refactor: Use small_vector in surfaceOnApproach (#1120)

very uncontroversial
acts-project · Dec 15, 2021 · 6d6d4f0 · 6d6d4f0
1 parent ae508f3
commit 6d6d4f0
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/Core/src/Geometry/GenericApproachDescriptor.cpp b/Core/src/Geometry/GenericApproachDescriptor.cpp
@@ -13,6 +13,8 @@
 
 #include <algorithm>
 
+#include <boost/container/small_vector.hpp>
+
 void Acts::GenericApproachDescriptor::registerLayer(const Layer& lay) {
   // go through the surfaces
   for (auto& sf : m_surfaceCache) {
@@ -25,7 +27,8 @@ Acts::ObjectIntersection<Acts::Surface>
 Acts::GenericApproachDescriptor::approachSurface(
     const GeometryContext& gctx, const Vector3& position,
     const Vector3& direction, const BoundaryCheck& bcheck) const {
-  std::vector<ObjectIntersection<Surface>> sIntersections;
+  // almost always 2
+  boost::container::small_vector<ObjectIntersection<Surface>, 2> sIntersections;
   sIntersections.reserve(m_surfaceCache.size());
   for (auto& sf : m_surfaceCache) {
     auto sfIntersection = sf->intersect(gctx, position, direction, bcheck);