include/root/TFoamSampler.h

0001 // @(#)root/mathcore:$Id$
0002 // Author: L. Moneta Fri Sep 22 15:06:47 2006
0003
0004 /**********************************************************************
0005  *                                                                    *
0006  * Copyright (c) 2006  LCG ROOT Math Team, CERN/PH-SFT                *
0007  *                                                                    *
0008  *                                                                    *
0009  **********************************************************************/
0010 // Header file for class TFoamSampler
0011
0012 #ifndef ROOT_TFoamSampler
0013 #define ROOT_TFoamSampler
0014
0015
0016 #include "Math/DistSampler.h"
0017
0018
0019 namespace ROOT {
0020
0021    namespace Fit {
0022
0023       class DataRange;
0024       class BinData;
0025       class UnBinData;
0026    }
0027
0028    namespace Math {
0029    }
0030 }
0031
0032 class TFoamIntegrand;
0033
0034
0035 class TRandom;
0036 class TF1;
0037 class TFoam;
0038
0039 class TFoamSampler : public ROOT::Math::DistSampler {
0040
0041 public:
0042
0043    /// default constructor
0044    TFoamSampler();
0045
0046
0047    /// virtual destructor
0048    ~TFoamSampler() override;
0049
0050
0051    using DistSampler::SetFunction;
0052
0053    /// set the parent function distribution to use for random sampling (one dim case)
0054    void SetFunction(const ROOT::Math::IGenFunction & func) override  {
0055       fFunc1D = &func;
0056       SetFunction<const ROOT::Math::IGenFunction>(func, 1);
0057    }
0058
0059    /// set the Function using a TF1 pointer
0060    void SetFunction(TF1 * pdf);
0061
0062
0063    /**
0064       initialize the generators with the default options
0065    */
0066    bool Init(const char * = "") override;
0067
0068    /**
0069       initialize the generators with the given options
0070    */
0071    bool Init(const ROOT::Math::DistSamplerOptions & opt ) override;
0072
0073    /**
0074        Set the random engine to be used
0075        Needs to be called before Init to have effect
0076    */
0077    void SetRandom(TRandom * r) override;
0078
0079    /**
0080        Set the random seed for the TRandom instances used by the sampler
0081        classes
0082        Needs to be called before Init to have effect
0083    */
0084    void SetSeed(unsigned int seed) override;
0085
0086
0087    /**
0088       Get the random engine used by the sampler
0089     */
0090    TRandom * GetRandom() override;
0091
0092
0093    /**
0094       sample one event in multi-dimension by filling the given array
0095       return false if sampling failed
0096    */
0097    bool Sample(double * x) override;
0098
0099    /**
0100       sample one bin given an estimated of the pdf in the bin
0101       (this can be function value at the center or its integral in the bin
0102       divided by the bin width)
0103       By default do not do random sample, just return the function values
0104     */
0105    bool SampleBin(double prob, double & value, double *error = nullptr) override;
0106
0107
0108
0109 protected:
0110
0111
0112 private:
0113
0114 //    bool                              fOneDim;      // flag to indicate if the function is 1 dimension
0115 //    bool                              fHasMode;     // flag to indicate if a mode is set
0116 //    bool                              fHasArea;     // flag to indicate if a area is set
0117 //    double                            fMode;        // mode of dist
0118 //    double                            fArea;        // area of dist
0119    const ROOT::Math::IGenFunction *  fFunc1D;      // 1D function pointer
0120    TFoam *                           fFoam;        // foam engine class
0121    TFoamIntegrand *                  fFoamDist;    // foam distribution interface
0122
0123    //ClassDefOverride(TFoamSampler,1)  //Distribution sampler class based on FOAM
0124
0125 };
0126
0127
0128
0129 #endif /* ROOT_TFoamSampler */