DAWS
This function evaluates Dawson’s function.
Function Return Value
DAWS — Function value. (Output)
Required Arguments
X — Argument for which the function value is desired. (Input)
FORTRAN 90 Interface
Generic: DAWS (X)
Specific: The specific interface names are S_DAWS and D_DAWS.
FORTRAN 77 Interface
Single: DAWS (X)
Double: The double precision function name is DDAWS.
Description
Dawson’s function is defined to be
It is closely related to the error function for imaginary arguments.
So that Dawson’s function does not underflow, ∣x∣ must be less than 1/(2s). Here, s = AMACH(1) is the smallest representable positive floating‑point number.
Comments
Informational Error
Type | Code | Description |
|---|
3 | 2 | The function underflows because the absolute value of X is too large. |
The Dawson function is closely related to the error function for imaginary arguments.
Example
In this example, DAWS(1.0) is computed and printed.
USE DAWS_INT
USE UMACH_INT
IMPLICIT NONE
! Declare variables
INTEGER NOUT
REAL VALUE, X
! Compute
X = 1.0
VALUE = DAWS(X)
! Print the results
CALL UMACH (2, NOUT)
WRITE (NOUT,99999) X, VALUE
99999 FORMAT (' DAWS(', F6.3, ') = ', F6.3)
END
Output
DAWS( 1.000) = 0.538
