[R-sig-ME] Extracting model matrices used by lmer

Ben Bolker bbolker at gmail.com
Fri Nov 16 05:04:34 CET 2012

Asaf Weinstein <asafw.at.wharton at ...> writes:

> Hello again,
> Is there an easy way of obtaining the X and Z model matrices in
> *y = X*Beta + Z*u + eps*
> with the lmer function? I am trying to extract these because I want to
> obtain maximum likelihood estimates for the case where sigma sq (error
> variance) is known.



As shown in the examples:

   (nmME <- eval(formals(getME)$name))
 [1] "X"       "Z"       "Zt"      "u"       "Gp"      "L"       "Lambda" 
 [8] "Lambdat" "A"       "flist"   "RX"      "RZX"     "beta"    "theta"  
[15] "REML"    "n_rtrms" "is_REML"

so getME(model,"X") and getME(model,"Z") should do what you want.

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