[Help-gsl] What does gsl_siman_metric_t provide?

[Stefano Bolli]

Hi all.

I'm using GSL library for application of simulated annealing, in
particular I'm interesting in function gsl_siman_solve(...).

It isn't clear to me what does the function passed as the parameter
gsl_siman_metric_t provide.
Reading the documentation is explained that it represent the metric
(distance) between 2 different solution, but I tried with the 2
example
provided with the library (example trivial and TSP) and the result
doesn't change even if I use NULL instead of the "distance function"
expressed above.

How can be used sl_siman_metric_t parameters and why is it useful?

Thanks
Best regards,
Stefano Bolli