% TOE_TIMES_Y       Computes the Toeplitz matrix-vector multiplication.
%
% [CTY] = TOE_TIMES_Y(ct,y)
%
% This function uses the modified Durbin-Levinson's algorithm to calculate 
% the matrix-vector product, i.e. Q*y, where Q is a strictly Toeplitz
% matrix, with ct defined as the top row of Q, and y is any vector of
% length as the same size of Q.
%
% Inputs:
%       ct  = Top row of Toeplitz matrix, Q, of dimension {1 x N}
%       y   = Column vector of dimension {N x 1}
%
% Outputs:
%       CTY = Returns the matrix-vector product of Q*y
%
%
% The computation is written in C code for execution of fast algorithm. 
% The origin of the fast algorithm is contributed by Y. Zhang (2005) for 
% the use in Gaussian Process Prior Models.
%
%
% (C) Gaussian Process Toeplitz Toolbox 1.0
% (C) Copyright 2005-2007, Keith Neo <keith.neo@nuim.ie>
%                          http://www.hamilton.ie