update find_peaks algorithm

This commit updates the find peaks algorithm with several improvements which
together drastically improve its ability to find Cerenkov rings:

- when computing the Hough transform, instead of charge we weight each PMT hit
  by the probability that it is a multi-photon PMT hit
- we don't subtract off previously found rings (this makes the code simpler and
  I don't think it previously had a huge effect)
- ignore PMT hits who are within approximately 5 degrees of any previously
  found ring (previously we ignored all hits within the center of previously
  found rings)
- ignore PMT hits which have a time residual of more than 10 nanoseconds to
  hopefully ignore more reflected and/or scattered light
- switch from weighting the Hough transform by exp(-fabs(cos(theta)-1/n)/0.1)
  -> exp(-pow(cos(theta)-1/n,2)/0.01). I'm still not sure if this has a huge
  effect, but the reason I switched is that the PDF for Cerenkov light looks
  closer to the second form.
- switch to calling quad with f = 1.0 in test-find-peaks (I still need to add
  this update to fit.c but will do that in a later commit).

1 files changed, 3 insertions, 3 deletions

diff --git a/src/test-find-peaks.c b/src/test-find-peaks.c
index 2ccc90d..fd8d0cd 100644
--- a/src/test-find-peaks.c
+++ b/src/test-find-peaks.c
@@ -362,7 +362,7 @@ int main(int argc, char **argv)
         }
 
         /* Guess the position and t0 of the event using the QUAD fitter. */
-        status = quad(&ev,pos,&t0,10000,0.1);
+        status = quad(&ev,pos,&t0,10000,1.0);
 
         if (status || t0 < 0 || t0 > GTVALID || NORM(pos) > PSUP_RADIUS) {
             /* If the QUAD fitter fails or returns something outside the PSUP or
@@ -374,9 +374,9 @@ int main(int argc, char **argv)
             pos[2] = 0.0;
         }
 
-        get_hough_transform(&ev,pos,x,y,n,m,result,0,0);
+        get_hough_transform(&ev,pos,t0,x,y,n,m,result,0,0);
 
-        find_peaks(&ev,pos,n,m,peak_theta,peak_phi,&npeaks,max_npeaks,0.1);
+        find_peaks(&ev,pos,t0,n,m,peak_theta,peak_phi,&npeaks,max_npeaks,0.1);
 
         printf("gtid %i\n", ev.gtid);
         for (i = 0; i < npeaks; i++) {