add cbrt

Author: heltonmc

src/U_polynomials.jl

@@ -1,5 +1,5 @@
 function Uk_poly_Jn(p, v, p2, x::T) where T <: Float64
-    if v > 5.0 + 1.00033*x + (1427.61*x)^(1/3)
+    if v > 5.0 + 1.00033*x + cbrt(1427.61*x)
         return Uk_poly10(p, v, p2, even_odd_poly_minus)
     else
         return Uk_poly20(p, v, p2, even_odd_poly_minus)

src/besselj.jl

@@ -166,7 +166,7 @@ function _besselj(nu, x)
     (x > large_arg_cutoff && x > 20.0) && return besselj_large_argument(nu, x)
 
 
-    debye_cutoff = 2.0 + 1.00035*x + (302.681*x)^(1/3)
+    debye_cutoff = 2.0 + 1.00035*x + cbrt(302.681*x)
     nu > debye_cutoff && return besselj_debye(nu, x)
 
     if nu >= x