[petsc-users] How to get the eigenvectors in Slepc

[Karl Rupp]

Hi Sonya,

I really suggest you familiarize yourself with eigenvalues and 
eigenvectors. For each eigenvector v, alpha*v is also an eigenvector to 
the same eigenvalue, where alpha can be any nonzero scalar. If the sign 
doesn't fit your expectations, just multiply it with -1. :-)

Best regards,
Karli


On 04/15/2013 04:02 AM, Sonya Blade wrote:
> Even If I have normalization at the exact solution this doesn't explain
> how the sign of it has changed, as a result square roots of sum of squares
> can never have negative value (vector length).
>
> Basically what I need to do, to get the Slepc results matching with the exact ones.
> Do I need to call any function before Slepc normalizes them or something else?
>
> Regards, 		 	   		
>