Re: GSL_Wigner_6J error

[Brian Gough <bjg at network-theory dot co dot uk>]

Gerard Jungman writes:
 > So I will have to fix it. I will also add a function for
 > Racah-W. The current functions will survive as
 > gsl_sf_coupling_6j_INCORRECT_e() and
 > gsl_sf_coupling_6j_INCORRECT(), so anybody using them doesn't have
 > to think hard about changing their code. But these will be
 > deprecated and undocumented.
 >  Does that seem reasonable to everybody?.

Sounds fine.  

If you want to be safe with the deprecation here is a useful trick
from the Guile developers:

1) Define new versions of the functions, e.g. gsl_sf_wigner_3j,
gsl_sf_wigner_6j, gsl_sf_wigner_9j (by making a copy of the source
file and doing a search/replace, then making any fixes. Leave the
original file untouched). Document that people should start using
the new functions in the NEWS file.

2) Wrap the old gsl_sf_coupling_ versions with

#if (GSL_DEBUG_DEPRECATED == 0)
...
#endif

This allows people to test whether they are using any deprecated
functions by compiling with -DGSL_DEBUG_DEPRECATED=1 (which removes
the definitions).

3) Remove the actual gsl_sf_coupling_ definitions one release later
(remove its source file).

Brian