condA=cond(A)
xRellerrDueToMatlab=condA*eps
if xRellerrDueToMatlab >= 1
    disp('*** Error: There is no reasonable solution')
else
    x=A\b
    if xRellerrDueToMatlab > 0.001
            fprintf('*** estmated error %.1f%%\n',...
                xRellerrDueToMatlab*100)
    end
end
