Bessel functions Jn( z) and Yn( z) of integer order and complex argument

Abstract

This paper describes computer subroutines which were developed to compute Bessel functions of the first and second kind ( J n ( z) and Y n ( z), respectively) for a complex argument z and a range of integer orders. A novel way of determ ining the starting point of backward recurrence is used, and the algorithm for Y n ( z) improves on previous algorithms in terms of accuracy and restrictions on the range of orders.