distribution.h

/*****************************************************************************
 * VCLib                                                                     *
 * Visual Computing Library                                                  *
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 * Copyright(C) 2021-2025                                                    *
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#ifndef VCL_MATH_DISTRIBUTION_H
#define VCL_MATH_DISTRIBUTION_H
 
#include <vclib/types.h>
 
#include <cmath>
#include <limits>
#include <set>
 
namespace vcl {
 
template<typename Scalar>
class Distribution
{
    std::set<Scalar> mSet;
 
    Scalar mMin = std::numeric_limits<Scalar>::max();
    Scalar mMax = std::numeric_limits<Scalar>::lowest();
 
    Scalar mSum     = 0;
    Scalar mSqrdSum = 0;
    Scalar mAvg     = 0;
    Scalar mSqrdAvg = 0;
    Scalar mRMS     = 0;
 
public:
    Distribution() = default;
 
    void clear()
    {
        mSet.clear();
        mMin     = std::numeric_limits<Scalar>::max();
        mMax     = std::numeric_limits<Scalar>::lowest();
        mSum     = 0;
        mSqrdSum = 0;
        mAvg     = 0;
        mSqrdAvg = 0;
        mRMS     = 0;
    }
 
    void add(Scalar v)
    {
        mSet.insert(v);
        if (v < mMin)
            mMin = v;
        if (v > mMax)
            mMax = v;
        mSum += v;
        mSqrdSum += v * v;
        mAvg     = mSum / mSet.size();
        mSqrdAvg = mSqrdSum / mSet.size();
        mRMS     = std::sqrt(mSqrdAvg);
    }
 
    Scalar min() const { return mMin; }
 
    Scalar max() const { return mMax; }
 
    uint size() const { return mSet.size(); }
 
    Scalar sum() const { return mSum; }
 
    Scalar average() const { return mAvg; }
 
    Scalar rootMeanSquare() const { return mRMS; }
 
    Scalar variance() const { return mSqrdAvg - mAvg * mAvg; }
 
    Scalar standardDeviation() const { return std::sqrt(variance()); }
 
    Scalar percentile(Scalar perc) const
    {
        assert(!mSet.empty());
        assert(perc >= 0 && perc <= 1);
 
        int index = mSet.size() * perc - 1;
        if (index < 0)
            index = 0;
        auto it = mSet.begin();
        std::advance(it, index);
        return *it;
    }
};
 
} // namespace vcl
 
#endif // VCL_MATH_DISTRIBUTION_H