eigh: eigenvalue order

Nils Wagner nwagner at iam.uni-stuttgart.de
Tue Oct 24 14:26:30 EDT 2006


On Tue, 24 Oct 2006 11:16:19 -0700
  "Keith Goodman" <kwgoodman at gmail.com> wrote:
> Is there any guarantee on the order of eigenvalues (and 
>eigenvectors)
> returned by numpy.linalg.eigh?
> 
> If I want to make sure the eigenvalues are in ascending 
>order of
> magnitude should I sort them myself?
> 
> -------------------------------------------------------------------------
> Using Tomcat but need to do more? Need to support web 
>services, security?
> Get stuff done quickly with pre-integrated technology to 
>make your job easier
> Download IBM WebSphere Application Server v.1.0.1 based 
>on Apache Geronimo
> http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
> _______________________________________________
> Numpy-discussion mailing list
> Numpy-discussion at lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/numpy-discussion

AFAIK eigh is based on dsyevd.f
http://www.netlib.org/lapack/double/dsyevd.f. (real 
symmetric)
http://www.netlib.org/lapack/complex16/zheevd.f (complex 
Hermitian).
If INFO = 0, the eigenvalues are given in ascending order.

Please correct me if I get it wrong.

Nils

-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642




More information about the NumPy-Discussion mailing list