initial fix - test passes always to do to unfixed FIXME in check_op_count

Author: phager90

tests/test_backend.py

@@ -2994,6 +2994,21 @@ def test_gemm_pattern3(self):
         def func(a, b, c):
             x_ = tf.matmul(a, b) + c
             return tf.identity(x_, name=_TFOUTPUT)
+        self._run_test_case(func, [_OUTPUT], {_INPUT: x_val1, _INPUT1: x_val2, _INPUT2: x_val3},
+                            graph_validator=lambda g: check_op_count(g, "Gemm", 1) )
+
+    # test for gemm pattern4: A*B + C [addbias] - 1D bias!
+    def test_gemm_pattern4(self):
+        max_number = 10
+        m = np.random.randint(max_number)
+        n = np.random.randint(max_number)
+        k = np.random.randint(max_number) # bias add requires 1D tensor
+        x_val1 = np.random.rand(m, n).astype("float32")
+        x_val2 = np.random.rand(n, k).astype("float32")
+        x_val3 = np.random.rand(k).astype("float32")
+        def func(a, b, c):
+            x_ = tf.nn.bias_add(tf.matmul(a, b), c)
+            return tf.identity(x_, name=_TFOUTPUT)
         self._run_test_case(func, [_OUTPUT], {_INPUT: x_val1, _INPUT1: x_val2, _INPUT2: x_val3},
                             graph_validator=lambda g: check_op_count(g, "Gemm", 1))
 

tf2onnx/rewriter/gemm_rewriter.py

@@ -55,7 +55,14 @@ def rewrite_gemm(g, ops):
             OpTypePattern('*', name='C'),
         ])
 
-    pattern_list = [pattern0, pattern1, pattern2, pattern3]
+    # pattern4: A*B + c
+    pattern4 = \
+        OpTypePattern('BiasAdd', name='add', inputs=[
+            OpTypePattern('MatMul', name='matmul'),
+            OpTypePattern('*', name='C'),
+        ])
+
+    pattern_list = [pattern0, pattern1, pattern2, pattern3, pattern4]
 
     for pattern in pattern_list:
         matcher = GraphMatcher(pattern, allow_reorder=True)