function [fout, h]=wiener_levinson(b,d);
%WIENER_LEVINSON  Shape the input vector to look like the desired output
%	The input and the desired output must be equal length column vectors.
%
% b is the input trace.
% d is the desired output. 
% fout is the output of the filtering (actual output)
% h is the wiener filter. 
%
%	This function uses the algorithm descibed in Robinson and Tritel's
%  Geophysical Signal Analysis (1981) on page 191.
%
%

ac=xcorr(b);
r1=ac(length(b):end);

xc=xcorr(b,d);
g1=xc(length(b):end);


h=(glev(r1,g1));                   % This solves the system R * h = g for the filter, h

fout=conv(h,b);          % Convolve the filter with the input trace

fout=fout(1:length(b));  % trim the output to the same length as the input