nag_general_elliptic_integral_f (s21dac) Example Program Results
      z          akp      a       b                 y
( 1.2,  3.7)     0.5     1.0     1.0  (   1.9713e+00,    5.0538e-01)
( 9.2, -3.4)     0.8     0.4     2.7  (   2.5042e+00,   -1.1709e-01)