BinEstimators.h

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#ifndef YODA_BINESTIMATORS_H
#define YODA_BINESTIMATORS_H
 
#include "YODA/Utils/fastlog.h"
#include "YODA/Utils/MathUtils.h"
#include <cstdlib>
 
namespace YODA {
 
    struct BinEstimator {
 
      virtual ~BinEstimator() {}
 
      size_t estindex(double x) const {
        if (_N == 0) return 0;
        const int i = _est(x);
        if (i < 0) return 0;
        const size_t i2 = (size_t) i;
        if (i2 >= _N) return _N+1;
        return i2 + 1;
      }
 
      size_t operator() (double x) const {
        return estindex(x);
      }
 
    protected:
 
      virtual int _est(double x) const = 0;
 
      size_t _N;
    };
 
 
    struct LinBinEstimator : public BinEstimator {
 
      LinBinEstimator(size_t nbins, double xlow, double xhigh) {
        _N = nbins;
        _c = xlow;
        _m = (double) nbins / (xhigh - xlow);
      }
 
      LinBinEstimator(const LinBinEstimator& other) {
        _N = other._N;
        _c = other._c;
        _m = other._m;
      }
 
      int _est(double x) const {
        int res = (int) floor(_m * (x - _c));
        return res;
      }
 
    protected:
      double _c, _m;
    };
 
 
    class LogBinEstimator : public BinEstimator {
    public:
 
      LogBinEstimator(size_t nbins, double xlow, double xhigh) {
        _N = nbins;
        _c = Utils::fastlog2(xlow);
        _m = nbins / (Utils::fastlog2(xhigh) - _c);
      }
 
      int _est(double x) const {
        if (x <= 0.)  return -1;
        int res = (int) floor(_m * (Utils::fastlog2(x) - _c));
        return res;
 
      }
 
    protected:
      double _c, _m;
    };
}
 
#endif