RE: [AMBER-Developers] cuda and sp/dp question

From: Ross Walker <>
Date: Thu, 18 Mar 2010 12:48:18 -0700

Hi Jason,

> I have a quick question about pmemd.cuda and running it on various
> nVidia cards. I'm getting the message "No double-precision capable
> gpu located, exiting." even though I compiled with SPSP options (which
> makes sense since that message is not located within any kind of ifdef
> statement). Does this mean that card is unsuitable for pmemd.cuda (in
> other words, double-precision is required even though I specified
> single-single?)

The SPSP option is for DEBUGGING ONLY. Do NOT use it for production
calculations. Also note that it still does shake in double precision since
you need 10^-6 or better tolerances. I will be writing documentation to this
effect along with manuscripts showing the differences between the various
precision models when I get a chance to actually start removing things from
my TODO list faster than they accumulate. For the moment the use of single
precision for the entire calculation has not been fully characterized and
indeed blows up for systems where the box size gets large - note why several
benchmarks in the literature that use just single precision for 500K+ atom
systems only show timings for 50 steps. ;-)

Short answer is only cards with SM version 1.3 or later are supported. That
is GT-2XX series and C10XX series or Fermi.

Last time I checked the SPSP and DPDP options are not documented in the
configure script.

      -cuda Builds the NVIDIA GPU accelerated version of pmemd
                  with default SPDP hybrid precision.
                  (Note: this option is exclusive of mpi and only works with
                  and intel at present. CUDA_HOME must point to your cuda
                  tools installation path.).

Where did you find these options? It is important that users do not
arbitrarily start messing with such things so if it is in some obvious
documentation somewhere I'd like to remove it.

All the best

|\oss Walker

| Assistant Research Professor |
| San Diego Supercomputer Center |
| Tel: +1 858 822 0854 | EMail:- |
| | |

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Received on Thu Mar 18 2010 - 13:00:03 PDT
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