% TOEP2_INVCY           Computes the inverse matrix product of a Toeplitz
% matrix and a vector.
%
% [INVB] = TOEP2_INVCY(ct,y)
%
% This function uses the modified Durbin-Levinson's algorithm to calculate 
% the inverse-matrix-product, i.e. inv(Q)*y, where Q is a strictly Toeplitz
% matrix, and y is any vector of the same size as that of Q.
%
% Inputs:
%       ct  = Top row of Toeplitz matrix, Q, of dimension {1 x N}
%       y   = Column vector of dimension {N x 1}
%
% Output:
%       INVB    = Returns the inverse-matrix product of inv(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