Fixed GEMM conversion (#4412)

* Fixed GEMM conversion

* Renaming
Co-authored-by: Scott Cyphers <diyessi@users.noreply.github.com>

src/ngraph/frontend/onnx_import/op/gemm.cpp

@@ -73,15 +73,20 @@ namespace ngraph
                     input_a = ngraph::builder::opset1::flatten(input_a, 1);
                     input_b = ngraph::builder::opset1::flatten(input_b, 1);
 
-                    auto matmul_node = std::make_shared<default_opset::MatMul>(input_a, input_b);
+                    std::shared_ptr<ngraph::Node> matmul_node =
+                        std::make_shared<default_opset::MatMul>(input_a, input_b);
+
+                    if (alpha != 1)
+                    {
+                        matmul_node =
+                            std::make_shared<default_opset::Multiply>(matmul_node, alpha_node);
+                    }
 
-                    auto alpha_times_product =
-                        std::make_shared<default_opset::Multiply>(alpha_node, matmul_node);
                     auto beta_times_input_c =
                         std::make_shared<default_opset::Multiply>(beta_node, input_c);
 
-                    return NodeVector{std::make_shared<default_opset::Add>(alpha_times_product,
-                                                                           beta_times_input_c)};
+                    return NodeVector{
+                        std::make_shared<default_opset::Add>(matmul_node, beta_times_input_c)};
                 }
 
             } // namespace set_1
@@ -116,16 +121,20 @@ namespace ngraph
                     const bool trans_a = node.get_attribute_value<int64_t>("transA", 0);
                     const bool trans_b = node.get_attribute_value<int64_t>("transB", 0);
 
-                    auto matmul_node =
+                    std::shared_ptr<ngraph::Node> matmul_node =
                         std::make_shared<default_opset::MatMul>(input_a, input_b, trans_a, trans_b);
 
-                    auto alpha_times_product =
-                        std::make_shared<default_opset::Multiply>(alpha_node, matmul_node);
+                    if (alpha != 1)
+                    {
+                        matmul_node =
+                            std::make_shared<default_opset::Multiply>(matmul_node, alpha_node);
+                    }
+
                     auto beta_times_input_c =
                         std::make_shared<default_opset::Multiply>(beta_node, input_c);
 
-                    return NodeVector{std::make_shared<default_opset::Add>(alpha_times_product,
-                                                                           beta_times_input_c)};
+                    return NodeVector{
+                        std::make_shared<default_opset::Add>(matmul_node, beta_times_input_c)};
                 }
 
             } // namespace set_6