Re: [R] PRESS criterion in leaps

From: Richard M. Heiberger <>
Date: Mon, 14 May 2007 13:34:17 -0400 (EDT)

The main reason for explicitly constructing the Q matrix is for the pedagogical value of seeing it. As Thomas points out, if you want to actually use Q in a calculation, there will almost always be a much more efficient way of constructing the real goal of the calculation.

For help in that construction, you can use the qr.Q and qr.R functions to see what Q and R look like. This will help you confirm in tiny cases that you have done the more efficient calculation correctly.

Rich mailing list PLEASE do read the posting guide and provide commented, minimal, self-contained, reproducible code. Received on Mon 14 May 2007 - 17:39:14 GMT

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