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### Matrix/Tensor derivative for Stress Tensor

I need to do define/calculate the following stress tensor in an elegant way (given in latex-syntax):

T_{i,j} := -p \delta_{i,j} + \eta (\partial_i v_j + \partial_j v_i)

where i,j can be x,y,z and

\partial_x v_y := \frac{\partial v_y}{\partial x}

I've found the sage-function kronecker_delta for the first term, but I am having problems with the two partial derivatives.

### Matrix/Tensor derivative for Stress Tensor

I need to do define/calculate the following stress tensor in an elegant way (given in latex-syntax):way:

T_{i,j} $T_{i,j} := -p \delta_{i,j} + \eta (\partial_i v_j + \partial_j v_i)v_i)$

where i,j can be x,y,z and

\partial_x v_y $\partial_i v_j := \frac{\partial v_y}{\partial x}v_j}{\partial i}$

I've found the sage-function kronecker_delta for the first term, but I am having problems with the two partial derivatives.