igamma {distr}R Documentation

Inverse of the digamma function

Description

Function igamma is a numerical inverse of digamma.

Usage

igamma(v)

Arguments

v

a numeric in the range [-100000,18]

Details

igamma is vectorized; it is won by spline inversion of a grid; it works well for range [digamma(1e-5);digamma(1e8)] or [-100000,18].

Value

igamma(x) is a value u such that digamma(u is approximately x.

Author(s)

Peter Ruckdeschel peter.ruckdeschel@uni-oldenburg.de

See Also

digamma

Examples

igamma(digamma(c(1e-4,1,20,1e8)))

[Package distr version 2.9.3 Index]