2002.02.25_lobocki

大名鼎鼎的海洋数值计算模型-pom模型源代码及说明书和示例

Dear POMers,

I have just tried the POM2K and I must say the coding is impressive.
While trying it on a few machines around, I've got a minor execution error 
on a NEC-SX4B (f90 compiler, default options): in line 520:
      write(6,'('' lramp      = '',i10)') lramp
lramp is logical while the format specifier is of integer type. Most 
compilers tolerate this, but you may wish to fix it just
to get closer to perfectness.

*** NOTE: bug introduced by Princeton (not Hunter) and was fixed (l10 format).
*** (T.E.)


Lech Lobocki
Warsaw University of Technology, Poland


 --------------------------------

POM2K, seamount problem,  DTE=6 sec, ISPLIT=30, DAYS=0.25

                                               (65x49x21) (251x61x21)
PII/233,    Compaq Visual Fortran 6.5, Win98         234 s    1140 s
PIII/2x733, Portland Group Fortran, Linux RH7.0:
            -fast                                     87 s     460 s
            -Mconcur, NCPUS=2                         54 s     305 s

NEC SX-4, 1CPU, f90 -C vsafe                                   113 s
NEC SX-4, 1CPU, f90 -C hopt                                    106 s



----------------------------------------------------------------------
Dear POM-ers:

An amendment to the timing table 'published' in my former e-mail:

the test was done with the code taken as is, with as few changes
as it was necessary to run the model - I had to disable the netcdf
output as I did not have it installed on every machine/compiler.

The printing diagnostics interval option prtd1 was used with its
original value 0.0125, which put some burden on CPU time (although
the screen output was redirected to a file). Giorgio Amati suggested
the test to be repeated for this reason. When prtd was changed
to exceed the simulation time, the changes were small for PC boxes
(a few seconds), but large on the NEC (a factor of two), which was
not surprising.

With the reduced printing (initial timestep printouts still remain),
the timing is now:
POM2K, seamount problem,  DTE=6 sec, ISPLIT=30, DAYS=0.25


						(65x49x21)  (251x61x21)
NEC-SX4B, 1 CPU, f90 -C vsafe                                 75 s 
		     -C hopt                                  55 s


PIII/2x733, (133 MHz FSB, 133 MHz SDRAM) Portland Group Fortran, Linux
RH7.0:
                       -fast (1 CPU)           80 s           456 s
                 -Mconcur ,  NCPUS=2	       50 s           297 s

PIII/2x733, running VMWare virtual machine with Win-98 SE under Linux
RH7.0,
Compaq Visual Fortran 6.6 (previously DEC VF 5.0 and earlier yet
Microsoft Powerstation 4.0),
'Release' settings (1 CPU):		       85 s            450 s

There was also neither no attempt to optimize speed by choosing the grid

dimensions, geometry,
etc. nor to fit the particular machine architecture, e.g. cache memory.
It appears that
PC's run the POM at the rate of minutes to hours, per day simulated
depending on the grid
size, and the single-CPU of the NEC-SX4B (comparable to T90 in some
other benchmarks
with POM) does it almost 10x faster.

Lech Lobocki