[molpro-user] SURF - BATCH3D

[Dinu, Dennis Florian]

Dear Molpro Community,

I am trying to calculate a quite large PES, by using a HPC with a walltime of 10 days. That means, i have to control the SURF Program somehow, to dump parts of the PES within this walltime. Now I need some help in understanding the BATCH3D option of the SURF Program. It says:

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After calculating a number of grid points within the iterative interpolation
scheme the convergence of the individual surfaces will be
checked and, if provided by the keyword DUMP, dumped to disk.
This leads typically to 3-5 iterations and thus the same number of
restart points within the calculation of the 1D, 2D, ... surfaces (I). As
the number of 3D and 4D terms can be very large this is not sufficient
in these cases. Therefore, the lists of 3D and 4D terms is cut
into batches which will be processed subsequently (II). BATCH3D and
BATCH4D control the number of 3D and 4D surfaces within each
batch. By default BATCH3D is set to 30 times the number of processors
and BATCH4D to 10 times the number of processors. Accordingly
the number of restart points is increased. Smaller values for
BATCH3D and BATCH4D, e.g. BATCH3D=20, increase the number
of restart points on cost of the efficiency of the parallelization.
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(I) Why does this lead to 3-5 Iterations?

(II) What is a List? Is it a list of Grid-Points, or a list of full 3D sub-potentials? Or something else?

I am trying to figure out the correct BATCH3D settings for my needs.
When I do
grep "MODE" *log* | wc
I get the number of Grid-points. In my case after 10 days calculation on 32 processors -> 24494
With the default BATCH3D=30, the DUMP should happen after 30*32=960 Grid-points. As this did not happen, my next quess is that the DUMP happens after 960 3D sub-potentials.
That means when one 3D sub-potential comprises 16*16*16 = 4096 grid-points (roughly spoken with NGRID=16 and ignoring symmetry and prescreening), then i have just 6 3D sub-potentials within 10 days. That means I would have to set BATCH3D=0.2, to have DUMP after 0.2*32=6.4 3D sub-potentials. Does this make any sense to you?

greets
Dennis


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