In article <388A1D61-4B3A-4BEB-854D-99047F58191E@schabel-family.org>, boost@schabel-family.org says...
The flow coefficient is Q/sqrt(dP), a volumetric flow/sqrt(pressure). We have derived and defined a unit that would be the si standard for this quantity if there was one and things work fine. I have a runtime unit system that then converts between user values that make sense, to our internal si version that does not but works.
[cut]
The second part is what I can't find. The conversion templates in conversion.hpp seem to specifically expect base units which at least the si part is not and my conversions should use my funky si unit as their basis. So the question I have is how can I write conversions such that I can do this:
quantitysi::flow_coefficient fc(42 * Kv);
and this:
void f(quantityKv::coefficient); void f(quantityCv::coefficient); void f(quantitysi::coefficient);
Where Kv and Cv are base units in their own systems.
The units all need to be dimensionally equivalent to be convertible. That is, as long as Cv::coefficient, Kv::coefficient, and si::coefficient have the same dimensions, and conversions are defined between all base units, conversion should work transparently. It's hard to provide more input without seeing the definitions for the three flow coefficients.
Matthias
From the quoted text above:
"The flow coefficient is Q/sqrt(dP), a volumetric flow/sqrt(pressure)." The units, specifically, are: Kv = (m3/h)/sqrt(bar) Cv = (usgal/min)/sqrt(psi) Repasted from the omitted text: "The only way I can think of to do it is to make a system with the components within the derived dimension and make conversion factors for those. The problem is that I am not sure such systems can be coherent and it would be a significant effort above and beyond the direct conversion factors I already know." -- http://crazyeddiecpp.blogspot.com/