simplex minimization

Tim F fenn@agora.dhs.org
Mon Jan 6 05:51:00 GMT 2003


On Fri, 3 Jan 2003 ivo.alxneit@psi.ch wrote:

> >   // set up solver
> >   T = gsl_multimin_fminimizer_nmsimplex;
> >   s = gsl_multimin_fminimizer_alloc(T, p);
> >   ss = gsl_vector_alloc(p);
> >   gsl_multimin_fminimizer_set(s, &f, &param.vector, ss);
> > 
> you did not initialize ss! ss should be initialized by a reasonable step
> size for each of the parameters. this is needed to calculate n more
> corners (n parameters) for the initial simplex. the elements of ss seem
> to be all zero thus the initial size of the simplex is zero as well and
> the minimizer stop right away
> 

doh!  I knew it would be something dumb I was doing wrong...  Thanks -
that fixed it.

	Regards,
	Tim F



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