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Miscellaneous functions included in dr

The function dr.direction takes two arguments, the object name, and which directions are wanted (for, example, 1:3 returns the first three directions). It returns the matrix $XU$, scaled to have unit column length unless the argument norm is false, where $U$ gives the specified eigenvectors. The function calls dr.x(i1) and dr.y(i1) return the model matrix and the response, respectively. dr.z(i1,center=T,rotate=T) returns the centered and rotated $Z$ matrix from $X$. You can also use dr.z by explicity providing a matrix $X$ in place of the first argument, and if necessary a vector of weights as a second argument. The routine used for slicing is called dr.slices(y,h) to slice y into h slices. If y has $p$ columns and h has $p$ elements, then slicing is done recursively. The first column of y is sliced into h[1] slices. Within each of these slices, the second column of y is sliced into h[2] slices, giving h[1]*h[2] slices. This process is then repeated for any additional columns. If h is a scalar, then each dimension is sliced into the smallest integer larger than h$^{1/p}$ slices. For example, if $p=2$ and h$=8$, then each dimension has 3 slices for a total of 9.
next up previous
Next: Bug Reports Up: Dimension Reduction Regression in Previous: Weights
Sandy Weisberg 2002-01-10