Re: [ferret_users] EOFSVD_STAT error

[Manche Shivashankar <mancheshivashankar@xxxxxxxxx>]

Thank you so much Russ for your advice

Here are the details of my data

it is daily ssh data covering north Indian ocean having dimensions 320 by 240 by 4866 latitude longitude and time respectively.

and the script I am using as follows

yes? use sla.nc

yes? let Eof_Grid = sla[x=30:110,y=-30:30,l=1:4886]

yes? let Eof_Stat = eofsvd_stat(Eof_Grid)

then ferret is asking for memory size to increase after increasing the memory by

set memory/size= command the error is coming like this

**ERROR in efcn_compute() allocating -92862752 bytes of memory
    work array 5:  X=1:1604808814, Y=1:2, Z=1:1, T=1:1, E=1:1, F=1:1
 **ERROR: error in external function

how I can solve this problem

I am great full if someone helps me.

thanks and regards

shiva shankar

On Thu, Oct 6, 2016 at 8:14 AM, Russ Fiedler <russell.fiedler@xxxxxxxx> wrote:

Hi,

The problem is that you are requesting too much memory. The work array 5 looks to have 2.3 billion elements which comes to about 10GB if single precision or 20GB if double. The negative in the first error message indicates an integer overflow.

From the documentation

http://ferret.pmel.noaa.gov/Ferret/documentation/users-guide/appendix-a-external-functions/EOF-STAT?searchterm=eof

"The EOFSVD analysis solves a matrix problem where the matrix is dimensioned (NX*NY*NZ) by NT, which can quickly become quite large. The EOFSVD functions use other workspace as well which demands even more memory, and often memory must be increased with the SET MEMORY command. Regridding to a coarser grid or restricting the region may be necessary."

Could you show the size of your variable and the exact commands that you are using to do the eof computation? Somebody may be able to suggest a better way to do this.

Russ

On 06/10/16 13:02, Manche Shivashankar wrote:

Dear all,

I am trying to see each eigen mode variance by list/i=1:10/j=2 eofsvd_stat  command after eof decomposition of data. While trying it the error comes like this


**ERROR in efcn_compute() allocating -92862752 bytes of memory
    work array 5:  X=1:1604808814, Y=1:2, Z=1:1, T=1:1, E=1:1, F=1:1
 **ERROR: error in external function

what could be the reason.

Please help me.

Thanks in advance.

Regards

Shiva shankar