Maxima Function
bfpsi (n, z, fpprec)
bfpsi0(z,fpprec)
bfpsi is the polygamma function of real argument z and integer order n.
bfpsi0 is the digamma function.
bfpsi0 (z, fpprec) is equivalent to bfpsi (0, z, fpprec).
These functions return bigfloat values. fpprec is the bigfloat precision of the return value.
load ("bffac") loads these functions.