Faster simulation algorithm for SDD
[u/mrichter/AliRoot.git] / ITS / AliITSetfSDD.cxx
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b0f5e3fc 1/**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
3 * *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
6 * *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
15
b0f5e3fc 16#include <iostream.h>
17#include <TMath.h>
18#include "AliITSetfSDD.h"
19
20////////////////////////////////////////////////////////////////////////
21// Version: 0
22// Written by Piergiorgio Cerello
23// November 23 1999
24//
b0f5e3fc 25//_____________________________________________________________________________
b669392e 26
27
b0f5e3fc 28ClassImp(AliITSetfSDD)
29
30Int_t ppower(Int_t b, Int_t e) {
e8189707 31 Int_t power = 1;
32 for(Int_t i=0; i<e; i++) power *= b;
b0f5e3fc 33 return power;
34}
35
e8189707 36AliITSetfSDD::AliITSetfSDD(Double_t timestep)
b0f5e3fc 37{
38 // sampling time in ns
e8189707 39
40 fSamplingTime = timestep;
41
b0f5e3fc 42 fT0 = 0.;
b669392e 43 fDf = ppower(10,9)/(kMaxNofSamples*fSamplingTime);
b0f5e3fc 44 fA0 = 9000.;
45
e8189707 46 Int_t i,j;
b669392e 47 for(i=0; i<kMaxNofPoles; i++) {
e8189707 48 fZeroM[i] = 0.;
49 fZeroR[i] = 0.;
50 fZeroI[i] = 0.;
51 fPoleM[i] = 0.;
52 fPoleR[i] = 0.;
53 fPoleI[i] = 0.;
b0f5e3fc 54 }
e8189707 55 fPoleM[0] = 1.;
56 fPoleR[0] = -2100000.;
57 fPoleI[0] = fPoleR[0];
58 fPoleM[1] = 1.;
59 fPoleR[1] = -2100000.;
60 fPoleI[1] = -fPoleR[1];
b0f5e3fc 61
62 // Compute Transfer Function
63
64 Double_t PI = acos(-1.);
b669392e 65 for(i=0; i<=kMaxNofSamples/2; i++) {
b0f5e3fc 66 Double_t frequency = fDf*i;
67 Double_t VM = fA0;
68 Double_t VA = 0.;
b669392e 69 for(Int_t k=0; k<kMaxNofPoles; k++) {
e8189707 70 if(fZeroM[k]) {
71 Double_t VZR = -fZeroR[k];
72 Double_t VZI = frequency - fZeroI[k];
b0f5e3fc 73 Double_t VZM = TMath::Sqrt(VZR*VZR+VZI*VZI);
74 Double_t VZA = TMath::ATan2(VZI,VZR);
75 // cout << "VZM: " << VZM << ", VZA: " << VZA << endl;
76 // cout << "VZR: " << VZR << ", VZI: " << VZI << endl;
e8189707 77 for(j=1; j<= (Int_t) fZeroM[k]; j++) {
b0f5e3fc 78 VM *= VZM;
79 VA += VZA;
80 if(VA >= PI) VA -= (2.*PI);
81 if(VA <= -PI) VA += (2.*PI);
82 //cout << "VM: " << VM << ", VA: " << VA << endl;
83 }
84 }
85
e8189707 86 if(fPoleM[k]) {
87 Double_t VPR = -fPoleR[k];
88 Double_t VPI = frequency - fPoleI[k];
b0f5e3fc 89 Double_t VPM = TMath::Sqrt(VPR*VPR+VPI*VPI);
90 Double_t VPA = TMath::ATan2(VPI,VPR);
91 //cout << "VPM: " << VPM << ", VPA: " << VPA << endl;
92 //cout << "VPR: " << VPR << ", VPI: " << VPI << endl;
e8189707 93 for(j=1; j<= (Int_t) fPoleM[k]; j++) {
b0f5e3fc 94 VM /= VPM;
95 VA -= VPA;
96 if(VA >= PI) VA -= (2.*PI);
97 if(VA <= -PI) VA += (2.*PI);
98 //cout << "VM: " << VM << ", VA: " << VA << endl;
99 }
100 }
101 Double_t VR = VM*cos(VA);
102 Double_t VI = VM*sin(VA);
103 //cout << "VM: " << VM << ", VA: " << VA << endl;
104 //cout << "VR: " << VR << ", VI: " << VI << endl;
e8189707 105 fTfR[i] = VR*ppower(10,9);
106 fTfI[i] = VI*ppower(10,9);
107 //cout << "fTfR[" << i << "] = " << fTfR[i] << endl;
108 //cout << "fTfI[" << i << "] = " << fTfI[i] << endl;
b0f5e3fc 109 if(i) {
b669392e 110 fTfR[kMaxNofSamples-i] = fTfR[i];
111 fTfI[kMaxNofSamples-i] = -fTfI[i];
b0f5e3fc 112 }
113 }
114 }
115
116 // Compute Fourier Weights
117
b669392e 118 for(i=0; i<=kMaxNofSamples/2; i++) {
119 fWR[i] = cos(-2.*PI*i/kMaxNofSamples);
120 fWI[i] = sin(-2.*PI*i/kMaxNofSamples);
b0f5e3fc 121 if(i) {
b669392e 122 fWR[kMaxNofSamples-i] = fWR[i];
123 fWI[kMaxNofSamples-i] = -fWI[i];
b0f5e3fc 124 }
125 }
126
127}
128
e8189707 129void AliITSetfSDD::PrintElectronics()
b0f5e3fc 130{
b0f5e3fc 131 cout << "Sampling Time " << fSamplingTime << endl;
b669392e 132 cout << "Number of Time Samples " << kMaxNofSamples << endl;
b0f5e3fc 133 cout << "fT0 " << fT0 << endl;
134 cout << "fDf " << fDf << endl;
135 cout << "fA0 " << fA0 << endl;
136
137 cout << "Zero's and Pole's" << endl;
e8189707 138 cout << "fZeroM " << endl;
139 Int_t i;
b669392e 140 for(i=0; i<kMaxNofPoles; i++) cout << fZeroM[i] << endl;
b0f5e3fc 141 cout << "fZero_R " << endl;
b669392e 142 for(i=0; i<kMaxNofPoles; i++) cout << fZeroR[i] << endl;
e8189707 143 cout << "fZeroI " << endl;
b669392e 144 for(i=0; i<kMaxNofPoles; i++) cout << fZeroI[i] << endl;
e8189707 145 cout << "fPoleM " << endl;
b669392e 146 for(i=0; i<kMaxNofPoles; i++) cout << fPoleM[i] << endl;
e8189707 147 cout << "fPoleR " << endl;
b669392e 148 for(i=0; i<kMaxNofPoles; i++) cout << fPoleR[i] << endl;
e8189707 149 cout << "fPoleI " << endl;
b669392e 150 for(i=0; i<kMaxNofPoles; i++) cout << fPoleI[i] << endl;
b0f5e3fc 151
152 cout << "Transfer function" << endl;
153 cout << "Real Part" << endl;
b669392e 154 for(i=0; i<kMaxNofSamples; i++) cout << fTfR[i] << endl;
b0f5e3fc 155 cout << "Imaginary Part " << endl;
b669392e 156 for(i=0; i<kMaxNofSamples; i++) cout << fTfI[i] << endl;
b0f5e3fc 157
158 cout << "Fourier Weights" << endl;
159 cout << "Real Part" << endl;
b669392e 160 for(i=0; i<kMaxNofSamples; i++) cout << fWR[i] << endl;
b0f5e3fc 161 cout << "Imaginary Part " << endl;
b669392e 162 for(i=0; i<kMaxNofSamples; i++) cout << fWI[i] << endl;
b0f5e3fc 163}
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