First, in h_pattern_recognition.f we have:

https://github.com/zahmed9/engine/blob/mkj/HTRACKING/h_pattern_recognition.f#L139
(hdc_wire_center(yy)-hdc_wire_center(yyprime))**2 .lt. (hspace_point_criterion(ich))

So I changed
https://github.com/zahmed9/hcana/blob/develop/src/THcDriftChamber.cxx#L292
TMath::Abs(fHits[plane_hitind]->GetPos() - fHits[planep_hitind]->GetPos()) < fSpacePointCriterion

to

pow((fHits[plane_hitind]->GetPos() - fHits[planep_hitind]->GetPos()),2) < fSpacePointCriterion

Second, the value of MAX_SPACE_POINTS in ENGINE is 100 so in hcana I changed it from 50 to 100.