Re: [Bug-gsl] Nelder Mead bug

[Brian Gough]

At Sun, 4 May 2008 21:23:27 -0400,
Michael Kuklik wrote:
> Nelder Mead , i.e. simplex search has a bug. In the function
> static int
> nmsimplex_iterate (void *vstate, gsl_multimin_function * f,
>                    gsl_vector * x, double *size, double *fval)
> 
> in multimin/simplex.c
> a piece of code that determines the highest , second highest and lowest
> vertex fails when first value in y1 is the highest.
> It returns second highest equal to the highest. Later that influence
> decision in the algorithm.
> 
> FIX:
> add lines:
>   ds_hi = gsl_vector_get (y1, 1);
>   s_hi = 1;
> before the loop
> 

Thanks for the bug report, you're right.  I will commit a fix for
that.

-- 
Brian Gough

GNU Scientific Library -
http://www.gnu.org/software/gsl/