libopenms-dev 1.11.1-5 / usr / include / OpenMS / MATH / STATISTICS / GammaDistributionFitter.h

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// $Maintainer: Andreas Bertsch $
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#ifndef OPENMS_MATH_STATISTICS_GAMMADISTRIBUTIONFITTER_H
#define OPENMS_MATH_STATISTICS_GAMMADISTRIBUTIONFITTER_H

#include <OpenMS/DATASTRUCTURES/String.h>
#include <OpenMS/DATASTRUCTURES/DPosition.h>

#include <vector>

// gsl includes
#include <gsl/gsl_rng.h>
#include <gsl/gsl_vector.h>
#include <gsl/gsl_multifit_nlin.h>


namespace OpenMS
{
  namespace Math
  {
    /**
      @brief Implements a fitter for the Gamma distribution.

      This class fits a Gamma distribution to a number of data points.
      The results as well as the initial guess are specified using the struct
          GammaDistributionFitResult.

      The formula with the fitted parameters can be transformed into a
      gnuplot formula using getGnuplotFormulai() after fitting.

          The implementation is done using GSL fitting algorithms.

          @ingroup Math
      */
    class OPENMS_DLLAPI GammaDistributionFitter
    {
public:

      /// struct to represent the parameters of a gamma distribution
      struct GammaDistributionFitResult
      {
public:

        GammaDistributionFitResult() :
          b(1.0),
          p(5.0)
        {
        }

        GammaDistributionFitResult(const GammaDistributionFitResult & rhs) :
          b(rhs.b),
          p(rhs.p)
        {
        }

        GammaDistributionFitResult & operator=(const GammaDistributionFitResult & rhs)
        {
          if (this != &rhs)
          {
            b = rhs.b;
            p = rhs.p;
          }
          return *this;
        }

        /// parameter b of the gamma distribution
        double b;

        /// parameter p of the gamma distribution
        double p;
      };

      /// Default constructor
      GammaDistributionFitter();
      /// Destructor
      virtual ~GammaDistributionFitter();

      /// sets the gamma distribution start parameters b and p for the fitting
      void setInitialParameters(const GammaDistributionFitResult & result);

      /**
          @brief Fits a gamma distribution to the given data points

          @param points Input parameter which represents the point used for the fitting

          @exception Exception::UnableToFit is thrown if fitting cannot be performed
      */
      GammaDistributionFitResult fit(std::vector<DPosition<2> > & points);

      /// returns the gnuplot formula of the fitted gamma distribution
      const String & getGnuplotFormula() const;

protected:

      static int gammaDistributionFitterf_(const gsl_vector * x, void * params, gsl_vector * f);

      static int gammaDistributionFitterdf_(const gsl_vector * x, void * params, gsl_matrix * J);

      static int gammaDistributionFitterfdf_(const gsl_vector * x, void * params, gsl_vector * f, gsl_matrix * J);

      void printState_(size_t iter, gsl_multifit_fdfsolver * s);

      GammaDistributionFitResult init_param_;

      String gnuplot_formula_;

private:
      /// Copy constructor (not implemented)
      GammaDistributionFitter(const GammaDistributionFitter & rhs);
      /// assignment operator (not implemented)
      GammaDistributionFitter & operator=(const GammaDistributionFitter & rhs);
    };
  }
}

#endif