🚀 go-pugleaf

Several people mentioned that they did not receive the earlier
comparison of the Transputer to other machines on the Flux
Corrected Transport fluid dynamics code, so I am posting it
again - with figures for the Motorola 88000 added.

Results are given for both one-D and two-D versions.  The one-
D version has longer vectors, giving the better vector
machines an edge.

The one-D results show the machine, execution time in seconds,
relative speed ratio (assuming that 1 T800 = 1.0), approximate
cost in $1,000 units, and relative speed/cost ratio (assuming
8 T800s = 1.0 this time).  The number of points in the one-D
problem was 2048, and 100 time steps were calculated.

All machines ran the same Fortran code.  The T800s were on
Definicon boards, running at 20 MHz.  The 88k system was on
Tektronix's development board, also running  at 25 MHz.

                               Speed   Approx.    Rel. Cost.
Machine       # Proc.   Time   Ratio    Cost.       Effect.
===========================================================
Ardent Titan     4      18.2     64.4    206          0.515
Alliant FX/8     8      20.6     56.9   1000          0.094
SG 240 GTX       4      43.4     27.0    263          0.169
T800             8     148.5      7.9     13          1.0
VAX 8650         1     293.3      4.0    300          0.021
SUN 4/280        1     306.9      4.0     78          0.081
T800             1    1172.3      1.0     --          -----


The SG 240 GTX is a Silicon Graphics machine.

The two-D problem was 32 x 32 points, again with 100 time
steps. NCube times are taken from Gustafson's article in the
SIAM Scientific & Statistical Computation Journal, July, 1988. 
We assume he was running the same code, since ours also came
from Sandia.
 
                               Speed   Approx.    Rel. Cost.
Machine       # Proc.   Time   Ratio    Cost.       Effect.
===========================================================
Alliant FX/8     8        4.7   101.4   1000          0.171
Ardent Titan     4        7.3    65.3    206          0.535
T800             8       62.2     7.7     13          1.0
88000            1      109.3     4.4     15          0.495
VAX 8650         1      111.8     4.3    300          0.024
NCube           16      118.3     4.0     30          0.225
SUN 4/280        1      132.0     3.6     78          0.078
T800             1      476.4     1.0     --           -----

The cost for the T800 system assumes $1.5k per processor plus
$1k for a cheap PC clone host.  The cost for the 88k assumes
$10k for the processor board plus another $5k for some type of
VME host (a used Sun?? - I'm not really familiar with prices
here).  This month's (Sept.) Electronics on p. 21 describes a
company that provides an 88k VME board with one processor for
about $10k.

The 88k results are courtesy of Jean Michel Favre of
Tektronix.

NCube has indicated the next release of their processor will
be four times faster than the current one.

Dyke Stiles
Electrical Engineering
Utah State Univ.
Stiles@cc.usu.edu
Stiles@usu.bitnet