feat: configurable maximum number of bins in SP grid (#2325)

Protection for large number of bins which is set by default to `std::numeric_limits<int>::max()`

This comes from PR #2166, I am splitting the changes into smaller PRs.

Core/include/Acts/Seeding/SpacePointGrid.hpp

@@ -46,6 +46,8 @@ struct SpacePointGridConfig {
   // return 1 neighbor on either side of the current phi-bin (and you want to
   // cover the full phi-range of minPT), leave this at 1.
   int phiBinDeflectionCoverage = 1;
+  // maximum number of phi bins
+  int maxPhiBins = 10000;
   // enable non equidistant binning in z
   std::vector<float> zBinEdges;
   bool isInInternalUnits = false;

Core/include/Acts/Seeding/SpacePointGrid.ipp

@@ -94,6 +94,11 @@ Acts::SpacePointGridCreator::createGrid(
     // consecutive phi bins in the seed making step.
     // Each individual bin should be approximately a fraction (depending on this
     // number) of the maximum expected azimutal deflection.
+
+    // set protection for large number of bins, by default it is large
+    if (phiBins > config.maxPhiBins) {
+      phiBins = config.maxPhiBins;
+    }
   }
 
   Acts::detail::Axis<detail::AxisType::Equidistant,

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

@@ -374,6 +374,7 @@ def itkSeedingAlgConfig(
     phiMax = 2 * math.pi
     phiBinDeflectionCoverage = 3
     numPhiNeighbors = 1
+    maxPhiBins = 200
     # only used in orthogonal seeding
     deltaPhiMax = 0.025
 
@@ -575,6 +576,7 @@ def itkSeedingAlgConfig(
         phiBinDeflectionCoverage=phiBinDeflectionCoverage,
         phi=(phiMin, phiMax),
         impactMax=impactMax,
+        maxPhiBins=maxPhiBins,
     )
     seedingAlgorithmConfigArg = SeedingAlgorithmConfigArg(
         allowSeparateRMax=allowSeparateRMax,

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

@@ -89,9 +89,10 @@
         "phiBinDeflectionCoverage",
         "impactMax",
         "deltaRMax",
+        "maxPhiBins",
         "phi",  # (min,max)
     ],
-    defaults=[None] * 5 + [(None, None)] * 1,
+    defaults=[None] * 6 + [(None, None)] * 1,
 )
 
 SeedingAlgorithmConfigArg = namedtuple(
@@ -209,7 +210,7 @@ def addSeeding(
         Defaults specified in Core/include/Acts/Seeding/SeedFinderConfig.hpp
     seedFilterConfigArg : SeedFilterConfigArg(compatSeedWeight, compatSeedLimit, numSeedIncrement, seedWeightIncrement, seedConfirmation, maxSeedsPerSpMConf, maxQualitySeedsPerSpMConf, useDeltaRorTopRadius)
                                 Defaults specified in Core/include/Acts/Seeding/SeedFilterConfig.hpp
-    spacePointGridConfigArg : SpacePointGridConfigArg(rMax, zBinEdges, phiBinDeflectionCoverage, phi, impactMax)
+    spacePointGridConfigArg : SpacePointGridConfigArg(rMax, zBinEdges, phiBinDeflectionCoverage, phi, maxPhiBins, impactMax)
                                 SpacePointGridConfigArg settings. phi is specified as a tuple of (min,max).
         Defaults specified in Core/include/Acts/Seeding/SpacePointGrid.hpp
     seedingAlgorithmConfigArg : SeedingAlgorithmConfigArg(allowSeparateRMax, zBinNeighborsTop, zBinNeighborsBottom, numPhiNeighbors)
@@ -605,6 +606,7 @@ def addStandardSeeding(
             cotThetaMax=seedFinderConfig.cotThetaMax,
             phiMin=spacePointGridConfigArg.phi[0],
             phiMax=spacePointGridConfigArg.phi[1],
+            maxPhiBins=spacePointGridConfigArg.maxPhiBins,
             impactMax=spacePointGridConfigArg.impactMax,
             zBinEdges=spacePointGridConfigArg.zBinEdges,
             phiBinDeflectionCoverage=spacePointGridConfigArg.phiBinDeflectionCoverage,

Examples/Python/src/TrackFinding.cpp

@@ -224,6 +224,7 @@ void addTrackFinding(Context& ctx) {
     ACTS_PYTHON_MEMBER(deltaRMax);
     ACTS_PYTHON_MEMBER(cotThetaMax);
     ACTS_PYTHON_MEMBER(phiBinDeflectionCoverage);
+    ACTS_PYTHON_MEMBER(maxPhiBins);
     ACTS_PYTHON_MEMBER(impactMax);
     ACTS_PYTHON_MEMBER(zBinEdges);
     ACTS_PYTHON_STRUCT_END();