BID
This function evaluates the derivative of the Airy function of the second kind.
Function Return Value
BID — Function value. (Output)
Required Arguments
X — Argument for which the Airy function value is desired. (Input)
FORTRAN 90 Interface
Generic: BID (X)
Specific: The specific interface names are S_BID and D_BID.
FORTRAN 77 Interface
Single: BID (X)
Double: The double precision name is DBID.
Description
The function Biʹ(x) is defined to be the derivative of the Airy function of the second kind, Bi(x) (see BI).
If , then the answer will have no precision. If , the answer will be less accurate than half precision. In addition, x should not be so large that overflows. If overflows are a problem, consider using BIDE instead. Here, ɛ = AMACH(4) is the machine precision.
Example
In this example, Biʹ (–4.9) is computed and printed.
 
USE BID_INT
USE UMACH_INT
 
IMPLICIT NONE
! Declare variables
INTEGER NOUT
REAL VALUE, X
! Compute
X = -4.9
VALUE = BID(X)
! Print the results
CALL UMACH (2, NOUT)
WRITE (NOUT,99999) X, VALUE
99999 FORMAT (' BID(', F6.3, ') = ', F6.3)
END
Output
 
BID(-4.900) = 0.827