BasicStatistics.h

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// BasicStatistics.h:
// ------------------
//

#ifndef __IPSDKMATH_BASICSTATISTICS_H__
#define __IPSDKMATH_BASICSTATISTICS_H__

#include <IPSDKMath/IPSDKMathExports.h>
#include <IPSDKUtil/BaseTypes.h>
#include <IPSDKUtil/Tools/NumericLimits.h>
#include <algorithm>
#include <vector>

namespace ipsdk {
namespace math {


template <typename IteratorType>
void
extractMinMax(const IteratorType& iterBegin,
              const IteratorType& iterEnd,
              typename std::iterator_traits<IteratorType>::value_type& minValue,
              typename std::iterator_traits<IteratorType>::value_type& maxValue)
{
    // initialize output values
    typedef typename std::iterator_traits<IteratorType>::value_type T;
    minValue = NumericLimits<T>::max();
    maxValue = NumericLimits<T>::min();

    // parse all data
    IteratorType iter = iterBegin;
    while (iter != iterEnd) {
    
        if (*iter < minValue)
            minValue = *iter;
        if (*iter > maxValue)
            maxValue = *iter;

        ++iter;
    }
}
template <typename ContainerType>
void
extractMinMax(const ContainerType& coll,
              typename ContainerType::value_type& minValue,
              typename ContainerType::value_type& maxValue)
{
    extractMinMax(coll.begin(), coll.end(), minValue, maxValue);
}

template <typename T>
T
median(std::vector<T>& coll)
{
    // check for collection size
    const ipUInt32 size = static_cast<ipUInt32>(coll.size());
    if (size == 0)
        return 0;

    // compute median value
    std::nth_element(coll.begin(),
                     coll.begin() + size / 2,
                     coll.end());

    return coll[size / 2];
}

template <typename T>
IPSDKMATH_API ipReal64
mean(const std::vector<T>& coll);

template <typename T>
IPSDKMATH_API ipReal64
variance(const std::vector<T>& coll);

template <typename T>
IPSDKMATH_API ipReal64
stdDev(const std::vector<T>& coll);

template <typename T>
IPSDKMATH_API std::pair<ipReal64, ipReal64>
meanAndVariance(const std::vector<T>& coll);

template <typename T>
IPSDKMATH_API ipReal64
correlation(const std::vector<T>& coll1, const std::vector<T>& coll2);


} // end of namespace math
} // end of namespace ipsdk

#endif // __IPSDKMATH_BASICSTATISTICS_H__