include/root/RooInvTransform.h

0001 /*****************************************************************************
0002  * Project: RooFit                                                           *
0003  * Package: RooFitCore                                                       *
0004  *    File: $Id: RooInvTransform.h,v 1.6 2007/05/11 09:11:30 verkerke Exp $
0005  * Authors:                                                                  *
0006  *   WV, Wouter Verkerke, UC Santa Barbara, verkerke@slac.stanford.edu       *
0007  *   DK, David Kirkby,    UC Irvine,         dkirkby@uci.edu                 *
0008  *                                                                           *
0009  * Copyright (c) 2000-2005, Regents of the University of California          *
0010  *                          and Stanford University. All rights reserved.    *
0011  *                                                                           *
0012  * Redistribution and use in source and binary forms,                        *
0013  * with or without modification, are permitted according to the terms        *
0014  * listed in LICENSE (http://roofit.sourceforge.net/license.txt)             *
0015  *****************************************************************************/
0016 #ifndef ROO_INV_TRANSFORM
0017 #define ROO_INV_TRANSFORM
0018
0019 #include "RooAbsFunc.h"
0020
0021 class RooInvTransform : public RooAbsFunc {
0022 public:
0023   RooInvTransform(const RooAbsFunc &func);
0024
0025   inline double operator()(const double xvector[]) const override {
0026     double xinv= 1./xvector[0];
0027     return (*_func)(&xinv)*xinv*xinv;
0028   }
0029   inline double getMinLimit(UInt_t index) const override { return 1/_func->getMaxLimit(index); }
0030   inline double getMaxLimit(UInt_t index) const override { return 1/_func->getMinLimit(index); }
0031
0032 protected:
0033   const RooAbsFunc *_func; ///< Input function binding
0034
0035   ClassDefOverride(RooInvTransform,0) // Function binding returning inverse of other function binding
0036 };
0037
0038 #endif
0039