xgboost/tests/cpp/tree/test_gpu_hist.cu

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/*!
* Copyright 2017-2018 XGBoost contributors
*/
#include <thrust/device_vector.h>
#include <xgboost/base.h>
#include <random>
#include <string>
#include <vector>
#include "../helpers.h"
#include "gtest/gtest.h"
#include "../../../src/data/sparse_page_source.h"
#include "../../../src/gbm/gbtree_model.h"
#include "../../../src/tree/updater_gpu_hist.cu"
#include "../../../src/tree/updater_gpu_common.cuh"
#include "../../../src/common/common.h"
namespace xgboost {
namespace tree {
template <typename GradientSumT>
void BuildGidx(DeviceShard<GradientSumT>* shard, int n_rows, int n_cols,
bst_float sparsity=0) {
auto dmat = CreateDMatrix(n_rows, n_cols, sparsity, 3);
const SparsePage& batch = *(*dmat)->GetRowBatches().begin();
common::HistCutMatrix cmat;
cmat.row_ptr = {0, 3, 6, 9, 12, 15, 18, 21, 24};
cmat.min_val = {0.1f, 0.2f, 0.3f, 0.1f, 0.2f, 0.3f, 0.2f, 0.2f};
// 24 cut fields, 3 cut fields for each feature (column).
cmat.cut = {0.30f, 0.67f, 1.64f,
0.32f, 0.77f, 1.95f,
0.29f, 0.70f, 1.80f,
0.32f, 0.75f, 1.85f,
0.18f, 0.59f, 1.69f,
0.25f, 0.74f, 2.00f,
0.26f, 0.74f, 1.98f,
0.26f, 0.71f, 1.83f};
auto is_dense = (*dmat)->Info().num_nonzero_ ==
(*dmat)->Info().num_row_ * (*dmat)->Info().num_col_;
shard->InitCompressedData(cmat, batch, is_dense);
delete dmat;
}
TEST(GpuHist, BuildGidxDense) {
int constexpr kNRows = 16, kNCols = 8;
TrainParam param;
param.max_depth = 1;
param.n_gpus = 1;
param.max_leaves = 0;
DeviceShard<GradientPairPrecise> shard(0, 0, kNRows, param);
BuildGidx(&shard, kNRows, kNCols);
std::vector<common::CompressedByteT> h_gidx_buffer(shard.gidx_buffer.size());
dh::CopyDeviceSpanToVector(&h_gidx_buffer, shard.gidx_buffer);
common::CompressedIterator<uint32_t> gidx(h_gidx_buffer.data(), 25);
ASSERT_EQ(shard.ellpack_matrix.row_stride, kNCols);
std::vector<uint32_t> solution = {
0, 3, 8, 9, 14, 17, 20, 21,
0, 4, 7, 10, 14, 16, 19, 22,
1, 3, 7, 11, 14, 15, 19, 21,
2, 3, 7, 9, 13, 16, 20, 22,
2, 3, 6, 9, 12, 16, 20, 21,
1, 5, 6, 10, 13, 16, 20, 21,
2, 5, 8, 9, 13, 17, 19, 22,
2, 4, 6, 10, 14, 17, 19, 21,
2, 5, 7, 9, 13, 16, 19, 22,
0, 3, 8, 10, 12, 16, 19, 22,
1, 3, 7, 10, 13, 16, 19, 21,
1, 3, 8, 10, 13, 17, 20, 22,
2, 4, 6, 9, 14, 15, 19, 22,
1, 4, 6, 9, 13, 16, 19, 21,
2, 4, 8, 10, 14, 15, 19, 22,
1, 4, 7, 10, 14, 16, 19, 21,
};
for (size_t i = 0; i < kNRows * kNCols; ++i) {
ASSERT_EQ(solution[i], gidx[i]);
}
}
TEST(GpuHist, BuildGidxSparse) {
int constexpr kNRows = 16, kNCols = 8;
TrainParam param;
param.max_depth = 1;
param.n_gpus = 1;
param.max_leaves = 0;
DeviceShard<GradientPairPrecise> shard(0, 0, kNRows, param);
BuildGidx(&shard, kNRows, kNCols, 0.9f);
std::vector<common::CompressedByteT> h_gidx_buffer(shard.gidx_buffer.size());
dh::CopyDeviceSpanToVector(&h_gidx_buffer, shard.gidx_buffer);
common::CompressedIterator<uint32_t> gidx(h_gidx_buffer.data(), 25);
ASSERT_LE(shard.ellpack_matrix.row_stride, 3);
// row_stride = 3, 16 rows, 48 entries for ELLPack
std::vector<uint32_t> solution = {
15, 24, 24, 0, 24, 24, 24, 24, 24, 24, 24, 24, 20, 24, 24, 24,
24, 24, 24, 24, 24, 5, 24, 24, 0, 16, 24, 15, 24, 24, 24, 24,
24, 7, 14, 16, 4, 24, 24, 24, 24, 24, 9, 24, 24, 1, 24, 24
};
for (size_t i = 0; i < kNRows * shard.ellpack_matrix.row_stride; ++i) {
ASSERT_EQ(solution[i], gidx[i]);
}
}
std::vector<GradientPairPrecise> GetHostHistGpair() {
// 24 bins, 3 bins for each feature (column).
std::vector<GradientPairPrecise> hist_gpair = {
{0.8314f, 0.7147f}, {1.7989f, 3.7312f}, {3.3846f, 3.4598f},
{2.9277f, 3.5886f}, {1.8429f, 2.4152f}, {1.2443f, 1.9019f},
{1.6380f, 2.9174f}, {1.5657f, 2.5107f}, {2.8111f, 2.4776f},
{2.1322f, 3.0651f}, {3.2927f, 3.8540f}, {0.5899f, 0.9866f},
{1.5185f, 1.6263f}, {2.0686f, 3.1844f}, {2.4278f, 3.0950f},
{1.5105f, 2.1403f}, {2.6922f, 4.2217f}, {1.8122f, 1.5437f},
{0.0000f, 0.0000f}, {4.3245f, 5.7955f}, {1.6903f, 2.1103f},
{2.4012f, 4.4754f}, {3.6136f, 3.4303f}, {0.0000f, 0.0000f}
};
return hist_gpair;
}
template <typename GradientSumT>
void TestBuildHist(GPUHistBuilderBase<GradientSumT>& builder) {
int const kNRows = 16, kNCols = 8;
TrainParam param;
param.max_depth = 6;
param.n_gpus = 1;
param.max_leaves = 0;
DeviceShard<GradientSumT> shard(0, 0, kNRows, param);
BuildGidx(&shard, kNRows, kNCols);
xgboost::SimpleLCG gen;
xgboost::SimpleRealUniformDistribution<bst_float> dist(0.0f, 1.0f);
std::vector<GradientPair> h_gpair(kNRows);
for (auto &gpair : h_gpair) {
bst_float grad = dist(&gen);
bst_float hess = dist(&gen);
gpair = GradientPair(grad, hess);
}
int num_symbols = shard.n_bins + 1;
thrust::host_vector<common::CompressedByteT> h_gidx_buffer (
shard.gidx_buffer.size());
common::CompressedByteT* d_gidx_buffer_ptr = shard.gidx_buffer.data();
dh::safe_cuda(cudaMemcpy(h_gidx_buffer.data(), d_gidx_buffer_ptr,
sizeof(common::CompressedByteT) * shard.gidx_buffer.size(),
cudaMemcpyDeviceToHost));
auto gidx = common::CompressedIterator<uint32_t>(h_gidx_buffer.data(),
num_symbols);
shard.ridx_segments.resize(1);
shard.ridx_segments[0] = Segment(0, kNRows);
shard.hist.AllocateHistogram(0);
dh::CopyVectorToDeviceSpan(shard.gpair, h_gpair);
thrust::sequence(
thrust::device_pointer_cast(shard.ridx.Current()),
thrust::device_pointer_cast(shard.ridx.Current() + shard.ridx.Size()));
builder.Build(&shard, 0);
DeviceHistogram<GradientSumT> d_hist = shard.hist;
auto node_histogram = d_hist.GetNodeHistogram(0);
// d_hist.data stored in float, not gradient pair
thrust::host_vector<GradientSumT> h_result (d_hist.Data().size() / 2);
size_t data_size =
sizeof(GradientSumT) /
(sizeof(GradientSumT) / sizeof(typename GradientSumT::ValueT));
data_size *= d_hist.Data().size();
dh::safe_cuda(cudaMemcpy(h_result.data(), node_histogram.data(), data_size,
cudaMemcpyDeviceToHost));
std::vector<GradientPairPrecise> solution = GetHostHistGpair();
std::cout << std::fixed;
for (size_t i = 0; i < h_result.size(); ++i) {
EXPECT_NEAR(h_result[i].GetGrad(), solution[i].GetGrad(), 0.01f);
EXPECT_NEAR(h_result[i].GetHess(), solution[i].GetHess(), 0.01f);
}
}
TEST(GpuHist, BuildHistGlobalMem) {
GlobalMemHistBuilder<GradientPairPrecise> double_builder;
TestBuildHist(double_builder);
GlobalMemHistBuilder<GradientPair> float_builder;
TestBuildHist(float_builder);
}
TEST(GpuHist, BuildHistSharedMem) {
SharedMemHistBuilder<GradientPairPrecise> double_builder;
TestBuildHist(double_builder);
SharedMemHistBuilder<GradientPair> float_builder;
TestBuildHist(float_builder);
}
common::HistCutMatrix GetHostCutMatrix () {
common::HistCutMatrix cmat;
cmat.row_ptr = {0, 3, 6, 9, 12, 15, 18, 21, 24};
cmat.min_val = {0.1f, 0.2f, 0.3f, 0.1f, 0.2f, 0.3f, 0.2f, 0.2f};
// 24 cut fields, 3 cut fields for each feature (column).
// Each row of the cut represents the cuts for a data column.
cmat.cut = {0.30f, 0.67f, 1.64f,
0.32f, 0.77f, 1.95f,
0.29f, 0.70f, 1.80f,
0.32f, 0.75f, 1.85f,
0.18f, 0.59f, 1.69f,
0.25f, 0.74f, 2.00f,
0.26f, 0.74f, 1.98f,
0.26f, 0.71f, 1.83f};
return cmat;
}
// TODO(trivialfis): This test is over simplified.
TEST(GpuHist, EvaluateSplits) {
constexpr int kNRows = 16;
constexpr int kNCols = 8;
TrainParam param;
param.max_depth = 1;
param.n_gpus = 1;
param.colsample_bynode = 1;
param.colsample_bylevel = 1;
param.colsample_bytree = 1;
param.min_child_weight = 0.01;
// Disable all parameters.
param.reg_alpha = 0.0;
param.reg_lambda = 0;
param.max_delta_step = 0.0;
for (size_t i = 0; i < kNCols; ++i) {
param.monotone_constraints.emplace_back(0);
}
int max_bins = 4;
// Initialize DeviceShard
std::unique_ptr<DeviceShard<GradientPairPrecise>> shard {
new DeviceShard<GradientPairPrecise>(0, 0, kNRows, param)};
// Initialize DeviceShard::node_sum_gradients
shard->node_sum_gradients = {{6.4f, 12.8f}};
// Initialize DeviceShard::cut
common::HistCutMatrix cmat = GetHostCutMatrix();
// Copy cut matrix to device.
shard->ba.Allocate(0,
&(shard->feature_segments), cmat.row_ptr.size(),
&(shard->min_fvalue), cmat.min_val.size(),
&(shard->gidx_fvalue_map), 24,
&(shard->monotone_constraints), kNCols);
dh::CopyVectorToDeviceSpan(shard->feature_segments, cmat.row_ptr);
dh::CopyVectorToDeviceSpan(shard->gidx_fvalue_map, cmat.cut);
dh::CopyVectorToDeviceSpan(shard->monotone_constraints,
param.monotone_constraints);
shard->ellpack_matrix.feature_segments = shard->feature_segments;
shard->ellpack_matrix.gidx_fvalue_map = shard->gidx_fvalue_map;
dh::CopyVectorToDeviceSpan(shard->min_fvalue, cmat.min_val);
shard->ellpack_matrix.min_fvalue = shard->min_fvalue;
// Initialize DeviceShard::hist
shard->hist.Init(0, (max_bins - 1) * kNCols);
shard->hist.AllocateHistogram(0);
// Each row of hist_gpair represents gpairs for one feature.
// Each entry represents a bin.
std::vector<GradientPairPrecise> hist_gpair = GetHostHistGpair();
std::vector<bst_float> hist;
for (auto pair : hist_gpair) {
hist.push_back(pair.GetGrad());
hist.push_back(pair.GetHess());
}
ASSERT_EQ(shard->hist.Data().size(), hist.size());
thrust::copy(hist.begin(), hist.end(),
shard->hist.Data().begin());
// Initialize GPUHistMaker
GPUHistMakerSpecialised<GradientPairPrecise> hist_maker =
GPUHistMakerSpecialised<GradientPairPrecise>();
hist_maker.param_ = param;
hist_maker.shards_.push_back(std::move(shard));
hist_maker.column_sampler_.Init(kNCols,
param.colsample_bynode,
param.colsample_bylevel,
param.colsample_bytree,
false);
RegTree tree;
MetaInfo info;
info.num_row_ = kNRows;
info.num_col_ = kNCols;
hist_maker.info_ = &info;
hist_maker.node_value_constraints_.resize(1);
hist_maker.node_value_constraints_[0].lower_bound = -1.0;
hist_maker.node_value_constraints_[0].upper_bound = 1.0;
std::vector<DeviceSplitCandidate> res =
hist_maker.EvaluateSplits({ 0,0 }, &tree);
ASSERT_EQ(res[0].findex, 7);
ASSERT_EQ(res[1].findex, 7);
ASSERT_NEAR(res[0].fvalue, 0.26, xgboost::kRtEps);
ASSERT_NEAR(res[1].fvalue, 0.26, xgboost::kRtEps);
}
TEST(GpuHist, ApplySplit) {
GPUHistMakerSpecialised<GradientPairPrecise> hist_maker =
GPUHistMakerSpecialised<GradientPairPrecise>();
int constexpr kNId = 0;
int constexpr kNRows = 16;
int constexpr kNCols = 8;
TrainParam param;
std::vector<std::pair<std::string, std::string>> args = {};
param.InitAllowUnknown(args);
// Initialize shard
for (size_t i = 0; i < kNCols; ++i) {
param.monotone_constraints.emplace_back(0);
}
hist_maker.shards_.resize(1);
hist_maker.shards_[0].reset(new DeviceShard<GradientPairPrecise>(0, 0, kNRows, param));
auto& shard = hist_maker.shards_.at(0);
shard->ridx_segments.resize(3); // 3 nodes.
shard->node_sum_gradients.resize(3);
shard->ridx_segments[0] = Segment(0, kNRows);
shard->ba.Allocate(0, &(shard->ridx), kNRows,
&(shard->position), kNRows);
shard->ellpack_matrix.row_stride = kNCols;
thrust::sequence(
thrust::device_pointer_cast(shard->ridx.Current()),
thrust::device_pointer_cast(shard->ridx.Current() + shard->ridx.Size()));
// Initialize GPUHistMaker
hist_maker.param_ = param;
RegTree tree;
DeviceSplitCandidate candidate;
candidate.Update(2, kLeftDir,
0.59, 4, // fvalue has to be equal to one of the cut field
GradientPair(8.2, 2.8), GradientPair(6.3, 3.6),
GPUTrainingParam(param));
ExpandEntry candidate_entry {0, 0, candidate, 0};
candidate_entry.nid = kNId;
// Used to get bin_id in update position.
common::HistCutMatrix cmat = GetHostCutMatrix();
hist_maker.hmat_ = cmat;
MetaInfo info;
info.num_row_ = kNRows;
info.num_col_ = kNCols;
info.num_nonzero_ = kNRows * kNCols; // Dense
// Initialize gidx
int n_bins = 24;
int row_stride = kNCols;
int num_symbols = n_bins + 1;
size_t compressed_size_bytes =
common::CompressedBufferWriter::CalculateBufferSize(row_stride * kNRows,
num_symbols);
shard->ba.Allocate(0, &(shard->gidx_buffer), compressed_size_bytes,
&(shard->feature_segments), cmat.row_ptr.size(),
&(shard->min_fvalue), cmat.min_val.size(),
&(shard->gidx_fvalue_map), 24);
dh::CopyVectorToDeviceSpan(shard->feature_segments, cmat.row_ptr);
dh::CopyVectorToDeviceSpan(shard->gidx_fvalue_map, cmat.cut);
shard->ellpack_matrix.feature_segments = shard->feature_segments;
shard->ellpack_matrix.gidx_fvalue_map = shard->gidx_fvalue_map;
dh::CopyVectorToDeviceSpan(shard->min_fvalue, cmat.min_val);
shard->ellpack_matrix.min_fvalue = shard->min_fvalue;
shard->ellpack_matrix.is_dense = true;
common::CompressedBufferWriter wr(num_symbols);
// gidx 14 should go right, 12 goes left
std::vector<int> h_gidx (kNRows * row_stride, 14);
h_gidx[4] = 12;
h_gidx[12] = 12;
std::vector<common::CompressedByteT> h_gidx_compressed (compressed_size_bytes);
wr.Write(h_gidx_compressed.data(), h_gidx.begin(), h_gidx.end());
dh::CopyVectorToDeviceSpan(shard->gidx_buffer, h_gidx_compressed);
shard->ellpack_matrix.gidx_iter = common::CompressedIterator<uint32_t>(
shard->gidx_buffer.data(), num_symbols);
hist_maker.info_ = &info;
hist_maker.ApplySplit(candidate_entry, &tree);
hist_maker.UpdatePosition(candidate_entry, &tree);
ASSERT_FALSE(tree[kNId].IsLeaf());
int left_nidx = tree[kNId].LeftChild();
int right_nidx = tree[kNId].RightChild();
ASSERT_EQ(shard->ridx_segments[left_nidx].begin, 0);
ASSERT_EQ(shard->ridx_segments[left_nidx].end, 2);
ASSERT_EQ(shard->ridx_segments[right_nidx].begin, 2);
ASSERT_EQ(shard->ridx_segments[right_nidx].end, 16);
}
void TestSortPosition(const std::vector<int>& position_in, int left_idx,
int right_idx) {
std::vector<int64_t> left_count = {
std::count(position_in.begin(), position_in.end(), left_idx)};
thrust::device_vector<int64_t> d_left_count = left_count;
thrust::device_vector<int> position = position_in;
thrust::device_vector<int> position_out(position.size());
thrust::device_vector<bst_uint> ridx(position.size());
thrust::sequence(ridx.begin(), ridx.end());
thrust::device_vector<bst_uint> ridx_out(ridx.size());
dh::CubMemory tmp;
SortPosition(
&tmp, common::Span<int>(position.data().get(), position.size()),
common::Span<int>(position_out.data().get(), position_out.size()),
common::Span<bst_uint>(ridx.data().get(), ridx.size()),
common::Span<bst_uint>(ridx_out.data().get(), ridx_out.size()), left_idx,
right_idx, d_left_count.data().get(), nullptr);
thrust::host_vector<int> position_result = position_out;
thrust::host_vector<int> ridx_result = ridx_out;
// Check position is sorted
EXPECT_TRUE(std::is_sorted(position_result.begin(), position_result.end()));
// Check row indices are sorted inside left and right segment
EXPECT_TRUE(
std::is_sorted(ridx_result.begin(), ridx_result.begin() + left_count[0]));
EXPECT_TRUE(
std::is_sorted(ridx_result.begin() + left_count[0], ridx_result.end()));
// Check key value pairs are the same
for (auto i = 0ull; i < ridx_result.size(); i++) {
EXPECT_EQ(position_result[i], position_in[ridx_result[i]]);
}
}
TEST(GpuHist, SortPosition) {
TestSortPosition({1, 2, 1, 2, 1}, 1, 2);
TestSortPosition({1, 1, 1, 1}, 1, 2);
TestSortPosition({2, 2, 2, 2}, 1, 2);
TestSortPosition({1, 2, 1, 2, 3}, 1, 2);
}
} // namespace tree
} // namespace xgboost