[petsc-users] EPS iteration number

[Jose E. Roman]

> El 16/9/2015, a las 21:44, Xujun Zhao <xzhao99 at gmail.com> escribió:
> 
> The following is another test, which shows the outer iteration is 2, and MatMult is performed 24 times. So it means the first outer iteration performs 16, and the subsequent iterations performs 8. (24=16+8)
> 
> What parameters can I tune to accelerate the convergence? Will changing ncv work better?
> The following nconv=1 and unconverged value, what do they mean?
> 
> 2 EPS nconv=1 first unconverged value (error) 0.0140231 (1.32666590e-02)
> 
> --->test: EPS solve results:
>           the eigenvalue: 0.009301
>           Solution method: krylovschur
>           Number of iterations of the method: 2
>           EPS converged reason : 2

2 outer iterations is very fast, your problem seems very easy. You can try changing ncv but I would bet you won’t get the result with much less than 24 MatMult’s. Just try.

The monitor you are using shows the number of converged eigenvalues and the first non-converged Ritz value.

Jose