function xw=gauss(N,ab)
%GAUSS Gauss quadrature rule.
% GAUSS(N,AB) generates the Nx2 array XW of Gauss quadrature
% nodes and weights for a given weight function W. The nodes,
% in increasing order, are placed into the first column of XW,
% and the corresponding weights into the second column. The
% weight function W is specified by the Nx2 input array AB
% of recurrence coefficients for the polynomials orthogonal
% with respect to the weight function W.
N0=size(ab,1); if N0