add the gru operator

src/include/migraphx/operators.hpp

@@ -1067,8 +1067,8 @@ struct rnn
         bidirectional,
     };
 
-    std::size_t hidden_size   = 1;
-    operation actv_func       = tanh{};
+    std::size_t hidden_size = 1;
+    operation actv_func{tanh{}};
     rnn_direction_t direction = forward;
     float clip                = 0.0f;
 
@@ -1076,14 +1076,14 @@ struct rnn
     shape compute_shape(std::vector<shape> inputs) const
     {
         auto in_dims     = inputs[0].lens();
-        auto hidden_dims = inputs[1].lens();
-        if(hidden_size != hidden_dims[1])
+        auto hidden_dims = inputs[2].lens();
+        if(hidden_size != hidden_dims[2])
         {
             MIGRAPHX_THROW("RNN: hidden size mismatch in attribute and input");
         }
 
         std::size_t num_directions = 1;
-        if(direction == rnn_direction_t::bidirectional)
+        if(direction == bidirectional)
         {
             num_directions = 2;
         }
@@ -1101,6 +1101,50 @@ struct rnn
     }
 };
 
+struct gru
+{
+    enum gru_direction_t
+    {
+        forward,
+        reverse,
+        bidirectional,
+    };
+
+    std::size_t hidden_size = 1;
+    std::vector<operation> actv_funcs{sigmoid{}, tanh{}};
+    gru_direction_t direction = forward;
+    float clip                = 0.0f;
+    int linear_before_reset   = 0;
+
+    std::string name() const { return "gru"; }
+    shape compute_shape(std::vector<shape> inputs) const
+    {
+        auto in_dims     = inputs[0].lens();
+        auto hidden_dims = inputs[2].lens();
+        if(hidden_size != hidden_dims[2])
+        {
+            MIGRAPHX_THROW("GRU: hidden size mismatch in attribute and input");
+        }
+
+        std::size_t num_directions = 1;
+        if(direction == bidirectional)
+        {
+            num_directions = 2;
+        }
+
+        if(num_directions != hidden_dims[0])
+        {
+            MIGRAPHX_THROW("GRU: num_direction does not match the direction attribute");
+        }
+
+        std::vector<std::size_t> out_dims(in_dims);
+        out_dims.insert(out_dims.begin() + 1, num_directions);
+        out_dims.back() = hidden_size;
+
+        return {inputs[0].type(), out_dims};
+    }
+};
+
 } // namespace op
 } // namespace MIGRAPHX_INLINE_NS
 } // namespace migraphx