Go forward to exp
Go backward to cosh
Go up to Math
Go to the top op libm
`erf', `erff', `erfc', `erfcf'--error function
double erf(double X);
float erff(float X);
double erfc(double X);
float erfcf(float X);
`erf' calculates an approximation to the "error function", which
estimates the probability that an observation will fall within X
standard deviations of the mean (assuming a normal distribution).
`erfc' calculates the complementary probability; that is, `erfc(X)'
is `1 - erf(X)'. `erfc' is computed directly, so that you can use it
to avoid the loss of precision that would result from subtracting large
probabilities (on large X) from 1.
`erff' and `erfcf' differ from `erf' and `erfc' only in the argument
and result types.
For positive arguments, `erf' and all its variants return a
probability--a number between 0 and 1.
None of the variants of `erf' are ANSI C.
Created Mon Nov 8 17:42:56 2004 on tillpc with info_to_html version 0.9.6.