One may also calculate the total differential of the Hamiltonian H with respect to coordinates ⁠ q i ⁠, ⁠ p i ⁠, ⁠ t ⁠ instead of ⁠ q i ⁠, ⁠ q ˙ ˙ i ⁠, ⁠ t ⁠, yielding: d H = ∑ ∑ i ( ∂ ∂ H ∂ ∂ q i d q i + ∂ ∂ H ∂ ∂ p i d p i ) + ∂ ∂ H ∂ ∂ t d t .