eic-opticks/u4/U4UniformRand.h

0001 #pragma once
0002 /**
0003 U4UniformRand.h
0004 =================
0005
0006 As this is headeronly and can benefit from a static UU
0007 include this header into a compilation unit with::
0008
0009     #include "U4UniformRand.h"
0010     NP* U4UniformRand::UU = nullptr ;
0011
0012 And where appropriate set the UU to a reference array of randoms.
0013
0014
0015 Headers for random setup:
0016
0017 Randomize.hh
0018     Geant4 level setup that includes Randomize.h and does::
0019
0020         #define G4UniformRand() CLHEP::HepRandom::getTheEngine()->flat()
0021 Randomize.h
0022     CLHEP level setup
0023
0024
0025 Tried to avoid duplication between this and SUniformRand.h using::
0026
0027     #include "Randomize.hh"
0028     typedef SUniformRand<CLHEP::HepRandom> U4UniformRand ;
0029
0030 It kinda works, see sysrap/tests/SUniformRand_test.cc, but runs
0031 into duplicate symbol issues.  So are simply duplicating.
0032
0033 Actually maybe easier to get rid of U4UniformRand::UU and use some
0034 another symbol like SEvt::UU (or SLOG::UU) to hold the randoms as
0035 that can always be made accessible : and avoid duplicate symbols
0036 troubles ?
0037
0038 **/
0039
0040 #include <string>
0041 #include <iomanip>
0042 #include "Randomize.hh"
0043 #include "NPX.h"
0044
0045 struct U4UniformRand
0046 {
0047     static NP* UU ;
0048     static constexpr const double EPSILON = 1e-6 ;
0049
0050     static double Get();
0051     static double Burn(int n);
0052
0053     static void Get(std::vector<double>& uu);
0054     static std::string Desc(int n=10);
0055
0056     static NP* Get(int n);
0057     static int Find(double u, const NP* uu=UU ) ;
0058     static std::string Desc(double u, const NP* uu=UU ) ;
0059 };
0060
0061 inline double U4UniformRand::Get() // static
0062 {
0063     return G4UniformRand();  // ONLY dependency on Geant4/CLHEP is here
0064 }
0065 inline double U4UniformRand::Burn(int n) // static
0066 {
0067     double u = -1. ;
0068     for(int i=0 ; i < n ; i++) u = Get();
0069     return u ;
0070 }
0071 inline void U4UniformRand::Get(std::vector<double>& uu ) // static
0072 {
0073     for(unsigned i=0 ; i < uu.size() ; i++) uu[i] = Get();
0074 }
0075 inline std::string U4UniformRand::Desc(int n )
0076 {
0077     std::vector<double> uu(n) ;
0078     Get(uu);
0079     std::stringstream ss ;
0080     ss << "U4UniformRand::Desc" << std::endl ;
0081     for(int i=0 ; i < n ; i++)
0082     {
0083         ss << std::setw(6) << i
0084            << " " << std::setw(10) << std::fixed << std::setprecision(5) << uu[i]
0085            << std::endl
0086            ;
0087     }
0088     std::string s = ss.str();
0089     return s;
0090 }
0091 inline NP* U4UniformRand::Get(int n)
0092 {
0093     std::vector<double> uu(n) ;
0094     Get(uu);
0095     return NPX::Make<double>(uu) ;
0096 }
0097 inline int U4UniformRand::Find(double u, const NP* uu)
0098 {
0099     return uu ? uu->find_value_index(u, EPSILON) : -2 ;
0100 }
0101 inline std::string U4UniformRand::Desc(double u, const NP* uu)
0102 {
0103     std::stringstream ss ;
0104     ss << "UU["
0105        << std::setw(7) << std::fixed << std::setprecision(5) << u
0106        << " "
0107        << std::setw(6) << Find(u, uu)
0108        << "]"
0109        ;
0110     std::string s = ss.str();
0111     return s;
0112 }
0113