PacConvolvedExponential.h

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/***************************************************************************
 *   Copyright (C) 2008-2010 by Matthias Nagl                              *
 *   mnagl@uni-goettingen.de                                               *
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 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
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 *   (at your option) any later version.                                   *
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 *   This program is distributed in the hope that it will be useful,       *
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 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
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#ifndef PACCONVOLVEDEXPONENTIAL_H
#define PACCONVOLVEDEXPONENTIAL_H

#include <vector>
#include <math.h>
#ifndef M_LN2l
#define M_LN2l         0.6931471805599453094172321214581766L  /* log_e 2 */
#endif
#ifndef M_SQRT1_2l
#define M_SQRT1_2l     0.7071067811865475244008443621048490L  /* 1/sqrt(2) */
#endif
#include "PacAbstractFitFunction.h"
#include <QtDebug>

class PacConvolvedExponential : public PacAbstractFitFunction
{
public:
  PacConvolvedExponential(const std::vector<double> &params);
  PacConvolvedExponential();
  ~PacConvolvedExponential();

  QList<Pac::FitParameterProperties> parameterProperties() const;
  PacParameterState initialParameterSet() const;
  QPixmap formulaAsPixmap() const;
  QString formulaExplanation() const;

  QVector<double> fitResultCurve(const QVector<double> &xvals, const ROOT::Minuit2::MnUserParameterState &params) const;
  double operator()(const std::vector<double> &x) const;

private:
  inline double myexp(double x, double a, double b, double c, double t, double t0, double s) const {
    const long double s_t = s / t;
    const long double dt = x - t0;
    double result = a * 0.5L * powl( 2.0L, 0.5L*s_t*s_t*M_LN2l - dt/t ) * erfcl( s_t*M_LN2l*M_SQRT1_2l - dt/s*M_SQRT1_2l) + b * expl(-0.5L*dt*dt/s/s) + c;
    return isnan(result) ? std::numeric_limits<double>::max() : result;
  };
};

#endif