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no exception throwing within omp parallel; set nthread in Learner (#1421)

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This commit is contained in:
Vadim Khotilovich
2016-07-29 12:08:03 -05:00
committed by Tianqi Chen
parent 89c4f67f59
commit 75f401481f
4 changed files with 35 additions and 19 deletions
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27
src/gbm/gbtree.cc
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@@ -26,8 +26,6 @@ DMLC_REGISTRY_FILE_TAG(gbtree);
/*! \brief training parameters */
struct GBTreeTrainParam : public dmlc::Parameter<GBTreeTrainParam> {
/*! \brief number of threads */
int nthread;
/*!
* \brief number of parallel trees constructed each iteration
* use this option to support boosted random forest
@@ -37,8 +35,6 @@ struct GBTreeTrainParam : public dmlc::Parameter<GBTreeTrainParam> {
std::string updater_seq;
// declare parameters
DMLC_DECLARE_PARAMETER(GBTreeTrainParam) {
DMLC_DECLARE_FIELD(nthread).set_lower_bound(0).set_default(0)
.describe("Number of threads used for training.");
DMLC_DECLARE_FIELD(num_parallel_tree).set_lower_bound(1).set_default(1)
.describe("Number of parallel trees constructed during each iteration."\
" This option is used to support boosted random forest");
@@ -145,9 +141,6 @@ class GBTree : public GradientBooster {
for (const auto& up : updaters) {
up->Init(cfg);
}
if (tparam.nthread != 0) {
omp_set_num_threads(tparam.nthread);
}
}
void Load(dmlc::Stream* fi) override {
@@ -247,12 +240,16 @@ class GBTree : public GradientBooster {
const RowBatch &batch = iter->Value();
// parallel over local batch
const bst_omp_uint nsize = static_cast<bst_omp_uint>(batch.size);
int ridx_error = 0;
#pragma omp parallel for schedule(static)
for (bst_omp_uint i = 0; i < nsize; ++i) {
const int tid = omp_get_thread_num();
RegTree::FVec &feats = thread_temp[tid];
int64_t ridx = static_cast<int64_t>(batch.base_rowid + i);
CHECK_LT(static_cast<size_t>(ridx), info.num_row);
if (static_cast<size_t>(ridx) >= info.num_row) {
ridx_error = 1;
continue;
}
// loop over output groups
for (int gid = 0; gid < mparam.num_output_group; ++gid) {
this->Pred(batch[i],
@@ -262,6 +259,7 @@ class GBTree : public GradientBooster {
ntree_limit);
}
}
CHECK(!ridx_error) << "ridx out of bounds";
}
}
@@ -368,19 +366,28 @@ class GBTree : public GradientBooster {
const int* leaf_position) {
const RowSet& rowset = p_fmat->buffered_rowset();
const bst_omp_uint ndata = static_cast<bst_omp_uint>(rowset.size());
int pred_counter_error = 0, tid_error = 0;
#pragma omp parallel for schedule(static)
for (bst_omp_uint i = 0; i < ndata; ++i) {
const bst_uint ridx = rowset[i];
const int64_t bid = this->BufferOffset(buffer_offset + ridx, bst_group);
const int tid = leaf_position[ridx];
CHECK_EQ(pred_counter[bid], trees.size());
CHECK_GE(tid, 0);
if (pred_counter[bid] != trees.size()) {
pred_counter_error = 1;
continue;
}
if (tid < 0) {
tid_error = 1;
continue;
}
pred_buffer[bid] += new_tree[tid].leaf_value();
for (int i = 0; i < mparam.size_leaf_vector; ++i) {
pred_buffer[bid + i + 1] += new_tree.leafvec(tid)[i];
}
pred_counter[bid] += tparam.num_parallel_tree;
}
CHECK(!pred_counter_error) << "incorrect pred_counter[bid]";
CHECK(!tid_error) << "tid cannot be negative";
}
// make a prediction for a single instance
inline void Pred(const RowBatch::Inst &inst,