/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserve.

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 "paddle/operators/iou_similarity_op.h"

namespace paddle {
namespace operators {

class IOUSimilarityOp : public framework::OperatorWithKernel {
 public:
  using framework::OperatorWithKernel::OperatorWithKernel;

 protected:
  void InferShape(framework::InferShapeContext *ctx) const override {
    auto x_dims = ctx->GetInputDim("X");
    auto y_dims = ctx->GetInputDim("Y");

    PADDLE_ENFORCE_EQ(x_dims.size(), 2UL, "The shape of X is [N, 4]");
    PADDLE_ENFORCE_EQ(x_dims[1], 4UL, "The shape of X is [N, 4]");
    PADDLE_ENFORCE_EQ(y_dims.size(), 2UL, "The shape of Y is [M, 4]");
    PADDLE_ENFORCE_EQ(y_dims[1], 4UL, "The shape of Y is [M, 4]");

    ctx->SetOutputDim("Out", framework::make_ddim({x_dims[0], y_dims[0]}));
  }
};

class IOUSimilarityOpMaker : public framework::OpProtoAndCheckerMaker {
 public:
  IOUSimilarityOpMaker(OpProto *proto, OpAttrChecker *op_checker)
      : OpProtoAndCheckerMaker(proto, op_checker) {
    AddInput(
        "X",
        "(Tensor, default Tensor<float>) "
        "BoxList X holding N boxes, each box is "
        "represented as [xmin, ymin, xmax, ymax], the shape of X is [N, 4].");
    AddInput(
        "Y",
        "(Tensor, default Tensor<float>) "
        "BoxList Y holding M boxes, each box is "
        "represented as [xmin, ymin, xmax, ymax], the shape of X is [N, 4].");

    AddOutput(
        "Out",
        "(Tensor) The output of iou_similarity op, a tensor with shape [N, M] "
        "representing pairwise iou scores.");

    AddComment(R"DOC(
IOU Similarity Operator.
Computes pairwise intersection-over-union between box collections.
)DOC");
  }
};
}  // namespace operators
}  // namespace paddle

namespace ops = paddle::operators;
REGISTER_OP_WITHOUT_GRADIENT(iou_similarity, ops::IOUSimilarityOp,
                             ops::IOUSimilarityOpMaker);

REGISTER_OP_CPU_KERNEL(
    iou_similarity,
    ops::IOUSimilarityKernel<paddle::platform::CPUDeviceContext, float>,
    ops::IOUSimilarityKernel<paddle::platform::CPUDeviceContext, double>);