[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Unidata 64-bit N-AWIPS binary question



David,
Do you know what maximum number of headers NCEP GEMPAK uses? We can first test
this.

Fanyou


Steve Chiswell wrote:
Gregg,

The general difference in my release is I increase the maximum number of
headers in the distribution (to 30,000) so it is possible to create a
grid file using the Unidata
distribution with more grids in it than the NCEP distribution would be
able to handle.
The solution there is simply to use hourly files with maximum number of
grids
that the NCEP distribution can handle.

On my dcgrib2 decoder I provide, I allow for storage of GRIB2 products
using GRIB2 packing which makes the products much smaller and the
decoder faster than if
the data had to be unpacked and repacked into GRIB1. That is
controllable by a
decoder flag.

The WRF wrfpost I have creates GRIB1 output, so the above shouldn't
be an issue (unless they are creating GRIB2 format  files for decoding
into GEMPAK....then they can either tell dcgrib2 to use GRIB1 packing,
or use nagrib2 for decoding to GEMPAK files).

I don't make 32/64 bit modifications to the distribution, but do provide
both
32 and 64 bit executables for Linux. The 64 bit environment is
that which NCEP provides, and ensures that the pr/ library functions
return
the correct size arguments.

Can you provide any infomation about the files, eg number of grids
(GDINFO output)
in the GEMPAK file, and/or how they are creating GEMPAK files?
Steve CHiswell
Unidata User Support


On Mon, 2007-04-09 at 12:05 -0500, Gregory Grosshans wrote:

Hi Steve,

The Storm Prediction Center and the University of Oklahoma is
interested in what differences exist between the Unidata 64-bit Linux
executables and the Unidata Linux executables compared to the NCEP
release.

OU is running a 10 member 4km WRF storm scale ensemble (x=753 ,y=663)
on an AMD 64-bit supercomputer creating NetCDF output.  OU then uses a
program to convert the NetCDF output into GEMPAK grids using the 64bit
Gempak Linux executables.  When the SPC receives the GEMPAK grids from
OU/supercomputer the NCEP NMAP2 core dumps when using the ensemble
functionality of NMAP2 (i.e. datatype, mod_res.tbl, etc.).  The NCEP
NMAP2 will display individual WRF output gempak files created on the
supercomputer.

SPC has taken the GEMPAK files from the supercomputer and used NCEP
GDCFIL and GDMOD to create a new GEMPAK file and copy over the
Supercomputer GEMPAK contents to the NCEP 32-bit GEMPAK file.  Then
NCEP NMAP2 successfully displays the data using the ensemble functionality.

We're wondering if this may be a 32 vs 64-bit issue, or NCEP vs
Unidata GEMPAK issue, or both?  Any information you can provide on
what differences may exist between the Unidata release and NCEP is
appreciated.
Thanks,
Gregg

--
________________________________________________________________________
Fanyou Kong, Ph.D
Center for Analysis and Prediction of Storms   address@hidden
The University of Oklahoma                     Tel: (405) 325-7353 (work)
120 David L. Boren Blvd., Suite 2500           Fax: (405) 325-1119
Norman, OK 73072                           http://www.caps.ou.edu/~fkong/