%
%  code10Fb.m -- log-log error plots -- 08 nov 02 (djm)
%

Etest = [1.1325 0.2167 0.0505 0.0124];
Ntest = [100 400 1600 6400];

Itest = [-0.0013 -3.8225e-04 -2.9076e-05 -1.8999e-06];

figure(2);  clf;  hold on
plot(log10(Ntest),log10(abs(Etest)),'x')
plot(log10(Ntest),log10(abs(Itest)),'o')

axis([1.8 4 -6 0.5])
plot([3 4],[-1 -2],'r')
plot([3 4],[-4 -6],'r')
text(3.3,-1.2,'\bf slope=-1')
text(3.3,-4.2,'\bf slope=-2')

title('\bf log-log plot of |error(N)| for Euler''s methods')
xlabel('\bf N-axis')
ylabel('\bf |error|-axis')