log

Natural logarithm

Description

float log(float $num, float $base = M_E)

If the optional base parameter is specified, log returns log_base num, otherwise log returns the natural logarithm of num.

Parameters

num: The value to calculate the logarithm for
base: The optional logarithmic base to use (defaults to 'e' and so to the natural logarithm).

Return Values

The logarithm of num to base, if given, or the natural logarithm.

See Also

log10
exp
pow
error_log