feat: make interaction point cut optional in seedFinder

Core/include/Acts/Seeding/Seedfinder.ipp

@@ -116,33 +116,36 @@ void Seedfinder<external_spacepoint_t, platform_t>::createSeedsForGroup(
       // points away from the interaction point in addition to a translation
       // transformation we also perform a rotation in order to keep the
       // curvature of the circle tangent to the x axis
-      float xVal = (topSP->x() - spM->x()) * (spM->x() / rM) +
-                   (topSP->y() - spM->y()) * (spM->y() / rM);
-      float yVal = (topSP->y() - spM->y()) * (spM->x() / rM) -
-                   (topSP->x() - spM->x()) * (spM->y() / rM);
-      if (std::abs(rM * yVal) > m_config.impactMax * xVal) {
-        // conformal transformation u=x/(x²+y²) v=y/(x²+y²) transform the circle
-        // into straight lines in the u/v plane the line equation can be
-        // described in terms of aCoef and bCoef, where v = aCoef * u + bCoef
-        float uT = xVal / (xVal * xVal + yVal * yVal);
-        float vT = yVal / (xVal * xVal + yVal * yVal);
-        // in the rotated frame the interaction point is positioned at x = -rM
-        // and y ~= impactParam
-        float uIP = -1. / rM;
-        float vIP = m_config.impactMax / (rM * rM);
-        if (yVal > 0.)
-          vIP = -vIP;
-        // we can obtain aCoef as the slope dv/du of the linear function,
-        // estimated using du and dv between the two SP bCoef is obtained by
-        // inserting aCoef into the linear equation
-        float aCoef = (vT - vIP) / (uT - uIP);
-        float bCoef = vIP - aCoef * uIP;
-        // the distance of the straight line from the origin (radius of the
-        // circle) is related to aCoef and bCoef by d^2 = bCoef^2 / (1 +
-        // aCoef^2) = 1 / (radius^2) and we can apply the cut on the curvature
-        if ((bCoef * bCoef) >
-            (1 + aCoef * aCoef) / m_config.minHelixDiameter2) {
-          continue;
+      if (m_config.interactionPointCut) {
+        float xVal = (topSP->x() - spM->x()) * (spM->x() / rM) +
+                     (topSP->y() - spM->y()) * (spM->y() / rM);
+        float yVal = (topSP->y() - spM->y()) * (spM->x() / rM) -
+                     (topSP->x() - spM->x()) * (spM->y() / rM);
+        if (std::abs(rM * yVal) > m_config.impactMax * xVal) {
+          // conformal transformation u=x/(x²+y²) v=y/(x²+y²) transform the
+          // circle into straight lines in the u/v plane the line equation can
+          // be described in terms of aCoef and bCoef, where v = aCoef * u +
+          // bCoef
+          float uT = xVal / (xVal * xVal + yVal * yVal);
+          float vT = yVal / (xVal * xVal + yVal * yVal);
+          // in the rotated frame the interaction point is positioned at x = -rM
+          // and y ~= impactParam
+          float uIP = -1. / rM;
+          float vIP = m_config.impactMax / (rM * rM);
+          if (yVal > 0.)
+            vIP = -vIP;
+          // we can obtain aCoef as the slope dv/du of the linear function,
+          // estimated using du and dv between the two SP bCoef is obtained by
+          // inserting aCoef into the linear equation
+          float aCoef = (vT - vIP) / (uT - uIP);
+          float bCoef = vIP - aCoef * uIP;
+          // the distance of the straight line from the origin (radius of the
+          // circle) is related to aCoef and bCoef by d^2 = bCoef^2 / (1 +
+          // aCoef^2) = 1 / (radius^2) and we can apply the cut on the curvature
+          if ((bCoef * bCoef) >
+              (1 + aCoef * aCoef) / m_config.minHelixDiameter2) {
+            continue;
+          }
         }
       }
       state.compatTopSP.push_back(topSP);
@@ -185,33 +188,36 @@ void Seedfinder<external_spacepoint_t, platform_t>::createSeedsForGroup(
       // points away from the interaction point in addition to a translation
       // transformation we also perform a rotation in order to keep the
       // curvature of the circle tangent to the x axis
-      float xVal = (bottomSP->x() - spM->x()) * (spM->x() / rM) +
-                   (bottomSP->y() - spM->y()) * (spM->y() / rM);
-      float yVal = (bottomSP->y() - spM->y()) * (spM->x() / rM) -
-                   (bottomSP->x() - spM->x()) * (spM->y() / rM);
-      if (std::abs(rM * yVal) > -m_config.impactMax * xVal) {
-        // conformal transformation u=x/(x²+y²) v=y/(x²+y²) transform the circle
-        // into straight lines in the u/v plane the line equation can be
-        // described in terms of aCoef and bCoef, where v = aCoef * u + bCoef
-        float uB = xVal / (xVal * xVal + yVal * yVal);
-        float vB = yVal / (xVal * xVal + yVal * yVal);
-        // in the rotated frame the interaction point is positioned at x = -rM
-        // and y ~= impactParam
-        float uIP = -1. / rM;
-        float vIP = m_config.impactMax / (rM * rM);
-        if (yVal < 0.)
-          vIP = -vIP;
-        // we can obtain aCoef as the slope dv/du of the linear function,
-        // estimated using du and dv between the two SP bCoef is obtained by
-        // inserting aCoef into the linear equation
-        float aCoef = (vB - vIP) / (uB - uIP);
-        float bCoef = vIP - aCoef * uIP;
-        // the distance of the straight line from the origin (radius of the
-        // circle) is related to aCoef and bCoef by d^2 = bCoef^2 / (1 +
-        // aCoef^2) = 1 / (radius^2) and we can apply the cut on the curvature
-        if ((bCoef * bCoef) >
-            (1 + aCoef * aCoef) / m_config.minHelixDiameter2) {
-          continue;
+      if (m_config.interactionPointCut) {
+        float xVal = (bottomSP->x() - spM->x()) * (spM->x() / rM) +
+                     (bottomSP->y() - spM->y()) * (spM->y() / rM);
+        float yVal = (bottomSP->y() - spM->y()) * (spM->x() / rM) -
+                     (bottomSP->x() - spM->x()) * (spM->y() / rM);
+        if (std::abs(rM * yVal) > -m_config.impactMax * xVal) {
+          // conformal transformation u=x/(x²+y²) v=y/(x²+y²) transform the
+          // circle into straight lines in the u/v plane the line equation can
+          // be
+          // described in terms of aCoef and bCoef, where v = aCoef * u + bCoef
+          float uB = xVal / (xVal * xVal + yVal * yVal);
+          float vB = yVal / (xVal * xVal + yVal * yVal);
+          // in the rotated frame the interaction point is positioned at x = -rM
+          // and y ~= impactParam
+          float uIP = -1. / rM;
+          float vIP = m_config.impactMax / (rM * rM);
+          if (yVal < 0.)
+            vIP = -vIP;
+          // we can obtain aCoef as the slope dv/du of the linear function,
+          // estimated using du and dv between the two SP bCoef is obtained by
+          // inserting aCoef into the linear equation
+          float aCoef = (vB - vIP) / (uB - uIP);
+          float bCoef = vIP - aCoef * uIP;
+          // the distance of the straight line from the origin (radius of the
+          // circle) is related to aCoef and bCoef by d^2 = bCoef^2 / (1 +
+          // aCoef^2) = 1 / (radius^2) and we can apply the cut on the curvature
+          if ((bCoef * bCoef) >
+              (1 + aCoef * aCoef) / m_config.minHelixDiameter2) {
+            continue;
+          }
         }
       }
       state.compatBottomSP.push_back(bottomSP);

Core/include/Acts/Seeding/SeedfinderConfig.hpp

@@ -65,6 +65,9 @@ struct SeedfinderConfig {
   // parameters for forward seed confirmation
   SeedConfirmationRange forwardSeedConfirmationRange;
 
+  // enable cut on the compatibility between interaction point and SPs
+  bool interactionPointCut = false;
+
   // non equidistant binning in z
   std::vector<float> zBinEdges;
 

Examples/Python/src/TrackFinding.cpp

@@ -106,6 +106,7 @@ void addTrackFinding(Context& ctx) {
     ACTS_PYTHON_MEMBER(impactMax);
     ACTS_PYTHON_MEMBER(zBinEdges);
     ACTS_PYTHON_MEMBER(enableCutsForSortedSP);
+    ACTS_PYTHON_MEMBER(interactionPointCut);
     ACTS_PYTHON_MEMBER(zBinEdges);
     ACTS_PYTHON_MEMBER(rRangeMiddleSP);
     ACTS_PYTHON_MEMBER(useVariableMiddleSPRange);

Examples/Scripts/Python/itk_seeding.py

@@ -69,6 +69,7 @@ def runITkSeeding(field, csvInputDir, outputDir, s=None):
         beamPos=acts.Vector2(0 * u.mm, 0 * u.mm),
         impactMax=gridConfig.impactMax,
         maxPtScattering=float("inf") * u.GeV,
+        interactionPointCut=True,
         zBinEdges=gridConfig.zBinEdges,
         enableCutsForSortedSP=True,  # enable cotTheta sorting in SeedFinder
         rRangeMiddleSP=[