flux cannot changed during fitting

[zouhu]

I try to use tractor galaxy profile fit an source using the scipy.optimize.fmin_l_bfgs_b (I didnot use tractor optimizer).During fitting the image, all parameters are changing except the flux. The flux value keep same. What is the reason

[dstndstn]

Could you please send a code snippet or test case?

What do you get if you do:
tractor.printThawedParams()
to show which parameters are being fit?

What happens if you use the tractor.optimize() routine instead? I have never tried using the scipy.optimize.* routines. Does the parameter vector you are using have enough elements?

Thanks!