Re: Efficient creation of regression design matrix

*To*: mathgroup at smc.vnet.net*Subject*: [mg82316] Re: Efficient creation of regression design matrix*From*: "Michael Weyrauch" <michael.weyrauch at gmx.de>*Date*: Wed, 17 Oct 2007 04:09:27 -0400 (EDT)*References*: <ff1ovf$8g5$1@smc.vnet.net>

Hello, the following simple one-liner does what you want (I believe) Outer[S, n, m] /. S[a_, b_] /; a == b -> 1 /. S[__]->0 where "m" is your vector of properties and "n" your data vector, e.g. m = {r, b, g, y} n = {r, b, b, y, y, g, g} For S you can take anything you like. If this code is particularly efficient I don't know... Michael