Another relevant consideration Re: Motion P1788/M0009.01_ExactDotProduct

[Ralph Baker Kearfott <rbk@xxxxxxxxxxxx>]

P-1788,

I've been trying to decide how to vote on this issue, and
am wrestling with the following consideration:  If we demand
the exact dot product as stated in the motion, we will obtain
reproducibility.  However, this will be at the expense of having
an efficient software implementation.  We have efficient software
implementations (e.g. Rump et al) of faithfully rounded dot products, which
would be standard-conforming, and would to my knowledge satisfy
the needs of applications requiring an accurate dot product, if we
loosened the requirement, but I don't know if we can word the
standard to both allow these and for the results to be bit-wise
reproducible.

This is just some food for thought, or for refutation.

Baker

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R. Baker Kearfott,    rbk@xxxxxxxxxxxxx   (337) 482-5346 (fax)
(337) 482-5270 (work)                     (337) 993-1827 (home)
URL: http://interval.louisiana.edu/kearfott.html
Department of Mathematics, University of Louisiana at Lafayette
(Room 217 Maxim D. Doucet Hall, 1403 Johnston Street)
Box 4-1010, Lafayette, LA 70504-1010, USA
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