die...@duenenhof-wilhelm.de (H. Dieter Wilhelm) writes: > Hello Org, > > for some engineering most often I need estimations with unit > conversions, Emacs Calc is perfect for this. > > When it comes to reporting and documentation I'd like to do it with > org-mode, of course. For numerical stuff and visualisation purposes I'm > using already R and TikZ. But for unit conversions and symbolic maths > I'm in a bind when trying to do this with free programs.
If you're on a linux of some sort, you probably have the "units" command line program installed. That's sort of the mother of all unit converters, as far as I'm concerned -- you could call out to it and return the results. What do you think? > - R :: Do you have experience with a units packages under the R-project? > What I've seen so far is not so reassuring... > > - Maxima :: I think there is a nice and intuitive units package for > maxima. But this would mean learning an additional tool and mentally > switching between both within one document. > > - Calc :: I'd prefer to do it with Calc but the Babel interface is > (yet?) restricted > > For example, I can define functions and do some unit conversions: > > #+BEGIN_SRC emacs-lisp > (defmath cvun(a b) > (math-convert-units a b)) > #+END_SRC > > > #+RESULTS: > : calcFunc-cvun > > #+BEGIN_SRC calc :var L1 = "5 mm" > cvun( L1, m) > #+END_SRC > > > #+RESULTS: > : 5e-3 m > > But what is missing is to assign variables within a source block > > > #+BEGIN_SRC calc :var L1 = "5 mm" > L2 := cvun( L1, m) > #+END_SRC > > > Unfortunately this is not working. Do you have an idea how to > implement this? > > - Are you using (better) alternatives? > > Thanks for your insights > > Dieter