Optimized cy_expect_rho_vec
Optimized cy_expect_rho_vec

Here we calculate only what is required.
zasdfgbnm/qutip,anubhavvardhan/qutip,anubhavvardhan/qutip,qutip/qutip,cgranade/qutip,cgranade/qutip,qutip/qutip,zasdfgbnm/qutip