Hello,

Sorry, but it was you that misread some of the suggestions. I have written raw=TRUE not raw=raw. Just see


m <- matrix(1:6, ncol=2)  # your example

p2 <- poly(m, degree=2, raw=TRUE) # it's raw=TRUE, not raw=raw !!!
deg2 <- attr(p2, 'degree') == 2
p2[, deg2]

p6 <- poly(m, degree=6, raw=TRUE) # now degree 6
deg6 <- attr(p6, 'degree') == 6
p6[, deg6]


Hope this helps,

Rui Barradas

Em 02-07-2012 23:52, YTP escreveu:
I think you have taken my toy example seriously. Perhaps I wasn't clear, but
I am in fact not working with a dataset of 3 observations of the numbers 1
through 6 and trying to estimate anything; that was an example to illustrate
what I am asking for, namely, turning two variables like this

  X1 X2
   1  4
   2  5
   3  6


into a dataset like this

  1  4   16
  4  10  25
  9  18  36


where each column is the interaction between certain polynomial terms of the
original variables, such that each column has a sum of exponents equal to 2
(or whatever degree n is desired). My apologies if I wasn't clear, any other
ideas would be appreciated. It appears the poly command you mentioned is
only taking powers of a single vector.



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