GNU Scientific Library Reference Manual - Third Edition (v1.12) by M. Galassi, J. Davies, J. Theiler, B. Gough, G. Jungman, P. Alken, M. Booth, F. Rossi Paperback (6"x9"), 592 pages, 60 figures ISBN 0954612078 RRP £24.95 ($39.95) Get a printed copy>>>

GNU Scientific Library Reference Manual - Third Edition (v1.12) Buy the book here >>> learn more

7.28.2 Trigamma Function

Function: double gsl_sf_psi_1_int (int n)

Function: int gsl_sf_psi_1_int_e (int n, gsl_sf_result * result)

These routines compute the Trigamma function \psi'(n) for positive integer n.

Function: double gsl_sf_psi_1 (double x)

Function: int gsl_sf_psi_1_e (double x, gsl_sf_result * result)

These routines compute the Trigamma function \psi'(x) for general x.