```Date: Apr 18, 2013 10:29 PM
Author: Nasser Abbasi
Subject: Re: vector and array element multiplication

On 4/18/2013 8:26 PM, Gorbeña wrote:> Hi,> I would like to create a second order polynomial from a vector or a matrix. Each element>of the vector or matrix corresponds to an independedent variable.>> Given vector A, where A = [x1 x2 x3], I want the following result:>> [x1  x1²  x1*x2  x1*x3  x2  x2*x1  x2²  x1*x3  x3  x3*x1  x3*x2  x3²]>> In case I have matrix B = [a1 a2 a3; b1 b2 b3], the desired result will be:>> [a1  a1²  a1*a2  a1*a3  a2  a2*a1  a2²  a1*a3  a3  a3*a1  a3*a2  a3²;>   b1  b1²  b1*b2  b1*b3  b2  b2*b1  b2²  b1*b3  b3  b3*b1  b3*b2  b3²]>> Does anybody knows how to do this?>> Thanks>You can make each poly by multiplying each row by itself but aftertransposing. (i.e. do an outer product)-----------------syms x1 x2 x3V = [x1 x2 x3]  %one rowC = V.'*V;C = [V C(:).']---------------------  [ x1, x2, x3, x1^2, x1*x2, x1*x3, x1*x2, x2^2, x2*x3, x1*x3, x2*x3, x3^2]So for a matrix, just do the above outer product for its of its rows.--Nasser
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