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/*****************************************************************************
 * Project: RooFit                                                           *
 * Package: RooFitModels                                                     *
 * @(#)root/roofit:$Id$
 * Authors:                                                                  *
 *   WV, Wouter Verkerke, UC Santa Barbara, verkerke@slac.stanford.edu       *
 *   DK, David Kirkby,    UC Irvine,         dkirkby@uci.edu                 *
 *                                                                           *
 * Copyright (c) 2000-2005, Regents of the University of California          *
 *                          and Stanford University. All rights reserved.    *
 *                                                                           *
 * Redistribution and use in source and binary forms,                        *
 * with or without modification, are permitted according to the terms        *
 * listed in LICENSE (http://roofit.sourceforge.net/license.txt)             *
 *****************************************************************************/

//////////////////////////////////////////////////////////////////////////////
//
// BEGIN_HTML
// Plain Gaussian p.d.f
// END_HTML
//

#include "RooFit.h"

#include "Riostream.h"
#include "Riostream.h"
#include <math.h>

#include "RooGaussian.h"
#include "RooAbsReal.h"
#include "RooRealVar.h"
#include "RooRandom.h"
#include "RooMath.h"

using namespace std;

ClassImp(RooGaussian)


//_____________________________________________________________________________
RooGaussian::RooGaussian(const char *name, const char *title,
			 RooAbsReal& _x, RooAbsReal& _mean,
			 RooAbsReal& _sigma) :
  RooAbsPdf(name,title),
  x("x","Observable",this,_x),
  mean("mean","Mean",this,_mean),
  sigma("sigma","Width",this,_sigma)
{
}



//_____________________________________________________________________________
RooGaussian::RooGaussian(const RooGaussian& other, const char* name) : 
  RooAbsPdf(other,name), x("x",this,other.x), mean("mean",this,other.mean),
  sigma("sigma",this,other.sigma)
{
}



//_____________________________________________________________________________
Double_t RooGaussian::evaluate() const
{
  Double_t arg= x - mean;  
  Double_t sig = sigma ;
  Double_t ret =exp(-0.5*arg*arg/(sig*sig)) ;
//   if (gDebug>2) {
//     cout << "gauss(" << GetName() << ") x = " << x << " mean = " << mean << " sigma = " << sigma << " ret = " << ret << endl ;
//   }
  return ret ;
}



//_____________________________________________________________________________
Double_t RooGaussian::getLogVal(const RooArgSet* set) const 
{
  // calculate and return the negative log-likelihood of the Poisson                                                                                                                                    
  return RooAbsPdf::getLogVal(set) ;
//   Double_t prob = getVal(set) ;
//   return log(prob) ;

  Double_t arg= x - mean;  
  Double_t sig = sigma ;
  
  //static const Double_t rootPiBy2 = sqrt(atan2(0.0,-1.0)/2.0);
  //Double_t extra = -0.5*arg*arg/(sig*sig) - log(2*rootPiBy2*sig) ;
  Double_t extra = -0.5*arg*arg/(sig*sig) - log(analyticalIntegral(1,0)) ;
  
  return extra ; 
  
}


//_____________________________________________________________________________
Int_t RooGaussian::getAnalyticalIntegral(RooArgSet& allVars, RooArgSet& analVars, const char* /*rangeName*/) const 
{
  if (matchArgs(allVars,analVars,x)) return 1 ;
  if (matchArgs(allVars,analVars,mean)) return 2 ;
  return 0 ;
}



//_____________________________________________________________________________
Double_t RooGaussian::analyticalIntegral(Int_t code, const char* rangeName) const 
{
  assert(code==1 || code==2) ;

  static const Double_t root2 = sqrt(2.) ;
  static const Double_t rootPiBy2 = sqrt(atan2(0.0,-1.0)/2.0);
  Double_t xscale = root2*sigma;
  Double_t ret = 0;
  if(code==1){  
    ret = rootPiBy2*sigma*(RooMath::erf((x.max(rangeName)-mean)/xscale)-RooMath::erf((x.min(rangeName)-mean)/xscale));
//     if (gDebug>2) {
//       cout << "Int_gauss_dx(mean=" << mean << ",sigma=" << sigma << ", xmin=" << x.min(rangeName) << ", xmax=" << x.max(rangeName) << ")=" << ret << endl ;
//     }
  } else if(code==2) {
    ret = rootPiBy2*sigma*(RooMath::erf((mean.max(rangeName)-x)/xscale)-RooMath::erf((mean.min(rangeName)-x)/xscale));
  } else{
    cout << "Error in RooGaussian::analyticalIntegral" << endl;
  }
  return ret ;

}




//_____________________________________________________________________________
Int_t RooGaussian::getGenerator(const RooArgSet& directVars, RooArgSet &generateVars, Bool_t /*staticInitOK*/) const
{
  if (matchArgs(directVars,generateVars,x)) return 1 ;  
  if (matchArgs(directVars,generateVars,mean)) return 2 ;  
  return 0 ;
}



//_____________________________________________________________________________
void RooGaussian::generateEvent(Int_t code)
{
  assert(code==1 || code==2) ;
  Double_t xgen ;
  if(code==1){
    while(1) {    
      xgen = RooRandom::randomGenerator()->Gaus(mean,sigma);
      if (xgen<x.max() && xgen>x.min()) {
	x = xgen ;
	break;
      }
    }
  } else if(code==2){
    while(1) {    
      xgen = RooRandom::randomGenerator()->Gaus(x,sigma);
      if (xgen<mean.max() && xgen>mean.min()) {
	mean = xgen ;
	break;
      }
    }
  } else {
    cout << "error in RooGaussian generateEvent"<< endl;
  }

  return;
}

 RooGaussian.cxx:1
 RooGaussian.cxx:2
 RooGaussian.cxx:3
 RooGaussian.cxx:4
 RooGaussian.cxx:5
 RooGaussian.cxx:6
 RooGaussian.cxx:7
 RooGaussian.cxx:8
 RooGaussian.cxx:9
 RooGaussian.cxx:10
 RooGaussian.cxx:11
 RooGaussian.cxx:12
 RooGaussian.cxx:13
 RooGaussian.cxx:14
 RooGaussian.cxx:15
 RooGaussian.cxx:16
 RooGaussian.cxx:17
 RooGaussian.cxx:18
 RooGaussian.cxx:19
 RooGaussian.cxx:20
 RooGaussian.cxx:21
 RooGaussian.cxx:22
 RooGaussian.cxx:23
 RooGaussian.cxx:24
 RooGaussian.cxx:25
 RooGaussian.cxx:26
 RooGaussian.cxx:27
 RooGaussian.cxx:28
 RooGaussian.cxx:29
 RooGaussian.cxx:30
 RooGaussian.cxx:31
 RooGaussian.cxx:32
 RooGaussian.cxx:33
 RooGaussian.cxx:34
 RooGaussian.cxx:35
 RooGaussian.cxx:36
 RooGaussian.cxx:37
 RooGaussian.cxx:38
 RooGaussian.cxx:39
 RooGaussian.cxx:40
 RooGaussian.cxx:41
 RooGaussian.cxx:42
 RooGaussian.cxx:43
 RooGaussian.cxx:44
 RooGaussian.cxx:45
 RooGaussian.cxx:46
 RooGaussian.cxx:47
 RooGaussian.cxx:48
 RooGaussian.cxx:49
 RooGaussian.cxx:50
 RooGaussian.cxx:51
 RooGaussian.cxx:52
 RooGaussian.cxx:53
 RooGaussian.cxx:54
 RooGaussian.cxx:55
 RooGaussian.cxx:56
 RooGaussian.cxx:57
 RooGaussian.cxx:58
 RooGaussian.cxx:59
 RooGaussian.cxx:60
 RooGaussian.cxx:61
 RooGaussian.cxx:62
 RooGaussian.cxx:63
 RooGaussian.cxx:64
 RooGaussian.cxx:65
 RooGaussian.cxx:66
 RooGaussian.cxx:67
 RooGaussian.cxx:68
 RooGaussian.cxx:69
 RooGaussian.cxx:70
 RooGaussian.cxx:71
 RooGaussian.cxx:72
 RooGaussian.cxx:73
 RooGaussian.cxx:74
 RooGaussian.cxx:75
 RooGaussian.cxx:76
 RooGaussian.cxx:77
 RooGaussian.cxx:78
 RooGaussian.cxx:79
 RooGaussian.cxx:80
 RooGaussian.cxx:81
 RooGaussian.cxx:82
 RooGaussian.cxx:83
 RooGaussian.cxx:84
 RooGaussian.cxx:85
 RooGaussian.cxx:86
 RooGaussian.cxx:87
 RooGaussian.cxx:88
 RooGaussian.cxx:89
 RooGaussian.cxx:90
 RooGaussian.cxx:91
 RooGaussian.cxx:92
 RooGaussian.cxx:93
 RooGaussian.cxx:94
 RooGaussian.cxx:95
 RooGaussian.cxx:96
 RooGaussian.cxx:97
 RooGaussian.cxx:98
 RooGaussian.cxx:99
 RooGaussian.cxx:100
 RooGaussian.cxx:101
 RooGaussian.cxx:102
 RooGaussian.cxx:103
 RooGaussian.cxx:104
 RooGaussian.cxx:105
 RooGaussian.cxx:106
 RooGaussian.cxx:107
 RooGaussian.cxx:108
 RooGaussian.cxx:109
 RooGaussian.cxx:110
 RooGaussian.cxx:111
 RooGaussian.cxx:112
 RooGaussian.cxx:113
 RooGaussian.cxx:114
 RooGaussian.cxx:115
 RooGaussian.cxx:116
 RooGaussian.cxx:117
 RooGaussian.cxx:118
 RooGaussian.cxx:119
 RooGaussian.cxx:120
 RooGaussian.cxx:121
 RooGaussian.cxx:122
 RooGaussian.cxx:123
 RooGaussian.cxx:124
 RooGaussian.cxx:125
 RooGaussian.cxx:126
 RooGaussian.cxx:127
 RooGaussian.cxx:128
 RooGaussian.cxx:129
 RooGaussian.cxx:130
 RooGaussian.cxx:131
 RooGaussian.cxx:132
 RooGaussian.cxx:133
 RooGaussian.cxx:134
 RooGaussian.cxx:135
 RooGaussian.cxx:136
 RooGaussian.cxx:137
 RooGaussian.cxx:138
 RooGaussian.cxx:139
 RooGaussian.cxx:140
 RooGaussian.cxx:141
 RooGaussian.cxx:142
 RooGaussian.cxx:143
 RooGaussian.cxx:144
 RooGaussian.cxx:145
 RooGaussian.cxx:146
 RooGaussian.cxx:147
 RooGaussian.cxx:148
 RooGaussian.cxx:149
 RooGaussian.cxx:150
 RooGaussian.cxx:151
 RooGaussian.cxx:152
 RooGaussian.cxx:153
 RooGaussian.cxx:154
 RooGaussian.cxx:155
 RooGaussian.cxx:156
 RooGaussian.cxx:157
 RooGaussian.cxx:158
 RooGaussian.cxx:159
 RooGaussian.cxx:160
 RooGaussian.cxx:161
 RooGaussian.cxx:162
 RooGaussian.cxx:163
 RooGaussian.cxx:164
 RooGaussian.cxx:165
 RooGaussian.cxx:166
 RooGaussian.cxx:167
 RooGaussian.cxx:168
 RooGaussian.cxx:169
 RooGaussian.cxx:170