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Unidata Support: 960620: Optimizations for Cray version of netCDF

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  • Subject: Unidata Support: 960620: Optimizations for Cray version of netCDF
  • Date: Thu, 20 Jun 1996 15:55:30 -0600
Steve and Jeff,

I'm forwarding this note from Bob Swanson in case you're interested in his
Cray improvements for the current netCDF release.  I'll also send him a
reply saying I forwarded this note to you, so he'll know who you are if you
request his code.

--Russ

------- Forwarded Message

Date:    Thu, 20 Jun 1996 14:43:47 -0600
From:    Unidata Support <address@hidden>
To:      address@hidden
Subject: 960620: Optimizations for Cray version of netCDF

>To: address@hidden
>From: "Bob Swanson" <address@hidden>
>Subject: Optimizations for Cray version of netCDF
>Organization: .
>Keywords: 199606201950.AA07255

Hello,

We have installed the latest 2.4.2 version of the
netCDF library on our Cray C94. Our analysis of
the performance, however, uncovered some unoptimized
sections in the library for Cray use.

We have written 2 modifications to the library that:

*) improve the output side of our user's models dramatically
        by making the "fill" function work the same
        as the "write" function, utilizing the "xdr_floats"
        function instead of "xdr_float".

*) improving error handling when a user's program runs out
        of memory. With this new library's use of FFIO,
        the memory requirements on the Cray are very high,
        and a typical user job hits its memory limit while
        executing. The default error handling system generates
        garbled or empty error messages, complicating analysis
        of the actual problem. Our suggested changes generate
        a readable error message more often than the default
        system.

If you are interested in the code for these two items, I
will be happy to supply.

Bob Swanson

- - -- 
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+
| Robert Swanson -                                                    | 
| Lockheed Martin Technical Services   |  EMail:  address@hidden    |
| National Environmental Supercomputing Center                        |  
| 135 Washington Avenue   |    Tel : 517-894-7625                     |
| Bay City, MI 48708      |    Fax : 517-894-7676                     |
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+

------- End of Forwarded Message