BSY1
This function evaluates the Bessel function of the second kind of order one.
Function Return Value
BSY1 — Function value. (Output)
Required Arguments
X — Argument for which the function value is desired. (Input)
FORTRAN 90 Interface
Generic: BSY1 (X)
Specific: The specific interface names are S_BSY1 and D_BSY1.
FORTRAN 77 Interface
Single: BSY1 (X)
Double: The double precision function name is DBSY1.
Description
The Bessel function Y1(x) is defined to be
Y1(x) is defined for x > 0. To prevent the answer from being less accurate than half precision, x should be smaller than
For the result to have any precision at all, ∣x∣ must be less than 1/ɛ. Here, ɛ is the machine precision, ɛ = AMACH(4).
Example
In this example, Y1(3.0) is computed and printed.
USE BSY1_INT
USE UMACH_INT
IMPLICIT NONE
! Declare variables
INTEGER NOUT
REAL VALUE, X
! Compute
X = 3.0
VALUE = BSY1(X)
! Print the results
CALL UMACH (2, NOUT)
WRITE (NOUT,99999) X, VALUE
99999 FORMAT (' BSY1(', F6.3, ') = ', F6.3)
END
Output
BSY1( 3.000) = 0.325
