From 2ceedb0cd2d93cde294cf74acffef8a1a5494270 Mon Sep 17 00:00:00 2001 From: shahoian Date: Wed, 1 Oct 2025 14:20:45 +0200 Subject: [PATCH] Suppress reduntant versions of HelixHelper --- .../DCAFitter/include/DCAFitter/HelixHelper.h | 307 ------------------ .../include/DetectorsVertexing/HelixHelper.h | 307 ------------------ 2 files changed, 614 deletions(-) delete mode 100644 Common/DCAFitter/include/DCAFitter/HelixHelper.h delete mode 100644 Detectors/Vertexing/include/DetectorsVertexing/HelixHelper.h diff --git a/Common/DCAFitter/include/DCAFitter/HelixHelper.h b/Common/DCAFitter/include/DCAFitter/HelixHelper.h deleted file mode 100644 index d197cba256c0e..0000000000000 --- a/Common/DCAFitter/include/DCAFitter/HelixHelper.h +++ /dev/null @@ -1,307 +0,0 @@ -// Copyright 2019-2020 CERN and copyright holders of ALICE O2. -// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders. -// All rights not expressly granted are reserved. -// -// This software is distributed under the terms of the GNU General Public -// License v3 (GPL Version 3), copied verbatim in the file "COPYING". -// -// In applying this license CERN does not waive the privileges and immunities -// granted to it by virtue of its status as an Intergovernmental Organization -// or submit itself to any jurisdiction. - -/// \file HelixHelper.h -/// \brief Helper classes for helical tracks manipulations -/// \author ruben.shahoyan@cern.ch - -#ifndef _ALICEO2_HELIX_HELPER_ -#define _ALICEO2_HELIX_HELPER_ - -#include "CommonConstants/MathConstants.h" -#include "MathUtils/Utils.h" -#include "MathUtils/Primitive2D.h" - -namespace o2 -{ -namespace track -{ - -///__________________________________________________________________________ -//< precalculated track radius, center, alpha sin,cos and their combinations -struct TrackAuxPar : public o2::math_utils::CircleXYf_t { - float c, s, cc, ss, cs; // cos ans sin of track alpha and their products - - GPUdDefault() TrackAuxPar() = default; - - template - GPUd() TrackAuxPar(const T& trc, float bz) - { - set(trc, bz); - } - GPUd() float cosDif(const TrackAuxPar& t) const { return c * t.c + s * t.s; } // cos(alpha_this - alha_t) - GPUd() float sinDif(const TrackAuxPar& t) const { return s * t.c - c * t.s; } // sin(alpha_this - alha_t) - - template - GPUd() void set(const T& trc, float bz) - { - trc.getCircleParams(bz, *this, s, c); - cc = c * c; - ss = s * s; - cs = c * s; - } - ClassDefNV(TrackAuxPar, 1); -}; - -//__________________________________________________________ -//< crossing coordinates of 2 circles -struct CrossInfo { - static constexpr float MaxDistXYDef = 10.; - float xDCA[2] = {}; - float yDCA[2] = {}; - int nDCA = 0; - - GPUd() int circlesCrossInfo(const TrackAuxPar& trax0, const TrackAuxPar& trax1, float maxDistXY = MaxDistXYDef, bool isCollinear = false) - { - const auto& trcA = trax0.rC > trax1.rC ? trax0 : trax1; // designate the largest circle as A - const auto& trcB = trax0.rC > trax1.rC ? trax1 : trax0; - nDCA = 0; - float xDist = trcB.xC - trcA.xC, yDist = trcB.yC - trcA.yC; - float dist2 = xDist * xDist + yDist * yDist, dist = o2::gpu::GPUCommonMath::Sqrt(dist2), rsum = trcA.rC + trcB.rC; - if (dist < 1e-12) { - return nDCA; // circles are concentric? - } - if (dist > rsum) { // circles don't touch, chose a point in between - // the parametric equation of lines connecting the centers is - // x = x0 + t/dist * (x1-x0), y = y0 + t/dist * (y1-y0) - if (dist - rsum > maxDistXY) { // too large distance - return nDCA; - } - notTouchingXY(dist, xDist, yDist, trcA, trcB.rC, isCollinear); - } else if (auto dfr = dist + trcB.rC - trcA.rC; dfr < 0.) { // the small circle is nestled into large one w/o touching - if (dfr > -maxDistXY) { - // select the point of closest approach of 2 circles - notTouchingXY(dist, xDist, yDist, trcA, -trcB.rC, isCollinear); - } else { - return nDCA; - } - } else { // 2 intersection points - if (isCollinear) { - /// collinear tracks, e.g. electrons from photon conversion - /// if there are 2 crossings of the circle it is better to take - /// a weighted average of the crossing points as a radius - float r2r = trcA.rC + trcB.rC; - float r1_r = trcA.rC / r2r; - float r2_r = trcB.rC / r2r; - xDCA[0] = r2_r * trcA.xC + r1_r * trcB.xC; - yDCA[0] = r2_r * trcA.yC + r1_r * trcB.yC; - nDCA = 1; - } else if (o2::gpu::GPUCommonMath::Abs(xDist) < o2::gpu::GPUCommonMath::Abs(yDist)) { - // to simplify calculations, we move to new frame x->x+Xc0, y->y+Yc0, so that - // the 1st one is centered in origin - float a = (trcA.rC * trcA.rC - trcB.rC * trcB.rC + dist2) / (2. * yDist), b = -xDist / yDist, ab = a * b, bb = b * b; - float det = ab * ab - (1. + bb) * (a * a - trcA.rC * trcA.rC); - if (det > 0.) { - det = o2::gpu::GPUCommonMath::Sqrt(det); - xDCA[0] = (-ab + det) / (1. + b * b); - yDCA[0] = a + b * xDCA[0] + trcA.yC; - xDCA[0] += trcA.xC; - xDCA[1] = (-ab - det) / (1. + b * b); - yDCA[1] = a + b * xDCA[1] + trcA.yC; - xDCA[1] += trcA.xC; - nDCA = 2; - } else { // due to the finite precision the det<=0, i.e. the circles are barely touching, fall back to this special case - notTouchingXY(dist, xDist, yDist, trcA, trcB.rC); - } - } else { - float a = (trcA.rC * trcA.rC - trcB.rC * trcB.rC + dist2) / (2. * xDist), b = -yDist / xDist, ab = a * b, bb = b * b; - float det = ab * ab - (1. + bb) * (a * a - trcA.rC * trcA.rC); - if (det > 0.) { - det = o2::gpu::GPUCommonMath::Sqrt(det); - yDCA[0] = (-ab + det) / (1. + bb); - xDCA[0] = a + b * yDCA[0] + trcA.xC; - yDCA[0] += trcA.yC; - yDCA[1] = (-ab - det) / (1. + bb); - xDCA[1] = a + b * yDCA[1] + trcA.xC; - yDCA[1] += trcA.yC; - nDCA = 2; - } else { // due to the finite precision the det<=0, i.e. the circles are barely touching, fall back to this special case - notTouchingXY(dist, xDist, yDist, trcA, trcB.rC); - } - } - } - return nDCA; - } - - GPUd() void notTouchingXY(float dist, float xDist, float yDist, const TrackAuxPar& trcA, float rBSign, bool isCollinear = false) - { - if (isCollinear) { - /// for collinear tracks it is better to take - /// a weighted average of the crossing points as a radius - float r2r = trcA.rC + rBSign; - float r1_r = trcA.rC / r2r; - float r2_r = rBSign / r2r; - xDCA[0] = r2_r * trcA.xC + r1_r * (xDist + trcA.xC); - yDCA[0] = r2_r * trcA.yC + r1_r * (yDist + trcA.yC); - } else { - // fast method to calculate DCA between 2 circles, assuming that they don't touch each outer: - // the parametric equation of lines connecting the centers is x = xA + t/dist * xDist, y = yA + t/dist * yDist - // with xA,yY being the center of the circle A ( = trcA.xC, trcA.yC ), xDist = trcB.xC = trcA.xC ... - // There are 2 special cases: - // (a) small circle is inside the large one: provide rBSign as -trcB.rC - // (b) circle are side by side: provide rBSign as trcB.rC - auto t2d = (dist + trcA.rC - rBSign) / dist; - xDCA[0] = trcA.xC + 0.5 * (xDist * t2d); - yDCA[0] = trcA.yC + 0.5 * (yDist * t2d); - } - nDCA = 1; - } - - template - GPUd() int linesCrossInfo(const TrackAuxPar& trax0, const T& tr0, - const TrackAuxPar& trax1, const T& tr1, float maxDistXY = MaxDistXYDef) - { - /// closest approach of 2 straight lines - /// TrackParam propagation can be parameterized in lab in a form - /// xLab(t) = (x*cosAlp - y*sinAlp) + t*(cosAlp - sinAlp* snp/csp) = xLab0 + t*(cosAlp - sinAlp* snp/csp) - /// yLab(t) = (x*sinAlp + y*cosAlp) + t*(sinAlp + cosAlp* snp/csp) = yLab0 + t*(sinAlp + cosAlp* snp/csp) - /// zLab(t) = z + t * tgl / csp = zLab0 + t * tgl / csp - /// where t is the x-step in the track alpha-frame, xLab,yLab,zLab are reference track coordinates in lab - /// frame (filled by TrackAuxPar for straight line tracks). - /// - /// Therefore, for the parametric track equation in lab 3D we have (wrt tracking-X increment t) - /// xL(t) = xL + t Kx; Kx = (cosAlp - sinAlp* snp/csp) - /// yL(t) = yL + t Ky; Ky = (sinAlp + cosAlp* snp/csp) - /// zL(t) = zL + t Kz; Kz = tgl / csp - /// Note that Kx^2 + Ky^2 + Kz^2 = (1+tgl^2) / csp^2 - nDCA = 0; - float dx = trax1.xC - trax0.xC; // for straight line TrackAuxPar stores lab coordinates at referene point!!! - float dy = trax1.yC - trax0.yC; // - float dz = tr1.getZ() - tr0.getZ(); - auto csp0i2 = 1. / tr0.getCsp2(); // 1 / csp^2 - auto csp0i = o2::gpu::GPUCommonMath::Sqrt(csp0i2); - auto tgp0 = tr0.getSnp() * csp0i; - float kx0 = trax0.c - trax0.s * tgp0; - float ky0 = trax0.s + trax0.c * tgp0; - float kz0 = tr0.getTgl() * csp0i; - auto csp1i2 = 1. / tr1.getCsp2(); // 1 / csp^2 - auto csp1i = o2::gpu::GPUCommonMath::Sqrt(csp1i2); - auto tgp1 = tr1.getSnp() * o2::gpu::GPUCommonMath::Sqrt(csp1i2); - float kx1 = trax1.c - trax1.s * tgp1; - float ky1 = trax1.s + trax1.c * tgp1; - float kz1 = tr1.getTgl() * csp1i; - /// Minimize |vecL1 - vecL0|^2 wrt t0 and t1: point of closest approach - /// Leads to system - /// A Dx = B with Dx = {dx0, dx1} - /// with A = - /// | kx0^2+ky0^2+kz0^2 -(kx0*kx1+ky0*ky1+kz0*kz1) | = (1+tgl0^2) / csp0^2 .... - /// | -(kx0*kx1+ky0*ky1+kz0*kz1) kx0^2+ky0^2+kz0^2 | ..... (1+tgl1^2) / csp1^2 - /// and B = {(dx Kx0 + dy Ky0 + dz Kz0), -(dx Kx1 + dy Ky1 + dz Kz1) } - /// - float a00 = (1.f + tr0.getTgl() * tr0.getTgl()) * csp0i2, a11 = (1.f + tr1.getTgl() * tr1.getTgl()) * csp1i2, a01 = -(kx0 * kx1 + ky0 * ky1 + kz0 * kz1); - float b0 = dx * kx0 + dy * ky0 + dz * kz0, b1 = -(dx * kx1 + dy * ky1 + dz * kz1); - float det = a00 * a11 - a01 * a01, det0 = b0 * a11 - b1 * a01, det1 = a00 * b1 - a01 * b0; - if (o2::gpu::GPUCommonMath::Sqrt(det) > o2::constants::math::Almost0) { - auto detI = 1. / det; - auto t0 = det0 * detI; - auto t1 = det1 * detI; - float addx0 = kx0 * t0, addy0 = ky0 * t0, addx1 = kx1 * t1, addy1 = ky1 * t1; - dx += addx1 - addx0; // recalculate XY distance at DCA - dy += addy1 - addy0; - if (dx * dx + dy * dy > maxDistXY * maxDistXY) { - return nDCA; - } - xDCA[0] = (trax0.xC + addx0 + trax1.xC + addx1) * 0.5; - yDCA[0] = (trax0.yC + addy0 + trax1.yC + addy1) * 0.5; - nDCA = 1; - } - return nDCA; - } - - template - GPUd() int circleLineCrossInfo(const TrackAuxPar& trax0, const T& tr0, - const TrackAuxPar& trax1, const T& tr1, float maxDistXY = MaxDistXYDef) - { - /// closest approach of line and circle - /// TrackParam propagation can be parameterized in lab in a form - /// xLab(t) = (x*cosAlp - y*sinAlp) + t*(cosAlp - sinAlp* snp/csp) = xLab0 + t*(cosAlp - sinAlp* snp/csp) - /// yLab(t) = (x*sinAlp + y*cosAlp) + t*(sinAlp + cosAlp* snp/csp) = yLab0 + t*(sinAlp + cosAlp* snp/csp) - /// zLab(t) = z + t * tgl / csp = zLab0 + t * tgl / csp - /// where t is the x-step in the track alpha-frame, xLab,yLab,zLab are reference track coordinates in lab - /// frame (filled by TrackAuxPar for straight line tracks). - /// - /// Therefore, for the parametric track equation in lab 3D we have (wrt tracking-X increment t) - /// xL(t) = xL + t Kx; Kx = (cosAlp - sinAlp* snp/csp) - /// yL(t) = yL + t Ky; Ky = (sinAlp + cosAlp* snp/csp) - /// zL(t) = zL + t Kz; Kz = tgl / csp - /// Note that Kx^2 + Ky^2 = 1 / csp^2 - - const auto& traxH = trax0.rC > trax1.rC ? trax0 : trax1; // circle (for the line rC is set to 0) - const auto& traxL = trax0.rC > trax1.rC ? trax1 : trax0; // line - const auto& trcL = trax0.rC > trax1.rC ? tr1 : tr0; // track of the line - - // solve quadratic equation of line crossing the circle - float dx = traxL.xC - traxH.xC; // X distance between the line lab reference and circle center - float dy = traxL.yC - traxH.yC; // Y... - // t^2(kx^2+ky^2) + 2t(dx*kx+dy*ky) + dx^2 + dy^2 - r^2 = 0 - auto cspi2 = 1. / trcL.getCsp2(); // 1 / csp^2 == kx^2 + ky^2 - auto cspi = o2::gpu::GPUCommonMath::Sqrt(cspi2); - auto tgp = trcL.getSnp() * cspi; - float kx = traxL.c - traxL.s * tgp; - float ky = traxL.s + traxL.c * tgp; - double dk = dx * kx + dy * ky; - double det = dk * dk - cspi2 * (dx * dx + dy * dy - traxH.rC * traxH.rC); - if (det > 0) { // 2 crossings - det = o2::gpu::GPUCommonMath::Sqrt(det); - float t0 = (-dk + det) * cspi2; - float t1 = (-dk - det) * cspi2; - xDCA[0] = traxL.xC + kx * t0; - yDCA[0] = traxL.yC + ky * t0; - xDCA[1] = traxL.xC + kx * t1; - yDCA[1] = traxL.yC + ky * t1; - nDCA = 2; - } else { - // there is no crossing, find the point of the closest approach on the line which is closest to the circle center - float t = -dk * cspi2; - float xL = traxL.xC + kx * t, yL = traxL.yC + ky * t; // point on the line, need to average with point on the circle - float dxc = xL - traxH.xC, dyc = yL - traxH.yC, dist = o2::gpu::GPUCommonMath::Sqrt(dxc * dxc + dyc * dyc); - if (dist - traxH.rC > maxDistXY) { // too large distance - return nDCA; - } - float drcf = traxH.rC / dist; // radius / distance to circle center - float xH = traxH.xC + dxc * drcf, yH = traxH.yC + dyc * drcf; - xDCA[0] = (xL + xH) * 0.5; - yDCA[0] = (yL + yH) * 0.5; - nDCA = 1; - } - return nDCA; - } - - template - GPUd() int set(const TrackAuxPar& trax0, const T& tr0, const TrackAuxPar& trax1, const T& tr1, float maxDistXY = MaxDistXYDef, bool isCollinear = false) - { - // calculate up to 2 crossings between 2 circles - nDCA = 0; - if (trax0.rC > o2::constants::math::Almost0 && trax1.rC > o2::constants::math::Almost0) { // both are not straight lines - nDCA = circlesCrossInfo(trax0, trax1, maxDistXY, isCollinear); - } else if (trax0.rC < o2::constants::math::Almost0 && trax1.rC < o2::constants::math::Almost0) { // both are straigt lines - nDCA = linesCrossInfo(trax0, tr0, trax1, tr1, maxDistXY); - } else { - nDCA = circleLineCrossInfo(trax0, tr0, trax1, tr1, maxDistXY); - } - // - return nDCA; - } - - GPUdDefault() CrossInfo() = default; - - template - GPUd() CrossInfo(const TrackAuxPar& trax0, const T& tr0, const TrackAuxPar& trax1, const T& tr1, float maxDistXY = MaxDistXYDef, bool isCollinear = false) - { - set(trax0, tr0, trax1, tr1, maxDistXY, isCollinear); - } - ClassDefNV(CrossInfo, 1); -}; - -} // namespace track -} // namespace o2 - -#endif diff --git a/Detectors/Vertexing/include/DetectorsVertexing/HelixHelper.h b/Detectors/Vertexing/include/DetectorsVertexing/HelixHelper.h deleted file mode 100644 index d197cba256c0e..0000000000000 --- a/Detectors/Vertexing/include/DetectorsVertexing/HelixHelper.h +++ /dev/null @@ -1,307 +0,0 @@ -// Copyright 2019-2020 CERN and copyright holders of ALICE O2. -// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders. -// All rights not expressly granted are reserved. -// -// This software is distributed under the terms of the GNU General Public -// License v3 (GPL Version 3), copied verbatim in the file "COPYING". -// -// In applying this license CERN does not waive the privileges and immunities -// granted to it by virtue of its status as an Intergovernmental Organization -// or submit itself to any jurisdiction. - -/// \file HelixHelper.h -/// \brief Helper classes for helical tracks manipulations -/// \author ruben.shahoyan@cern.ch - -#ifndef _ALICEO2_HELIX_HELPER_ -#define _ALICEO2_HELIX_HELPER_ - -#include "CommonConstants/MathConstants.h" -#include "MathUtils/Utils.h" -#include "MathUtils/Primitive2D.h" - -namespace o2 -{ -namespace track -{ - -///__________________________________________________________________________ -//< precalculated track radius, center, alpha sin,cos and their combinations -struct TrackAuxPar : public o2::math_utils::CircleXYf_t { - float c, s, cc, ss, cs; // cos ans sin of track alpha and their products - - GPUdDefault() TrackAuxPar() = default; - - template - GPUd() TrackAuxPar(const T& trc, float bz) - { - set(trc, bz); - } - GPUd() float cosDif(const TrackAuxPar& t) const { return c * t.c + s * t.s; } // cos(alpha_this - alha_t) - GPUd() float sinDif(const TrackAuxPar& t) const { return s * t.c - c * t.s; } // sin(alpha_this - alha_t) - - template - GPUd() void set(const T& trc, float bz) - { - trc.getCircleParams(bz, *this, s, c); - cc = c * c; - ss = s * s; - cs = c * s; - } - ClassDefNV(TrackAuxPar, 1); -}; - -//__________________________________________________________ -//< crossing coordinates of 2 circles -struct CrossInfo { - static constexpr float MaxDistXYDef = 10.; - float xDCA[2] = {}; - float yDCA[2] = {}; - int nDCA = 0; - - GPUd() int circlesCrossInfo(const TrackAuxPar& trax0, const TrackAuxPar& trax1, float maxDistXY = MaxDistXYDef, bool isCollinear = false) - { - const auto& trcA = trax0.rC > trax1.rC ? trax0 : trax1; // designate the largest circle as A - const auto& trcB = trax0.rC > trax1.rC ? trax1 : trax0; - nDCA = 0; - float xDist = trcB.xC - trcA.xC, yDist = trcB.yC - trcA.yC; - float dist2 = xDist * xDist + yDist * yDist, dist = o2::gpu::GPUCommonMath::Sqrt(dist2), rsum = trcA.rC + trcB.rC; - if (dist < 1e-12) { - return nDCA; // circles are concentric? - } - if (dist > rsum) { // circles don't touch, chose a point in between - // the parametric equation of lines connecting the centers is - // x = x0 + t/dist * (x1-x0), y = y0 + t/dist * (y1-y0) - if (dist - rsum > maxDistXY) { // too large distance - return nDCA; - } - notTouchingXY(dist, xDist, yDist, trcA, trcB.rC, isCollinear); - } else if (auto dfr = dist + trcB.rC - trcA.rC; dfr < 0.) { // the small circle is nestled into large one w/o touching - if (dfr > -maxDistXY) { - // select the point of closest approach of 2 circles - notTouchingXY(dist, xDist, yDist, trcA, -trcB.rC, isCollinear); - } else { - return nDCA; - } - } else { // 2 intersection points - if (isCollinear) { - /// collinear tracks, e.g. electrons from photon conversion - /// if there are 2 crossings of the circle it is better to take - /// a weighted average of the crossing points as a radius - float r2r = trcA.rC + trcB.rC; - float r1_r = trcA.rC / r2r; - float r2_r = trcB.rC / r2r; - xDCA[0] = r2_r * trcA.xC + r1_r * trcB.xC; - yDCA[0] = r2_r * trcA.yC + r1_r * trcB.yC; - nDCA = 1; - } else if (o2::gpu::GPUCommonMath::Abs(xDist) < o2::gpu::GPUCommonMath::Abs(yDist)) { - // to simplify calculations, we move to new frame x->x+Xc0, y->y+Yc0, so that - // the 1st one is centered in origin - float a = (trcA.rC * trcA.rC - trcB.rC * trcB.rC + dist2) / (2. * yDist), b = -xDist / yDist, ab = a * b, bb = b * b; - float det = ab * ab - (1. + bb) * (a * a - trcA.rC * trcA.rC); - if (det > 0.) { - det = o2::gpu::GPUCommonMath::Sqrt(det); - xDCA[0] = (-ab + det) / (1. + b * b); - yDCA[0] = a + b * xDCA[0] + trcA.yC; - xDCA[0] += trcA.xC; - xDCA[1] = (-ab - det) / (1. + b * b); - yDCA[1] = a + b * xDCA[1] + trcA.yC; - xDCA[1] += trcA.xC; - nDCA = 2; - } else { // due to the finite precision the det<=0, i.e. the circles are barely touching, fall back to this special case - notTouchingXY(dist, xDist, yDist, trcA, trcB.rC); - } - } else { - float a = (trcA.rC * trcA.rC - trcB.rC * trcB.rC + dist2) / (2. * xDist), b = -yDist / xDist, ab = a * b, bb = b * b; - float det = ab * ab - (1. + bb) * (a * a - trcA.rC * trcA.rC); - if (det > 0.) { - det = o2::gpu::GPUCommonMath::Sqrt(det); - yDCA[0] = (-ab + det) / (1. + bb); - xDCA[0] = a + b * yDCA[0] + trcA.xC; - yDCA[0] += trcA.yC; - yDCA[1] = (-ab - det) / (1. + bb); - xDCA[1] = a + b * yDCA[1] + trcA.xC; - yDCA[1] += trcA.yC; - nDCA = 2; - } else { // due to the finite precision the det<=0, i.e. the circles are barely touching, fall back to this special case - notTouchingXY(dist, xDist, yDist, trcA, trcB.rC); - } - } - } - return nDCA; - } - - GPUd() void notTouchingXY(float dist, float xDist, float yDist, const TrackAuxPar& trcA, float rBSign, bool isCollinear = false) - { - if (isCollinear) { - /// for collinear tracks it is better to take - /// a weighted average of the crossing points as a radius - float r2r = trcA.rC + rBSign; - float r1_r = trcA.rC / r2r; - float r2_r = rBSign / r2r; - xDCA[0] = r2_r * trcA.xC + r1_r * (xDist + trcA.xC); - yDCA[0] = r2_r * trcA.yC + r1_r * (yDist + trcA.yC); - } else { - // fast method to calculate DCA between 2 circles, assuming that they don't touch each outer: - // the parametric equation of lines connecting the centers is x = xA + t/dist * xDist, y = yA + t/dist * yDist - // with xA,yY being the center of the circle A ( = trcA.xC, trcA.yC ), xDist = trcB.xC = trcA.xC ... - // There are 2 special cases: - // (a) small circle is inside the large one: provide rBSign as -trcB.rC - // (b) circle are side by side: provide rBSign as trcB.rC - auto t2d = (dist + trcA.rC - rBSign) / dist; - xDCA[0] = trcA.xC + 0.5 * (xDist * t2d); - yDCA[0] = trcA.yC + 0.5 * (yDist * t2d); - } - nDCA = 1; - } - - template - GPUd() int linesCrossInfo(const TrackAuxPar& trax0, const T& tr0, - const TrackAuxPar& trax1, const T& tr1, float maxDistXY = MaxDistXYDef) - { - /// closest approach of 2 straight lines - /// TrackParam propagation can be parameterized in lab in a form - /// xLab(t) = (x*cosAlp - y*sinAlp) + t*(cosAlp - sinAlp* snp/csp) = xLab0 + t*(cosAlp - sinAlp* snp/csp) - /// yLab(t) = (x*sinAlp + y*cosAlp) + t*(sinAlp + cosAlp* snp/csp) = yLab0 + t*(sinAlp + cosAlp* snp/csp) - /// zLab(t) = z + t * tgl / csp = zLab0 + t * tgl / csp - /// where t is the x-step in the track alpha-frame, xLab,yLab,zLab are reference track coordinates in lab - /// frame (filled by TrackAuxPar for straight line tracks). - /// - /// Therefore, for the parametric track equation in lab 3D we have (wrt tracking-X increment t) - /// xL(t) = xL + t Kx; Kx = (cosAlp - sinAlp* snp/csp) - /// yL(t) = yL + t Ky; Ky = (sinAlp + cosAlp* snp/csp) - /// zL(t) = zL + t Kz; Kz = tgl / csp - /// Note that Kx^2 + Ky^2 + Kz^2 = (1+tgl^2) / csp^2 - nDCA = 0; - float dx = trax1.xC - trax0.xC; // for straight line TrackAuxPar stores lab coordinates at referene point!!! - float dy = trax1.yC - trax0.yC; // - float dz = tr1.getZ() - tr0.getZ(); - auto csp0i2 = 1. / tr0.getCsp2(); // 1 / csp^2 - auto csp0i = o2::gpu::GPUCommonMath::Sqrt(csp0i2); - auto tgp0 = tr0.getSnp() * csp0i; - float kx0 = trax0.c - trax0.s * tgp0; - float ky0 = trax0.s + trax0.c * tgp0; - float kz0 = tr0.getTgl() * csp0i; - auto csp1i2 = 1. / tr1.getCsp2(); // 1 / csp^2 - auto csp1i = o2::gpu::GPUCommonMath::Sqrt(csp1i2); - auto tgp1 = tr1.getSnp() * o2::gpu::GPUCommonMath::Sqrt(csp1i2); - float kx1 = trax1.c - trax1.s * tgp1; - float ky1 = trax1.s + trax1.c * tgp1; - float kz1 = tr1.getTgl() * csp1i; - /// Minimize |vecL1 - vecL0|^2 wrt t0 and t1: point of closest approach - /// Leads to system - /// A Dx = B with Dx = {dx0, dx1} - /// with A = - /// | kx0^2+ky0^2+kz0^2 -(kx0*kx1+ky0*ky1+kz0*kz1) | = (1+tgl0^2) / csp0^2 .... - /// | -(kx0*kx1+ky0*ky1+kz0*kz1) kx0^2+ky0^2+kz0^2 | ..... (1+tgl1^2) / csp1^2 - /// and B = {(dx Kx0 + dy Ky0 + dz Kz0), -(dx Kx1 + dy Ky1 + dz Kz1) } - /// - float a00 = (1.f + tr0.getTgl() * tr0.getTgl()) * csp0i2, a11 = (1.f + tr1.getTgl() * tr1.getTgl()) * csp1i2, a01 = -(kx0 * kx1 + ky0 * ky1 + kz0 * kz1); - float b0 = dx * kx0 + dy * ky0 + dz * kz0, b1 = -(dx * kx1 + dy * ky1 + dz * kz1); - float det = a00 * a11 - a01 * a01, det0 = b0 * a11 - b1 * a01, det1 = a00 * b1 - a01 * b0; - if (o2::gpu::GPUCommonMath::Sqrt(det) > o2::constants::math::Almost0) { - auto detI = 1. / det; - auto t0 = det0 * detI; - auto t1 = det1 * detI; - float addx0 = kx0 * t0, addy0 = ky0 * t0, addx1 = kx1 * t1, addy1 = ky1 * t1; - dx += addx1 - addx0; // recalculate XY distance at DCA - dy += addy1 - addy0; - if (dx * dx + dy * dy > maxDistXY * maxDistXY) { - return nDCA; - } - xDCA[0] = (trax0.xC + addx0 + trax1.xC + addx1) * 0.5; - yDCA[0] = (trax0.yC + addy0 + trax1.yC + addy1) * 0.5; - nDCA = 1; - } - return nDCA; - } - - template - GPUd() int circleLineCrossInfo(const TrackAuxPar& trax0, const T& tr0, - const TrackAuxPar& trax1, const T& tr1, float maxDistXY = MaxDistXYDef) - { - /// closest approach of line and circle - /// TrackParam propagation can be parameterized in lab in a form - /// xLab(t) = (x*cosAlp - y*sinAlp) + t*(cosAlp - sinAlp* snp/csp) = xLab0 + t*(cosAlp - sinAlp* snp/csp) - /// yLab(t) = (x*sinAlp + y*cosAlp) + t*(sinAlp + cosAlp* snp/csp) = yLab0 + t*(sinAlp + cosAlp* snp/csp) - /// zLab(t) = z + t * tgl / csp = zLab0 + t * tgl / csp - /// where t is the x-step in the track alpha-frame, xLab,yLab,zLab are reference track coordinates in lab - /// frame (filled by TrackAuxPar for straight line tracks). - /// - /// Therefore, for the parametric track equation in lab 3D we have (wrt tracking-X increment t) - /// xL(t) = xL + t Kx; Kx = (cosAlp - sinAlp* snp/csp) - /// yL(t) = yL + t Ky; Ky = (sinAlp + cosAlp* snp/csp) - /// zL(t) = zL + t Kz; Kz = tgl / csp - /// Note that Kx^2 + Ky^2 = 1 / csp^2 - - const auto& traxH = trax0.rC > trax1.rC ? trax0 : trax1; // circle (for the line rC is set to 0) - const auto& traxL = trax0.rC > trax1.rC ? trax1 : trax0; // line - const auto& trcL = trax0.rC > trax1.rC ? tr1 : tr0; // track of the line - - // solve quadratic equation of line crossing the circle - float dx = traxL.xC - traxH.xC; // X distance between the line lab reference and circle center - float dy = traxL.yC - traxH.yC; // Y... - // t^2(kx^2+ky^2) + 2t(dx*kx+dy*ky) + dx^2 + dy^2 - r^2 = 0 - auto cspi2 = 1. / trcL.getCsp2(); // 1 / csp^2 == kx^2 + ky^2 - auto cspi = o2::gpu::GPUCommonMath::Sqrt(cspi2); - auto tgp = trcL.getSnp() * cspi; - float kx = traxL.c - traxL.s * tgp; - float ky = traxL.s + traxL.c * tgp; - double dk = dx * kx + dy * ky; - double det = dk * dk - cspi2 * (dx * dx + dy * dy - traxH.rC * traxH.rC); - if (det > 0) { // 2 crossings - det = o2::gpu::GPUCommonMath::Sqrt(det); - float t0 = (-dk + det) * cspi2; - float t1 = (-dk - det) * cspi2; - xDCA[0] = traxL.xC + kx * t0; - yDCA[0] = traxL.yC + ky * t0; - xDCA[1] = traxL.xC + kx * t1; - yDCA[1] = traxL.yC + ky * t1; - nDCA = 2; - } else { - // there is no crossing, find the point of the closest approach on the line which is closest to the circle center - float t = -dk * cspi2; - float xL = traxL.xC + kx * t, yL = traxL.yC + ky * t; // point on the line, need to average with point on the circle - float dxc = xL - traxH.xC, dyc = yL - traxH.yC, dist = o2::gpu::GPUCommonMath::Sqrt(dxc * dxc + dyc * dyc); - if (dist - traxH.rC > maxDistXY) { // too large distance - return nDCA; - } - float drcf = traxH.rC / dist; // radius / distance to circle center - float xH = traxH.xC + dxc * drcf, yH = traxH.yC + dyc * drcf; - xDCA[0] = (xL + xH) * 0.5; - yDCA[0] = (yL + yH) * 0.5; - nDCA = 1; - } - return nDCA; - } - - template - GPUd() int set(const TrackAuxPar& trax0, const T& tr0, const TrackAuxPar& trax1, const T& tr1, float maxDistXY = MaxDistXYDef, bool isCollinear = false) - { - // calculate up to 2 crossings between 2 circles - nDCA = 0; - if (trax0.rC > o2::constants::math::Almost0 && trax1.rC > o2::constants::math::Almost0) { // both are not straight lines - nDCA = circlesCrossInfo(trax0, trax1, maxDistXY, isCollinear); - } else if (trax0.rC < o2::constants::math::Almost0 && trax1.rC < o2::constants::math::Almost0) { // both are straigt lines - nDCA = linesCrossInfo(trax0, tr0, trax1, tr1, maxDistXY); - } else { - nDCA = circleLineCrossInfo(trax0, tr0, trax1, tr1, maxDistXY); - } - // - return nDCA; - } - - GPUdDefault() CrossInfo() = default; - - template - GPUd() CrossInfo(const TrackAuxPar& trax0, const T& tr0, const TrackAuxPar& trax1, const T& tr1, float maxDistXY = MaxDistXYDef, bool isCollinear = false) - { - set(trax0, tr0, trax1, tr1, maxDistXY, isCollinear); - } - ClassDefNV(CrossInfo, 1); -}; - -} // namespace track -} // namespace o2 - -#endif