MATLAB: Why is 1+ nan*1i = NaN + NaNi

Question

Dear all,

I am trying to figure out how to store some information using complex numbers and retrieving that information later on.

For an operation like

1+nan*1i,

I would like to be able to retrieve "1" by doing

real(1+nan*1i)

and retrieve "nan" by doing

imag(1+nan*1i).

The first case does not work because matlab stores 1+ nan*1i as NaN + NaNi. Is there any workaround to this?

Thanks

Answer 1

I don't envision any workaround that would specifically make NaNs work. Speaking mathematically very loosely, the NaN in your original expression could be a "complex NaN", such that the NaN-ness leaks over to the real part.

I can imagine, without deep thinking, a couple workarounds, that are annoying in their own way, but might work in your particular situation.

• Use another matrix dimension to keep real and imaginary parts separate
• Define your own complex number object, that has the properties you outline above.