Add LOGISTIC operator to relay tflite frontend (apache#3313)

python/tvm/relay/frontend/tflite.py

@@ -67,6 +67,7 @@ def __init__(self, model, subgraph, exp_tab):
             'MUL': self.convert_mul,
             'FULLY_CONNECTED': self.convert_fully_connected,
             'PAD': self.convert_pad,
+            'LOGISTIC': self.convert_logistic,
         }
 
     def check_unsupported_ops(self):
@@ -218,6 +219,23 @@ def convert_reshape(self, op):
 
         return out
 
+    def convert_logistic(self, op):
+        """Convert TFLite LOGISTIC"""
+        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.sigmoid(in_expr)
+        return out
+
     def convert_softmax(self, op):
         """Convert TFLite softmax"""
         try:

tests/python/frontend/tflite/test_forward.py

@@ -423,6 +423,22 @@ def test_forward_pad():
                np.array([[1, 1], [2, 2]], dtype=np.int32)])
 
 
+#######################################################################
+# Logistic
+# --------
+
+def _test_logistic(data):
+    """ One iteration of LOGISTIC """
+    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_logistic():
+    """ LOGISTIC """
+    _test_logistic(np.arange(6.0, dtype=np.float32).reshape((1, 6)))
+
+
 #######################################################################
 # Softmax
 # -------
@@ -563,6 +579,7 @@ def test_forward_inception_v4_net():
 
     # NN
     test_forward_convolution()
+    test_forward_logistic()
     test_forward_pooling()
     test_forward_softmax()
     test_forward_fully_connected()