B=fcgltran(A,direction)

function B=fcgltran(A,direction)

% Fast Chebyshev Transform 
%
% Performs the fast transform of data sampled at the
% Chebyshev-Gauss-Lobatto Nodes x=cos(k*pi/N);
%
% A - original data in columns
% B - transformed data in columns
% direction - set equal to 1 for nodal to spectral
%             anything else for spectral to nodal
%
% Written by Greg von Winckel 03/08/04  
% Contact: [e-mail]

[N,M]=size(A);

if direction==1 % Nodal-to-spectral
    F=ifft([A(1:N,:);A(N-1:-1:2,:)]);
    B=([F(1,:); 2*F(2:(N-1),:); F(N,:)]);
else            % Spectral-to-nodal
    F=fft([A(1,:); [A(2:N,:);A(N-1:-1:2,:)]/2]);
    B=(F(1:N,:));
end