Function: psi [<n>](<x>) The derivative of
log (gamma (<x>)) of order
psi(<x>) is the first derivative,
psi(<x>) is the second derivative, etc.
Maxima does not know how, in general, to compute a numerical value of
psi, but it can compute some exact values for rational args. Several variables control what range of rational args
psi will return an exact value, if possible. See
maxpsifracdenom. That is, <x> must lie between
maxpsiposint. If the absolute value of the fractional part of <x> is rational and has a numerator less than
maxpsifracnum and has a denominator less than
psi will return an exact value.
bfpsi in the
bffac package can compute numerical values.
There are also some inexact matches for
?? psi to see them.
(%o1) true (%i2)