psi
Digamma and polygamma functions
Syntax
Description
evaluates the
digamma function
for each element of array Y
= psi(X
)X
, which must be real and nonnegative.
evaluates the polygamma function
of Y
= psi(k
,X
)X
, which is the k
th derivative of the digamma
function at X
. Thus, psi(0,X)
is the digamma function,
psi(1,X)
is the trigamma function, psi(2,X)
is the
tetragamma function, and so on.
Examples
Input Arguments
More About
References
[1] Abramowitz, M. and I. A. Stegun, Handbook of Mathematical Functions, Dover Publications, 1965, Sections 6.3 and 6.4.
Extended Capabilities
Version History
Introduced before R2006a