Independent parameters in nonlin_residmin

[Pavel Hofman]

Hi,

Please is there a way to tell nonlin_residmin that some parameters are 
related to some items in the residua vector only and do not affect the 
other residual vector items? In other words I would like to run single 
nonlin_residmin call for fitting multiple parameter sets with 
independent results.

The reason is my function takes rather long but can provide results for 
all the parameter sets at once.

Details: I am measuring harmonic distortion residua from soundcard 
loopback (playrec) using FFT. FFT requires/takes 1 second of data (long 
iteration), providing all the harmonic values at once. But each harmonic 
is independent from the others. At each iteration I would like to 
improve values of all harmonic corrections. Value = amplitude and phase 
(2 numbers). Once the correction values for one harmonic frequency 
result in low-enough recorded/FFTed distortion amplitude (a single item 
in the residuals vector), I do not want to change the found/fitted 
values in the next iteration run - they have no impact on residual 
vector items for other harmonics.

I could run nonlin_residmin iterations for each harmonic frequency 
separately but that would take multiple time.

So far I was not able to find an optimisation parameter for this.

Thanks a lot for any help/hints.

Best regards,

Pavel.