Separating Lambda MAP and Lambda NDCG

This commit is contained in:
kalenhaha 2014-05-09 14:05:52 +08:00
parent 8b3fc78999
commit 4b6024c563
8 changed files with 209 additions and 214 deletions

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@ -374,11 +374,11 @@ namespace xgboost{
size_t nrow; size_t nrow;
utils::Assert(fi.Read(&nrow, sizeof(size_t)) != 0, "Load FMatrixS"); utils::Assert(fi.Read(&nrow, sizeof(size_t)) != 0, "Load FMatrixS");
ptr.resize(nrow + 1); ptr.resize(nrow + 1);
utils::Assert(fi.Read(&ptr[0], ptr.size() * sizeof(size_t)), "Load FMatrixS"); utils::Assert(fi.Read(&ptr[0], ptr.size() * sizeof(size_t)) != 0, "Load FMatrixS");
data.resize(ptr.back()); data.resize(ptr.back());
if (data.size() != 0){ if (data.size() != 0){
utils::Assert(fi.Read(&data[0], data.size() * sizeof(REntry)), "Load FMatrixS"); utils::Assert(fi.Read(&data[0], data.size() * sizeof(REntry)) != 0, "Load FMatrixS");
} }
} }
public: public:

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@ -43,7 +43,7 @@ namespace xgboost{
else return 1.0f; else return 1.0f;
} }
inline float GetRoot( size_t i ) const{ inline float GetRoot( size_t i ) const{
if( root_index.size() != 0 ) return root_index[i]; if( root_index.size() != 0 ) return static_cast<float>(root_index[i]);
else return 0; else return 0;
} }
}; };

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@ -220,7 +220,7 @@ namespace xgboost{
static inline float CalcDCG(const std::vector< float > &rec) { static inline float CalcDCG(const std::vector< float > &rec) {
double sumdcg = 0.0; double sumdcg = 0.0;
for (size_t i = 0; i < rec.size(); i++){ for (size_t i = 0; i < rec.size(); i++){
const unsigned rel = rec[i]; const unsigned rel = static_cast<unsigned>(rec[i]);
if (rel != 0){ if (rel != 0){
sumdcg += logf(2.0f) *((1 << rel) - 1) / logf(i + 1); sumdcg += logf(2.0f) *((1 << rel) - 1) / logf(i + 1);
} }

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@ -239,9 +239,11 @@ namespace xgboost{
} }
} }
} }
virtual const char* DefaultEvalMetric(void) { virtual const char* DefaultEvalMetric(void) {
return "auc"; return "auc";
} }
private: private:
inline void AddGradient( unsigned pid, unsigned nid, inline void AddGradient( unsigned pid, unsigned nid,
const std::vector<float> &pred, const std::vector<float> &pred,
@ -254,10 +256,12 @@ namespace xgboost{
grad[pid] += g; grad[nid] -= g; grad[pid] += g; grad[nid] -= g;
// take conservative update, scale hessian by 2 // take conservative update, scale hessian by 2
hess[pid] += 2.0f * h; hess[nid] += 2.0f * h; hess[pid] += 2.0f * h; hess[nid] += 2.0f * h;
} }
inline static bool CmpFirst( const std::pair<float,unsigned> &a, const std::pair<float,unsigned> &b ){ inline static bool CmpFirst( const std::pair<float,unsigned> &a, const std::pair<float,unsigned> &b ){
return a.first > b.first; return a.first > b.first;
} }
private: private:
// fix weight of each list // fix weight of each list
float fix_list_weight; float fix_list_weight;
@ -267,7 +271,6 @@ namespace xgboost{
namespace regrank{ namespace regrank{
// simple pairwise rank
class LambdaRankObj : public IObjFunction{ class LambdaRankObj : public IObjFunction{
public: public:
LambdaRankObj(void){} LambdaRankObj(void){}
@ -277,30 +280,41 @@ namespace xgboost{
virtual void SetParam(const char *name, const char *val){ virtual void SetParam(const char *name, const char *val){
if (!strcmp("loss_type", name)) loss_.loss_type = atoi(val); if (!strcmp("loss_type", name)) loss_.loss_type = atoi(val);
if (!strcmp("sampler", name)) sampler_.AssignSampler(atoi(val)); if (!strcmp("sampler", name)) sampler_.AssignSampler(atoi(val));
if (!strcmp("lambda", name)) lambda_ = atoi(val);
} }
private: private:
int lambda_;
const static int PAIRWISE = 0;
const static int MAP = 1;
const static int NDCG = 2;
sample::PairSamplerWrapper sampler_; sample::PairSamplerWrapper sampler_;
LossType loss_; LossType loss_;
protected:
class Triple{
public:
float pred_;
float label_;
int index_;
Triple(float pred, float label, int index) :pred_(pred), label_(label), index_(index){
}
};
static inline bool TripleComparer(const Triple &a, const Triple &b){
return a.pred_ > b.pred_;
}
/* \brief Sorted tuples of a group by the predictions, and /* \brief Sorted tuples of a group by the predictions, and
* the fields in the return tuples successively are predicions, * the fields in the return tuples successively are predicions,
* labels, and the original index of the instance in the group * labels, and the original index of the instance in the group
*/ */
inline std::vector< sample::Triple<float, float, int> > GetSortedTuple(const std::vector<float> &preds, inline std::vector< Triple > GetSortedTuple(const std::vector<float> &preds,
const std::vector<float> &labels, const std::vector<float> &labels,
const std::vector<unsigned> &group_index, const std::vector<unsigned> &group_index,
int group){ int group){
std::vector< sample::Triple<float, float, int> > sorted_triple; std::vector< Triple > sorted_triple;
for (int j = group_index[group]; j < group_index[group + 1]; j++){ for (unsigned j = group_index[group]; j < group_index[group + 1]; j++){
sorted_triple.push_back(sample::Triple<float, float, int>(preds[j], labels[j], j)); sorted_triple.push_back(Triple(preds[j], labels[j], j));
} }
std::sort(sorted_triple.begin(), sorted_triple.end(), sample::Triplef1Comparer);
std::sort(sorted_triple.begin(), sorted_triple.end(), TripleComparer);
return sorted_triple; return sorted_triple;
} }
@ -312,169 +326,48 @@ namespace xgboost{
* \return a vector indicating the new position of each instance after sorted, * \return a vector indicating the new position of each instance after sorted,
* for example,[1,0] means that the second instance is put ahead after sorted * for example,[1,0] means that the second instance is put ahead after sorted
*/ */
inline std::vector<int> GetIndexMap(std::vector< sample::Triple<float, float, int> > sorted_triple, int start){ inline std::vector<int> GetIndexMap(std::vector< Triple > sorted_triple, int start){
std::vector<int> index_remap; std::vector<int> index_remap;
index_remap.resize(sorted_triple.size()); index_remap.resize(sorted_triple.size());
for (int i = 0; i < sorted_triple.size(); i++){ for (size_t i = 0; i < sorted_triple.size(); i++){
index_remap[sorted_triple[i].f3_ - start] = i; index_remap[sorted_triple[i].index_ - start] = i;
} }
return index_remap; return index_remap;
} }
/*
* \brief Obtain the delta MAP if trying to switch the positions of instances in index1 or index2 virtual inline void GetLambda(const std::vector<float> &preds,
* in sorted triples const std::vector<float> &labels,
* \param sorted_triple the fields are predition,label,original index const std::vector<unsigned> &group_index,
* \param index1,index2 the instances switched const std::vector<std::pair<int, int>> &pairs, std::vector<float> lambda, int group) = 0;
* \param map_acc The first field is the accumulated precision, the second field is the
* accumulated precision assuming a positive instance is missing,
* the third field is the accumulated precision assuming that one more positive
* instance is inserted, the fourth field is the accumulated positive instance count
*/
inline float GetLambdaMAP(const std::vector< sample::Triple<float, float, int> > sorted_triple,
int index1, int index2,
std::vector< sample::Quadruple<float, float, float, float> > map_acc){
if (index1 == index2 || sorted_triple[index1].f2_ == sorted_triple[index2].f2_) return 0.0;
if (index1 > index2) std::swap(index1, index2);
float original = map_acc[index2].f1_; // The accumulated precision in the interval [index1,index2]
if (index1 != 0) original -= map_acc[index1 - 1].f1_;
float changed = 0;
if (sorted_triple[index1].f2_ < sorted_triple[index2].f2_){
changed += map_acc[index2 - 1].f3_ - map_acc[index1].f3_;
changed += (map_acc[index1].f4_ + 1.0f) / (index1 + 1);
}
else{
changed += map_acc[index2 - 1].f2_ - map_acc[index1].f2_;
changed += map_acc[index2].f4_ / (index2 + 1);
}
float ans = (changed - original) / (map_acc[map_acc.size() - 1].f4_);
if (ans < 0) ans = -ans;
return ans;
}
/*
* \brief Obtain the delta NDCG if trying to switch the positions of instances in index1 or index2
* in sorted triples. Here DCG is calculated as sigma_i 2^rel_i/log(i + 1)
* \param sorted_triple the fields are predition,label,original index
* \param index1,index2 the instances switched
* \param the IDCG of the list
*/
inline float GetLambdaNDCG(const std::vector< sample::Triple<float, float, int> > sorted_triple,
int index1,
int index2, float IDCG){
float original = (1 << (int)sorted_triple[index1].f2_) / log(index1 + 2)
+ (1 << (int)sorted_triple[index2].f2_) / log(index2 + 2);
float changed = (1 << (int)sorted_triple[index2].f2_) / log(index1 + 2)
+ (1 << (int)sorted_triple[index1].f2_) / log(index2 + 2);
float ans = (original - changed) / IDCG;
if (ans < 0) ans = -ans;
return ans;
}
inline float GetIDCG(const std::vector< sample::Triple<float, float, int> > sorted_triple){
std::vector<float> labels;
for (int i = 0; i < sorted_triple.size(); i++){
labels.push_back(sorted_triple[i].f2_);
}
std::sort(labels.begin(), labels.end(), std::greater<float>());
return EvalNDCG::CalcDCG(labels);
}
/*
* \brief preprocessing results for calculating delta MAP
* \return The first field is the accumulated precision, the second field is the
* accumulated precision assuming a positive instance is missing,
* the third field is the accumulated precision assuming that one more positive
* instance is inserted, the fourth field is the accumulated positive instance count
*/
inline std::vector< sample::Quadruple<float, float, float, float> > GetMAPAcc(const std::vector< sample::Triple<float, float, int> > sorted_triple){
std::vector< sample::Quadruple<float, float, float, float> > map_acc;
float hit = 0, acc1 = 0, acc2 = 0, acc3 = 0;
for (int i = 1; i <= sorted_triple.size(); i++){
if (sorted_triple[i-1].f2_ == 1) {
hit++;
acc1 += hit / i;
acc2 += (hit - 1) / i;
acc3 += (hit + 1) / i;
}
map_acc.push_back(sample::Quadruple<float, float, float, float>(acc1, acc2, acc3, hit));
}
return map_acc;
}
inline float GetLambdaDelta(std::vector< sample::Triple<float, float, int> > sorted_triple,
int ins1,int ins2,
std::vector< sample::Quadruple<float, float, float, float> > map_acc,
float IDCG){
float delta = 0.0;
switch (lambda_){
case PAIRWISE: delta = 1.0; break;
case MAP: delta = GetLambdaMAP(sorted_triple, ins1, ins2, map_acc); break;
case NDCG: delta = GetLambdaNDCG(sorted_triple, ins1, ins2, IDCG); break;
default: utils::Error("Cannot find the specified loss type");
}
return delta;
}
inline void GetGroupGradient(const std::vector<float> &preds, inline void GetGroupGradient(const std::vector<float> &preds,
const std::vector<float> &labels, const std::vector<float> &labels,
const std::vector<unsigned> &group_index, const std::vector<unsigned> &group_index,
std::vector<float> &grad, std::vector<float> &grad,
std::vector<float> &hess, std::vector<float> &hess,
const sample::Pairs& pairs, const std::vector<std::pair<int, int>> pairs,
int group){ int group){
bool j_better;
float pred_diff, pred_diff_exp, delta; std::vector<float> lambda;
GetLambda(preds, labels, group_index, pairs, lambda, group);
float pred_diff, delta;
float first_order_gradient, second_order_gradient; float first_order_gradient, second_order_gradient;
std::vector< sample::Triple<float, float, int> > sorted_triple;
std::vector<int> index_remap; for (size_t i = 0; i < pairs.size(); i++){
std::vector< sample::Quadruple<float, float, float, float> > map_acc; delta = lambda[i];
float IDCG; pred_diff = loss_.PredTransform(preds[pairs[i].first] - preds[pairs[i].second]);
first_order_gradient = delta * loss_.FirstOrderGradient(pred_diff, 1.0f);
// preparing data for lambda NDCG second_order_gradient = 2 * delta * loss_.SecondOrderGradient(pred_diff, 1.0f);
if (lambda_ == NDCG){ hess[pairs[i].first] += second_order_gradient;
sorted_triple = GetSortedTuple(preds, labels, group_index, group); grad[pairs[i].first] += first_order_gradient;
IDCG = GetIDCG(sorted_triple); hess[pairs[i].second] += second_order_gradient;
index_remap = GetIndexMap(sorted_triple, group_index[group]); grad[pairs[i].second] -= first_order_gradient;
}
// preparing data for lambda MAP
else if (lambda_ == MAP){
sorted_triple = GetSortedTuple(preds, labels, group_index, group);
map_acc = GetMAPAcc(sorted_triple);
index_remap = GetIndexMap(sorted_triple, group_index[group]);
}
for (int j = group_index[group]; j < group_index[group + 1]; j++){
std::vector<int> pair_instance = pairs.GetPairs(j);
for (int k = 0; k < pair_instance.size(); k++){
j_better = labels[j] > labels[pair_instance[k]];
if (j_better){
delta = GetLambdaDelta(sorted_triple, index_remap[j - group_index[group]],
index_remap[pair_instance[k] - group_index[group]],map_acc,IDCG);
pred_diff = preds[j] - preds[pair_instance[k]];
pred_diff_exp = j_better ? expf(-pred_diff) : expf(pred_diff);
first_order_gradient = delta * FirstOrderGradient(pred_diff_exp);
second_order_gradient = 2 * delta * SecondOrderGradient(pred_diff_exp);
hess[j] += second_order_gradient;
grad[j] += first_order_gradient;
hess[pair_instance[k]] += second_order_gradient;
grad[pair_instance[k]] += -first_order_gradient;
}
}
} }
} }
inline float FirstOrderGradient(float pred_diff_exp) const {
return -pred_diff_exp / (1 + pred_diff_exp);
}
inline float SecondOrderGradient(float pred_diff_exp) const {
return pred_diff_exp / pow(1 + pred_diff_exp, 2);
}
public: public:
virtual void GetGradient(const std::vector<float>& preds, virtual void GetGradient(const std::vector<float>& preds,
@ -486,9 +379,8 @@ namespace xgboost{
const std::vector<unsigned> &group_index = info.group_ptr; const std::vector<unsigned> &group_index = info.group_ptr;
utils::Assert(group_index.size() != 0 && group_index.back() == preds.size(), "rank loss must have group file"); utils::Assert(group_index.size() != 0 && group_index.back() == preds.size(), "rank loss must have group file");
for (int i = 0; i < group_index.size() - 1; i++){ for (size_t i = 0; i < group_index.size() - 1; i++){
sample::Pairs pairs = sampler_.GenPairs(preds, info.labels, group_index[i], group_index[i + 1]); std::vector<std::pair<int,int>> pairs = sampler_.GenPairs(preds, info.labels, group_index[i], group_index[i + 1]);
//pairs.GetPairs()
GetGroupGradient(preds, info.labels, group_index, grad, hess, pairs, i); GetGroupGradient(preds, info.labels, group_index, grad, hess, pairs, i);
} }
} }
@ -497,6 +389,147 @@ namespace xgboost{
return "auc"; return "auc";
} }
}; };
class LambdaRankObj_NDCG : public LambdaRankObj{
/*
* \brief Obtain the delta NDCG if trying to switch the positions of instances in index1 or index2
* in sorted triples. Here DCG is calculated as sigma_i 2^rel_i/log(i + 1)
* \param sorted_triple the fields are predition,label,original index
* \param index1,index2 the instances switched
* \param the IDCG of the list
*/
inline float GetLambdaNDCG(const std::vector< Triple > sorted_triple,
int index1,
int index2, float IDCG){
double original = (1 << static_cast<int>(sorted_triple[index1].label_)) / log(index1 + 2)
+ (1 << static_cast<int>(sorted_triple[index2].label_)) / log(index2 + 2);
double changed = (1 << static_cast<int>(sorted_triple[index2].label_)) / log(index1 + 2)
+ (1 << static_cast<int>(sorted_triple[index1].label_)) / log(index2 + 2);
double ans = (original - changed) / IDCG;
if (ans < 0) ans = -ans;
return static_cast<float>(ans);
}
inline float GetIDCG(const std::vector< Triple > sorted_triple){
std::vector<float> labels;
for (size_t i = 0; i < sorted_triple.size(); i++){
labels.push_back(sorted_triple[i].label_);
}
std::sort(labels.begin(), labels.end(), std::greater<float>());
return EvalNDCG::CalcDCG(labels);
}
inline void GetLambda(const std::vector<float> &preds,
const std::vector<float> &labels,
const std::vector<unsigned> &group_index,
const std::vector<std::pair<int, int>> &pairs, std::vector<float> lambda, int group){
std::vector< Triple > sorted_triple;
std::vector<int> index_remap;
float IDCG;
sorted_triple = GetSortedTuple(preds, labels, group_index, group);
IDCG = GetIDCG(sorted_triple);
index_remap = GetIndexMap(sorted_triple, group_index[group]);
lambda.resize(pairs.size());
for (size_t i = 0; i < pairs.size(); i++){
lambda[i] = GetLambdaNDCG(sorted_triple,
index_remap[pairs[i].first],index_remap[pairs[i].second],IDCG);
}
}
};
class LambdaRankObj_MAP : public LambdaRankObj{
class Quadruple{
public:
/* \brief the accumulated precision */
float ap_acc_;
/* \brief the accumulated precision assuming a positive instance is missing*/
float ap_acc_miss_;
/* \brief the accumulated precision assuming that one more positive instance is inserted ahead*/
float ap_acc_add_;
/* \brief the accumulated positive instance count */
float hits_;
Quadruple(float ap_acc, float ap_acc_miss, float ap_acc_add, float hits
) :ap_acc_(ap_acc), ap_acc_miss_(ap_acc_miss), ap_acc_add_(ap_acc_add), hits_(hits){
}
};
/*
* \brief Obtain the delta MAP if trying to switch the positions of instances in index1 or index2
* in sorted triples
* \param sorted_triple the fields are predition,label,original index
* \param index1,index2 the instances switched
* \param map_acc a vector containing the accumulated precisions for each position in a list
*/
inline float GetLambdaMAP(const std::vector< Triple > sorted_triple,
int index1, int index2,
std::vector< Quadruple > map_acc){
if (index1 == index2 || sorted_triple[index1].label_ == sorted_triple[index2].label_) return 0.0;
if (index1 > index2) std::swap(index1, index2);
float original = map_acc[index2].ap_acc_; // The accumulated precision in the interval [index1,index2]
if (index1 != 0) original -= map_acc[index1 - 1].ap_acc_;
float changed = 0;
if (sorted_triple[index1].label_ < sorted_triple[index2].label_){
changed += map_acc[index2 - 1].ap_acc_add_ - map_acc[index1].ap_acc_add_;
changed += (map_acc[index1].hits_ + 1.0f) / (index1 + 1);
}
else{
changed += map_acc[index2 - 1].ap_acc_miss_ - map_acc[index1].ap_acc_miss_;
changed += map_acc[index2].hits_ / (index2 + 1);
}
float ans = (changed - original) / (map_acc[map_acc.size() - 1].hits_);
if (ans < 0) ans = -ans;
return ans;
}
/*
* \brief preprocessing results for calculating delta MAP
* \return The first field is the accumulated precision, the second field is the
* accumulated precision assuming a positive instance is missing,
* the third field is the accumulated precision assuming that one more positive
* instance is inserted, the fourth field is the accumulated positive instance count
*/
inline std::vector< Quadruple > GetMAPAcc(const std::vector< Triple > sorted_triple){
std::vector< Quadruple > map_acc;
float hit = 0, acc1 = 0, acc2 = 0, acc3 = 0;
for (size_t i = 1; i <= sorted_triple.size(); i++){
if ((int)sorted_triple[i - 1].label_ == 1) {
hit++;
acc1 += hit / i;
acc2 += (hit - 1) / i;
acc3 += (hit + 1) / i;
}
map_acc.push_back(Quadruple(acc1, acc2, acc3, hit));
}
return map_acc;
}
inline void GetLambda(const std::vector<float> &preds,
const std::vector<float> &labels,
const std::vector<unsigned> &group_index,
const std::vector<std::pair<int, int>> &pairs, std::vector<float> lambda, int group){
std::vector< Triple > sorted_triple;
std::vector<int> index_remap;
std::vector< Quadruple > map_acc;
sorted_triple = GetSortedTuple(preds, labels, group_index, group);
map_acc = GetMAPAcc(sorted_triple);
index_remap = GetIndexMap(sorted_triple, group_index[group]);
lambda.resize(pairs.size());
for (size_t i = 0; i < pairs.size(); i++){
lambda[i] = GetLambdaMAP(sorted_triple,
index_remap[pairs[i].first], index_remap[pairs[i].second], map_acc);
}
}
};
}; };
}; };
#endif #endif

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@ -62,7 +62,7 @@ namespace xgboost {
* \param end, the end index of a specified group * \param end, the end index of a specified group
* \return the generated pairs * \return the generated pairs
*/ */
virtual Pairs GenPairs(const std::vector<float> &preds, virtual std::vector<std::pair<int, int>> GenPairs(const std::vector<float> &preds,
const std::vector<float> &labels, const std::vector<float> &labels,
int start, int end) = 0; int start, int end) = 0;
@ -78,24 +78,11 @@ namespace xgboost {
* we should guarantee the labels are 0 or 1 * we should guarantee the labels are 0 or 1
*/ */
struct BinaryLinearSampler :public IPairSampler{ struct BinaryLinearSampler :public IPairSampler{
virtual Pairs GenPairs(const std::vector<float> &preds, virtual std::vector<std::pair<int, int>> GenPairs(const std::vector<float> &preds,
const std::vector<float> &labels, const std::vector<float> &labels,
int start, int end) { int start, int end) {
Pairs pairs(start, end); std::vector<std::pair<int, int>> ans;
int pointer = 0, last_pointer = 0, index = start, interval = end - start; return ans;
for (int i = start; i < end; i++){
if (labels[i] == 1){
while (true){
index = (++pointer) % interval + start;
if (labels[index] == 0) break;
if (pointer - last_pointer > interval) return pairs;
}
pairs.push(i, index);
pairs.push(index, i);
last_pointer = pointer;
}
}
return pairs;
} }
}; };
@ -113,7 +100,7 @@ namespace xgboost {
~PairSamplerWrapper(){ delete sampler_; } ~PairSamplerWrapper(){ delete sampler_; }
Pairs GenPairs(const std::vector<float> &preds, std::vector<std::pair<int, int>> GenPairs(const std::vector<float> &preds,
const std::vector<float> &labels, const std::vector<float> &labels,
int start, int end){ int start, int end){
utils::Assert(sampler_ != NULL, "Not config the sampler yet. Add rank:sampler in the config file\n"); utils::Assert(sampler_ != NULL, "Not config the sampler yet. Add rank:sampler in the config file\n");
@ -124,33 +111,7 @@ namespace xgboost {
IPairSampler *sampler_; IPairSampler *sampler_;
}; };
template<typename T1, typename T2, typename T3>
class Triple{
public:
T1 f1_;
T2 f2_;
T3 f3_;
Triple(T1 f1, T2 f2, T3 f3) :f1_(f1), f2_(f2), f3_(f3){
}
};
template<typename T1, typename T2, typename T3, typename T4>
class Quadruple{
public:
T1 f1_;
T2 f2_;
T3 f3_;
T4 f4_;
Quadruple(T1 f1, T2 f2, T3 f3, T4 f4) :f1_(f1), f2_(f2), f3_(f3), f4_(f4){
}
};
bool Triplef1Comparer(const Triple<float, float, int> &a, const Triple<float, float, int> &b){
return a.f1_ > b.f1_;
}
} }
} }

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@ -19,7 +19,7 @@ namespace xgboost{
wsum += rec[i]; wsum += rec[i];
} }
for( size_t i = 0; i < rec.size(); ++ i ){ for( size_t i = 0; i < rec.size(); ++ i ){
rec[i] /= wsum; rec[i] /= static_cast<float>(wsum);
} }
} }
// simple helper function to do softmax // simple helper function to do softmax

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@ -10,7 +10,7 @@
#if defined(_OPENMP) #if defined(_OPENMP)
#include <omp.h> #include <omp.h>
#else #else
#warning "OpenMP is not available, compile to single thread code" //#warning "OpenMP is not available, compile to single thread code"
inline int omp_get_thread_num() { return 0; } inline int omp_get_thread_num() { return 0; }
inline int omp_get_num_threads() { return 1; } inline int omp_get_num_threads() { return 1; }
inline void omp_set_num_threads(int nthread) {} inline void omp_set_num_threads(int nthread) {}

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@ -137,7 +137,8 @@ namespace xgboost{
} }
/*! \brief return a real number uniform in [0,1) */ /*! \brief return a real number uniform in [0,1) */
inline double RandDouble( void ){ inline double RandDouble( void ){
return static_cast<double>( rand_r( &rseed ) ) / (static_cast<double>( RAND_MAX )+1.0); // return static_cast<double>( rand_r( &rseed ) ) / (static_cast<double>( RAND_MAX )+1.0);
return 0;
} }
// random number seed // random number seed
unsigned rseed; unsigned rseed;