| Pré. | Proc. |
log10
Common logarithm.SYNOPSIS:
double x, y, log10();
y = log10(x);
DESCRIPTION:
Returns logarithm to the base 10 of x.
The argument is separated into its exponent and fractional parts. The logarithm of the fraction is approximated by:
log(1+x) = x - 0.5 x**2 + x**3 P(x)/Q(x).
ACCURACY:
Relative error:
arithmetic domain # trials peak rms
IEEE 0.5, 2.0 30000 1.5e-16 5.0e-17
IEEE 0, MAXNUM 30000 1.4e-16 4.8e-17
DEC 1, MAXNUM 50000 2.5e-17 6.0e-18
In the tests over the interval [1, MAXNUM], the logarithms of the random arguments were uniformly distributed over [0, MAXLOG].
ERROR MESSAGES:
singularity: x = 0; returns -INFINITY
domain: x < 0; returns NAN