Difference between STD and CE from charge flip

[areinsvo]

The charge flip fix introduces differences between STD and CE. In particular, the effects on CE are relatively small but STD gets worse by all metrics. As discussed in the slides on March 5, there are 10x as many tracks with negative pt in STD. Maybe there is a bug in STD that causes negative pt tracks. This would have been hidden previously, because we use abs(pt) in all of the relevant places. But with the charge flip fix, we change the charge for those tracks, which might be why STD is now messed up.

[osschar]

While debugging with -O0 and USE_INTRINSICS := -DMPT_SIZE=1 in Makefile.config I noticed that number of tracks found by STD increases by up to 10% (using quality-val). This was with gcc-10.