[petsc-users] parallel 3D convolution

[LikunTan]

Dear all,

I am trying to use FFT to calculate the demagnetizing field in micromagnetics, which is of a discrete convolution form,

Hdemag(i,j,k)=\sum_{p=0}^Nx\sum_{q=0}^Ny\sum_{r=0}^Nz DemagTensor(i-p,j-q,k-r)aM(p,q,r)

I wrote a subroutine based on the examples ex121.c(sequential convolution) and ex158.c (parallel FFT) in Petsc website, but the result is inconsistent with the one from direct method. I've attached my code. My concern is in the implementation of zero-padding and wrap-around order. I would very much appreciate your time to take a look and direct me to any possible problems.

regards,
Likun



 		 	   		  
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