WIP: Digitizer speedup: Replace FindBin calls and cut away some of the outer neighboring pixels (manual merge into master)

Closed Kevin Sedlaczek requested to merge (removed):RadDam_speedup_part1_master_merge into master

Oversaw some newer changes in master and have to rearrange the code. Will update this soon.

This is the manual merge of most of the changes from !33151 (merged) (that were then automatically merged into 21.3) into master, due to the new file structure in master. Partly merge of the changes as validation of others is ongoing (as discussed in ATLPHYSVAL-654 and agreed upon in RadDam team).

Description of changes: In order to save the amount of CPU time spent inside the large number of FindBin calls inside the inner most loop over the neighboring pixels, the FindBin calls are replaced by the arithmetic implemented inside ROOT's FindBin function. This is possible, because the histograms are read in from maps and do not change during the execution. In order to reduce the large number of iterations in the inner most loop (over the nearest neighboring pixels (p,q) for every charge) I reduced the limits for the iterators. The edge cases (p==+-2 || q==+-2) make 2/3 of the neighbors and do not change the results significantly.

Edited by Kevin Sedlaczek

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