🚀 go-pugleaf

>>>>> On 15 Jun 91 22:23:08 GMT, dik@cwi.nl (Dik T. Winter) said:

Dik> In article <9106150258.AA16308@ucbvax.Berkeley.EDU>
Dik> jbs@WATSON.IBM.COM writes:

JBS> [....]  3.  Do you know of any machine where the above code will
JBS> average 3x (or less) the time of a single multiply?

Dik> So this is irrelevant.

Winter is claiming that Shearer is trying to obfuscate the issues
about the performance of interval arithmetic (in terms of timing, not
the usefulness of the results.  

I see Shearer asking a very simple question: Please provide *specific*
information on machines where Winter's algorithms for interval add and
interval multiply perform less than 3 times slower than the equivalent
simple operation with a single rounding mode.

Then I suppose that the next step is to compare the performance of
interval arithmetic with 128-bit arithmetic on a machine like the
RS/6000.  To do this, we will first need to find someone who knows how
expensive the rounding mode change is in the RS/6000 FPU pipe, and
then someone who knows the timings of quad-precision arithmetic on the
RS/6000.  (I will be able to learn the latter as soon as I get xlf
version 2 installed on my machine).
--
John D. McCalpin			mccalpin@perelandra.cms.udel.edu
Assistant Professor			mccalpin@brahms.udel.edu
College of Marine Studies, U. Del.	J.MCCALPIN/OMNET