Modifying dseries does not work as expected
zero = dseries(zeros(8,1), '2011q1');
% Modifying all of b (this works)
a = dseries((1:8)', '2011q1');
b = a;
b = b + 1;
assert(~all(a - b == zero));
% Modifying only part of b (this does not work as it modifies a as well)
a = dseries((1:8)', '2011q1');
b = a;
b(dates('2012q2'):dates('2012q4')) = b(dates('2012q2'):dates('2012q4')) + 1;
assert(~all(a - b == zero), 'a and b should not be equal here');