Factorization in PMEGridSize

From: Edelmiro Moman (moman_at_titus.u-strasbg.fr)
Date: Wed Jun 07 2006 - 04:36:54 CDT

Hi,

In the PME section of the input file of the Ubiquitin tutorial, one can
read:

/Furthermore, for speed in computing Fast Fourier Transforms,
PMEGridSizeX should be chosen so that it can be factorized by 2, 3, or
5. If your cellBasisVector1 = (60, 0, 0), a good choice for PMEGridSizeX
might be 64, since 60 Å / 64 = 0.9375 Å and $64=2^{6}$./

I am not a mathematician and I am not very familiar FFTs. I have the
following situation:

/cellBasisVector1 = (86, 0, 0)
//cellBasisVector2 = (0, 73, 0)
//cellBasisVector3 = (0, 0, 108)

/Should I make, for instance:/

//PMEGridSizeX = 90 (2*3^2*5)
//PMEGridSizeY = 80 (2^4*5)/
/PMEGridSizeZ = 120 (2^3*3*5)
/
?

Miro/
//

/

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