erf(x): Error¶

Error function.

Declaration¶

Syntax¶

retval = erf(x)
elemental real function erf(x)

Arguments¶

x the input value must be of type real.

Return values¶

The return value is of type real and of the same kind as of the input parameter x.

Описание¶

erf(x) computes the error function of x. The result lies in the range:

\(-1 \leq erf (x) \leq 1\)

It is calculated using:

\(\frac{2}{\sqrt\pi}\int_0^xe^{-t^2}dt\)

Types¶

Supported argument types is real.

interface erf
    module procedure serf, derf
end interface

contains

elemental real(sp) function serf(x)
real(sp), intent(in) :: x
end function

elemental real(dp) function derf(x)
real(dp), intent(in) :: x
end function

Examples¶

program intrinsics_erf
	print *, erf(0.5)
end program

Result:

0.520499877