Schema evolution for RooBernsteinFast (with custom streamers)

interface/RooBernsteinFast.h

@@ -1,146 +1,70 @@
-/*****************************************************************************
- * RooBernsteinFast
- * Josh Bendavid (CERN)
- * Fast templated version of RooBernstein class using SMatrices
- * 
- * 
- *   
- *       
- *****************************************************************************/
 #ifndef ROO_BERNSTEINFAST
 #define ROO_BERNSTEINFAST
 
-#include "RooAbsPdf.h"
-#include "RooRealProxy.h"
+#include "RooBernstein.h"
 #include "RooListProxy.h"
-#include "RooChangeTracker.h"
-#include "TMath.h"
-#include "Math/SMatrix.h"
+#include "RooRealConstant.h"
+#include "RooAbsReal.h"
+#include "TClass.h"
+#include "TDataMember.h"
 
-class RooRealVar;
-class RooArgList ;
-
-template<int N> class RooBernsteinFast : public RooAbsPdf {
+template<int N> class RooBernsteinFast : public RooBernstein {
 public:
 
+  RooBernsteinFast() = default;
 
-
-  RooBernsteinFast() {}
-
   RooBernsteinFast(const char *name, const char *title,
-                RooAbsReal& x, const RooArgList& coefList) :
-    RooAbsPdf(name, title),
-    _x("x", "Dependent", this, x),
-    _coefList("coefList","List of coefficients",this)
-    {
-      _coefList.add(coefList);
-
-
-      //precompute coefficients for integral
-      for (int ipow=0; ipow<=N; ++ipow) {
-        _rvector(ipow) = 1.0/((double)ipow+1.0);
-      }
+                   RooAbsReal& x, const RooArgList& coefList) :
+    RooBernstein(name, title,
+                 dynamic_cast<RooAbsRealLValue&>(x),
+                 buildFullList(coefList))
+  {}
 
-      //precompute coefficients for conversion from bernstein basis to power basis
-      for (int ibern=0; ibern<=N; ++ibern) {
-        for (int ipow=0; ipow<ibern; ++ipow) {
-          _cmatrix(ipow,ibern) = 0.;
-        }
-        for (int ipow=ibern; ipow<=N; ++ipow) {
-          _cmatrix(ipow, ibern) = pow(-1.,ipow-ibern)*TMath::Binomial(N,ipow)*TMath::Binomial(ipow,ibern);
-        }
-      }
-
-    }                
-
+  ClassDefOverride(RooBernsteinFast, 2)
 
-  RooBernsteinFast(const RooBernsteinFast& other, const char* name = 0) :
-      RooAbsPdf(other, name), 
-    _x("x", this, other._x), 
-    _coefList("coefList",this,other._coefList),
-    _cmatrix(other._cmatrix),
-    _rvector(other._rvector),
-    _bernvector(other._bernvector),
-    _powvector(other._powvector),
-    _xvector(other._xvector) {}
-
-
-  TObject* clone(const char* newname) const override { return new RooBernsteinFast(*this, newname); }
-  ~RooBernsteinFast() override { }
-
-
-  Int_t getAnalyticalIntegral(RooArgSet& allVars, RooArgSet& analVars, const char* rangeName=0) const override
-    {
-
-      // No analytical calculation available (yet) of integrals over subranges (as for standard RooBernstein)
-      if (rangeName && strlen(rangeName)) {
-        return 0 ;
-      }      
-
-      if (matchArgs(allVars, analVars, _x)) return 1;
-      return 0;
-    }
-
-
-  Double_t analyticalIntegral(Int_t code, const char* rangeName=0) const override
-    {
+private:
 
-      _bernvector[0] = 1.0;
-      for (int ipow=1; ipow<=N; ++ipow) {
-        _bernvector[ipow] = static_cast<RooAbsReal*>(_coefList.at(ipow-1))->getVal();
-      }     
-
-      _powvector = _cmatrix*_bernvector;
-
-      double xmin = _x.min();
-      double xmax = _x.max();    
-      return (xmax-xmin)*ROOT::Math::Dot(_powvector,_rvector);
+  // RooBernstein expects N+1 coefficients; RooBernsteinFast fixed c0=1 internally,
+  // so we prepend a constant 1.0 to the user-supplied N coefficients.
+  static RooArgList buildFullList(const RooArgList& coefList) {
+    RooArgList full;
+    full.add(RooRealConstant::value(1.0));
+    full.add(coefList);
+    return full;
+  }
 
-    }
+};
 
-protected:
+// Custom Streamer: handles reading old (v1) files where RooBernsteinFast
+// inherited from RooAbsPdf and stored N coefficients (c0=1 was implicit).
+template<int N>
+void RooBernsteinFast<N>::Streamer(TBuffer &R__b) {
+  if (R__b.IsReading()) {
+    UInt_t R__s, R__c;
+    Version_t R__v = R__b.ReadVersion(&R__s, &R__c);
+    R__b.ReadClassBuffer(RooBernsteinFast::Class(), this, R__v, R__s, R__c);
 
-  typedef ROOT::Math::SMatrix<double,N+1,N+1,ROOT::Math::MatRepStd<double,N+1,N+1> > MType;
-  typedef ROOT::Math::SVector<double,N+1> VType;
-
-  RooRealProxy _x;
-  RooListProxy _coefList ;
-  MType _cmatrix;            //conversion matrix between bernstein and power bases
-  VType _rvector;            //vector of integration coefficients
-  mutable VType _bernvector; //coefficients in bernstein basis
-  mutable VType _powvector;  //coefficients in power basis
-  mutable VType _xvector;    //vector of powers of x variable
-
-  Double_t evaluate() const override
-    {
+    if (R__v < 2) {
+      // Old version stored N coefficients (c0=1 was implicit).
+      // RooBernstein expects N+1 explicit coefficients. Prepend 1.0.
+      TClass *cl = TClass::GetClass("RooBernstein");
+      TDataMember *dm = cl ? cl->GetDataMember("_coefList") : nullptr;
+      if (dm) {
+        auto &proxy = *reinterpret_cast<RooListProxy *>(
+            reinterpret_cast<char *>(static_cast<RooBernstein *>(this)) + dm->GetOffset());
 
-      _bernvector[0] = 1.0;
-      bool changed = false;
-      for (int ipow=1; ipow<=N; ++ipow) {
-        double rval = static_cast<RooAbsReal*>(_coefList.at(ipow-1))->getVal();
-        if (_bernvector[ipow] != rval) {
-          _bernvector[ipow] = rval;
-          changed = true;
+        if (proxy.size() == static_cast<std::size_t>(N)) {
+          RooArgList updated;
+          updated.add(RooRealConstant::value(1.0));
+          updated.add(proxy);
+          proxy.removeAll();
+          proxy.add(updated);
         }
       }
-
-      if (changed) {
-        _powvector = _cmatrix*_bernvector;   
-      }
-
-      double xmin = _x.min();
-      double xmax = _x.max();
-      double x = (_x - xmin) / (xmax - xmin); // rescale to [0,1]
-      _xvector[0] = 1.;
-      for (int ipow=1; ipow<=N; ++ipow) {
-        _xvector[ipow] = x*_xvector[ipow-1];
-      }
-
-      return ROOT::Math::Dot(_powvector,_xvector);
-
     }
-
-  ClassDefOverride(RooBernsteinFast,1) // Polynomial PDF
-};
+  } else {
+    R__b.WriteClassBuffer(RooBernsteinFast::Class(), this);
+  }
+}
 
 #endif

src/RooBernsteinFast.cc

@@ -1,44 +1,5 @@
-/*****************************************************************************
- * Project: RooFit                                                           *
- * Package: RooFitModels                                                     *
- * @(#)root/roofit:$Id: RooBernsteinFast.cxx 44507 2012-06-04 12:30:41Z axel $
- * 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
-// RooBernsteinFast 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 "../interface/RooBernsteinFast.h"
-#include "RooAbsReal.h"
-#include "RooRealVar.h"
-#include "RooArgList.h"
 
-using namespace std;
+using namespace RooFit;
 
-templateClassImp(RooBernsteinCoeffs)
 templateClassImp(RooBernsteinFast)