Trailing-Edge
-
PDP-10 Archives
-
decuslib20-02
-
decus/20-0026/besy.doc
There are 2 other files named besy.doc in the archive. Click here to see a list.
SUBROUTINE BESY
PURPOSE
COMPUTE THE Y BESSEL FUNCTION FOR A GIVEN ARGUMENT AND ORDER
USAGE
CALL BESY(X,N,BY,IER)
DESCRIPTION OF PARAMETERS
X -THE ARGUMENT OF THE Y BESSEL FUNCTION DESIRED
N -THE ORDER OF THE Y BESSEL FUNCTION DESIRED
BY -THE RESULTANT Y BESSEL FUNCTION
IER-RESULTANT ERROR CODE WHERE
IER=0 NO ERROR
IER=1 N IS NEGATIVE
IER=2 X IS NEGATIVE OR ZERO
IER=3 BY HAS EXCEEDED MAGNITUDE OF 10**70
REMARKS
VERY SMALL VALUES OF X MAY CAUSE THE RANGE OF THE LIBRARY
FUNCTION ALOG TO BE EXCEEDED
X MUST BE GREATER THAN ZERO
N MUST BE GREATER THAN OR EQUAL TO ZERO
SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED
NONE
METHOD
RECURRENCE RELATION AND POLYNOMIAL APPROXIMATION TECHNIQUE
AS DESCRIBED BY A.J.M.HITCHCOCK,'POLYNOMIAL APPROXIMATIONS
TO BESSEL FUNCTIONS OF ORDER ZERO AND ONE AND TO RELATED
FUNCTIONS', M.T.A.C., V.11,1957,PP.86-88, AND G.N. WATSON,
'A TREATISE ON THE THEORY OF BESSEL FUNCTIONS', CAMBRIDGE
UNIVERSITY PRESS, 1958, P. 62