[petsc-users] Implementation of Power Iteration method in PETSc

[Yingjie Wu]

Dear Petsc developer:
Hi,

Thank you very much for your previous reply,  they really helped me a lot.

I've been doing neutron calculations recently, and I want to use the power
Iteration method to calculate the neutron flux, essentially to solve linear
equations, but after each solution is done, a scalar *K* is updated to form
a new right end term *b*, and the next linear equation system is solved
until the convergence criterion is satisfied. The flow of the source
iteration algorithm is as follows:


1: *Φ*(0) = arbitrary nonzero vector 2: K(0) = arbitrary nonzero constant
3: *for* n = 1; 2; 3; ::: do 4: *b *= 1 / K(n-1) *F * Φ(n-1)   5: *Φ*(n) * M
   = *b* 6: K(n) = k(n-1)* (F * *Φ*(n)  ,F *Φ*(n)  ) / (F  *Φ*(n-1)  ,F  *Φ*
(n-1)  )

7: check convergence of eigenvalue and eigenvector 8: *end for*


(F , M are the coefficient matrix.)


The difficulty is that I need to set up an extra loop to regulate KSP. Does
PETSc have such an example? How do I implement this algorithm in PETsc?
Please tell me the key functions if possible.


Thanks,

Yingjie
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