Jonathan wrote: > > > On Aug 13, 12:01 pm, "Dr. David Kirkby" <david.kir...@onetel.net> > wrote: >> Jonathan wrote: >>> As a physical scientists I am definitely excited about this. I think >>> the basic plans are sound. >>> I presently do units as symbolic variable defined in terms of a list >>> of standard SI units. I also define a list of physical constants with >>> units. This works quite well, but as mentioned by others this means >>> everything ends up expressed in terms of the fundamental units. I >>> then either have to recognize what derived unit the fundamental >>> expression is or divide it by derived units to see what I have. >>> So here are the key things beyond the already existing functionality >>> that would be ideal: >>> 1) Automatic look up of physical units and their uncertainties at the >>> NIST web site. I think the package should maintain a table and then >>> have a check_physical_constants() function. >> That might be a bit difficult. They are not in any easily accessible >> format. >> >> It is interesting that the charge on an electron returned by Mathematica >> (or Wolfram Alpha) is not the recommended value. Both NPL in the UK and >> NIST reference some document (2006 I think), yet WRI's value is not that >> value. It is however correct within the uncertainty of the measurement. > NIST supplies a simple table format. I even started to write a > parser, but I'm a lot better at parsing in perl and java, so decided I > didn't have time. If somebody wants to tackle the parsing, I can > probably dig up the link. > > Jonathan
I would worry a bit about automatic updating of values, in case things go wrong on the NIST web site. I think it would be better to update them on a new release of sage. The constants don't change that often - a bit of a play on words there. Dave --~--~---------~--~----~------------~-------~--~----~ To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
