# Gradient of a matrix

I want to calculate following:

$\nabla I(\phi(x,p))$

Where p is a 3d vector and I is a matrix. I have no idea to do this calculation and I'm not sure if it's possible to calculate the gradient of a matrix.

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Can you give some context about why exactly you want to calculate this? What are you trying to achieve? There certainly is a way to calculate some kind of derivative, but you probably shouldn't call it a gradient, and it's a somewhat cumbersome rank-3 object. So it would be good to know what you're really after so that one can give a helpful answer. – Rahul Narain May 17 '12 at 10:38