root/RooStats/SequentialProposal.h

0001 // @(#)root/roostats:$Id$
0002 // Authors: Giovanni Petrucciani 4/21/2011
0003 /*************************************************************************
0004  * Copyright (C) 1995-2008, Rene Brun and Fons Rademakers.               *
0005  * All rights reserved.                                                  *
0006  *                                                                       *
0007  * For the licensing terms see $ROOTSYS/LICENSE.                         *
0008  * For the list of contributors see $ROOTSYS/README/CREDITS.             *
0009  *************************************************************************/
0010
0011 #ifndef RooStats_SequentialProposal
0012 #define RooStats_SequentialProposal
0013
0014 #include "Rtypes.h"
0015 #include "RooStats/ProposalFunction.h"
0016 #include "RooArgSet.h"
0017
0018 namespace RooStats {
0019
0020 class SequentialProposal : public ProposalFunction {
0021
0022    public:
0023    SequentialProposal() : RooStats::ProposalFunction(), fDivisor(0) {}
0024       SequentialProposal(double divisor) ;
0025
0026       /// Populate xPrime with a new proposed point
0027       void Propose(RooArgSet& xPrime, RooArgSet& x) override;
0028
0029       /// Determine whether or not the proposal density is symmetric for
0030       /// points x1 and x2 - that is, whether the probability of reaching x2
0031       /// from x1 is equal to the probability of reaching x1 from x2
0032       bool IsSymmetric(RooArgSet& x1, RooArgSet& x2) override ;
0033
0034       /// Return the probability of proposing the point x1 given the starting
0035       /// point x2
0036       double GetProposalDensity(RooArgSet& x1, RooArgSet& x2) override;
0037
0038       ClassDefOverride(SequentialProposal,1) // A concrete implementation of ProposalFunction, that uniformly samples the parameter space.
0039
0040     private:
0041
0042       double fDivisor;
0043 };
0044
0045 }
0046
0047 #endif