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MCOL-3503 Use long double arithmetic for tie breaking to avoid integer truncation

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This commit is contained in:
David Hall
2019-10-11 12:05:13 -05:00
parent 5a4c406216
commit c7d594304b
1 changed files with 5 additions and 3 deletions
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8
utils/regr/moda.cpp
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@ -280,7 +280,7 @@ template<class T>
mcsv1_UDAF::ReturnCode Moda_impl_T<T>::evaluate(mcsv1Context* context, static_any::any& valOut) mcsv1_UDAF::ReturnCode Moda_impl_T<T>::evaluate(mcsv1Context* context, static_any::any& valOut)
{ {
uint64_t maxCnt = 0; uint64_t maxCnt = 0;
T avg = 0; long double avg = 0;
T val = 0; T val = 0;
ModaData* data = static_cast<ModaData*>(context->getUserData()); ModaData* data = static_cast<ModaData*>(context->getUserData());
std::unordered_map<T, uint32_t>* map = data->getMap<T>(); std::unordered_map<T, uint32_t>* map = data->getMap<T>();
@ -304,8 +304,10 @@ mcsv1_UDAF::ReturnCode Moda_impl_T<T>::evaluate(mcsv1Context* context, static_an
else if (iter->second == maxCnt) else if (iter->second == maxCnt)
{ {
// Tie breaker: choose the closest to avg. If still tie, choose smallest // Tie breaker: choose the closest to avg. If still tie, choose smallest
if ((std::fabs(val-avg) > std::fabs(iter->first-avg)) long double dist1 = val > avg ? (long double)val-avg : avg-(long double)val;
|| ((std::fabs(val-avg) == std::fabs(iter->first-avg)) && (std::fabs(val) > std::fabs(iter->first)))) long double dist2 = iter->first > avg ? (long double)iter->first-avg : avg-(long double)iter->first;
if ((dist1 > dist2)
|| ((dist1 == dist2) && (std::fabs(val) > std::fabs(iter->first))))
{ {
val = iter->first; val = iter->first;
} }