From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian Gough To: Nicolai Hanssing Cc: gsl-discuss@sources.redhat.com Subject: Re: Error in multifit_lmsder (?) Date: Wed, 19 Dec 2001 13:20:00 -0000 Message-id: <15175.30749.460209.349460@debian> References: X-SW-Source: 2001/msg00280.html I've compiled the program but it will take me a while to study it. Nicolai Hanssing writes: > Dear listmembers > > I have struggeled with the "gsl_multifit_fdfsolver_lmsder", and it works > fine *once*. I have tried to look over the source of "gsl_multifit_", but > haven't found anything. > > I still think that it's probably my own routine, > but it follows the example ing gsl-ref closely... > > The "lmsder" converges correctly the firste time, but when the routine is > called again [with the same parameters] it fails, and sends X= ['nan' > 'nan' 'nan'] to the solverfunctions f and df. > > I do allocate space for the solver, initialize the solver, and I do free > the solver afterwards. And I cant find any reason for the behaivour of the > solver. > > 3 calls as the following fails... [And I dont get it :-)] > solve_nonlin_sys_multifit_nlin(&v_topp.vector,v_alpha); /* OK */ > solve_nonlin_sys_multifit_nlin(&v_topp.vector,v_alpha); /* FAILS */ > solve_nonlin_sys_multifit_nlin(&v_topp.vector,v_alpha); /* FAILS */ > > ANy insight will be much appreciated. > > The problem solved is n>=3 equations: 0 = P0 - X0*sin(X1*P1+X2) > > Regards > Nicolai Hanssing > Denmark >