Cache the InversePitch instead of computing it each time.
[u/mrichter/AliRoot.git] / MUON / AliMUONMathieson.cxx
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7e4a628d 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
16/* $Id$ */
17
7e4a628d 18#include "AliMUONMathieson.h"
471035eb 19
20#include "AliLog.h"
a713db22 21#include "AliMUONGeometrySegmentation.h"
7e4a628d 22
471035eb 23#include <TClass.h>
24#include <TMath.h>
25#include <TRandom.h>
7e4a628d 26
27ClassImp(AliMUONMathieson)
28
29//__________________________________________________________________________
a713db22 30 AliMUONMathieson::AliMUONMathieson() :
31 fSqrtKx3(0.),
32 fKx2(0.),
33 fKx4(0.),
34 fSqrtKy3(0.),
35 fKy2(0.),
36 fKy4(0.),
8bd8c4ce 37 fPitch(0.),
38 fInversePitch(0.)
7e4a628d 39{
40// Default constructor
41
42}
43
44 //__________________________________________________________________________
45void AliMUONMathieson::SetSqrtKx3AndDeriveKx2Kx4(Float_t SqrtKx3)
46{
47 // Set to "SqrtKx3" the Mathieson parameter K3 ("fSqrtKx3")
48 // in the X direction, perpendicular to the wires,
49 // and derive the Mathieson parameters K2 ("fKx2") and K4 ("fKx4")
50 // in the same direction
51 fSqrtKx3 = SqrtKx3;
52 fKx2 = TMath::Pi() / 2. * (1. - 0.5 * fSqrtKx3);
53 Float_t cx1 = fKx2 * fSqrtKx3 / 4. / TMath::ATan(Double_t(fSqrtKx3));
54 fKx4 = cx1 / fKx2 / fSqrtKx3;
55}
56
57 //__________________________________________________________________________
58void AliMUONMathieson::SetSqrtKy3AndDeriveKy2Ky4(Float_t SqrtKy3)
59{
60 // Set to "SqrtKy3" the Mathieson parameter K3 ("fSqrtKy3")
61 // in the Y direction, along the wires,
62 // and derive the Mathieson parameters K2 ("fKy2") and K4 ("fKy4")
63 // in the same direction
64 fSqrtKy3 = SqrtKy3;
65 fKy2 = TMath::Pi() / 2. * (1. - 0.5 * fSqrtKy3);
66 Float_t cy1 = fKy2 * fSqrtKy3 / 4. / TMath::ATan(Double_t(fSqrtKy3));
67 fKy4 = cy1 / fKy2 / fSqrtKy3;
68}
7e4a628d 69
471035eb 70//_____________________________________________________________________________
71Float_t
72AliMUONMathieson::IntXY(Float_t xi1, Float_t yi1, Float_t xi2, Float_t yi2) const
73{
8bd8c4ce 74 //
75 // Integrate the Mathieson over x and y
76 //
77 xi1 *= fInversePitch;
78 xi2 *= fInversePitch;
79 yi1 *= fInversePitch;
80 yi2 *= fInversePitch;
471035eb 81 //
82 // The Mathieson function
83 Double_t ux1=fSqrtKx3*TMath::TanH(fKx2*xi1);
84 Double_t ux2=fSqrtKx3*TMath::TanH(fKx2*xi2);
85
86 Double_t uy1=fSqrtKy3*TMath::TanH(fKy2*yi1);
87 Double_t uy2=fSqrtKy3*TMath::TanH(fKy2*yi2);
88
89
90 return Float_t(4.*fKx4*(TMath::ATan(ux2)-TMath::ATan(ux1))*
91 fKy4*(TMath::ATan(uy2)-TMath::ATan(uy1)));
92}
93
a713db22 94// -------------------------------------------
95Float_t AliMUONMathieson::IntXY(Int_t idDE, AliMUONGeometrySegmentation* segmentation)
96{
97// Calculate charge on current pad according to Mathieson distribution
98// using Detection elt
a713db22 99//
100// Integration limits defined by segmentation model
101//
102 Float_t xi1, xi2, yi1, yi2;
103 segmentation->IntegrationLimits(idDE, xi1,xi2,yi1,yi2);
471035eb 104 return IntXY(xi1,yi1,xi2,yi2);
a713db22 105}
8bd8c4ce 106
107//______________________________________________________________________________
108void
109AliMUONMathieson::SetPitch(Float_t p1)
110{
111 //
112 // Defines the pitch, and store its inverse, which is what is used in fact.
113 //
114 fPitch = p1;
115 if ( fPitch )
116 {
117 fInversePitch = 1/fPitch;
118 }
119 else
120 {
121 AliError(Form("Invalid pitch %e",p1));
122 fInversePitch = 0.0;
123 }
124}
125