In the course of debugging the polar co-ordinate implementation integrated in !44381 (merged), it was found that in the digitisation co-ordinates are read from the HITS file and passed to the polar design class as cartesian.
This MR creates a specialisation of the hitLocalToLocal method to detect if a polar endcap is being used, and then applies a conversion to polar co-orinates.
The polar endcap is detected by defining a new detector shape enum, which is only returned when the design has been created with polar endcaps, which is ultimately controlled by an additional flag in the geometry file. This ensures that other workflows are unaffected.
The conversion to polar co-ordinates uses standard library functions to minimise the additional CPU cost. It is hoped that performing the transformation here will be quicker than repeatedly performing it in the digitisation and reconstruction.
This is in support of ATLITKSW-42.