material-func does not take µ values

[LingLuIOP]

Dear Steven,

I found that geometries defined by material-func is not compatible with the \mu material definition.
All materials defined this way have \mu = 1.

[stevengj]

You currently have to have at least one actual object in the geometry with µ≠1, otherwise it ignores µ. That object can be zero size, or hidden behind another object.

I should probably add an extra-materials variable like in Meep.

[stevengj]

Actually, I forgot, there is an input variable force-mu?. So, if you return mu from a material function, you should do

(set! force-mu? true)

to tell MPB that you need µ support.

[stevengj]

(The Python interface, in NanoComp/meep#222, is similar.)

[LingLuIOP]

indeed, problem solved. Thank you!