function r = g(w)% g.m - 'g' function Villemoes's construction% % Written by Lexing Ying and Laurent Demanet, 2006  r = zeros(size(w));  gd = w<5*pi/6 & w>-7*pi/6;  r(gd) = abs(sf(w(gd)-3*pi/2));  %----------------------------------------------------------------------function r = sf(w)  r = zeros(size(w));    aw = abs(w);  r(aw<=2*pi/3) = 0;    gd = aw>=2*pi/3 & aw<=4*pi/3;  r(gd) = 1/sqrt(2) * hf(w(gd)/2+pi);    gd = aw>=4*pi/3 & aw<=8*pi/3;  r(gd) = 1/sqrt(2) * hf(w(gd)/4);    r(aw>8*pi/2) = 0;  function r = hf(w)  w = mod(w+pi,2*pi) - pi;  r = zeros(size(w));  w = abs(w);    r = sqrt(2) * cos(pi/2 * beta(3*w/pi-1));  r(w<=pi/3) = sqrt(2);  r(w>=2*pi/3) = 0;  function r = beta(x)  r = (1-cos(pi*x))/2;  %t = (1-cos(pi*x))/2;  r = (1-cos(pi*t))/2;  %r = x.^4 .*(35-84*x + 70*x.^2 -20*x.^3);