ATLAS Offline Software
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This tool is concrete implementation for ISiDetElementsRoadMaker and is devoted for list<const InDetDD::SiDetectorElement*>&) production.
During initialization step this tool produce a map all Pixels and SCT detetector elements ordered in set logical layers sorted in radius order for barrel and Z coordinate order for endcap. In each layer all detector elements are sorted in azimuthal angle order.
The input information for this tool is track parameters. Using globalPositions of IPropagator tool algorithm get list global positions of the posible trajectory. This list is input for fast comparison trajectory with map of detector elements. Algorith iterate through this list using straight line extrapolation between neighbouring points and compare position of the trajectory with position detector elements in the map. If trajectory can cross some detector element with some tolerance algorithm save this element to the list. All detector elments in the list sorted in propagation order and first detector element is closest to beam axis.
This algorithm uses IPropagator tool.