On Wed 05 Feb 2014 01:36:29 PM MST, Barry Smith wrote:
On Feb 5, 2014, at 2:05 PM, Jed Brown <[email protected]> wrote:
Klaus Zimmermann <[email protected]> writes:
Isn’t that a bit pessimistic? After all there is the out-of-core
facility with mumps.
I'll just note that out-of-core as an algorithmic device is dead on most
HPC machines.
But what about a non-HPC machine? Not everyone has huge machines but how
about a well-endowed server quality workstation setup with the best disks
available? Put as much physical memory as possible and then use the disks for
out of core.
This approach has worked fairly well for me. I have a workstation with
32GB of memory and 500GB on two SSD's in raid 0 configuration. The
out-of-core files for the matrix I was trying to factor are about 300GB
and the numerical factorization takes approximately 4hours. No idea how
this compares to the performance one would get on a workstation that
can fit the factors in ram. Perhaps not too big of a difference during
the factorization but a faster solve?
Cheers,
Dominic
Barry
There are a few machines with fast local SSD, but the
majority of HPC machines need about an hour to write the contents of
memory to disk. You can get more memory by running on more cores up to
the entire machine. If that's not enough, current computing awards
(e.g,, INCITE) are not large enough to store to disk at full-machine
scale more than a few times per year.
--
Dominic Meiser
Tech-X Corporation
5621 Arapahoe Avenue
Boulder, CO 80303
USA
Telephone: 303-996-2036
Fax: 303-448-7756
www.txcorp.com
