refactor: Allow track selection without reference surface (#3791)

Adds a flag to allow track selection without reference surface, which is off by default. Also refactors the track selector config handling in python to avoid that different uses get out of sync.

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **New Features**
	- Introduced a new configuration option, `requireReferenceSurface`, for track validation, enhancing track selection flexibility.
	- Added a function, `trackSelectorDefaultKWArgs`, to streamline track selection parameter configuration.

- **Improvements**
	- Refactored track validation logic for improved clarity and separation of concerns.
	- Enhanced configurability of track selection and seeding algorithms, allowing for more adaptable configurations.
	- Updated default values in the `TrackSelectorConfig` to accommodate the new field.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Core/include/Acts/TrackFinding/TrackSelector.hpp

@@ -80,6 +80,10 @@ class TrackSelector {
     std::size_t maxSharedHits = std::numeric_limits<std::size_t>::max();
     double maxChi2 = inf;
 
+    /// Whether a reference surface is required for the track
+    /// If false, the parameter cuts are not evaluated
+    bool requireReferenceSurface = true;
+
     // Defaults to: no cut
     MeasurementCounter measurementCounter;
 
@@ -447,22 +451,33 @@ bool TrackSelector::isValidTrack(const track_proxy_t& track) const {
 
   const Config& cuts = *cutsPtr;
 
-  return track.hasReferenceSurface() &&
-         within(track.transverseMomentum(), cuts.ptMin, cuts.ptMax) &&
-         (!m_isUnbinned || (within(absEta(), cuts.absEtaMin, cuts.absEtaMax) &&
-                            within(_eta, cuts.etaMin, cuts.etaMax))) &&
-         within(track.phi(), cuts.phiMin, cuts.phiMax) &&
-         within(track.loc0(), cuts.loc0Min, cuts.loc0Max) &&
-         within(track.loc1(), cuts.loc1Min, cuts.loc1Max) &&
-         within(track.time(), cuts.timeMin, cuts.timeMax) &&
-         checkMin(track.nMeasurements(), cuts.minMeasurements) &&
-         checkMax(track.nHoles(), cuts.maxHoles) &&
-         checkMax(track.nOutliers(), cuts.maxOutliers) &&
-         checkMax(track.nHoles() + track.nOutliers(),
-                  cuts.maxHolesAndOutliers) &&
-         checkMax(track.nSharedHits(), cuts.maxSharedHits) &&
-         checkMax(track.chi2(), cuts.maxChi2) &&
-         cuts.measurementCounter.isValidTrack(track);
+  auto parameterCuts = [&]() {
+    return within(track.transverseMomentum(), cuts.ptMin, cuts.ptMax) &&
+           (!m_isUnbinned ||
+            (within(absEta(), cuts.absEtaMin, cuts.absEtaMax) &&
+             within(_eta, cuts.etaMin, cuts.etaMax))) &&
+           within(track.phi(), cuts.phiMin, cuts.phiMax) &&
+           within(track.loc0(), cuts.loc0Min, cuts.loc0Max) &&
+           within(track.loc1(), cuts.loc1Min, cuts.loc1Max) &&
+           within(track.time(), cuts.timeMin, cuts.timeMax);
+  };
+
+  auto trackCuts = [&]() {
+    return checkMin(track.nMeasurements(), cuts.minMeasurements) &&
+           checkMax(track.nHoles(), cuts.maxHoles) &&
+           checkMax(track.nOutliers(), cuts.maxOutliers) &&
+           checkMax(track.nHoles() + track.nOutliers(),
+                    cuts.maxHolesAndOutliers) &&
+           checkMax(track.nSharedHits(), cuts.maxSharedHits) &&
+           checkMax(track.chi2(), cuts.maxChi2) &&
+           cuts.measurementCounter.isValidTrack(track);
+  };
+
+  if (cuts.requireReferenceSurface) {
+    return track.hasReferenceSurface() && parameterCuts() && trackCuts();
+  } else {
+    return trackCuts();
+  }
 }
 
 inline TrackSelector::TrackSelector(

Examples/Python/python/acts/examples/reconstruction.py

@@ -123,10 +123,42 @@
         "maxSharedHits",
         "maxChi2",
         "nMeasurementsGroupMin",
+        "requireReferenceSurface",
     ],
-    defaults=[(None, None)] * 7 + [None] * 7,
+    defaults=[(None, None)] * 7 + [None] * 8,
 )
 
+
+def trackSelectorDefaultKWArgs(c):
+    """
+    Encapsulate this boilerplate code into a function so different uses do not get out of sync
+    """
+    return acts.examples.defaultKWArgs(
+        loc0Min=c.loc0[0],
+        loc0Max=c.loc0[1],
+        loc1Min=c.loc1[0],
+        loc1Max=c.loc1[1],
+        timeMin=c.time[0],
+        timeMax=c.time[1],
+        phiMin=c.phi[0],
+        phiMax=c.phi[1],
+        etaMin=c.eta[0],
+        etaMax=c.eta[1],
+        absEtaMin=c.absEta[0],
+        absEtaMax=c.absEta[1],
+        ptMin=c.pt[0],
+        ptMax=c.pt[1],
+        minMeasurements=c.nMeasurementsMin,
+        maxHoles=c.maxHoles,
+        maxOutliers=c.maxOutliers,
+        maxHolesAndOutliers=c.maxHolesAndOutliers,
+        maxSharedHits=c.maxSharedHits,
+        maxChi2=c.maxChi2,
+        measurementCounter=c.nMeasurementsGroupMin,
+        requireReferenceSurface=c.requireReferenceSurface,
+    )
+
+
 CkfConfig = namedtuple(
     "CkfConfig",
     [
@@ -1424,32 +1456,10 @@ def addCKFTracks(
             else trackSelectorConfig
         )
     )
+
+    overwriteArgs = dict() if len(tslist) == 1 else dict(absEtaMax=None)
     cutSets = [
-        acts.TrackSelector.Config(
-            **acts.examples.defaultKWArgs(
-                loc0Min=c.loc0[0],
-                loc0Max=c.loc0[1],
-                loc1Min=c.loc1[0],
-                loc1Max=c.loc1[1],
-                timeMin=c.time[0],
-                timeMax=c.time[1],
-                phiMin=c.phi[0],
-                phiMax=c.phi[1],
-                etaMin=c.eta[0],
-                etaMax=c.eta[1],
-                absEtaMin=c.absEta[0],
-                absEtaMax=c.absEta[1] if len(tslist) == 1 else None,
-                ptMin=c.pt[0],
-                ptMax=c.pt[1],
-                minMeasurements=c.nMeasurementsMin,
-                maxHoles=c.maxHoles,
-                maxOutliers=c.maxOutliers,
-                maxHolesAndOutliers=c.maxHolesAndOutliers,
-                maxSharedHits=c.maxSharedHits,
-                maxChi2=c.maxChi2,
-                measurementCounter=c.nMeasurementsGroupMin,
-            )
-        )
+        acts.TrackSelector.Config(**(trackSelectorDefaultKWArgs(c) | overwriteArgs))
         for c in tslist
     ]
     if len(tslist) == 0:
@@ -1702,23 +1712,7 @@ def addTrackSelection(
 
     # single cut config for implicit single bin eta configuration
     selectorConfig = acts.TrackSelector.Config(
-        **acts.examples.defaultKWArgs(
-            loc0Min=trackSelectorConfig.loc0[0],
-            loc0Max=trackSelectorConfig.loc0[1],
-            loc1Min=trackSelectorConfig.loc1[0],
-            loc1Max=trackSelectorConfig.loc1[1],
-            timeMin=trackSelectorConfig.time[0],
-            timeMax=trackSelectorConfig.time[1],
-            phiMin=trackSelectorConfig.phi[0],
-            phiMax=trackSelectorConfig.phi[1],
-            etaMin=trackSelectorConfig.eta[0],
-            etaMax=trackSelectorConfig.eta[1],
-            absEtaMin=trackSelectorConfig.absEta[0],
-            absEtaMax=trackSelectorConfig.absEta[1],
-            ptMin=trackSelectorConfig.pt[0],
-            ptMax=trackSelectorConfig.pt[1],
-            minMeasurements=trackSelectorConfig.nMeasurementsMin,
-        )
+        **trackSelectorDefaultKWArgs(trackSelectorConfig)
     )
 
     trackSelector = acts.examples.TrackSelectorAlgorithm(

Examples/Python/src/ExampleAlgorithms.cpp

@@ -109,6 +109,7 @@ void addExampleAlgorithms(Context& ctx) {
       ACTS_PYTHON_MEMBER(maxSharedHits);
       ACTS_PYTHON_MEMBER(maxChi2);
       ACTS_PYTHON_MEMBER(measurementCounter);
+      ACTS_PYTHON_MEMBER(requireReferenceSurface);
       ACTS_PYTHON_STRUCT_END();
 
       pythonRangeProperty(c, "loc0", &Config::loc0Min, &Config::loc0Max);