diff options
| -rw-r--r-- | lib/msun/bsdsrc/b_tgamma.c | 29 |
1 files changed, 15 insertions, 14 deletions
diff --git a/lib/msun/bsdsrc/b_tgamma.c b/lib/msun/bsdsrc/b_tgamma.c index 784e563..5593bbd 100644 --- a/lib/msun/bsdsrc/b_tgamma.c +++ b/lib/msun/bsdsrc/b_tgamma.c @@ -49,7 +49,7 @@ __FBSDID("$FreeBSD$"); /* METHOD: * x < 0: Use reflection formula, G(x) = pi/(sin(pi*x)*x*G(x)) - * At negative integers, return +Inf and raise divide-by-zero. + * At negative integers, return NaN and raise invalid. * * x < 6.5: * Use argument reduction G(x+1) = xG(x) to reach the @@ -66,12 +66,12 @@ __FBSDID("$FreeBSD$"); * avoid premature round-off. * * Special values: - * -Inf: return +Inf (without raising any exception!); - * negative integer: return +Inf and raise divide-by-zero; + * -Inf: return NaN and raise invalid; + * negative integer: return NaN and raise invalid; * other x ~< 177.79: return +-0 and raise underflow; * +-0: return +-Inf and raise divide-by-zero; - * finite x ~> 171.63: return +Inf and raise divide-by-zero(!); - * +Inf: return +Inf and raise divide-by-zero(!); + * finite x ~> 171.63: return +Inf and raise overflow; + * +Inf: return +Inf; * NaN: return NaN. * * Accuracy: tgamma(x) is accurate to within @@ -135,7 +135,7 @@ tgamma(x) if (x >= 6) { if(x > 171.63) - return(one/zero); + return (x / zero); u = large_gam(x); return(__exp__D(u.a, u.b)); } else if (x >= 1.0 + LEFT + x0) @@ -143,12 +143,11 @@ tgamma(x) else if (x > 1.e-17) return (smaller_gam(x)); else if (x > -1.e-17) { - if (x == 0.0) - return (one/x); - one+1e-20; /* Raise inexact flag. */ + if (x != 0.0) + u.a = one - tiny; /* raise inexact */ return (one/x); } else if (!finite(x)) - return (x*x); /* x = NaN, -Inf */ + return (x - x); /* x is NaN or -Inf */ else return (neg_gam(x)); } @@ -282,11 +281,13 @@ neg_gam(x) struct Double lg, lsine; double y, z; - y = floor(x + .5); + y = ceil(x); if (y == x) /* Negative integer. */ - return (one/zero); - z = fabs(x - y); - y = .5*ceil(x); + return ((x - x) / zero); + z = y - x; + if (z > 0.5) + z = one - z; + y = 0.5 * y; if (y == ceil(y)) sgn = -1; if (z < .25) |
