Gated convolution

dnn/gatedconv.py

@@ -0,0 +1,62 @@
+from keras import backend as K
+from keras.engine.topology import Layer
+from keras.layers import activations, initializers, regularizers, constraints, InputSpec, Conv1D
+import numpy as np
+
+class GatedConv(Conv1D):
+    
+    def __init__(self, filters,
+                 kernel_size,
+                 dilation_rate=1,
+                 activation='tanh',
+                 use_bias=True,
+                 kernel_initializer='glorot_uniform',
+                 bias_initializer='zeros',
+                 kernel_regularizer=None,
+                 bias_regularizer=None,
+                 activity_regularizer=None,
+                 kernel_constraint=None,
+                 bias_constraint=None,
+                 return_memory=False,
+                 **kwargs):
+
+        super(GatedConv, self).__init__(
+            filters=2*filters,
+            kernel_size=kernel_size,
+            strides=1,
+            padding='valid',
+            data_format='channels_last',
+            dilation_rate=dilation_rate,
+            activation='linear',
+            use_bias=use_bias,
+            kernel_initializer=kernel_initializer,
+            bias_initializer=bias_initializer,
+            kernel_regularizer=kernel_regularizer,
+            bias_regularizer=bias_regularizer,
+            activity_regularizer=activity_regularizer,
+            kernel_constraint=kernel_constraint,
+            bias_constraint=bias_constraint,
+            **kwargs)
+        self.mem_size = dilation_rate*(kernel_size-1)
+        self.return_memory = return_memory
+        self.out_dims = filters
+        self.nongate_activation = activations.get(activation)
+        
+    def call(self, inputs, memory=None):
+        if memory is None:
+            mem = K.zeros((K.shape(inputs)[0], self.mem_size, K.shape(inputs)[-1]))
+        else:
+            mem = K.variable(K.cast_to_floatx(memory))
+        inputs = K.concatenate([mem, inputs], axis=1)
+        ret = super(GatedConv, self).call(inputs)
+        ret = self.nongate_activation(ret[:, :, :self.out_dims]) * activations.sigmoid(ret[:, :, self.out_dims:])
+        if self.return_memory:
+            ret = ret, inputs[:, :self.mem_size, :]
+        return ret
+
+    def compute_output_shape(self, input_shape):
+        assert input_shape and len(input_shape) >= 2
+        assert input_shape[-1]
+        output_shape = list(input_shape)
+        output_shape[-1] = self.out_dims
+        return tuple(output_shape)

dnn/wavenet.py

@@ -9,8 +9,9 @@ import numpy as np
 import h5py
 import sys
 from causalconv import CausalConv
+from gatedconv import GatedConv
 
-units=256
+units=128
 pcm_bits = 8
 pcm_levels = 2**pcm_bits
 nb_used_features = 38
@@ -37,10 +38,8 @@ def new_wavenet_model(fftnet=False):
         res = tmp
         tmp = Concatenate()([tmp, rfeat])
         dilation = 9-k if fftnet else k
-        c1 = CausalConv(units, 2, dilation_rate=2**dilation, activation='tanh')
+        c = GatedConv(units, 2, dilation_rate=2**dilation, activation='tanh')
-        c2 = CausalConv(units, 2, dilation_rate=2**dilation, activation='sigmoid')
+        tmp = Dense(units, activation='relu')(c(tmp))
-        tmp = Multiply()([c1(tmp), c2(tmp)])
-        tmp = Dense(units, activation='relu')(tmp)
         if k != 0:
             tmp = Add()([tmp, res])