> - are you using Decimal for the base-10-ness or the > extra precision Decimal provides? Or significant zeros? > Or compatibility with existing Decimal code, or what?
Oh boy, now I will finally prove myself illiterate... well, so be it. But i am after the extra precision: >>> from math import * >>> (1+1e-16)-1 0.0 ...in this trivial example above I will lose the 1e-16... which may be an issue if you code something that evaluates slightly more complex expressions. I would feel much more comfortable if I lose 1e-60. But in physics, one can get parts of an expression equal to 1e-16 while (by mistake or not) other parts are > 1. Hence it becomes a greater puzzle to debug the calculation. Having the possibility to increase precision would help. Sure, you can say, there is such a small market for this application, and maybe I should use other tools. Well, I found Python so much easier to use for other reasons. And, again, it seems like there is a desire for it outside of my own office. > - what 3 functions would you most like to see added? > For me, I think it would be something like sin, cos > and atan (or possibly atan2). Once you've got those > three, everything else is fairly easy. In particular, > atan/atan2 at least gives you access to pi. Agree: sin, cos and atan would do it. > FWIW, I'm the author of the current Decimal log, log10, exp > and pow functions, so I'm probably in a fairly good position > to try to implement reasonably high-quality versions of some > other elementary functions (again, just as an external > addition to the decimal module, not as part of the decimal > module itself). This is an itch I've often wanted > scratched, as well. I might just have a go.... > (Help in the form of code, tests, suggestions, etc. > would be welcome!) > > Mark Wow, i would never think my posting would go that high in the Python world. I can't wait to tell my colleagues after these holidays ;-) If I improve (in my view that is) the existing modules (dmath) etc. i will keep you posted. For now I am reducing large arguments of goniometric functions by adding the following into the dmath's sin(x) and cos(x): x=Decimal.__mod__(x,Decimal('2')*pi()) Works fine for what i need, but i am sure it's not the right way to do it. Thanks Mark! -- http://mail.python.org/mailman/listinfo/python-list