[CPMD-list] grid on real space

[Juerg Hutter]

Hi

KR1, KR2, KR3 are the dimensions of Fortran arrays
that are used to keep the real space grid values.
The grid size is actually NR1, NR2, NR3.
For performance reasons (memory access) it is a good idea
to choose KR1 = NR1+1.
You can think of KR1 as the leading dimension parameter
you can find e.g. in LAPACK.

regards

Juerg Hutter

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Juerg Hutter                   Phone : ++41 1 635 4491
Physical Chemistry Institute   FAX   : ++41 1 635 6838
University of Zurich           E-mail: hutter at pci.unizh.ch
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On Mon, 28 Mar 2005, Zhenyu LI wrote:

> Dear all,
>
> I am a liitle confused on the grid on real space. We found that
> MAXFFT=NNR1=KR1*KR2*KR3.
> So we expect a grid from 0 to KR1-1, or from 1 to KR1. According to
> PBC, in both case f(0)=f(KR1). But the real space wavefunction seems
> normalized to 1/Sqrt(NR1*NR2*NR3) instead of 1/Sqrt(KR!*KR2*KR3), and
> typically KR1=NR1+1.
>
> Would anybody please clarify this issue for me, thanks!
>
> best wishes,
> zhenyu
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