fitting functions which contain 'i'

[Harbinson, Jeremy]

Hi,
Does Octave have any ability to fit a function which contains 'i' (the square root of -1 in case 'i' is as unclear on your screen as it is on mine). The least squares fitting tool does not seem to work, or at least I could not get to work, and these are two quite different things, of course.

I need something that can be used to fit bioimpedance data and to date I have been using the LEVM programme, and though this works very well for me it is somewhat user unfriendly and certainly for our students 'somewhat user unfriendly' means, in most cases, total collapse.

all the best,
Jeremy Harbinson