foptions.m, filtering for matlab

				clear all
				eps = 0.0000001;
				npts = 5000;
				del = 1./ 5000.;
				t = 0. : del : 1.;
				% generate input sequence
				inp = 1.+ t.^3 + .5 .*t.^2 + cos(2.*pi*5 .* t) ;
				% read the intial estimate for the state vector
				X0 = [2,.1,.01]';
				% this is the update interval in seconds
				T = 100. * del;
				% this is the value of the smoothing coefficient
				xi = .1;
				[residual, estimate] = ghk_tracker (X0, xi, inp, npts, T, eps);
				figure(1)
				plot (residual(1:500),'k')
				xlabel ('Sample number')
				ylabel ('Residual error')
				grid
				figure(2)
				NN = 4999.;
				n = 1:NN;
				plot(n,estimate(1:NN),'k',n,inp(1:NN),'k--')
				xlabel ('Sample number')
				ylabel ('Position')
				legend ('Estimated','Input')
				figure(3)
				plot(inp,'k')
				xlabel ('Sample number')
				ylabel ('Position')