% Script File: Dot3Hist
% Histogram of 3-digit floating point error
% in computing 5-tuple dot products.

close all
x = randn(5,100);
y = randn(5,100);
er = zeros(100,1);

for k = 1:100
  er(k) = x(k)'*y(k)-Dot3(x(k),y(k));
end

hist(er,20)
% axis([-1 1 0 100])
title('Errors arising in 3-digit base-10 floating point calculations')
xlabel(sprintf('Mean = %5.3f. Median = %5.3f.',mean(er),median(er)))