[ROOT-5373] Bugs in TEveTrackPropagator::LineIntersectPlane Created: 17/Jul/13  Updated: 15/May/19  Resolved: 18/Jul/13

Status: Closed
Project: ROOT
Component/s: Core Libraries
Affects Version/s: 5.34/00
Fix Version/s: None

Type: Bug Priority: Medium
Reporter: Alessio Piucci Assignee: Matevz Tadel
Resolution: Fixed Votes: 0
Labels: None
Environment:

Apple MacBook Pro 15'', operating system: OSX Mountain Lion (10.8.4), compiler: gcc 4.8


Development:

 Description   

In TEveTrackPropagator class, the LineIntersectPlane function has two bugs and so calculates wrong intersection points:

  • at line 908 of TEveTrackPropagator.cxx, it would be 'delta = point - pos' (and not the 'delta = pos - point', unless you change later a sign at 910 line at d assignment);
  • at line 916 of TEveTrackPropagator.cxx, it would be 't = d / (p.Dot(normal))', that is 'time = distance / velocity' (and not 't = (p.Dot(normal)) / d').


 Comments   
Comment by Matevz Tadel [ 18/Jul/13 ]

Hi,

Thanks for this, I agree with both changes ... I must have been drunk when I was solving the equation for t previous time

Best,
Matevz

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