On 7/14/12, John Gilmore <jwgli...@gmail.com> wrote: > A little presumptuously perhaps, I shall reply for 'someone' He or > she would appear to be a soul mate. > > The remark about floating-point that Mr Hermannsfeldt attributes to > Knuth are relevant to HFP and, perhaps, BFP. Their timing moots any > relevance to Cowlishaw's DFP. > > Moreover, they arev not relevant to it: it uses decimal digits, sand > Mr Hermamnnsfeldt's post does not petray any acquaintance with it. > > The rest of Mr Hermannsfeldt's is also less than confidence-inspiring. > > Consider, > > <begin extract> > The period of the earth's orbit is 365.256363004 days, or known to > about 1 part in ten to the 11th. > </end extract> > > Now there are many measurements and calendrical definitions of the > period of the earth's orbit. The measurements most widely used are > those for the mean tropical year, the time between successive vernal > equinoxes. Its current value is 365.2421_9668, but its precision is > an elusive notion because its value is known to be dropping. > > Now one of the major differences between the old Julian calendar, > which has a mean year length during its four-year cycles of 365.25 > days, and the 'new' Gregorian calendar, which has a mean year length > of 365.2425 days during its 400-year cycles, is just their very > different leap-year rules, which give rise to these differences. > > Mr Hermannsfeldt's number suggests that the Julian calendar is better > at handling precession than the Gregorian one, but this is not the > professional consensus. > > E. B. White said long ago that people who like the word 'personalize' > should of course be free to use it but not perhaps to teach others to > do so. My view of Mr Hermannsfeldt's views on floating-point > arithmetic is of a piece. > > John Gilmore, Ashland, MA 01721 - USA >
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