I have a question on using d_commit_Helmholtz_3D and d_Helmholtz_3D. I would like to know if the right hand side of the Poisson's equation needs an FFT before assigning to "f" argument of these functions.
I need to assign the values of "f", the RHS of Poisson's equation, in three nested for-loops before calling Helmholtz 3D functions. The Poisson's equation is U=f(x,y,z). My question is: should I do an FFT on f(x,y,z) and then assign the transformed values of f(x,y,z) to the "f" argument of Helmholtz functions? Or I simply use the values of f(x,y,z) without any FFT for Helmholtz functions?