KVMultiGaussIsotopeFit.h

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#ifndef __KVMULTIGAUSSISOTOPEFIT_H
#define __KVMULTIGAUSSISOTOPEFIT_H
 
#include "TF1.h"
#include "TVirtualPad.h"
#include "TColor.h"
#include "TArrayI.h"
#include "KVNumberList.h"
#include "KVList.h"
 
#include <KVNameValueList.h>
 
class KVMultiGaussIsotopeFit : public TF1 {
   enum fit_param_index {
      bkg_cst = 1,
      bkg_slp = 2,
      gauss_wid = 3,
      pidvsA_a0 = 4,
      pidvsA_a1 = 5,
      pidvsA_a2 = 6
   };
   double centroid_fit(double* x, double* p)
   {
      /*
         centroids of gaussians are expected to increase linearly with mass A
         x[0]=A
         p[0]=offset
         p[1]=slope
         */
      return p[0] + p[1] * x[0] + p[2] * x[0] * x[0];
   }
 
   double FitFunc(double* x, double* p)
   {
      /*
         x[0] = PID
         p[0] = number of gaussians = Ng (fixed)
         p[1],p[2] = background parameters: exp(p[1]+p[2]*x)
         p[3]      = sigma for all gaussians
         p[4],p[5],p[6] = offset & slope for centroid PID vs. A correlation
         p[7]...p[6+Ng] = norm of each gaussian
         p[6+Ng+1]...p[6+2*Ng] = A of each gaussian
 
         Total number of parameters is 7+2*Ng
      */
      int Ng = p[0];
      double background = TMath::Exp(p[fit_param_index::bkg_cst] + p[fit_param_index::bkg_slp] * x[0]);
      for (int i = 1; i <= Ng; ++i) {
         background +=
            p[get_gauss_norm_index(i)] * TMath::Gaus(x[0], centroid_fit(&p[get_mass_index(i, Ng)],
                  &p[fit_param_index::pidvsA_a0]), p[fit_param_index::gauss_wid], kTRUE);
      }
      return background;
   }
   int get_gauss_norm_index(int ig) const
   {
      return 6 + ig;
   }
   int get_mass_index(int ig, int ng) const
   {
      return 6 + ng + ig;
   }
   int total_number_parameters(int ng) const
   {
      return 7 + 2 * ng;
   }
    int Z;
    int Niso;
    double PIDmin, PIDmax;
    std::vector<int> Alist;
    std::vector<double> PIDlist;
   double min_sigma = 1.e-2; // lower limit for width of gaussians
   double max_sigma = 1.e-1; // upper limit for width of gaussians
 
   double evaluate_gaussian(int i, double pid) const
   {
      return GetGaussianNorm(i) * TMath::Gaus(pid, GetCentroid(i), GetGaussianWidth(i), kTRUE);
   }
public:
   KVMultiGaussIsotopeFit() : TF1() {}
   KVMultiGaussIsotopeFit(int z, std::vector<int> alist)
      : TF1(),
        Z{z},
        Alist{alist}
   {
   }
   KVMultiGaussIsotopeFit(int z, int Ngauss, double PID_min, double PID_max, const KVNumberList& alist, std::vector<double> pidlist);
   KVMultiGaussIsotopeFit(int z, int Ngauss, double PID_min, double PID_max, const KVNumberList& alist,
                          double bkg_cst, double bkg_slp, double gaus_wid,
                          double pidvsa_a0, double pidvsa_a1, double pidvsa_a2);
   KVMultiGaussIsotopeFit(int z, const KVNameValueList&);
 
   void ReleaseCentroids()
   {
      SetParLimits(fit_param_index::pidvsA_a0, -50, 50);
      SetParLimits(fit_param_index::pidvsA_a1, 1.e-2, 5.);
      SetParLimits(fit_param_index::pidvsA_a2, -2.e-2, 5.);
   }
 
   double GetPIDvsAfit_a0() const
   {
      return GetParameter(fit_param_index::pidvsA_a0);
   }
   double GetPIDvsAfit_a1() const
   {
      return GetParameter(fit_param_index::pidvsA_a1);
   }
   double GetPIDvsAfit_a2() const
   {
      return GetParameter(fit_param_index::pidvsA_a2);
   }
 
   void UnDraw(TVirtualPad* pad = gPad) const;
 
   static void UnDrawGaussian(int z, int a, TVirtualPad* pad = gPad)
   {
 
      auto old_fit = pad->FindObject(get_name_of_isotope_gaussian(z, a));
      if (old_fit) delete old_fit;
   }
   static void UnDrawAnyGaussian(int z, TVirtualPad* pad = gPad)
   {
 
      TIter it(pad->GetListOfPrimitives());
      TObject* ob;
      KVList to_delete;
      while ((ob = it())) {
         TString obname = ob->GetName();
         if (obname.BeginsWith(get_root_name_of_isotope_gaussian(z))) to_delete.Add(ob);
      }
   }
 
   void DrawFitWithGaussians(Option_t* opt = "") const;
 
   int GetMostProbableA(double PID, double& P) const;
   double GetMeanA(double PID) const;
   std::map<int, double> GetADistribution(double PID) const;
   int GetA(double PID, double& P) const;
   double GetProbability(int A, double PID) const;
   double GetInterpolatedA(double PID) const
   {
 
      auto a = GetPIDvsAfit_a2();
      auto b = GetPIDvsAfit_a1();
      auto c = GetPIDvsAfit_a0() - PID;
      return (TMath::Sqrt(b * b - 4.*a * c) - b) / 2. / a;
   }
 
   static TString get_name_of_multifit(int z)
   {
      return Form("multigauss_fit_Z=%d", z);
   }
   static TString get_name_of_isotope_gaussian(int z, int a)
   {
      return Form("gauss_fit_Z=%d_A=%d", z, a);
   }
   static TString get_root_name_of_isotope_gaussian(int z)
   {
      return Form("gauss_fit_Z=%d_", z);
   }
 
   double GetBackgroundConstant() const
   {
      return GetParameter(fit_param_index::bkg_cst);
   }
   double GetBackgroundSlope() const
   {
      return GetParameter(fit_param_index::bkg_slp);
   }
   double GetCentroid(int i) const
   {
      assert(i > 0 && i <= Niso);
      return GetParameter(fit_param_index::pidvsA_a0)
             + (GetParameter(fit_param_index::pidvsA_a1)
                + GetParameter(fit_param_index::pidvsA_a2) * Alist[i - 1]) * Alist[i - 1];
   }
   double GetGaussianWidth(int) const
   {
      return GetParameter(fit_param_index::gauss_wid);
   }
   double GetGaussianNorm(int i) const
   {
      assert(i > 0 && i <= Niso);
      return GetParameter(get_gauss_norm_index(i));
   }
   void SetGaussianNorm(int i, double v)
   {
      assert(i > 0 && i <= Niso);
      SetParameter(get_gauss_norm_index(i), v);
   }
 
   void SetFitRange(double min, double max);
 
   double GetPIDmin() const
   {
      return PIDmin;
   }
   double GetPIDmax() const
   {
      return PIDmax;
   }
 
   double GetMinSigma() const
   {
      return min_sigma;
   }
   double GetMaxSigma() const
   {
      return max_sigma;
   }
   void SetSigmaLimits(double smin, double smax)
   {
      min_sigma = smin;
      max_sigma = smax;
      SetParLimits(fit_param_index::gauss_wid, min_sigma, max_sigma);
   }
 
   ClassDef(KVMultiGaussIsotopeFit, 1) //Function for fitting PID mass spectrum
};
 
#endif