ERFCE

This function evaluates the exponentially scaled complementary error function.

Function Return Value

ERFCE — Function value. (Output)

Required Arguments

X — Argument for which the function value is desired. (Input)

FORTRAN 90 Interface

Generic: ERFCE (X)

Specific: The specific interface names are S_ERFCE and D_ERFCE.

FORTRAN 77 Interface

Single: ERFCE (X)

Double: The double precision function name is DERFCE.

Description

The function ERFCE(X) computes

 

where erfc(x) is the complementary error function. See ERFC for its definition.

To prevent the answer from underflowing, x must be greater than

 

where b =  AMACH(2) is the largest representable floating‑point number.

Comments

Informational Error

 

Type	Code	Description
2	1	The function underflows because X is too large.

Example

In this example, ERFCE(1.0) = e1.0 erfc(1.0) is computed and printed.

 

USE ERFCE_INT

USE UMACH_INT

 

IMPLICIT NONE

! Declare variables

INTEGER NOUT

REAL VALUE, X

! Compute

X = 1.0

VALUE = ERFCE(X)

! Print the results

CALL UMACH (2, NOUT)

WRITE (NOUT,99999) X, VALUE

99999 FORMAT (' ERFCE(', F6.3, ') = ', F6.3)

END

Output

 

ERFCE( 1.000) = 0.428