File indexing completed on 2023-03-17 13:02:38
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0005 #include "Geometry/CommonTopologies/interface/GEMStripTopology.h"
0006 #include "FWCore/MessageLogger/interface/MessageLogger.h"
0007 #include <iostream>
0008 #include <cmath>
0009 #include <algorithm>
0010
0011 GEMStripTopology::GEMStripTopology(int ns, float aw, float dh, float r0)
0012 : numberOfStrips_(ns), angularWidth_(aw), detHeight_(dh), centreToIntersection_(r0) {
0013 assert(angularWidth_ != 0);
0014 assert(detHeight_ != 0);
0015 yAxisOrientation_ = 1;
0016 phiOfOneEdge_ = -(0.5 * numberOfStrips_) * angularWidth_ * yAxisOrientation_;
0017 yCentre_ = 0;
0018 LogTrace("GEMStripTopology") << "Constructing GEMStripTopology with"
0019 << " nstrips = " << ns << " angular width = " << aw << " det. height = " << dh
0020 << " r0 = " << r0 << "\n";
0021 }
0022
0023 GEMStripTopology::GEMStripTopology(int ns, float aw, float dh, float r0, float yAx)
0024 : numberOfStrips_(ns), angularWidth_(aw), detHeight_(dh), centreToIntersection_(r0), yAxisOrientation_(yAx) {
0025 assert(angularWidth_ != 0);
0026 assert(detHeight_ != 0);
0027 phiOfOneEdge_ = -(0.5 * numberOfStrips_) * angularWidth_ * yAxisOrientation_;
0028 yCentre_ = 0;
0029 LogTrace("GEMStripTopology") << "Constructing GEMStripTopology with"
0030 << " nstrips = " << ns << " angular width = " << aw << " det. height = " << dh
0031 << " r0 = " << r0 << " yAxOrientation = " << yAx << "\n";
0032 }
0033
0034 LocalPoint GEMStripTopology::localPosition(float strip) const {
0035 return LocalPoint(yAxisOrientation() * originToIntersection() * tan(stripAngle(strip)), 0);
0036 }
0037
0038 LocalPoint GEMStripTopology::localPosition(const MeasurementPoint& mp) const {
0039 const float
0040 y(mp.y() * detHeight() + yCentreOfStripPlane()),
0041 x(yAxisOrientation() * yDistanceToIntersection(y) * std::tan(stripAngle(mp.x())));
0042 return LocalPoint(x, y);
0043 }
0044
0045 LocalError GEMStripTopology::localError(float strip, float stripErr2) const {
0046 const double phi(stripAngle(strip)), t1(std::tan(phi)), t2(t1 * t1),
0047 tt(stripErr2 * std::pow(centreToIntersection() * angularWidth(), 2)),
0048 rr(std::pow(detHeight(), 2) * (1.f / 12.f)),
0049
0050 xx(tt + t2 * rr), yy(t2 * tt + rr), xy(t1 * (rr - tt));
0051
0052 return LocalError(xx, xy, yy);
0053 }
0054
0055 LocalError GEMStripTopology::localError(const MeasurementPoint& mp, const MeasurementError& me) const {
0056 const double phi(stripAngle(mp.x())), s1(std::sin(phi)), c1(std::cos(phi));
0057 assert(c1 != 0);
0058 const double cs(s1 * c1), s2(s1 * s1),
0059 c2(1 - s2),
0060
0061 T(angularWidth() * (centreToIntersection() + yAxisOrientation() * mp.y() * detHeight()) /
0062 c1),
0063 R(detHeight() / c1),
0064 tt(me.uu() * T * T),
0065 rr(me.vv() * R * R),
0066 tr(me.uv() * T * R),
0067
0068 xx(c2 * tt + 2 * cs * tr + s2 * rr), yy(s2 * tt - 2 * cs * tr + c2 * rr), xy(cs * (rr - tt) + tr * (c2 - s2));
0069
0070 return LocalError(xx, xy, yy);
0071 }
0072
0073 float GEMStripTopology::strip(const LocalPoint& lp) const {
0074 const float
0075 phi(std::atan2(lp.x(), yDistanceToIntersection(lp.y()))),
0076 aStrip((phi - yAxisOrientation() * phiOfOneEdge()) / angularWidth());
0077 return std::max(float(0), std::min((float)nstrips(), aStrip));
0078 }
0079
0080 int GEMStripTopology::nearestStrip(const LocalPoint& lp) const {
0081 return std::min(nstrips(), static_cast<int>(std::max(float(0), strip(lp))) + 1);
0082 }
0083
0084 MeasurementPoint GEMStripTopology::measurementPosition(const LocalPoint& lp) const {
0085 const float
0086 phi(yAxisOrientation() * std::atan2(lp.x(), yDistanceToIntersection(lp.y())));
0087 return MeasurementPoint(yAxisOrientation() * (phi - phiOfOneEdge()) / angularWidth(),
0088 (lp.y() - yCentreOfStripPlane()) / detHeight());
0089 }
0090
0091 MeasurementError GEMStripTopology::measurementError(const LocalPoint& p, const LocalError& e) const {
0092 const double yHitToInter(yDistanceToIntersection(p.y()));
0093 assert(yHitToInter != 0);
0094 const double t(yAxisOrientation() * p.x() / yHitToInter),
0095 cs(t / (1 + t * t)), s2(t * cs), c2(1 - s2),
0096
0097 T2(1. / (std::pow(angularWidth(), 2) *
0098 (std::pow(p.x(), 2) + std::pow(yHitToInter, 2)))),
0099 R2(c2 / std::pow(detHeight(), 2)),
0100
0101 uu((c2 * e.xx() - 2 * cs * e.xy() + s2 * e.yy()) * T2), vv((s2 * e.xx() + 2 * cs * e.xy() + c2 * e.yy()) * R2),
0102 uv((cs * (e.xx() - e.yy()) + e.xy() * (c2 - s2)) * std::sqrt(T2 * R2));
0103
0104 return MeasurementError(uu, uv, vv);
0105 }
0106
0107 int GEMStripTopology::channel(const LocalPoint& lp) const { return std::min(int(strip(lp)), numberOfStrips_ - 1); }
0108
0109 float GEMStripTopology::pitch() const { return localPitch(LocalPoint(0, 0)); }
0110
0111 float GEMStripTopology::localPitch(const LocalPoint& lp) const {
0112 const int istrip = std::min(nstrips(), static_cast<int>(strip(lp)) + 1);
0113 const float fangle = stripAngle(static_cast<float>(istrip) - 0.5);
0114 assert(std::cos(fangle - 0.5f * angularWidth()) != 0);
0115 return yDistanceToIntersection(lp.y()) * std::sin(angularWidth()) /
0116 std::pow(std::cos(fangle - 0.5f * angularWidth()), 2);
0117 }
0118
0119 float GEMStripTopology::stripAngle(float strip) const {
0120 return phiOfOneEdge() + yAxisOrientation() * strip * angularWidth();
0121 }
0122
0123 float GEMStripTopology::localStripLength(const LocalPoint& lp) const {
0124 assert(yDistanceToIntersection(lp.y()) != 0);
0125 return detHeight() * std::sqrt(1.f + std::pow(lp.x() / yDistanceToIntersection(lp.y()), 2));
0126 }
0127
0128 float GEMStripTopology::yDistanceToIntersection(float y) const {
0129 return yAxisOrientation() * y + originToIntersection();
0130 }
0131
0132 float GEMStripTopology::xOfStrip(int strip, float y) const {
0133 return yAxisOrientation() * yDistanceToIntersection(y) * std::tan(stripAngle(static_cast<float>(strip) - 0.5));
0134 }