% CHRI2 Modification by a quadratic factor.
%
% Given a weight function w(t) through the first n+2 recurrence
% coefficients ab0 of its orthogonal polynomials, ab=CHRI2(n,
% ab0,x,y) generates the first n recurrence coefficients
% of the orthogonal polynomials relative to the modified weight
% function ((t-x)^2+y^2)w(t). The alpha- and beta-coefficients
% of the original weight function are to be provided in the
% first and second column of the (n+2)x2 array ab0; those of the
% modified weight function are returned in the first and second
% column of the nx2 array ab.
%
function ab=chri2(N,ab0,x,y)
N0=size(ab0,1); if N0