On Tue, Mar 26, 2019 at 7:38 PM Ian Clark <earthspo...@gmail.com> wrote: > I will still employ my "mickey-mouse" method, because it's easily checked > once it's coded. I need built-into TABULA a number of physical constants > which the SI defines exactly, e.g. > • The thermodynamic temperature of the triple point of water, Ttpw , is > 273.16 K *exactly*. > • The speed of light in vacuo is 299792458 m/s *exactly*. > > The first I can generate and handle as: 27316r100 -whereas (x: 273.16) > is 6829r25 . If you multiply top and bottom by 4 you get my numeral. But > (x:) will round decimal numerals with more than 15 sig figs and so lose the > exactness.
I was looking at https://en.m.wikipedia.org/wiki/2019_redefinition_of_SI_base_units but I did not notice anything with more than 10 significant digits. So I am curious about the examples driving your concern here. (That said, if you're going to go there, and you have not already done so, I'd use your approach on strings, and I'd make it so that it would work properly on values like '6.62607015e-34'. I might also be tempted to make it accept group-of-three-digit representations to make obvious typos stand out visually. Perhaps: '6.626 070 15e-34') Thanks, -- Raul ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
