Computing solutions of the modified Bessel differential equation for imaginary orders and positive arguments
Amparo Gil, Javier Segura, Nico Μ. Τemme · ACM Transactions on Mathematical Software · 2004
We describe a variety of methods to compute the functions K ia ( x ), L ia ( x ) and their derivatives for real a and positive x . These functions are numerically satisfactory independent solutions of the differential equation x 2 w " + xw ' + ( a 2 − x 2 ) w = 0. In the accompanying paper [Gil et al. 2004], we describe the implementation of these methods in Fortran 77 codes.