Unidata - To provide the data services, tools, and cyberinfrastructure leadership that advance Earth system science, enhance educational opportunities, and broaden participation. Unidata
         
  advanced  
 

netcdf on the Cray, once more..

You can avoid the overhead of conversion to/from ieee floating point by
using one of the integer types.  Of course you need to use attributes
add_offset and scale_factor to scale the values.

I did a timing test to see how much time this saved.  In each case the
input array was dimensioned 12 x 56 x 64 while the output array was
56 x 64.  The job calculated the mean over the 1st dimension.
The same data was used for both tests.

With type float for both input and output the cpu (user) time was 0.59 sec.
With type short for both input and output the cpu (user) time was 0.35 sec.
Thus using shorts saved 41% of the time needed for floats!

Harvey Davies,                              Home: +61 3 772 5199
CSIRO Division of Atmospheric Research,     Work: +61 3 586 7574
Private Bag No. 1, Mordialloc,               Fax: +61 3 586 7600
Victoria 3195,  Australia                 E-mail: hld@xxxxxxxxxxxx



 
 
  Contact Us     Site Map     Search     Terms and Conditions     Privacy Policy     Participation Policy
 
National Science Foundation (NSF) UCAR Community Programs   Unidata is a member of the UCAR Community Programs, is managed by the University Corporation for Atmospheric Research, and is sponsored by the National Science Foundation.
P.O. Box 3000     Boulder, CO 80307-3000 USA     Tel: 303-497-8643     Fax: 303-497-8690