[Bug-gsl] parameter check typo in specfunc/bessel_y.c

[Kort Travis]

GSL version: 1.6

filename: specfunc/bessel_y.c

description:  This is a "typo" or design inconsistency, depending on how you 
look at it.

If lmax == 0, the following function has a "domain error".  


Perhaps I'm missing something, but this behavior is inconsistent with the behavior of 
"gsl_sf_bessel_jl_array" and there seems no valid numerical reason for this error (i.e. 
y0 exists and is well defined; two-dimensional arrays where one of the dimensions is "1" 
are well defined and have clearly predicable, cross-platform behavior; etc...).

lines 232..238: (I suggest that the lmax < 1 be changed to lmax < 0 as in 
"gsl_sf_bessel_jl_array" ):
...
int gsl_sf_bessel_yl_array(const int lmax, const double x, double * 
result_array)
{
 /* CHECK_POINTER(result_array) */

 if(lmax < 1 || x <= 0.0) {
   GSL_ERROR ("error", GSL_EDOM);
 }
...

Thanks!


--
Kort Travis
Universität Leipzig
Fakultät für Physik und Geowissenschaften
Abteilung Physik der weichen Materie
Linnéstrasse 5
04103 Leipzig
Germany

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