You'll want to include gsl/gsl_randist.h rather than gsl/gsl_rng.h.
The problem is that, since a prototype isn't available for gsl_ran_chisq_pdf() in the latter, the compiler likely defaults to an int return which is not what you want.
You'll want to include gsl/gsl_randist.h rather than gsl/gsl_rng.h.
The problem is that, since a prototype isn't available for gsl_ran_chisq_pdf() in the latter, the compiler likely defaults to an int return which is not what you want.