add parser support for TANH tflite operator (#3996)

python/tvm/relay/frontend/tflite.py

@@ -82,6 +82,7 @@ class OperatorConverter(object):
             'PAD': self.convert_pad,
             'PACK': self.convert_pack,
             'LOGISTIC': self.convert_logistic,
+            'TANH':self.convert_tanh,
             'SPLIT': self.convert_split,
             'TRANSPOSE': self.convert_transpose,
             'TILE': self.convert_tile,
@@ -326,6 +327,23 @@ class OperatorConverter(object):
 
         return out
 
+    def convert_tanh(self, op):
+        """Convert TFLite TANH"""
+        try:
+            from tflite.Operator import Operator
+        except ImportError:
+            raise ImportError("The tflite package must be installed")
+
+        assert isinstance(op, Operator)
+        input_tensors = self.get_input_tensors(op)
+        assert len(input_tensors) == 1, "input tensors length should be 1"
+
+        input_tensor = input_tensors[0]
+        in_expr = self.get_expr(input_tensor.tensor_idx)
+        out = _op.tanh(in_expr)
+
+        return out
+
     def convert_concatenation(self, op):
         """Convert TFLite concatenation"""
         try:

tests/python/frontend/tflite/test_forward.py

@@ -813,6 +813,20 @@ def test_forward_softmax():
     """ Softmax """
     _test_softmax(np.arange(6.0, dtype=np.float32).reshape((1, 6)))
 
+#######################################################################
+# Tanh
+# --------
+
+def _test_tanh(data):
+    """ One iteration of TANH """
+    with tf.Graph().as_default():
+        in_data = array_ops.placeholder(shape=data.shape, dtype=data.dtype)
+        out = math_ops.sigmoid(in_data)
+        compare_tflite_with_tvm(data, 'Placeholder:0', [in_data], [out])
+
+def test_forward_tanh():
+    """ TANH """
+    _test_tanh(np.arange(6.0, dtype=np.float32).reshape((1, 6)))
 
 #######################################################################
 # Fully Connected
@@ -976,6 +990,7 @@ if __name__ == '__main__':
     test_forward_logistic()
     test_forward_pooling()
     test_forward_softmax()
+    test_forward_tanh()
     test_forward_fully_connected()
 
     # Elemwise