Good evening Waldek, Trying to get access to the wiki site, get a 502 Proxy Error now.
Was able to get access much earlier today Hill Strong On Fri, Oct 4, 2024 at 11:56 PM Michael Soegtrop <[email protected]> wrote: > Dear Waldek, > > > There is no official support. Part of the problem is what such > > support should do? > > Indeed supporting units properly is a rather tricky problem. E.g. when > solving differential equations in Mathematica I frequently end up with > terms like a^e/b^e or log a - log b where a and b have the same unit. > This must be converted to (a/b)^e or log (a/b) - frequently manually - > to compute properly. > > Thank you for the links! I browsed the discussion and code. As FriCAS > noob I can't say much about the code, though. From a helicopter > perspective it looks like a traditional solution like in Maxima / > Mathematica, that is units and dimensions are computed at run time. I > didn't work with it, but the unit system of F# might be more suitable > for FriCAS. In F# units are described as parameterized number types. > That is unit computations and checks are done at type check time and not > at run time. This looks more appealing to my for many a reason. E.g. one > can check the correctness of units on symbolic terms and not only when > one inserts numerical values with units - a point at which things get > really messy in Maxima and Mathematica frequently. Having unit factors > (say x*kg) in symbolic terms as suggested in some of the discussions is > also not a feasible solution IMHO. > > Here is a paper on the F# solution: > http://typesatwork.imm.dtu.dk/material/TaW_Paper_TypesAtWork_Kennedy.pdf > > In how far one can solve the a^e/b^e or log a - log b problems this way > I cannot tell, but one could try it in F#. Also if such types would fit > well into the symbolic machinery of FriCAS I can't tell either - I am a > complete FriCAS noob and only read pieces of the FriCAS book. > > It is unlikely that the F# solution works as is in FriCAS - e.g. one > somehow has to handle the issue that a definite integral is no longer a > difference of anti-derivative values if logarithms are involved, e.g. by > giving a meaning to the logarithm of a unit. But if one finds a solution > to this, it would likely be very much superior to what other CAS have. > > Best regards, > > Michael > > -- > You received this message because you are subscribed to the Google Groups > "FriCAS - computer algebra system" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/fricas-devel/21b85099-654c-4df1-9770-eb5c225b254f%40michael-soegtrop.de > . > -- You received this message because you are subscribed to the Google Groups "FriCAS - computer algebra system" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/fricas-devel/CAEnaMTGN6ZThrxjt6pzH2EY9doCX1QDFhJPnpmMk8myDE_%2BxaA%40mail.gmail.com.
