bugs(s) in specfunc

[Thomas Walter]

Hello,
while writing some interface functions between 'octave' and 'gsl' I
think I found a few bugs.

The files 'gsl_sf_coulomb.h' and 'coulomb.c' seem out of sync.
The header file declares
    int gsl_sf_coulomb_wave_FGp_impl()
and the source file defines
    int
    gsl_sf_coulomb_wave_FGp_array_impl()

The file 'log.c' defines the functions
    int
    gsl_sf_log_1plusx_impl()
and
    int
    gsl_sf_log_1plusx_mx_impl()
I think the used series expansion for small x
  if(fabs(x) < GSL_ROOT5_DBL_EPSILON)
has the wrong sign for the constant 'c6'.

Also the series seems too short to fill a 'double' with valid digits.
You can verify this especially for 'gsl_sf_log_1plusx_mx_impl()' if
you call this function with values near the border
'GSL_ROOT5_DBL_EPSILON'.  I suggest to extend the series at least with
the constants 'c7 = -1/8' and 'c8 = 1/9'.

Bye
Thomas

-- 
Warum hat eine Leiterbahn keine 90 Grad Winkel sondern 2 mal 45 Grad?
Weil die Elektronen sonst immer gegen die Wand laufen 8-)))

----------------------------------------------
Dipl. Phys. Thomas Walter
Inst. f. Physiklische Chemie II
Egerlandstr. 3				Tel.: ++9131-85 27326 / 27330
91058 Erlangen, Germany			email: walter@pctc.chemie.uni-erlangen.de