RandomSamplerFromPDF.h

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#ifndef _utl_RandomSamplerFromPDF_h_
#define _utl_RandomSamplerFromPDF_h_

#include <vector>
#include <map>
#include <string>

#include <utl/VRandomSampler.h>
#include <utl/ShadowPtr.h>


namespace utl {

  class TabulatedFunction;
  class RandomSamplerFromCDF;

  class RandomSamplerFromPDF : public VRandomSampler {

  public:
    enum InterpolationType {
      eLinear,
      eDiscrete,
      eStep
    };

    RandomSamplerFromPDF(const std::vector<double>& x, const std::vector<double>& y,
                         const InterpolationType intType = eStep)
    { Init(x, y, intType); }

    RandomSamplerFromPDF(const TabulatedFunction& pdf,
                         const InterpolationType intType = eStep);

    RandomSamplerFromPDF(const std::vector<double>& pdf,
                         const InterpolationType intType = eStep)
    { Init(pdf, intType); }

    RandomSamplerFromPDF(const std::map<double, double>& pdf,
                         const InterpolationType intType = eDiscrete);

    RandomSamplerFromPDF(const std::string& function,
                         const std::string& independentVariableName,
                         const double min, const double max, const int bins = 100)
    { SetFunction(function, independentVariableName, min, max, bins); }

    RandomSamplerFromPDF(const std::string& function,
                         const double min, const double max, const int bins = 100)
    { SetFunction(function, "x", min, max, bins); }

    virtual ~RandomSamplerFromPDF();

    double GetInverseCDF(const double y) const;

  protected:
    virtual double MapRandom(const double rand) const
    { return GetInverseCDF(rand); }

  private:
    void SetFunction(const std::string& function,
                     const std::string& independentVariableName,
                     const double min, const double max, const int bins);

    void Init(const std::vector<double>& x, const std::vector<double>& y,
              const InterpolationType intType);

    void Init(const std::vector<double>& y,
              const InterpolationType intType);

    void InitDiscrete(const std::vector<double>& x, const std::vector<double>& y);

    void InitStep(const std::vector<double>& x, const std::vector<double>& y);

    void InitLinear(const std::vector<double>& x, const std::vector<double>& y);

    RandomSamplerFromCDF* fCDF;
    ShadowPtr<std::vector<double> > fPDF;
  };

}


#endif