diff options
Diffstat (limited to 'sysdeps/ieee754/dbl-64/e_jn.c')
| -rw-r--r-- | sysdeps/ieee754/dbl-64/e_jn.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/sysdeps/ieee754/dbl-64/e_jn.c b/sysdeps/ieee754/dbl-64/e_jn.c index bf4a13d974..d9d6f91762 100644 --- a/sysdeps/ieee754/dbl-64/e_jn.c +++ b/sysdeps/ieee754/dbl-64/e_jn.c @@ -215,7 +215,16 @@ static double zero = 0.00000000000000000000e+00; } } } - b = (t*__ieee754_j0(x)/b); + /* j0() and j1() suffer enormous loss of precision at and + * near zero; however, we know that their zero points never + * coincide, so just choose the one further away from zero. + */ + z = __ieee754_j0 (x); + w = __ieee754_j1 (x); + if (fabs (z) >= fabs (w)) + b = (t * z / b); + else + b = (t * w / a); } } if(sgn==1) return -b; else return b; |