yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

>    - CohFrictLaw : Eigen is returning nan quaternions after trivial operations, it is workarounded in the law.
>    
Raising attention on this fix, as other functors could have the same 
problem.

Take quaternions q1init,q1, q2init,q2, with q1 (resp. q2) close to 
q1init (resp. q2init). In that case, 
AngleAxisr(q1*q1init.conjugate*q2init*q2.conjugate) will sometimes 
return nan rotation while it should be null.

The fix in cohesiveFrictionalContactLaw.cpp:133 is :
if (isnan(aa.angle())) aa.angle()=0;

Bruno

p.s. This is the sort a jokes I was expecting from eigen move, when I 
was asking for strong testing... It took me 2 hours to find the 
problem.  Who knows if there are other surprises left?

p.s.2 : There is I think a potential memory leak with functions below, 
are they used?

+//FIXME : risk of memory leak with these "new"?
 static Quaternionr* Quaternionr_fromAxisAngle(const Vector3r&  axis, const Real angle){ return new Quaternionr(AngleAxisr(angle,axis)); }
 static Quaternionr* Quaternionr_fromAngleAxis(const Real angle, const Vector3r&  axis){ return new Quaternionr(AngleAxisr(angle,axis)); }