From maechler at stat.math.ethz.ch  Fri Oct 23 14:15:24 2009
From: maechler at stat.math.ethz.ch (maechler at stat.math.ethz.ch)
Date: Fri, 23 Oct 2009 14:15:24 +0200 (CEST)
Subject: [Rd] trigamma for very large arguments (PR#14020)
Message-ID: <20091023121524.CAB732832010@mail.pubhealth.ku.dk>

>>>>> "JL" == Jerry Lewis <Jerry.Lewis at BiogenIdec.com>
>>>>>     on Thu, 22 Oct 2009 04:20:13 +0200 (CEST) writes:

    JL> Full_Name: Jerry W. Lewis
    JL> Version: 2.9.2
    JL> OS: Windows XP Professional
    JL> Submission from: (NULL) (96.237.55.233)


    JL> trigamma(x) returns 0 for x>1e152, yet
    JL> trigamma <- function(x) 1/x
    JL> gives machine accuracy for any x>1e16

Thank you, yes, and the problem is worse for digamma().
I will fix this, but not anymore for R 2.10.0 (we are in code freeze!)

Martin Maechler, ETH Zurich



[Rd] trigamma for very large arguments (PR#14020)
maechler at stat.math.ethz.ch