[petsc-users] reg: Eigenvectors of general complex eigen value problem

[Jose E. Roman]

El 23/03/2014, a las 12:56, venkatesh g escribió:

> Hi,
> 
> I am using SLEPC example EX7.C, I am using complex binary matrices A and B written from matlab using Petscbinarywrite.m. 
> 
> I ran the example using "./ex7 -f1 A -f2 B -eps_type krylovschur -st_type sinvert -evecs out.mat -eps_smallest_magnitude"

You should not use -st_type sinvert together with -eps_smallest_magnitude. Read the documentation.

> 
> My plotted my eigenvectors using Petscbinaryread and comparing them to MATLAB's eigs command. 
> 
> It is wrong. It is right only if I use real matrices A and B. 
> 
> I compiled Petsc for complex scalars. How to get the correct eigenvectors for complex matrices, please note my eigenvalue is right but not my eigenvector.  

How do you know the eigenvectors are wrong? Did you check the residuals? If you want to compare the eigenvectors to the output of eigs, you may need to normalize them in the same way, for instance with v=v/max(v). 

Jose

> 
> Any help is greatly appreciated! Kindly help me out.
> 
> cheers,
> Venkatesh
> Sr. Research Fellow
> 
>