20040930: GEMPAK Overflow (Arakawa-E grid)

Charles,

GEMPAK has 3 parameters that determine the maximum grid size that can be
stored and used in computations.

Your 606x1067 grid is 646602 points.

Defined in $GEMPAK/include are:
LLMXTG which is the maximum grid that can be stores, and is 750,000 by default.
LLMXGD is the maximum size of a grid used in computations, which is 400,000.
LLMDGG is the amount of memory available for computations (eg your grid size
       times the number of grids needed for a computation, default is
       2504000).

Since you grid exceeds LLMXGD, you can use the IJSKIP parameter to
sample the number of points. You can also subset the GAREA
to use fewer grid points.

If your computation is a complicated function, you may have to do it in pieces
if your number of grid points times the number ofgrids used exceeds LLMDGG.
For example, if your subarea was halh of your points (323301), then
if your computation requires more than 7 grids (each parameter used
in the calculation and output grid), then you would need todo
do the calculation in pieces (gddiag would be useful there).
The alternative would be to build gempak with LLMXGD larger for
your entire grid, but this always has consequences in the LLMDGG heap
usage.

Steve Chiswell
Unidata User SUpport



>From: "Charles J. Alonge" <address@hidden>
>Organization: NASA - Goddard Space Flight Center
>Keywords: 200409301508.i8UF8cUE028623

>Hello Support,
>
>    I'm plotting data from NCEP'S ETA Model on the native Arakawa-E grid 
>(606x1067).  Whenever I attempt calculations with the data in GDPLOT or 
>GDCNTR I receive an error "Internal Grid List Full".  How can I go about 
>resolving this problem?
>
>Thanks for your consideration,
>Charles
>
>-- 
>
>Charles J. Alonge
>NASA Goddard Space Flight Center - SAIC
>Hydrological Sciences Branch
>NASA-GSFC Mail Code 974.1
>Greenbelt, MD 20771
>
>Office: Building 22, Room 008
>Phone:  (301) 286-8272
>Fax:    (301) 286-8624
>Email:  address@hidden
>
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