Merge pull request #16050 from jerrywgz/add_box_decoder_and_assign

Add box decoder and assign

paddle/fluid/API.spec

@@ -329,6 +329,7 @@ paddle.fluid.layers.polygon_box_transform (ArgSpec(args=['input', 'name'], varar
 paddle.fluid.layers.yolov3_loss (ArgSpec(args=['x', 'gtbox', 'gtlabel', 'anchors', 'anchor_mask', 'class_num', 'ignore_thresh', 'downsample_ratio', 'name'], varargs=None, keywords=None, defaults=(None,)), ('document', '991e934c3e09abf0edec7c9c978b4691'))
 paddle.fluid.layers.box_clip (ArgSpec(args=['input', 'im_info', 'name'], varargs=None, keywords=None, defaults=(None,)), ('document', '397e9e02b451d99c56e20f268fa03f2e'))
 paddle.fluid.layers.multiclass_nms (ArgSpec(args=['bboxes', 'scores', 'score_threshold', 'nms_top_k', 'keep_top_k', 'nms_threshold', 'normalized', 'nms_eta', 'background_label', 'name'], varargs=None, keywords=None, defaults=(0.3, True, 1.0, 0, None)), ('document', 'ca7d1107b6c5d2d6d8221039a220fde0'))
+paddle.fluid.layers.box_decoder_and_assign (ArgSpec(args=['prior_box', 'prior_box_var', 'target_box', 'box_score', 'box_clip', 'name'], varargs=None, keywords=None, defaults=(None,)), ('document', '005a5ae47d6c8fff721931d69d072b9f'))
 paddle.fluid.layers.accuracy (ArgSpec(args=['input', 'label', 'k', 'correct', 'total'], varargs=None, keywords=None, defaults=(1, None, None)), ('document', '9808534c12c5e739a10f73ebb0b4eafd'))
 paddle.fluid.layers.auc (ArgSpec(args=['input', 'label', 'curve', 'num_thresholds', 'topk', 'slide_steps'], varargs=None, keywords=None, defaults=('ROC', 4095, 1, 1)), ('document', 'e0e95334fce92d16c2d9db6e7caffc47'))
 paddle.fluid.layers.exponential_decay (ArgSpec(args=['learning_rate', 'decay_steps', 'decay_rate', 'staircase'], varargs=None, keywords=None, defaults=(False,)), ('document', '98a5050bee8522fcea81aa795adaba51'))

paddle/fluid/operators/detection/CMakeLists.txt

@@ -33,6 +33,7 @@ detection_library(rpn_target_assign_op SRCS rpn_target_assign_op.cc)
 detection_library(generate_proposal_labels_op SRCS generate_proposal_labels_op.cc)
 detection_library(box_clip_op SRCS box_clip_op.cc box_clip_op.cu)
 detection_library(yolov3_loss_op SRCS yolov3_loss_op.cc)
+detection_library(box_decoder_and_assign_op SRCS box_decoder_and_assign_op.cc box_decoder_and_assign_op.cu)
 
 if(WITH_GPU)
   detection_library(generate_proposals_op SRCS generate_proposals_op.cc generate_proposals_op.cu DEPS memory cub)

paddle/fluid/operators/detection/box_decoder_and_assign_op.cc

+/* Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
+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/fluid/operators/detection/box_decoder_and_assign_op.h"
+
+namespace paddle {
+namespace operators {
+
+using LoDTensor = framework::LoDTensor;
+
+class BoxDecoderAndAssignOp : public framework::OperatorWithKernel {
+ public:
+  using framework::OperatorWithKernel::OperatorWithKernel;
+
+ protected:
+  void InferShape(framework::InferShapeContext *ctx) const override {
+    PADDLE_ENFORCE(
+        ctx->HasInput("PriorBox"),
+        "Input(PriorBox) of BoxDecoderAndAssignOp should not be null.");
+    PADDLE_ENFORCE(
+        ctx->HasInput("PriorBoxVar"),
+        "Input(PriorBoxVar) of BoxDecoderAndAssignOp should not be null.");
+    PADDLE_ENFORCE(
+        ctx->HasInput("TargetBox"),
+        "Input(TargetBox) of BoxDecoderAndAssignOp should not be null.");
+    PADDLE_ENFORCE(
+        ctx->HasInput("BoxScore"),
+        "Input(BoxScore) of BoxDecoderAndAssignOp should not be null.");
+    PADDLE_ENFORCE(
+        ctx->HasOutput("DecodeBox"),
+        "Output(DecodeBox) of BoxDecoderAndAssignOp should not be null.");
+    PADDLE_ENFORCE(
+        ctx->HasOutput("OutputAssignBox"),
+        "Output(OutputAssignBox) of BoxDecoderAndAssignOp should not be null.");
+
+    auto prior_box_dims = ctx->GetInputDim("PriorBox");
+    auto prior_box_var_dims = ctx->GetInputDim("PriorBoxVar");
+    auto target_box_dims = ctx->GetInputDim("TargetBox");
+    auto box_score_dims = ctx->GetInputDim("BoxScore");
+
+    PADDLE_ENFORCE_EQ(prior_box_dims.size(), 2,
+                      "The rank of Input of PriorBox must be 2");
+    PADDLE_ENFORCE_EQ(prior_box_dims[1], 4, "The shape of PriorBox is [N, 4]");
+    PADDLE_ENFORCE_EQ(prior_box_var_dims.size(), 1,
+                      "The rank of Input of PriorBoxVar must be 1");
+    PADDLE_ENFORCE_EQ(prior_box_var_dims[0], 4,
+                      "The shape of PriorBoxVar is [4]");
+    PADDLE_ENFORCE_EQ(target_box_dims.size(), 2,
+                      "The rank of Input of TargetBox must be 2");
+    PADDLE_ENFORCE_EQ(box_score_dims.size(), 2,
+                      "The rank of Input of BoxScore must be 2");
+    PADDLE_ENFORCE_EQ(prior_box_dims[0], target_box_dims[0],
+                      "The first dim of prior_box and target_box is roi nums "
+                      "and should be same!");
+    PADDLE_ENFORCE_EQ(prior_box_dims[0], box_score_dims[0],
+                      "The first dim of prior_box and box_score is roi nums "
+                      "and should be same!");
+    PADDLE_ENFORCE_EQ(target_box_dims[1], box_score_dims[1] * prior_box_dims[1],
+                      "The shape of target_box is [N, classnum * 4], The shape "
+                      "of box_score is [N, classnum], The shape of prior_box "
+                      "is [N, 4]");
+
+    ctx->SetOutputDim("DecodeBox", framework::make_ddim({target_box_dims[0],
+                                                         target_box_dims[1]}));
+    ctx->ShareLoD("TargetBox", /*->*/ "DecodeBox");
+    ctx->SetOutputDim(
+        "OutputAssignBox",
+        framework::make_ddim({prior_box_dims[0], prior_box_dims[1]}));
+    ctx->ShareLoD("PriorBox", /*->*/ "OutputAssignBox");
+  }
+};
+
+class BoxDecoderAndAssignOpMaker : public framework::OpProtoAndCheckerMaker {
+ public:
+  void Make() override {
+    AddInput(
+        "PriorBox",
+        "(Tensor, default Tensor<float>) "
+        "Box list PriorBox is a 2-D Tensor with shape [N, 4] which holds N "
+        "boxes and each box is represented as [xmin, ymin, xmax, ymax], "
+        "[xmin, ymin] is the left top coordinate of the anchor box, "
+        "if the input is image feature map, they are close to the origin "
+        "of the coordinate system. [xmax, ymax] is the right bottom "
+        "coordinate of the anchor box.");
+    AddInput("PriorBoxVar",
+             "(Tensor, default Tensor<float>, optional) "
+             "PriorBoxVar is a 2-D Tensor with shape [N, 4] which holds N "
+             "group of variance. PriorBoxVar will set all elements to 1 by "
+             "default.")
+        .AsDispensable();
+    AddInput("TargetBox",
+             "(LoDTensor or Tensor) "
+             "This input can be a 2-D LoDTensor with shape "
+             "[N, classnum*4]. It holds N targets for N boxes.");
+    AddInput("BoxScore",
+             "(LoDTensor or Tensor) "
+             "This input can be a 2-D LoDTensor with shape "
+             "[N, classnum], each box is represented as [classnum] which is "
+             "the classification probabilities.");
+    AddAttr<float>("box_clip",
+                   "(float, default 4.135, np.log(1000. / 16.)) "
+                   "clip box to prevent overflowing")
+        .SetDefault(4.135f);
+    AddOutput("DecodeBox",
+              "(LoDTensor or Tensor) "
+              "the output tensor of op with shape [N, classnum * 4] "
+              "representing the result of N target boxes decoded with "
+              "M Prior boxes and variances for each class.");
+    AddOutput("OutputAssignBox",
+              "(LoDTensor or Tensor) "
+              "the output tensor of op with shape [N, 4] "
+              "representing the result of N target boxes decoded with "
+              "M Prior boxes and variances with the best non-background class "
+              "by BoxScore.");
+    AddComment(R"DOC(
+
+Bounding Box Coder.
+
+Decode the target bounding box with the prior_box information.
+
+The Decoding schema is described below:
+
+    $$
+    ox = (pw \\times pxv \\times tx + px) - \\frac{tw}{2} 
+    $$
+    $$
+    oy = (ph \\times pyv \\times ty + py) - \\frac{th}{2}
+    $$
+    $$
+    ow = \\exp (pwv \\times tw) \\times pw + \\frac{tw}{2}
+    $$
+    $$
+    oh = \\exp (phv \\times th) \\times ph + \\frac{th}{2}
+    $$
+
+where `tx`, `ty`, `tw`, `th` denote the target box's center coordinates, width
+and height respectively. Similarly, `px`, `py`, `pw`, `ph` denote the
+prior_box's (anchor) center coordinates, width and height. `pxv`, `pyv`, `pwv`,
+`phv` denote the variance of the prior_box and `ox`, `oy`, `ow`, `oh` denote the
+decoded coordinates, width and height in decode_box. 
+
+decode_box is obtained after box decode, then assigning schema is described below:
+
+For each prior_box, use the best non-background class's decoded values to 
+update the prior_box locations and get output_assign_box. So, the shape of
+output_assign_box is the same as PriorBox.
+)DOC");
+  }
+};
+
+}  // namespace operators
+}  // namespace paddle
+
+namespace ops = paddle::operators;
+REGISTER_OPERATOR(box_decoder_and_assign, ops::BoxDecoderAndAssignOp,
+                  ops::BoxDecoderAndAssignOpMaker,
+                  paddle::framework::EmptyGradOpMaker);
+REGISTER_OP_CPU_KERNEL(
+    box_decoder_and_assign,
+    ops::BoxDecoderAndAssignKernel<paddle::platform::CPUDeviceContext, float>,
+    ops::BoxDecoderAndAssignKernel<paddle::platform::CPUDeviceContext, double>);

paddle/fluid/operators/detection/box_decoder_and_assign_op.cu

+/* Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
+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/fluid/memory/memcpy.h"
+#include "paddle/fluid/operators/detection/box_decoder_and_assign_op.h"
+#include "paddle/fluid/platform/cuda_primitives.h"
+
+namespace paddle {
+namespace operators {
+
+template <typename T>
+__global__ void DecodeBoxKernel(const T* prior_box_data,
+                                const T* prior_box_var_data,
+                                const T* target_box_data, const int roi_num,
+                                const int class_num, const T box_clip,
+                                T* output_box_data) {
+  const int idx = threadIdx.x + blockIdx.x * blockDim.x;
+  if (idx < roi_num * class_num) {
+    int i = idx / class_num;
+    int j = idx % class_num;
+    T prior_box_width = prior_box_data[i * 4 + 2] - prior_box_data[i * 4] + 1;
+    T prior_box_height =
+        prior_box_data[i * 4 + 3] - prior_box_data[i * 4 + 1] + 1;
+    T prior_box_center_x = prior_box_data[i * 4] + prior_box_width / 2;
+    T prior_box_center_y = prior_box_data[i * 4 + 1] + prior_box_height / 2;
+
+    int offset = i * class_num * 4 + j * 4;
+    T dw = prior_box_var_data[2] * target_box_data[offset + 2];
+    T dh = prior_box_var_data[3] * target_box_data[offset + 3];
+    if (dw > box_clip) {
+      dw = box_clip;
+    }
+    if (dh > box_clip) {
+      dh = box_clip;
+    }
+    T target_box_center_x = 0, target_box_center_y = 0;
+    T target_box_width = 0, target_box_height = 0;
+    target_box_center_x =
+        prior_box_var_data[0] * target_box_data[offset] * prior_box_width +
+        prior_box_center_x;
+    target_box_center_y =
+        prior_box_var_data[1] * target_box_data[offset + 1] * prior_box_height +
+        prior_box_center_y;
+    target_box_width = expf(dw) * prior_box_width;
+    target_box_height = expf(dh) * prior_box_height;
+
+    output_box_data[offset] = target_box_center_x - target_box_width / 2;
+    output_box_data[offset + 1] = target_box_center_y - target_box_height / 2;
+    output_box_data[offset + 2] =
+        target_box_center_x + target_box_width / 2 - 1;
+    output_box_data[offset + 3] =
+        target_box_center_y + target_box_height / 2 - 1;
+  }
+}
+
+template <typename T>
+__global__ void AssignBoxKernel(const T* prior_box_data,
+                                const T* box_score_data, T* output_box_data,
+                                const int roi_num, const int class_num,
+                                T* output_assign_box_data) {
+  const int idx = threadIdx.x + blockIdx.x * blockDim.x;
+  if (idx < roi_num) {
+    int i = idx;
+    T max_score = -1;
+    int max_j = -1;
+    for (int j = 0; j < class_num; ++j) {
+      T score = box_score_data[i * class_num + j];
+      if (score > max_score && j > 0) {
+        max_score = score;
+        max_j = j;
+      }
+    }
+    if (max_j > 0) {
+      for (int pno = 0; pno < 4; pno++) {
+        output_assign_box_data[i * 4 + pno] =
+            output_box_data[i * class_num * 4 + max_j * 4 + pno];
+      }
+    } else {
+      for (int pno = 0; pno < 4; pno++) {
+        output_assign_box_data[i * 4 + pno] = prior_box_data[i * 4 + pno];
+      }
+    }
+  }
+}
+
+template <typename DeviceContext, typename T>
+class BoxDecoderAndAssignCUDAKernel : public framework::OpKernel<T> {
+ public:
+  void Compute(const framework::ExecutionContext& context) const override {
+    PADDLE_ENFORCE(platform::is_gpu_place(context.GetPlace()),
+                   "This kernel only runs on GPU device.");
+    auto* prior_box = context.Input<framework::LoDTensor>("PriorBox");
+    auto* prior_box_var = context.Input<framework::Tensor>("PriorBoxVar");
+    auto* target_box = context.Input<framework::LoDTensor>("TargetBox");
+    auto* box_score = context.Input<framework::LoDTensor>("BoxScore");
+    auto* output_box = context.Output<framework::Tensor>("DecodeBox");
+    auto* output_assign_box =
+        context.Output<framework::Tensor>("OutputAssignBox");
+
+    auto roi_num = target_box->dims()[0];
+    auto class_num = box_score->dims()[1];
+    auto* target_box_data = target_box->data<T>();
+    auto* prior_box_data = prior_box->data<T>();
+    auto* prior_box_var_data = prior_box_var->data<T>();
+    auto* box_score_data = box_score->data<T>();
+    output_box->mutable_data<T>({roi_num, class_num * 4}, context.GetPlace());
+    output_assign_box->mutable_data<T>({roi_num, 4}, context.GetPlace());
+    T* output_box_data = output_box->data<T>();
+    T* output_assign_box_data = output_assign_box->data<T>();
+
+    int block = 512;
+    int grid = (roi_num * class_num + block - 1) / block;
+    auto& device_ctx = context.cuda_device_context();
+
+    const T box_clip = context.Attr<T>("box_clip");
+
+    DecodeBoxKernel<T><<<grid, block, 0, device_ctx.stream()>>>(
+        prior_box_data, prior_box_var_data, target_box_data, roi_num, class_num,
+        box_clip, output_box_data);
+
+    context.device_context().Wait();
+    int assign_grid = (roi_num + block - 1) / block;
+    AssignBoxKernel<T><<<assign_grid, block, 0, device_ctx.stream()>>>(
+        prior_box_data, box_score_data, output_box_data, roi_num, class_num,
+        output_assign_box_data);
+    context.device_context().Wait();
+  }
+};
+
+}  // namespace operators
+}  // namespace paddle
+
+namespace ops = paddle::operators;
+REGISTER_OP_CUDA_KERNEL(
+    box_decoder_and_assign,
+    ops::BoxDecoderAndAssignCUDAKernel<paddle::platform::CUDADeviceContext,
+                                       float>,
+    ops::BoxDecoderAndAssignCUDAKernel<paddle::platform::CUDADeviceContext,
+                                       double>);

paddle/fluid/operators/detection/box_decoder_and_assign_op.h

+/* Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
+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 <algorithm>
+#include <string>
+#include <vector>
+#include "paddle/fluid/framework/op_registry.h"
+#include "paddle/fluid/operators/math/math_function.h"
+
+namespace paddle {
+namespace operators {
+
+template <typename DeviceContext, typename T>
+class BoxDecoderAndAssignKernel : public framework::OpKernel<T> {
+ public:
+  void Compute(const framework::ExecutionContext& context) const override {
+    auto* prior_box = context.Input<framework::LoDTensor>("PriorBox");
+    auto* prior_box_var = context.Input<framework::Tensor>("PriorBoxVar");
+    auto* target_box = context.Input<framework::LoDTensor>("TargetBox");
+    auto* box_score = context.Input<framework::LoDTensor>("BoxScore");
+    auto* output_box = context.Output<framework::Tensor>("DecodeBox");
+    auto* output_assign_box =
+        context.Output<framework::Tensor>("OutputAssignBox");
+    int roi_num = target_box->dims()[0];
+    int class_num = box_score->dims()[1];
+    auto* target_box_data = target_box->data<T>();
+    auto* prior_box_data = prior_box->data<T>();
+    auto* prior_box_var_data = prior_box_var->data<T>();
+    auto* box_score_data = box_score->data<T>();
+    output_box->mutable_data<T>({roi_num, class_num * 4}, context.GetPlace());
+    output_assign_box->mutable_data<T>({roi_num, 4}, context.GetPlace());
+    T* output_box_data = output_box->data<T>();
+    T* output_assign_box_data = output_assign_box->data<T>();
+    const T bbox_clip = context.Attr<T>("box_clip");
+
+    for (int i = 0; i < roi_num; ++i) {
+      T prior_box_width = prior_box_data[i * 4 + 2] - prior_box_data[i * 4] + 1;
+      T prior_box_height =
+          prior_box_data[i * 4 + 3] - prior_box_data[i * 4 + 1] + 1;
+      T prior_box_center_x = prior_box_data[i * 4] + prior_box_width / 2;
+      T prior_box_center_y = prior_box_data[i * 4 + 1] + prior_box_height / 2;
+      for (int j = 0; j < class_num; ++j) {
+        int64_t offset = i * class_num * 4 + j * 4;
+        T dw = std::min(prior_box_var_data[2] * target_box_data[offset + 2],
+                        bbox_clip);
+        T dh = std::min(prior_box_var_data[3] * target_box_data[offset + 3],
+                        bbox_clip);
+        T target_box_center_x = 0, target_box_center_y = 0;
+        T target_box_width = 0, target_box_height = 0;
+        target_box_center_x =
+            prior_box_var_data[0] * target_box_data[offset] * prior_box_width +
+            prior_box_center_x;
+        target_box_center_y = prior_box_var_data[1] *
+                                  target_box_data[offset + 1] *
+                                  prior_box_height +
+                              prior_box_center_y;
+        target_box_width = std::exp(dw) * prior_box_width;
+        target_box_height = std::exp(dh) * prior_box_height;
+
+        output_box_data[offset] = target_box_center_x - target_box_width / 2;
+        output_box_data[offset + 1] =
+            target_box_center_y - target_box_height / 2;
+        output_box_data[offset + 2] =
+            target_box_center_x + target_box_width / 2 - 1;
+        output_box_data[offset + 3] =
+            target_box_center_y + target_box_height / 2 - 1;
+      }
+
+      T max_score = -1;
+      int max_j = -1;
+      for (int j = 0; j < class_num; ++j) {
+        T score = box_score_data[i * class_num + j];
+        if (score > max_score && j > 0) {
+          max_score = score;
+          max_j = j;
+        }
+      }
+
+      if (max_j > 0) {
+        for (int pno = 0; pno < 4; pno++) {
+          output_assign_box_data[i * 4 + pno] =
+              output_box_data[i * class_num * 4 + max_j * 4 + pno];
+        }
+      } else {
+        for (int pno = 0; pno < 4; pno++) {
+          output_assign_box_data[i * 4 + pno] = prior_box_data[i * 4 + pno];
+        }
+      }
+    }
+  }
+};
+
+}  // namespace operators
+}  // namespace paddle

python/paddle/fluid/layers/detection.py

@@ -51,6 +51,7 @@ __all__ = [
     'yolov3_loss',
     'box_clip',
     'multiclass_nms',
+    'box_decoder_and_assign',
 ]
 
 
@@ -2221,3 +2222,65 @@ def multiclass_nms(bboxes,
     output.stop_gradient = True
 
     return output
+
+
+@templatedoc()
+def box_decoder_and_assign(prior_box,
+                           prior_box_var,
+                           target_box,
+                           box_score,
+                           box_clip,
+                           name=None):
+    """
+    ${comment}
+    Args:
+        prior_box(${prior_box_type}): ${prior_box_comment}
+        prior_box_var(${prior_box_var_type}): ${prior_box_var_comment}
+        target_box(${target_box_type}): ${target_box_comment}
+        box_score(${box_score_type}): ${box_score_comment}
+        box_clip(${box_clip_type}): ${box_clip_comment}
+        name(str|None): The name of this operator
+    Returns:
+        decode_box(Variable), output_assign_box(Variable):
+
+            two variables:
+
+            - decode_box(${decode_box_type}): ${decode_box_comment}
+            - output_assign_box(${output_assign_box_type}): ${output_assign_box_comment}
+
+    Examples:
+        .. code-block:: python
+
+            pb = fluid.layers.data(
+                name='prior_box', shape=[20, 4], dtype='float32')
+            pbv = fluid.layers.data(
+                name='prior_box_var', shape=[1, 4], dtype='float32')
+            loc = fluid.layers.data(
+                name='target_box', shape=[20, 4*81], dtype='float32')
+            scores = fluid.layers.data(
+                name='scores', shape=[20, 81], dtype='float32')
+            decoded_box, output_assign_box = fluid.layers.box_decoder_and_assign(
+                pb, pbv, loc, scores, 4.135)
+
+    """
+    helper = LayerHelper("box_decoder_and_assign", **locals())
+
+    decoded_box = helper.create_variable_for_type_inference(
+        dtype=prior_box.dtype)
+    output_assign_box = helper.create_variable_for_type_inference(
+        dtype=prior_box.dtype)
+
+    helper.append_op(
+        type="box_decoder_and_assign",
+        inputs={
+            "PriorBox": prior_box,
+            "PriorBoxVar": prior_box_var,
+            "TargetBox": target_box,
+            "BoxScore": box_score
+        },
+        attrs={"box_clip": box_clip},
+        outputs={
+            "DecodeBox": decoded_box,
+            "OutputAssignBox": output_assign_box
+        })
+    return decoded_box, output_assign_box

python/paddle/fluid/tests/unittests/test_box_decoder_and_assign_op.py

+#   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+#
+# 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.
+
+from __future__ import print_function
+
+import unittest
+import numpy as np
+import sys
+import math
+from op_test import OpTest
+
+
+def box_decoder_and_assign(deltas, weights, boxes, box_score, box_clip):
+    boxes = boxes.astype(deltas.dtype, copy=False)
+    widths = boxes[:, 2] - boxes[:, 0] + 1.0
+    heights = boxes[:, 3] - boxes[:, 1] + 1.0
+    ctr_x = boxes[:, 0] + 0.5 * widths
+    ctr_y = boxes[:, 1] + 0.5 * heights
+    wx, wy, ww, wh = weights
+    dx = deltas[:, 0::4] * wx
+    dy = deltas[:, 1::4] * wy
+    dw = deltas[:, 2::4] * ww
+    dh = deltas[:, 3::4] * wh
+    # Prevent sending too large values into np.exp()
+    dw = np.minimum(dw, box_clip)
+    dh = np.minimum(dh, box_clip)
+    pred_ctr_x = dx * widths[:, np.newaxis] + ctr_x[:, np.newaxis]
+    pred_ctr_y = dy * heights[:, np.newaxis] + ctr_y[:, np.newaxis]
+    pred_w = np.exp(dw) * widths[:, np.newaxis]
+    pred_h = np.exp(dh) * heights[:, np.newaxis]
+    pred_boxes = np.zeros(deltas.shape, dtype=deltas.dtype)
+    # x1
+    pred_boxes[:, 0::4] = pred_ctr_x - 0.5 * pred_w
+    # y1
+    pred_boxes[:, 1::4] = pred_ctr_y - 0.5 * pred_h
+    # x2 (note: "- 1" is correct; don't be fooled by the asymmetry)
+    pred_boxes[:, 2::4] = pred_ctr_x + 0.5 * pred_w - 1
+    # y2 (note: "- 1" is correct; don't be fooled by the asymmetry)
+    pred_boxes[:, 3::4] = pred_ctr_y + 0.5 * pred_h - 1
+
+    output_assign_box = []
+    for ino in range(len(pred_boxes)):
+        rank = np.argsort(-box_score[ino])
+        maxidx = rank[0]
+        if maxidx == 0:
+            maxidx = rank[1]
+        beg_pos = maxidx * 4
+        end_pos = maxidx * 4 + 4
+        output_assign_box.append(pred_boxes[ino, beg_pos:end_pos])
+    output_assign_box = np.array(output_assign_box)
+
+    return pred_boxes, output_assign_box
+
+
+class TestBoxDecoderAndAssignOpWithLoD(OpTest):
+    def test_check_output(self):
+        self.check_output()
+
+    def setUp(self):
+        self.op_type = "box_decoder_and_assign"
+        lod = [[4, 8, 8]]
+        num_classes = 10
+        prior_box = np.random.random((20, 4)).astype('float32')
+        prior_box_var = np.array([0.1, 0.1, 0.2, 0.2], dtype=np.float32)
+        target_box = np.random.random((20, 4 * num_classes)).astype('float32')
+        box_score = np.random.random((20, num_classes)).astype('float32')
+        box_clip = 4.135
+        output_box, output_assign_box = box_decoder_and_assign(
+            target_box, prior_box_var, prior_box, box_score, box_clip)
+
+        self.inputs = {
+            'PriorBox': (prior_box, lod),
+            'PriorBoxVar': prior_box_var,
+            'TargetBox': (target_box, lod),
+            'BoxScore': (box_score, lod),
+        }
+        self.attrs = {'box_clip': box_clip}
+        self.outputs = {
+            'DecodeBox': output_box,
+            'OutputAssignBox': output_assign_box
+        }
+
+
+if __name__ == '__main__':
+    unittest.main()