ROOT logo
/*****************************************************************************
 * Project: RooFit                                                           *
 * Package: RooFitModels                                                     *
 * @(#)root/roofit:$Id: RooPolynomial.cxx 25398 2008-09-15 09:31:59Z wouter $
 * 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
// RooPolynomial implements a polynomial p.d.f of the form
// <pre>
// f(x) = sum_i a_i * x^i
//</pre>
// By default coefficient a_0 is chosen to be 1, as polynomial
// probability density functions have one degree of freedome
// less than polynomial functions due to the normalization condition
// END_HTML
//

#include "RooFit.h"

#include "Riostream.h"
#include "Riostream.h"
#include "TMath.h"

#include "RooPolynomial.h"
#include "RooAbsReal.h"
#include "RooRealVar.h"
#include "RooArgList.h"

ClassImp(RooPolynomial)
;


//_____________________________________________________________________________
RooPolynomial::RooPolynomial()
{
  _coefIter = _coefList.createIterator() ;
}


//_____________________________________________________________________________
RooPolynomial::RooPolynomial(const char* name, const char* title, 
			     RooAbsReal& x, const RooArgList& coefList, Int_t lowestOrder) :
  RooAbsPdf(name, title),
  _x("x", "Dependent", this, x),
  _coefList("coefList","List of coefficients",this),
  _lowestOrder(lowestOrder) 
{
  // Constructor
  _coefIter = _coefList.createIterator() ;

  // Check lowest order
  if (_lowestOrder<0) {
    cout << "RooPolynomial::ctor(" << GetName() 
	 << ") WARNING: lowestOrder must be >=0, setting value to 0" << endl ;
    _lowestOrder=0 ;
  }

  TIterator* coefIter = coefList.createIterator() ;
  RooAbsArg* coef ;
  while((coef = (RooAbsArg*)coefIter->Next())) {
    if (!dynamic_cast<RooAbsReal*>(coef)) {
      cout << "RooPolynomial::ctor(" << GetName() << ") ERROR: coefficient " << coef->GetName() 
	   << " is not of type RooAbsReal" << endl ;
      assert(0) ;
    }
    _coefList.add(*coef) ;
  }
  delete coefIter ;
}



//_____________________________________________________________________________
RooPolynomial::RooPolynomial(const char* name, const char* title,
                           RooAbsReal& x) :
  RooAbsPdf(name, title),
  _x("x", "Dependent", this, x),
  _coefList("coefList","List of coefficients",this),
  _lowestOrder(1)
{
  _coefIter = _coefList.createIterator() ;
}                                                                                                                                 



//_____________________________________________________________________________
RooPolynomial::RooPolynomial(const RooPolynomial& other, const char* name) :
  RooAbsPdf(other, name), 
  _x("x", this, other._x), 
  _coefList("coefList",this,other._coefList),
  _lowestOrder(other._lowestOrder) 
{
  // Copy constructor
  _coefIter = _coefList.createIterator() ;
}




//_____________________________________________________________________________
RooPolynomial::~RooPolynomial()
{
  // Destructor
  delete _coefIter ;
}




//_____________________________________________________________________________
Double_t RooPolynomial::evaluate() const 
{
  Int_t order(_lowestOrder) ;
  Double_t sum(order<1 ? 0 : 1) ;

  _coefIter->Reset() ;

  RooAbsReal* coef ;
  const RooArgSet* nset = _coefList.nset() ;
  while((coef=(RooAbsReal*)_coefIter->Next())) {
    sum += coef->getVal(nset)*TMath::Power(_x,order++) ;
  }

//   if (sum<=0) {
    //cout << "RooPolynomial sum = " << sum << endl ;  
//   }
  return sum;
}



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



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

  Int_t order(_lowestOrder) ;
  
  Double_t sum(order>0 ? _x.max(rangeName)-_x.min(rangeName) : 0) ;
  //cout << "RooPolynomial::aI(" << GetName() << ") range = " << _x.min(rangeName) << " - " << _x.max(rangeName) << endl ;
  
  const RooArgSet* nset = _coefList.nset() ;
  _coefIter->Reset() ;
  RooAbsReal* coef ;

  // Primitive = sum(k) coef_k * 1/(k+1) x^(k+1)
  while((coef=(RooAbsReal*)_coefIter->Next())) {
    sum += coef->getVal(nset)*(TMath::Power(_x.max(rangeName),order+1)-TMath::Power(_x.min(rangeName),order+1))/(order+1) ; 
    order++ ;
  }

  return sum;  
  
}
 RooPolynomial.cxx:1
 RooPolynomial.cxx:2
 RooPolynomial.cxx:3
 RooPolynomial.cxx:4
 RooPolynomial.cxx:5
 RooPolynomial.cxx:6
 RooPolynomial.cxx:7
 RooPolynomial.cxx:8
 RooPolynomial.cxx:9
 RooPolynomial.cxx:10
 RooPolynomial.cxx:11
 RooPolynomial.cxx:12
 RooPolynomial.cxx:13
 RooPolynomial.cxx:14
 RooPolynomial.cxx:15
 RooPolynomial.cxx:16
 RooPolynomial.cxx:17
 RooPolynomial.cxx:18
 RooPolynomial.cxx:19
 RooPolynomial.cxx:20
 RooPolynomial.cxx:21
 RooPolynomial.cxx:22
 RooPolynomial.cxx:23
 RooPolynomial.cxx:24
 RooPolynomial.cxx:25
 RooPolynomial.cxx:26
 RooPolynomial.cxx:27
 RooPolynomial.cxx:28
 RooPolynomial.cxx:29
 RooPolynomial.cxx:30
 RooPolynomial.cxx:31
 RooPolynomial.cxx:32
 RooPolynomial.cxx:33
 RooPolynomial.cxx:34
 RooPolynomial.cxx:35
 RooPolynomial.cxx:36
 RooPolynomial.cxx:37
 RooPolynomial.cxx:38
 RooPolynomial.cxx:39
 RooPolynomial.cxx:40
 RooPolynomial.cxx:41
 RooPolynomial.cxx:42
 RooPolynomial.cxx:43
 RooPolynomial.cxx:44
 RooPolynomial.cxx:45
 RooPolynomial.cxx:46
 RooPolynomial.cxx:47
 RooPolynomial.cxx:48
 RooPolynomial.cxx:49
 RooPolynomial.cxx:50
 RooPolynomial.cxx:51
 RooPolynomial.cxx:52
 RooPolynomial.cxx:53
 RooPolynomial.cxx:54
 RooPolynomial.cxx:55
 RooPolynomial.cxx:56
 RooPolynomial.cxx:57
 RooPolynomial.cxx:58
 RooPolynomial.cxx:59
 RooPolynomial.cxx:60
 RooPolynomial.cxx:61
 RooPolynomial.cxx:62
 RooPolynomial.cxx:63
 RooPolynomial.cxx:64
 RooPolynomial.cxx:65
 RooPolynomial.cxx:66
 RooPolynomial.cxx:67
 RooPolynomial.cxx:68
 RooPolynomial.cxx:69
 RooPolynomial.cxx:70
 RooPolynomial.cxx:71
 RooPolynomial.cxx:72
 RooPolynomial.cxx:73
 RooPolynomial.cxx:74
 RooPolynomial.cxx:75
 RooPolynomial.cxx:76
 RooPolynomial.cxx:77
 RooPolynomial.cxx:78
 RooPolynomial.cxx:79
 RooPolynomial.cxx:80
 RooPolynomial.cxx:81
 RooPolynomial.cxx:82
 RooPolynomial.cxx:83
 RooPolynomial.cxx:84
 RooPolynomial.cxx:85
 RooPolynomial.cxx:86
 RooPolynomial.cxx:87
 RooPolynomial.cxx:88
 RooPolynomial.cxx:89
 RooPolynomial.cxx:90
 RooPolynomial.cxx:91
 RooPolynomial.cxx:92
 RooPolynomial.cxx:93
 RooPolynomial.cxx:94
 RooPolynomial.cxx:95
 RooPolynomial.cxx:96
 RooPolynomial.cxx:97
 RooPolynomial.cxx:98
 RooPolynomial.cxx:99
 RooPolynomial.cxx:100
 RooPolynomial.cxx:101
 RooPolynomial.cxx:102
 RooPolynomial.cxx:103
 RooPolynomial.cxx:104
 RooPolynomial.cxx:105
 RooPolynomial.cxx:106
 RooPolynomial.cxx:107
 RooPolynomial.cxx:108
 RooPolynomial.cxx:109
 RooPolynomial.cxx:110
 RooPolynomial.cxx:111
 RooPolynomial.cxx:112
 RooPolynomial.cxx:113
 RooPolynomial.cxx:114
 RooPolynomial.cxx:115
 RooPolynomial.cxx:116
 RooPolynomial.cxx:117
 RooPolynomial.cxx:118
 RooPolynomial.cxx:119
 RooPolynomial.cxx:120
 RooPolynomial.cxx:121
 RooPolynomial.cxx:122
 RooPolynomial.cxx:123
 RooPolynomial.cxx:124
 RooPolynomial.cxx:125
 RooPolynomial.cxx:126
 RooPolynomial.cxx:127
 RooPolynomial.cxx:128
 RooPolynomial.cxx:129
 RooPolynomial.cxx:130
 RooPolynomial.cxx:131
 RooPolynomial.cxx:132
 RooPolynomial.cxx:133
 RooPolynomial.cxx:134
 RooPolynomial.cxx:135
 RooPolynomial.cxx:136
 RooPolynomial.cxx:137
 RooPolynomial.cxx:138
 RooPolynomial.cxx:139
 RooPolynomial.cxx:140
 RooPolynomial.cxx:141
 RooPolynomial.cxx:142
 RooPolynomial.cxx:143
 RooPolynomial.cxx:144
 RooPolynomial.cxx:145
 RooPolynomial.cxx:146
 RooPolynomial.cxx:147
 RooPolynomial.cxx:148
 RooPolynomial.cxx:149
 RooPolynomial.cxx:150
 RooPolynomial.cxx:151
 RooPolynomial.cxx:152
 RooPolynomial.cxx:153
 RooPolynomial.cxx:154
 RooPolynomial.cxx:155
 RooPolynomial.cxx:156
 RooPolynomial.cxx:157
 RooPolynomial.cxx:158
 RooPolynomial.cxx:159
 RooPolynomial.cxx:160
 RooPolynomial.cxx:161
 RooPolynomial.cxx:162
 RooPolynomial.cxx:163
 RooPolynomial.cxx:164
 RooPolynomial.cxx:165
 RooPolynomial.cxx:166
 RooPolynomial.cxx:167
 RooPolynomial.cxx:168
 RooPolynomial.cxx:169
 RooPolynomial.cxx:170
 RooPolynomial.cxx:171
 RooPolynomial.cxx:172
 RooPolynomial.cxx:173
 RooPolynomial.cxx:174
 RooPolynomial.cxx:175