I am trying to use the units capabilities of Mathematica throughout a course that I am teaching, but am finding that it isn't uniformly implemented across many functions. In particular, I would love to be able to do the following:

p = (R T ρ)/M;
pressures = Quantity[{12.223, 25.20, 36.97, 60.37, 85.23, 101.3}, "kPa"];
massdensities = 
  Quantity[{0.225, 0.456, 0.664, 1.062, 1.468, 1.734}, "kg per (m m m)"];
data = {massdensities, pressures}\[Transpose];
R = Quantity["MolarGasConstant"];
T = Quantity[25 + 273.15, "Kelvins"];

FindFit[data, p, M, ρ]

Unfortunately, FindFit seems to require that everything be unitless. Am I missing something?

  • 3
    $\begingroup$ No, unit functionality isn't yet implemented in FindFit $\endgroup$
    – ilian
    Jan 10, 2018 at 3:21
  • $\begingroup$ Thank you. It's a shame, as the units functionality is quite useful, and yet my students and I are repeatedly coming across cases where we have to strip the units in order to do something, and it often takes quite some time to track down to it being the units that are the problem. $\endgroup$ Jan 15, 2018 at 23:31
  • $\begingroup$ Help > Give feedback brings you to: wolfram.com/support/contact/email $\endgroup$
    – rhermans
    Jul 9, 2018 at 22:53


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