A code to evaluate modified bessel functions based on thecontinued fraction method

Abstract We present an algorithm to evaluate the modified Bessel functions I_vand K_vof integral and half-integral order based on the calculation of the continued fraction for the I′_v s, the Wronskian and the application of forward recurrence relations for the K'vs and backward recurrence for the I′_v s. The main feature of the algorithm is that it does not require recalculations using normalization relations nor trial values to start the recurrences; the code evaluates in each step (already norm... Title of program: BESSIMIN, BESSIMSE Catalogue Id: ADGM_v1_0 Nature of problem We include two codes in order to evaluate: (1) Modified Spherical Bessel function (subroutine BESSIMSE) (2) Modified Bessel functions of integral order (subroutine BESSIMIN). Both codes evaluate Modified Bessel functions from the lower (positive) orders to a maximum order NMAX in the same run. Versions of this program held in the CPC repository in Mendeley Data ADGM_v1_0; BESSIMIN, BESSIMSE; 10.1016/S0010-4655(97)00069-6 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2019)