> On Jan 8, 2019, at 11:58 PM, Tony Duell via cctalk <cctalk@classiccmp.org>
> wrote:
>
> ...
> IIRC one of the manuals for the HP15C had a chapter on 'Why this
> calculator gives the wrong answers'. It covered things like rounding
> errors.
>
> -tony
That reminds me of a nice old quote.
"An electronic pocket calculator when used by a person unconversant with it
will most probably give a wrong answer in 9 decimal places" -- Dr. Anand
Prakash, 9 May 1975
Understanding rounding errors is perhaps the most significant part of
"numerical methods", a subdivision of computer science not as widely known as
it should be. I remember learning of the work of a scientist at DEC whose work
was all about this: making the DEC math libraries not only efficient but
accurate to the last bit. Apparently this isn't anywhere near as common as it
should be. And I wonder how many computer models are used for answering
important questions where the answers are significantly affected by numerical
errors. Do the authors of those models know about these considerations?
Maybe. Do the users of those models know? Probably not.
paul
