Concept definition

template<typename SpacePointType>
concept Acts::Experimental::CompositeSpacePoint =  requires(const SpacePointType sp) {
  
  { sp.localPosition() } -> std::same_as<const Vector3&>;
  
  { sp.sensorDirection() } -> std::same_as<const Vector3&>;
  
  { sp.toNextSensor() } -> std::same_as<const Vector3&>;
  
  { sp.planeNormal() } -> std::same_as<const Vector3&>;
  
  { sp.driftRadius() } -> std::same_as<double>;
  
  { sp.time() } -> std::same_as<double>;
  
  { sp.covariance() } -> std::same_as<const std::array<double, 3>&>;
 
  { sp.isStraw() } -> std::same_as<bool>;
  
  { sp.hasTime() } -> std::same_as<bool>;
  
  { sp.measuresLoc0() } -> std::same_as<bool>;
  
  { sp.measuresLoc1() } -> std::same_as<bool>;
}

Detailed Description

Concept definition of the station space points.

They're primarily used in composite detectors, like the Muon stations in side the ATLAS experiment. The stations usually consist of few layers of straw tubes which maybe sandwiched by strip detector layers. The straws are used to measure the passage of the particle in the bending plane, while the strips may supplement the track measurement by providing coordinates along the straw. The CompositeSpacePoint assumes an orthogonal coordinate system, where x-axis: Is parallel to the straw wires y-axis: Points to the next straw in a layer z-axis: Points outwards from the experiment