Daniel@0: function p = mkPolyFvec(x)
Daniel@0: % MKPOLYFVEC Make feature vector by constructing 2nd order polynomial from input data
Daniel@0: % function p = mkPolyFvec(x)
Daniel@0: %
Daniel@0: % x(:,i) for example i
Daniel@0: % p(:,i) = [x(1,i) x(2,i) x(3,i) x(1,i)^2 x(2,i)^2 x(3,i)^2 ..
Daniel@0: %           x(1,i)*x(2,i) x(1,i)*x(3,i) x(2,i)*x(3,i)]'
Daniel@0: %
Daniel@0: % Example
Daniel@0: % x = [4 5 6]'
Daniel@0: % p = [4 5 6  16 25 36  20 24 30]'
Daniel@0: 
Daniel@0: fvec = x;
Daniel@0: fvecSq = x.*x;
Daniel@0: [D N] = size(x);
Daniel@0: fvecCross = zeros(D*(D-1)/2, N);
Daniel@0: i = 1;
Daniel@0: for d=1:D
Daniel@0:   for d2=d+1:D
Daniel@0:     fvecCross(i,:) = x(d,:) .* x(d2,:);
Daniel@0:     i = i + 1;
Daniel@0:   end
Daniel@0: end
Daniel@0: p = [fvec; fvecSq; fvecCross];