Plus42 Equations, Preview Release

[Thomas Okken]

(12-19-2021 12:56 PM)roberto_abraham Wrote:  1 R = 1/(4 pi) 10^10 photon sec^−1 m^−2 Sr^−1

I bet this turns out to be a tricky edge case, since it involves two somewhat special situations. While 'photon' is part of the definition, it's just a dimensionless pure number that doesn't reduce to an SI base unit and instead should get carried along in calculations but stay symbolic. On the other hand, the solid angle is dimensionless but transforms to other dimensionless solid angle measures that have different exponents (e.g. arcsec^-2).

It sounds like the 'photon' part could be dealt with by making it possible to define new base units, not just derived units. That's simple enough; even in the existing code, the only special treatment that base units get is that UBASE and friends leave them alone.

I don't know about the solid angle, though. The 48G has only the Steradian, which is a base unit and doesn't convert to anything else: 1_sr 1_r^2 CONVERT => Inconsistent Units.