On 2/12/2020 4:11 PM, Warner Losh wrote: > > > On Wed, Feb 12, 2020, 11:13 AM Clem Cole > wrote: > > > > On Tue, Feb 11, 2020 at 10:01 PM Larry McVoy > wrote: > > What little Fortran background I have suggests that the difference > might be mind set.  Fortran programmers are formally trained (at > least I > was, there was a whole semester devoted to this) in accumulated > errors. > You did a deep dive into how to code stuff so that the error was > reduced > each time instead of increased.  It has a lot to do with how > floating > point works, it's not exact like integers are. > > Just a thought, but it might also be the training.   My Dad (a > mathematician and 'computer') passed a few years ago, I'd love to > have asked him.   But I suspect when he and his peeps were doing > this with a slide rule or at best an Friden mechanical adding > machine, they were acutely aware of how errors accumulated or not. > When they started to convert their processes/techniques to Fortran > in the early 1960s, I agree with you that I think they were > conscious of what they were doing.   I'm not sure modern CS types > are taught the same things as what might be taught in a course being > run by a pure scientist who cares in the same way folks like our > mothers and fathers did in the 1950s and 60s. > > > Most cs types barely know that 2.234 might not be an exact number when > converted to binary... A few, however can do sophisticated analysis on > the average ULP for complex functions over the expected range.. If that is true of some today, that is sad and disappointing. I think I was taught otherwise in my beginning C.S. course at UT-Austin in 1971. If I recall correctly: - all doctoral candidates ended up taking two semesters of numerical analysis. I still have two volume n.a. text in the attic (orange, but not "burnt orange", IIRC). - numerical analysis was covered on the doctoral qualifying exam. -- voice: +1.512.784.7526 e-mail: sauer at technologists.com fax: +1.512.346.5240 Web: https://technologists.com/sauer/ Facebook/Google/Skype/Twitter: CharlesHSauer