Added cx.Layer(bidirectional=mode)

conx/layers.py

@@ -175,6 +175,15 @@ def __init__(self, name, *args, **params):
         else:
             self.dropout = 0
 
+        if 'bidirectional' in params:
+            bidirectional = params['bidirectional']
+            del params["bidirectional"] # we handle it
+            if bidirectional not in ['sum', 'mul', 'concat', 'ave', True, None]:
+                raise Exception('bad bidirectional value: %s' % (bidirectional,))
+            self.bidirectional = bidirectional
+        else:
+            self.bidirectional = None
+
         if 'time_distributed' in params:
             time_distributed = params['time_distributed']
             del params["time_distributed"] # we handle time distributed wrappers
@@ -266,23 +275,39 @@ def make_keras_functions(self):
         Make all Keras functions for this layer, including its own,
         dropout, etc.
         """
-        from keras.layers import TimeDistributed
+        from keras.layers import TimeDistributed, Bidirectional
         k = self.make_keras_function() # can override
+        ### wrap layer:
+        if self.bidirectional:
+            if self.bidirectional is True:
+                k = Bidirectional(k, name=self.name)
+            else:
+                k = Bidirectional(k, merge_mode=self.bidirectional, name=self.name)
         if self.time_distributed:
             k = TimeDistributed(k, name=self.name)
+        ### sequence:
         if self.dropout > 0:
-            return [k, keras.layers.Dropout(self.dropout)]
+            k = [k] + [keras.layers.Dropout(self.dropout)]
         else:
-            return [k]
+            k = [k]
+        return k
 
     def make_keras_functions_text(self):
         """
         Make all Keras functions for this layer, including its own,
         dropout, etc.
         """
+        def bidir_mode(name):
+            if name in [True, None]:
+                return "concat"
+            else:
+                return name
         program = self.make_keras_function_text()
         if self.time_distributed:
             program = "keras.layers.TimeDistributed(%s, name='%s')" % (program, self.name)
+        if self.bidirectional:
+            program = "keras.layers.Bidirectional(%s, name='%s', mode='%s')" % (
+                program, self.name, bidir_mode(self.bidirectional))
         if self.dropout > 0:
             return "[%s, keras.layers.Dropout(self.dropout)]" % program
         else:
@@ -455,6 +480,8 @@ def format_range(minmax):
             retval += "\n shape = %s" % (self.shape, )
         if self.dropout:
             retval += "\n dropout = %s" % self.dropout
+        if self.bidirectional:
+            retval += "\n bidirectional = %s" % self.bidirectional
         if kind == "input":
             retval += "\n Keras class = Input"
         else:
@@ -545,6 +572,8 @@ def print_summary(self, fp=sys.stdout):
             print("        * **Activation function**:", self.activation, file=fp)
         if self.dropout:
             print("        * **Dropout percent**    :", self.dropout, file=fp)
+        if self.bidirectional:
+            print("        * **Bidirectional mode** :", self.bidirectional, file=fp)
 
     def make_keras_function(self):
         """