-            self.g.assign(tf.reshape(v_norm, (self.layer_depth,)))
+            g_tensor = self.g.assign(tf.reshape(v_norm, (self.layer_depth,)))
+            return [g_tensor]
 
     def _data_dep_init(self, inputs):
         """Data dependent initialization."""
         with tf.name_scope('data_dep_init'):
             # Generate data dependent init values
-            x_init = self._naked_layer(inputs)
+            x_init = self._naked_clone_layer(inputs)
             data_norm_axes = list(range(x_init.shape.rank - 1))
             m_init, v_init = tf.nn.moments(x_init, data_norm_axes)
             scale_init = 1. / tf.math.sqrt(v_init + 1e-10)
 
             # Assign data dependent init values
-            self.g.assign(self.g * scale_init)
+            g_tensor = self.g.assign(self.g * scale_init)
             if hasattr(self.layer, 'bias'):
-                self.layer.bias.assign(-m_init * scale_init)
+                bias_tensor = self.layer.bias.assign(-m_init * scale_init)
+                return [g_tensor, bias_tensor]
+            else:
+                return [g_tensor]
 
     def get_config(self):
         config = {'data_init': self.data_init}

tensorflow_addons/layers/wrappers_test.py

@@ -26,82 +26,52 @@
 
 @test_utils.run_all_in_graph_and_eager_modes
 class WeightNormalizationTest(tf.test.TestCase):
-    def test_weightnorm_dense_train(self):
-        model = tf.keras.models.Sequential()
-        model.add(
-            wrappers.WeightNormalization(
-                tf.keras.layers.Dense(2), input_shape=(3, 4)))
-        model.compile(
-            optimizer=tf.keras.optimizers.RMSprop(learning_rate=0.001),
-            loss='mse')
-        model.fit(
-            np.random.random((10, 3, 4)),
-            np.random.random((10, 3, 2)),
-            epochs=3,
-            batch_size=10)
-        self.assertTrue(hasattr(model.layers[0], 'g'))
-
-    def test_weightnorm_dense_train_notinit(self):
-        model = tf.keras.models.Sequential()
-        model.add(
-            wrappers.WeightNormalization(
-                tf.keras.layers.Dense(2), input_shape=(3, 4), data_init=False))
-
-        model.compile(
-            optimizer=tf.keras.optimizers.RMSprop(learning_rate=0.001),
-            loss='mse')
-        model.fit(
-            np.random.random((10, 3, 4)),
-            np.random.random((10, 3, 2)),
-            epochs=3,
-            batch_size=10)
-        self.assertTrue(hasattr(model.layers[0], 'g'))
-
-    def test_weightnorm_conv2d(self):
-        model = tf.keras.models.Sequential()
-        model.add(
-            wrappers.WeightNormalization(
-                tf.keras.layers.Conv2D(5, (2, 2), padding='same'),
-                input_shape=(4, 4, 3)))
-
-        model.add(tf.keras.layers.Activation('relu'))
-        model.compile(
-            optimizer=tf.keras.optimizers.RMSprop(learning_rate=0.001),
-            loss='mse')
-        model.fit(
-            np.random.random((2, 4, 4, 3)),
-            np.random.random((2, 4, 4, 5)),
-            epochs=3,
-            batch_size=10)
-
-        self.assertTrue(hasattr(model.layers[0], 'g'))
-
-    def test_weightnorm_applylayer(self):
-        images = tf.random.uniform((2, 4, 4, 3))
-        wn_wrapper = wrappers.WeightNormalization(
-            tf.keras.layers.Conv2D(32, [2, 2]), input_shape=(4, 4, 3))
-        wn_wrapper.apply(images)
-        self.assertTrue(hasattr(wn_wrapper, 'g'))
-
-    def test_weightnorm_nonlayer(self):
-        images = tf.random.uniform((2, 4, 43))
-        with self.assertRaises(AssertionError):
-            wrappers.WeightNormalization(images)
-
-    def test_weightnorm_nokernel(self):
-        with self.assertRaises(ValueError):
-            wrappers.WeightNormalization(tf.keras.layers.MaxPooling2D(
-                2, 2)).build((2, 2))
-
-    def test_weightnorm_keras(self):
-        input_data = np.random.random((10, 3, 4)).astype(np.float32)
+    def test_weightnorm(self):
+        test_utils.layer_test(
+            wrappers.WeightNormalization,
+            kwargs={
+                'layer': tf.keras.layers.Conv2D(5, (2, 2)),
+            },
+            input_shape=(2, 4, 4, 3))
+
+    def _check_data_init(self, data_init, input_data, expected_output):
+        layer = tf.keras.layers.Dense(
+            input_data.shape[-1],
+            activation=None,
+            kernel_initializer='identity',
+            bias_initializer='zeros')
         test_utils.layer_test(
             wrappers.WeightNormalization,
             kwargs={
-                'layer': tf.keras.layers.Dense(2),
-                'input_shape': (3, 4)
+                'layer': layer,
+                'data_init': data_init,
             },
-            input_data=input_data)
+            input_data=input_data,
+            expected_output=expected_output)
+
+    def test_weightnorm_with_data_init_is_false(self):
+        input_data = np.array([[[-4, -4], [4, 4]]], dtype=np.float32)
+        self._check_data_init(
+            data_init=False, input_data=input_data, expected_output=input_data)
+
+    def test_weightnorm_with_data_init_is_true(self):
+        input_data = np.array([[[-4, -4], [4, 4]]], dtype=np.float32)
+        self._check_data_init(
+            data_init=True,
+            input_data=input_data,
+            expected_output=input_data / 4)
+
+    def test_weightnorm_non_layer(self):
+        images = tf.random.uniform((2, 4, 43))
+        with self.assertRaises(AssertionError):
+            wrappers.WeightNormalization(images)
+
+    def test_weightnorm_non_kernel_layer(self):
+        images = tf.random.uniform((2, 2, 2))
+        with self.assertRaisesRegexp(ValueError, 'contains a `kernel`'):
+            non_kernel_layer = tf.keras.layers.MaxPooling2D(2, 2)
+            wn_wrapper = wrappers.WeightNormalization(non_kernel_layer)
+            wn_wrapper(images)
 
 
 if __name__ == "__main__":