qr.q2ty.r
"qr.q2ty" <-
function (qr, y)
{
if (!is.matrix(y)) {
y <- as.matrix(y)
}
dy <- dim(y)
dq <- dim(qr$qr)
rank <- qr$rank
if (dy[1] != dq[1])
stop("y and qr$qr should have same number of rows")
qr.qty(qr, y)[(rank + 1):dy[1], ]
}