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U.S. Department of Energy
Office of Scientific and Technical Information

CDC 6600/7600 subroutine for Bessel functions Y/sub. nu. /(x), x > 0,. nu. greater than or equal to 0. [BESY]

Technical Report ·
OSTI ID:5157015
Formulas for Y/sub ..nu../(x) and Y/sub ..nu..+1/(x) are implemented on intervals 0 < x less than or equal to 3, 3 < x < 20, x greater than or equal to 20 and -1/2 less than or equal to ..nu.. < 1/2 to start forward recursion for N member sequences Y/sub ..nu..+k-1/(x), k = 1,...,N. A recursive form of the power series is used on 0 < x less than or equal to 3, while the backward recursive Miller algorithm applied to a confluent hypergeometric representation is implemented on 3 < x < 20. For x greater than or equal to 20, Y/sub ..nu../(x) and Y/sub ..nu..+1/(x) are computed from the asymptotic expansion for x ..-->.. infinity. If the initial order ..nu.. is larger than NULIM, the sequence is started by using the uniform asymptotic expansion for ..nu.. ..-->.. infinity. Here NULIM = 70 if N = 1 or NULIM = 100 if N > 1. Overflow tests are made on the leading term of the uniform asymptotic expansion for large orders and small x.
Research Organization:
Sandia National Labs., Albuquerque, NM (USA)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
5157015
Report Number(s):
SAND-80-1498
Country of Publication:
United States
Language:
English