Re: [ferret_users] error while computinf EOF

[Karl Smith <karl.smith@xxxxxxxx>]

Hi Nitin,

First off, I hope you realize that your SET MEMORY /SIZE=3600 is
telling Ferret to immediate use about 13 Gb (3600 x 4 x 10^6 bytes) of
your machine's memory.  That might be necessary for what you are
trying to do, but maybe you do not to dedicate that much of your
machine's memory for Ferret's inner working and cache.  You might try
using smaller values.

The function you are using uses temporary work arrays in its
computations.  These work arrays use memory outside of that dedicated
for Ferret's inner working and cache.  The memory is obtained from
your system just prior to doing the computation and then returned to
the system immediately after the computation is done.  The problem you
are seeing is that you do not have enough system memory for the work
arrays this function requires.  (I admit that it does seem a bit
confusing that the work arrays do not come from the memory dedicated
to Ferret, but we did not want Ferret requiring a huge amount of
memory that it rarely, or never, used.)

I suspect that maybe so much of your system's memory is used for
Ferret's inner working and cache that there was not enough left for
the work arrays.  It may be that is you reduced the SET MEMORY /SIZE=
to something smaller (maybe 500 or 1000), then there may be enough
system memory still available for the work arrays.

The size of the work arrays for the eof_space function increase by the
square of the number of data points (277222510 = 16650 * 16650 + 10),
so if the above fails, you may want to consider working on a coarser
grid.  (There are nine work arrays for the eof_space function.)

Karl

On Thu, May 31, 2012 at 5:29 AM, nitin patil <nitinpatil85@xxxxxxxxx> wrote:
> Dear ferret users
>
> this is my script to display first four eofs:
>
> cancel data/all
> SET MEMORY/SIZE=3600
> show memory
> use hadisst.nc
> set region/x=50E:50W/y=32S:32N
> let eof_xyfcn=eof_space(sst[l=1001:1024],0.5)    !for 2 years
> SAVE/file=temp.nc eof_xyfcn[l=1:4]
>
> after executing this script i am getting the following error:
>
> ERROR in efcn_compute() allocating 1108890040 bytes of memory
> work array 5:  X=1:277222510, Y=1:1, Z=1:1, T=1:1
>  **ERROR: error in external function
> LIST/FORMAT=CDF/file=temp.nc eof_xyfcn[l=1:4]
> Command file, command group, or REPEAT execution aborted
>
> This script works fine with coads_climatology.
>
> Kindly let me know the possible solution.
>
> --
> Regards,
> Mr. Nitin Patil
> Ph.D. Research Scholar,
> Centre of Excellence in Climate Studies,
> Indian Institute of Technology (IIT) Bombay,
> Powai, Mumbai - 400076, INDIA.



-- 
Karl M. Smith, Ph.D.
JISAO Univ. Wash. and TMAP/PMEL NOAA
"The contents of this message are mine personally and do
not necessarily reflect any position of the Government
or the National Oceanic and Atmospheric Administration."