Merge pull request #11174 from kuke/argsort_dev

Add the argsort operator

Author: Yibing Liu

doc/fluid/api/layers.rst

@@ -1468,6 +1468,14 @@ argmax
 ..  autofunction:: paddle.fluid.layers.argmax
     :noindex:
 
+.. _api_fluid_layers_argsort:
+
+argsort
+-------
+
+..  autofunction:: paddle.fluid.layers.argsort
+    :noindex:
+
 .. _api_fluid_layers_ones:
 
 ones

paddle/fluid/operators/argsort_op.cc

@@ -0,0 +1,87 @@
+/* Copyright (c) 2016 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/argsort_op.h"
+
+namespace paddle {
+namespace operators {
+
+class ArgsortOp : public framework::OperatorWithKernel {
+ public:
+  using framework::OperatorWithKernel::OperatorWithKernel;
+
+  void InferShape(framework::InferShapeContext *ctx) const override {
+    PADDLE_ENFORCE(ctx->HasInput("X"),
+                   "Input(X) of ArgsortOp should not be null.");
+    PADDLE_ENFORCE(ctx->HasOutput("Out"),
+                   "Output(Out) of ArgsortOp should not be null.");
+    PADDLE_ENFORCE(ctx->HasOutput("Indices"),
+                   "Output(Indices) of ArgsortOp should not be null.");
+
+    auto in_dims = ctx->GetInputDim("X");
+    int axis = ctx->Attrs().Get<int>("axis");
+
+    auto num_dims = in_dims.size();
+    PADDLE_ENFORCE(axis < num_dims,
+                   "Attr(axis) %d of ArgsortOp is out of bounds for Input(X)'s "
+                   "rank %d.",
+                   axis, num_dims);
+    PADDLE_ENFORCE(axis >= -num_dims,
+                   "Attr(axis) %d of ArgsortOp must be not less than "
+                   "-rank(Input(X)) (%d).",
+                   axis, num_dims);
+
+    ctx->SetOutputDim("Out", in_dims);
+    ctx->SetOutputDim("Indices", in_dims);
+    ctx->ShareLoD("X", "Out");
+    ctx->ShareLoD("X", "Indices");
+  }
+};
+
+class ArgsortOpMaker : public framework::OpProtoAndCheckerMaker {
+ public:
+  void Make() override {
+    AddInput("X", "(Tensor) The input of Argsort op.");
+    AddOutput("Out",
+              "(Tensor) The sorted tensor of Argsort op, with the same "
+              "shape as Input(X).");
+    AddOutput("Indices",
+              "(Tensor) The indices of a tensor giving the sorted order, with "
+              "the same shape as Input(X).");
+    AddComment(R"DOC(
+Argsort operator
+
+Performs sorting on the input tensor along the given axis and outputs two 
+tensors, Output(Out) and Output(Indices). They reserve the same shape 
+with Input(X), and Output(Out) represents the sorted tensor while 
+Output(Indices) gives the sorted order along the given axis Attr(axis).
+
+ )DOC");
+    AddAttr<int>("axis",
+                 "(int, default -1) The axis along which to sort the tensor. "
+                 "When axis < 0, the actual axis will be the |axis|'th "
+                 "counting backwards. Default -1, the last dimension.")
+        .SetDefault(-1);
+  }
+};
+
+}  // namespace operators
+}  // namespace paddle
+
+namespace ops = paddle::operators;
+REGISTER_OPERATOR(argsort, ops::ArgsortOp, ops::ArgsortOpMaker,
+                  paddle::framework::EmptyGradOpMaker);
+REGISTER_OP_CPU_KERNEL(argsort,
+                       ops::ArgsortKernel<paddle::platform::CPUPlace, float>,
+                       ops::ArgsortKernel<paddle::platform::CPUPlace, double>);

paddle/fluid/operators/argsort_op.cu

@@ -0,0 +1,151 @@
+/* Copyright (c) 2016 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 <thrust/execution_policy.h>
+#include <thrust/sort.h>
+#include "paddle/fluid/framework/op_registry.h"
+#include "paddle/fluid/operators/argsort_op.h"
+#include "paddle/fluid/platform/assert.h"
+#include "paddle/fluid/platform/cuda_device_function.h"
+#include "paddle/fluid/platform/cuda_primitives.h"
+
+namespace paddle {
+namespace operators {
+
+using Tensor = framework::Tensor;
+using platform::PADDLE_CUDA_NUM_THREADS;
+
+const int kMaxRank = 9;  // The max rank of a tensor allowed in Fluid
+
+__global__ void ComputeTargetIdx(const int64_t* in_dims, int dims_size,
+                                 int axis, int64_t n, int64_t* trg_idx,
+                                 int64_t* med_ids) {
+  int64_t index = threadIdx.x + blockDim.x * blockIdx.x;
+  if (index < n) {
+    int64_t shape_out_axis[kMaxRank - 1] = {0};
+    int64_t dims_out_axis[kMaxRank - 1] = {0};
+    int64_t tmp = index;
+    int64_t pos_in_axis = 0;
+    int64_t i = dims_size - 2;
+    int64_t dim_axis = 0;
+    for (int64_t j = dims_size - 1; j >= 0; --j) {
+      int64_t dim = in_dims[j];
+      if (j != axis) {
+        shape_out_axis[i] = tmp % dim;
+        dims_out_axis[i] = dim;
+        i--;
+      } else {
+        dim_axis = dim;
+        pos_in_axis = tmp % dim_axis;
+      }
+      tmp /= dim;
+    }
+    int64_t group = (dims_size > 1) ? shape_out_axis[0] : 0;
+    for (int64_t j = 0; j < dims_size - 2; ++j) {
+      group = group * dims_out_axis[j + 1] + shape_out_axis[j + 1];
+    }
+
+    int64_t traget_idx = group * dim_axis + pos_in_axis;
+    trg_idx[index] = traget_idx;
+    med_ids[traget_idx] = pos_in_axis;
+  }
+}
+
+template <typename T>
+__global__ void PermuteInData(const T* in, const int64_t* trg_idx, int64_t n,
+                              T* med_out) {
+  int index = threadIdx.x + blockDim.x * blockIdx.x;
+  if (index < n) {
+    med_out[trg_idx[index]] = in[index];
+  }
+}
+
+template <typename T>
+__global__ void Sort(int64_t axis_dim, int64_t groups, T* med_out,
+                     int64_t* med_ids) {
+  int index = threadIdx.x + blockDim.x * blockIdx.x;
+  if (index < groups) {
+    thrust::sort_by_key(thrust::device, med_out + index * axis_dim,
+                        med_out + axis_dim * (1 + index),
+                        med_ids + index * axis_dim);
+  }
+}
+
+template <typename T>
+__global__ void PermuteMediateData(const T* med_out, const int64_t* med_ids,
+                                   const int64_t* trg_idx, int64_t n, T* out,
+                                   int64_t* indices) {
+  int index = threadIdx.x + blockDim.x * blockIdx.x;
+  if (index < n) {
+    out[index] = med_out[trg_idx[index]];
+    indices[index] = med_ids[trg_idx[index]];
+  }
+}
+
+template <typename T>
+class ArgsortOpCUDAKernel : public framework::OpKernel<T> {
+ public:
+  void Compute(const framework::ExecutionContext& ctx) const override {
+    auto* input = ctx.Input<Tensor>("X");
+    auto* output = ctx.Output<Tensor>("Out");
+    auto* indices = ctx.Output<Tensor>("Indices");
+    int axis = ctx.Attr<int>("axis");
+
+    auto in_dims = input->dims();
+    axis = (axis < 0) ? (in_dims.size() + axis) : axis;
+
+    const T* in_data = input->data<T>();
+    T* out_data = output->mutable_data<T>(ctx.GetPlace());
+    int64_t* ids_data = indices->mutable_data<int64_t>(ctx.GetPlace());
+
+    int64_t numel = input->numel();
+    int64_t groups = numel / in_dims[axis];
+
+    std::vector<int64_t> in_dims_vec = vectorize(in_dims);
+    thrust::device_vector<int64_t> in_dims_dev(in_dims_vec.begin(),
+                                               in_dims_vec.end());
+    int64_t* in_dims_data = thrust::raw_pointer_cast(in_dims_dev.data());
+    // Mediate tensor for sorting data and indices
+    Tensor mediate_output, mediate_indices;
+    T* med_out_data =
+        mediate_output.mutable_data<T>(input->dims(), ctx.GetPlace());
+    int64_t* med_ids_data =
+        mediate_indices.mutable_data<int64_t>(in_dims, ctx.GetPlace());
+    // Target index of each element along the given axis in the mediate tensors
+    Tensor trg_idx_t;
+    int64_t* trg_idx = trg_idx_t.mutable_data<int64_t>(in_dims, ctx.GetPlace());
+
+    auto stream = ctx.cuda_device_context().stream();
+    const int num_threads = PADDLE_CUDA_NUM_THREADS;
+
+    ComputeTargetIdx<<<(numel - 1) / num_threads + 1, num_threads, 0, stream>>>(
+        in_dims_data, in_dims.size(), axis, numel, trg_idx, med_ids_data);
+
+    PermuteInData<<<(numel - 1) / num_threads + 1, num_threads, 0, stream>>>(
+        in_data, trg_idx, numel, med_out_data);
+
+    Sort<<<(groups - 1) / num_threads + 1, num_threads, 0, stream>>>(
+        in_dims[axis], groups, med_out_data, med_ids_data);
+
+    PermuteMediateData<<<(numel - 1) / num_threads + 1, num_threads, 0,
+                         stream>>>(med_out_data, med_ids_data, trg_idx, numel,
+                                   out_data, ids_data);
+  }
+};
+
+}  // namespace operators
+}  // namespace paddle
+
+REGISTER_OP_CUDA_KERNEL(argsort, paddle::operators::ArgsortOpCUDAKernel<float>,
+                        paddle::operators::ArgsortOpCUDAKernel<double>);

paddle/fluid/operators/argsort_op.h

@@ -0,0 +1,81 @@
+/* Copyright (c) 2016 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 <utility>
+#include <vector>
+#include "paddle/fluid/framework/op_registry.h"
+
+namespace paddle {
+namespace operators {
+
+template <typename DeviceContext, typename T>
+class ArgsortKernel : public framework::OpKernel<T> {
+ public:
+  void Compute(const framework::ExecutionContext& ctx) const override {
+    auto* input = ctx.Input<framework::Tensor>("X");
+    auto* output = ctx.Output<framework::Tensor>("Out");
+    auto* indices = ctx.Output<framework::Tensor>("Indices");
+    int axis = ctx.Attr<int>("axis");
+
+    auto in_dims = input->dims();
+    axis = (axis < 0) ? (in_dims.size() + axis) : axis;
+
+    const T* in_data = input->data<T>();
+    T* out_data = output->mutable_data<T>(ctx.GetPlace());
+    int64_t* ids_data = indices->mutable_data<int64_t>(ctx.GetPlace());
+
+    int64_t groups = input->numel() / in_dims[axis];
+    int64_t stride = (axis == in_dims.size() - 1)
+                         ? 1
+                         : framework::product(framework::slice_ddim(
+                               in_dims, axis + 1, in_dims.size()));
+
+    for (int64_t i = 0; i < groups; ++i) {
+      int64_t idx = i;
+      std::vector<int64_t> shape_vec(in_dims.size(), 0);
+      for (int64_t dim = in_dims.size() - 1; dim >= 0; --dim) {
+        if (dim != axis) {
+          shape_vec[dim] = idx % in_dims[dim];
+          idx /= in_dims[dim];
+        }
+      }
+
+      int64_t start_index = shape_vec[0];
+      for (int64_t dim = 0; dim < in_dims.size() - 1; ++dim) {
+        start_index = start_index * in_dims[dim + 1] + shape_vec[dim + 1];
+      }
+
+      std::vector<int64_t> org_index_vec(in_dims[axis], start_index);
+      for (int64_t j = 1; j < in_dims[axis]; ++j) {
+        org_index_vec[j] += j * stride;
+      }
+
+      std::sort(org_index_vec.begin(), org_index_vec.end(),
+                [in_data](const int64_t v1, const int64_t v2) {
+                  return in_data[v1] < in_data[v2];
+                });
+
+      for (size_t j = 0; j < org_index_vec.size(); ++j) {
+        int64_t index = start_index + j * stride;
+        out_data[index] = in_data[org_index_vec[j]];
+        ids_data[index] = (org_index_vec[j] - start_index) / stride;
+      }
+    }
+  }
+};
+
+}  // namespace operators
+}  // namespace paddle