affy: hlog – R documentation

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hlog

Hybrid Log

Description

Given a constant c this function returns x if x is less than c and sign(x)*(c*log(abs(x)/c) + c) if its not. Notice this is a continuous odd ( f(-x)=-f(x) ) function with continuous first derivative. The main purpose is to perform log transformation when one has negative numbers, for example for PM-MM.

Usage

hlog(x, constant=1)

Arguments

`x`	a number.
`constant`	the constant c (see description).

Details

If constant is less than or equal to 0 log(x) is returned for all x. If constant is infinity x is returned for all x.

Author(s)

Rafael A. Irizarry

affy

Methods for Affymetrix Oligonucleotide Arrays

v1.68.0

LGPL (>= 2.0)

Authors

Rafael A. Irizarry <rafa@ds.harvard.edu>, Laurent Gautier <lgautier@gmail.com>, Benjamin Milo Bolstad <bmb@bmbolstad.com>, and Crispin Miller <cmiller@picr.man.ac.uk> with contributions from Magnus Astrand <Magnus.Astrand@astrazeneca.com>, Leslie M. Cope <cope@mts.jhu.edu>, Robert Gentleman, Jeff Gentry, Conrad Halling <challing@agilixcorp.com>, Wolfgang Huber, James MacDonald <jmacdon@u.washington.edu>, Benjamin I. P. Rubinstein, Christopher Workman <workman@cbs.dtu.dk>, John Zhang

Initial release