CGAL users discussion list

[Pierre Alliez <>]

Hello wildabc (I was unable to recover your first name from your email, 
hence I take your gmail adress),

Many thanks for sending feedback on this bug - I will double check this 
and correct it as soon as possible. Should you have any other 
suggestions I would be pleased to improve the PCA component as well.

best regards,

Pierre Alliez
INRIA Sophia Antipolis - Mediterranee 
Project-team GEOMETRICA 
http://www-sop.inria.fr/members/Pierre.Alliez/
Tel: +33 4 92 38 76 77
Fax: +33 4 97 15 53 95



杨成林 a écrit :
> Hello
>
> I am new to CGAL.I use  linear_least_squares_fitting_3 to estimate
> normals from point-cloud.But it can't give correct results
> sometimes.After examining the source code,I think line 709-710 in
> PCA_util.h(CGAL 3.4) may be incorrect.
>
> eigen_values[2] is the smallest eigenvalue,so "eigen_values[2] ==
> eigen_values[1]" means Degeneracy."eigen_values[0] == eigen_values[1]"
> just means the points distribute isotropically in the plane,but the
> fitting plane exists uniquely.
>
> I change this two lines to "if(eigen_values[2] != eigen_values[1])".It
> works well.
>