[SciPy-user] non linear optimisation

[Ramon Crehuet]

Dear all,
    I have a problem of non-linear optimisation (see below for a 
experimental description). I have many experimental curves (x,y) and 
want to fit the points to a non-linear function y=f(x; a,b,c...), where 
a,b,c... are the parameters. I know how to do that. But the tricky thing 
is that some parameters should be the same for all the curves, and some 
are different for each curve, and I don't know if there is any module 
that can help me in doing this non-linear fit of *all* the curves at the 
same time.
    For the experimental scientists, I will say that these curves 
correspond to absorption spectra for the same compound in different 
solvents. The model curve f(x; a,b,c...) has some parameters that depend 
on the solvent and others that depend only on the compound, and thus, 
should be the same for all the spectra.
    Before starting to program blindly, I'd like to know if someone has 
faced this problem before. I could not find anything in the 
documentation, probably because I don't know if there is a specific name 
for these kind of problems.
Thanks in advance,
Ramon