From 8ad2f190b98b6b1bf45d4dd2eb5f0cb1505a71d9 Mon Sep 17 00:00:00 2001
From: Sergey Gorbunov <se.gorbunov@gsi.de>
Date: Thu, 1 Feb 2024 08:14:24 +0000
Subject: [PATCH] Ca: patch to the RC2
the MR should fix the issue https://redmine.cbm.gsi.de/issues/3149
It contains the following fixes to the CA tracking:
1. bugfix in the Jacobian of the track extrapolation.
It was introduced during the rewrite of the math
2. tune binning of the hit grid.
A little decrease of the efficiency happened after the code rewrite
3. tune the cuts for newly introduced hit ranges.
The new formulae were not tuned
4. revert triplet cut on space + time chi2.
After the split of space and time Chi2 in the track fit,
the chi2 cut was changed w/o tuning. Replace it with the old cut.
MR 1624
Cherry-picked form 8b54c71b32068f4f7fc12e65890bd933a8bd1fd3
---
algo/ca/core/tracking/CaTrackFinderWindow.cxx | 5 +++--
algo/ca/core/tracking/CaTrackFit.cxx | 14 +++++++++++++-
algo/ca/core/tracking/CaTripletConstructor.cxx | 10 ++++++----
3 files changed, 22 insertions(+), 7 deletions(-)
diff --git a/algo/ca/core/tracking/CaTrackFinderWindow.cxx b/algo/ca/core/tracking/CaTrackFinderWindow.cxx
index d942c55333..15fe5df427 100644
--- a/algo/ca/core/tracking/CaTrackFinderWindow.cxx
+++ b/algo/ca/core/tracking/CaTrackFinderWindow.cxx
@@ -223,8 +223,9 @@ void TrackFinderWindow::CaTrackFinderSlice()
fscal sizeY = gridMaxY - gridMinY;
fscal sizeX = gridMaxX - gridMinX;
int nBins2D = 1 + nSliceHits;
- fscal yStep = sizeY / sqrt(nBins2D);
- fscal xStep = sizeX / sqrt(nBins2D);
+ // TODO: SG: the coefficients should be removed
+ fscal yStep = 0.3 * sizeY / sqrt(nBins2D);
+ fscal xStep = 0.8 * sizeX / sqrt(nBins2D);
fscal scale = frAlgo.GetParameters().GetStation(iS).GetZ<float>() - frAlgo.GetParameters().GetTargetPositionZ()[0];
diff --git a/algo/ca/core/tracking/CaTrackFit.cxx b/algo/ca/core/tracking/CaTrackFit.cxx
index 136c47d422..cd5642a8f3 100644
--- a/algo/ca/core/tracking/CaTrackFit.cxx
+++ b/algo/ca/core/tracking/CaTrackFit.cxx
@@ -746,11 +746,23 @@ namespace cbm::algo::ca
cnst stepW[5] = {0., h / fvec(6.), h / fvec(3.), h / fvec(3.), h / fvec(6.)};
+ fvec k[5][7][7] = {{0.}};
+ for (int step = 1; step <= 4; ++step) {
+ for (int i = 0; i < 7; i++) {
+ for (int j = 0; j < 7; j++) {
+ k[step][i][j] = F[step][i][j];
+ for (int m = 0; m < 7; m++) {
+ k[step][i][j] += stepDz[step] * F[step][i][m] * k[step - 1][m][j];
+ }
+ }
+ }
+ }
+
for (int i = 0; i < 7; i++) {
for (int j = 0; j < 7; j++) {
R[i][j] = R0[i][j];
for (int step = 1; step <= 4; step++) {
- R[i][j] += stepW[step] * F[step][i][j];
+ R[i][j] += stepW[step] * k[step][i][j];
}
}
}
diff --git a/algo/ca/core/tracking/CaTripletConstructor.cxx b/algo/ca/core/tracking/CaTripletConstructor.cxx
index 4c41eee11e..690d9e1fdf 100644
--- a/algo/ca/core/tracking/CaTripletConstructor.cxx
+++ b/algo/ca/core/tracking/CaTripletConstructor.cxx
@@ -260,18 +260,18 @@ void TripletConstructor::FitDoublets()
if ((staM().timeInfo) && (T2.NdfTime()[0] >= 0)) {
fscal dt = T2.Time()[0] + tt * dz - hitClone.T();
- if (fabs(dt) > sqrt(30. * T2.C55()[0]) + hitClone.RangeT()) {
+ if (!(fabs(dt) <= 3.5 * sqrt(T2.C55()[0]) + hitClone.RangeT())) {
continue;
}
}
fscal dx = T2.GetX()[0] + tx * dz - hitClone.X();
- if (fabs(dx) > 1.3 * (3.5 * sqrt(T2.C00()[0]) + hitClone.RangeX())) {
+ if (!(fabs(dx) <= 3.5 * sqrt(T2.C00()[0]) + hitClone.RangeX())) {
continue;
}
fscal dy = T2.Y()[0] + ty * dz - hitClone.Y();
- if (fabs(dy) > 1.6 * (3.5 * sqrt(T2.C11()[0]) + hitClone.RangeY())) {
+ if (!(fabs(dy) <= 3.5 * sqrt(T2.C11()[0]) + hitClone.RangeY())) {
continue;
}
@@ -643,7 +643,9 @@ void TripletConstructor::StoreTriplets()
TrackParamV& T3 = fTracks_3[i3];
- fscal chi2 = T3.GetChiSq()[0]; // / T3.NDF[0];
+ // TODO: SG: normalize chi2, separate cuts on time and space
+
+ fscal chi2 = T3.GetChiSq()[0] + T3.GetChiSqTime()[0];
const ca::HitIndex_t ihitl = fIhitL;
const ca::HitIndex_t ihitm = fHitsM_3[i3];
--
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