fix beta val

src/onnx/onnx.cpp

@@ -400,7 +400,7 @@ struct onnx_parser
     parse_gemm(const std::string&, attribute_map attributes, std::vector<instruction_ref> args)
     {
         float alpha = 1.0f;
-        float beta  = 0.0f;
+        float beta  = 1.0f;
         bool transa = false;
         bool transb = false;
         if(contains(attributes, "alpha"))
@@ -427,10 +427,14 @@ struct onnx_parser
             if(beta != 0.f)
             {
                 auto l3       = prog.add_instruction(op::dot{alpha}, l1, l2);
-                auto beta_val = prog.add_literal(beta);
-                auto l4       = prog.add_instruction(op::scalar{args[2]->get_shape()}, beta_val);
-                auto l5       = prog.add_instruction(op::mul{}, args[2], l4);
-                return add_broadcastable_binary_op(l3, l5, op::add{});
+                auto l4 = args[2];
+                if(beta == 1.f)
+                {
+                    auto beta_val = prog.add_literal(beta);
+                    auto l5       = prog.add_instruction(op::scalar{args[2]->get_shape()}, beta_val);
+                    l4            = prog.add_instruction(op::mul{}, args[2], l5);
+                }
+                return add_broadcastable_binary_op(l3, l4, op::add{});
             }
         }
         return prog.add_instruction(op::dot{alpha, beta}, l1, l2);