[ONNX] Slice op (#1610)

* [ONNX] Slice op

* Review fix pt. 1

* Review fix pt. 2

src/ngraph/frontend/onnx_import/CMakeLists.txt

@@ -88,11 +88,13 @@ add_library(onnx_import STATIC
         op/relu.hpp
         op/reshape.cpp
         op/reshape.hpp
-        op/shape.cpp
-        op/shape.hpp
         op/selu.cpp
         op/selu.hpp
+        op/shape.hpp
+        op/shape.cpp
         op/sigmoid.hpp
+        op/slice.cpp
+        op/slice.hpp
         op/softmax.cpp
         op/softmax.hpp
         op/softplus.cpp

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

+//*****************************************************************************
+// Copyright 2017-2018 Intel Corporation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//*****************************************************************************
+
+#include <algorithm>
+#include <memory>
+#include <vector>
+
+#include "ngraph/node.hpp"
+#include "ngraph/op/slice.hpp"
+
+#include "slice.hpp"
+#include "utils/common.hpp"
+
+static inline int64_t get_valid_array_idx(int64_t idx, int64_t last_idx)
+{
+    return (idx >= 0) ? std::min(idx, last_idx) : std::max<int64_t>(0, last_idx + idx);
+}
+
+namespace ngraph
+{
+    namespace onnx_import
+    {
+        namespace op
+        {
+            NodeVector slice(const Node& node)
+            {
+                std::shared_ptr<ngraph::Node> data = node.get_ng_inputs().at(0);
+                Shape data_shape = data->get_shape();
+
+                auto starts = node.get_attribute_value<std::vector<int64_t>>("starts");
+                auto ends = node.get_attribute_value<std::vector<int64_t>>("ends");
+
+                auto axes = node.get_attribute_value<std::vector<int64_t>>(
+                    "axes", common::get_monotonic_range<int64_t>(data_shape.size()));
+
+                Shape lower_bounds(data_shape.size());
+                Shape upper_bounds = data_shape;
+
+                for (auto idx = 0; idx < axes.size(); ++idx)
+                {
+                    size_t axis = axes.at(idx);
+                    lower_bounds.at(axis) =
+                        get_valid_array_idx(starts.at(idx), data_shape.at(axis));
+                    upper_bounds.at(axis) = get_valid_array_idx(ends.at(idx), data_shape.at(axis));
+                }
+
+                return {std::make_shared<ngraph::op::Slice>(data, lower_bounds, upper_bounds)};
+            }
+
+        } // namespace op
+
+    } // namespace onnx_import
+
+} // namespace ngraph

src/ngraph/frontend/onnx_import/op/slice.hpp

+//*****************************************************************************
+// Copyright 2017-2018 Intel Corporation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//*****************************************************************************
+
+#pragma once
+
+#include "ngraph/node_vector.hpp"
+
+#include "core/node.hpp"
+
+namespace ngraph
+{
+    namespace onnx_import
+    {
+        namespace op
+        {
+            NodeVector slice(const Node& node);
+        } // namespace op
+
+    } // namespace onnx_import
+
+} // namespace ngraph

src/ngraph/frontend/onnx_import/ops_bridge.cpp

@@ -61,6 +61,7 @@
 #include "op/selu.hpp"
 #include "op/shape.hpp"
 #include "op/sigmoid.hpp"
+#include "op/slice.hpp"
 #include "op/softmax.hpp"
 #include "op/softplus.hpp"
 #include "op/softsign.hpp"
@@ -171,9 +172,10 @@ namespace ngraph
                                   std::bind(op::reduce_sum_square, std::placeholders::_1));
                     m_map.emplace("Relu", std::bind(op::relu, std::placeholders::_1));
                     m_map.emplace("Reshape", std::bind(op::reshape, std::placeholders::_1));
-                    m_map.emplace("Shape", std::bind(op::shape, std::placeholders::_1));
                     m_map.emplace("Selu", std::bind(op::selu, std::placeholders::_1));
+                    m_map.emplace("Shape", std::bind(op::shape, std::placeholders::_1));
                     m_map.emplace("Sigmoid", std::bind(op::sigmoid, std::placeholders::_1));
+                    m_map.emplace("Slice", std::bind(op::slice, std::placeholders::_1));
                     m_map.emplace("Softmax", std::bind(op::softmax, std::placeholders::_1));
                     m_map.emplace("Softplus", std::bind(op::softplus, std::placeholders::_1));
                     m_map.emplace("Softsign", std::bind(op::softsign, std::placeholders::_1));