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Remove [rad] unit in variables section?
Posted 23.10.2013, 17:31 GMT-4 RF & Microwave Engineering, Parameters, Variables, & Functions Version 4.3b 2 Replies
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I have a variable set up for the Drude dielectric function: eps=1-(f0*omega^2)/((2*pi*freq)^2-i*(gamma*2*pi*freq)), with "freq" being another variable with units 1/s, "f0" as unitless, and the omega/gamma terms defined in rad/s. Why is the unit showing as "rad"?
I cannot change it to unitless by factoring by 1[1/rad], but if I factor by 1[s/rad], it turns the unit to "s"!
With [rad] being dimensionless, it does not affect the model--I just thought it was odd that you cannot make it dimensionless...
-ado
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Thanks for bringing this to our attention. The unit machinery thinks that rad is the most probable unit because rad occurs in the expression, but as you say, it does not affect the model. We will look at how we can improve this behavior for future versions.
As a side note, it is good practice to avoid using "eps" as a name of a user-defined parameter or variable because "eps" is a built-in constant in COMSOL, representing the machine precision (machine epsilon), which is about 2.22e-16 for double precision floating-point numbers.
Best regards,
Magnus Ringh, COMSOL
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I did not really use eps--for the sake of this post, the entire equation is simplified from my long-winded parameter names ;-)