I have this error
(%i1) taylor(struve_h(-1, x), x, 0, 1); taylor: encountered an unfamiliar singularity in: struve_h(- 2, x) -- an error. To debug this try: debugmode(true);
And this command never returns
taylor(struve_h(-1, x), x, 0, 2); (%i1) build_info(); (%o1) Maxima version: "branch_5_32_base_93_g33a7882" Maxima build date: "2014-03-27 19:40:19" Host type: "x86_64-unknown-linux-gnu" Lisp implementation type: "CLISP" Lisp implementation version: "2.49 (2010-07-07) (built 3575122160) (memory 3604934424)"
I've not looked at the second order expansion yet, but the problem with the first example is that we've got a recurrence relation for the derivative of
struve_h(v, z)
in terms ofstruve_h(v-1, z)
. When taylor tries to evaluate the derivative atz=0
, it has to evaluatestruve_h(-2, 0)
, which is a pole.Of course,
struve_h(-1, x)
is analytic so this isn't particularly impressive...