If e 1 , e 2 , e 3 are the basis vectors in a Cartesian coordinate system, with coordinates of points denoted by ( x 1 , x 2 , x 3 ), then the gradient of the tensor field T is given by ∇ ∇ T = ∂ ∂ T ∂ ∂ x i ⊗ ⊗ e i