%
% Example on epage 415
% Problem on epage 433
% 
% Written by:
% -- 
% John L. Weatherwax                2008-02-20
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

clear all; 
%close all; 
clc; 

addpath('../../Code/CSTool');
load helmets; 

[stime,inds] = sort(time); 
saccel = accel(inds);
x=stime; y=saccel; 

fd1=figure; rd=plot( time, accel, '.k' ); hold on; grid on; 
xlabel( 'time' ); ylabel( 'accel' ); 

x_sample = linspace( min(time), max(time), 300 ); 

% Create an inline function to evaluate the weights.
mystrg='(2*pi*h^2)^(-1/2)*exp(-0.5*((x - mu)/h).^2)';
wfun = inline(mystrg);

% Set up the space to store the estimated values.
% We will get the estimate at all values of x.
yhatnw = zeros(size(x));
n = length(x);
% Set the window width.
%h = .1;
%h = 1;
%h = 1.5;
h = 2;
%h = 3;
% find smooth at each value in x
for i = 1:n
  w = wfun(h,x(i),x);
  yhatnw(i) = sum(w.*y)/sum(w);
end

figure(fd1); 
plot(x,yhatnw,'-x');
title( ['the helmets data with a NW estimator; h=',num2str(h)] ); 
saveas( gcf, ['../../WriteUp/Graphics/Chapter10/prob_10_15_NW_est'], 'epsc' ); 

clear functions;