Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
Bill Moninger wrote:
Thats interesting. When you say "read" do you mean read all the data, or just opening the file? I assume netcdf 3 formatted files?Hi Robb,thanks for the information. I'll take a look at regenerating the gbx files.For what its worth--the *biggest* percentage slowdown is not with grib or grib2 files, but with netCDF files, surprisingly enough. My c routine (using an earlier version of netCDF) reads the files almost instantly--the java-netcdf4 arrangement reads the file much more slowly.
Can you send a sample program that has this slowdown? Are you comparing against a C program or earlier versions of java-netcdf?
BTW, java 1.6 should be 20-30% faster than java 1.5, particularly if you use the -server option.
-Bill On 3/31/2009 12:56 PM, Robb Kambic wrote:On Fri, 27 Mar 2009, Bill Moninger wrote:Hello netcdf-java folks,Thanks to good help from the netcdf-java staff, I'm now able to read and generate soundings from RUC files in netCDF, grib, and grib2 format. Its really nice to be able to use the same code for all three formats.Unfortunately, I find that, at least as I've implemented it, netcdf-java is 20% to 50% slower than my previous methods (using C).Bill,If you use the the grib index file, those are the files with the gbx suffix that are usually in the same dir as the grib file. You should delete them all and then regenerate them. The new index file read in much quicker. Currently, i working on grib performance issuesRobb...Moreover, it appears that java 1.6 is slower than 1.5 (though I haven't recompiled the underlying UCAR code in 1.6--only my code).If folks have any thoughts about how to speed things up, I will be much obliged to hear them.-Bill -- William R. Moninger http://www-frd.fsl.noaa.gov/~moninger/ NOAA / Earth Systems Research Laboratory / Global Systems Division 325 Broadway, R/GSD1 voice: 303-497-6435 Boulder, CO 80305 fax: 303-497-3329 _______________________________________________ netcdf-java mailing list netcdf-java@xxxxxxxxxxxxxxxxFor list information or to unsubscribe, visit: http://www.unidata.ucar.edu/mailing_lists/===============================================================================Robb Kambic Unidata Program Center Software Engineer III Univ. Corp for Atmospheric Research rkambic@xxxxxxxxxxxxxxxx WWW: http://www.unidata.ucar.edu/===============================================================================
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