> ... I can submit an additional patch that 1) Renames
> gsl_extrap_richardson to something like gsl_extrap_richardson_vector,
> 2) Provides  a scalar-only gsl_extrap_richardson that wraps up scalars
> and calls the gsl_extrap_richardson_vector routines under the covers,
> and 3) Exercises the scalar-only wrappers fully in the test suite.
> That way if someone later does need a faster scalar-only version, he
> or she can change over the underlying implementation without fear of
> regression.

Attached is a second patch that does exactly what I described above.  It builds
atop the prior patch from this thread.

- Rhys