EVOLUTION-MANAGER
Edit File: varFixed.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><title>R: Fixed Variance Function</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <link rel="stylesheet" type="text/css" href="R.css" /> </head><body> <table width="100%" summary="page for varFixed {nlme}"><tr><td>varFixed {nlme}</td><td style="text-align: right;">R Documentation</td></tr></table> <h2>Fixed Variance Function</h2> <h3>Description</h3> <p>This function is a constructor for the <code>varFixed</code> class, representing a variance function with fixed variances. Letting <i>v</i> denote the variance covariate defined in <code>value</code>, the variance function <i>s2(v)</i> for this class is <i>s2(v)=|v|</i>. The variance covariate <i>v</i> is evaluated once at initialization and remains fixed thereafter. No coefficients are required to represent this variance function. </p> <h3>Usage</h3> <pre> varFixed(value) </pre> <h3>Arguments</h3> <table summary="R argblock"> <tr valign="top"><td><code>value</code></td> <td> <p>a one-sided formula of the form <code>~ v</code> specifying a variance covariate <code>v</code>. Grouping factors are ignored.</p> </td></tr> </table> <h3>Value</h3> <p>a <code>varFixed</code> object representing a fixed variance function structure, also inheriting from class <code>varFunc</code>. </p> <h3>Author(s)</h3> <p>José Pinheiro and Douglas Bates <a href="mailto:bates@stat.wisc.edu">bates@stat.wisc.edu</a></p> <h3>References</h3> <p>Pinheiro, J.C., and Bates, D.M. (2000) "Mixed-Effects Models in S and S-PLUS", Springer. </p> <h3>See Also</h3> <p><code><a href="varClasses.html">varClasses</a></code>, <code><a href="varWeights.html">varWeights.varFunc</a></code>, <code><a href="varFunc.html">varFunc</a></code></p> <h3>Examples</h3> <pre> vf1 <- varFixed(~age) </pre> <hr /><div style="text-align: center;">[Package <em>nlme</em> version 3.1-139 <a href="00Index.html">Index</a>]</div> </body></html>