Dan Sandiford
Dan Sandiford
Example: ``` sr -= (stokes.div_u/mesh.dim)*eye(mesh.dim) inv2 = sr[0,0]**2 + sr[0,1]**2 + sr[1,0]**2 + sr[1,1]**2 inv2 = 1/2.*inv2 strainRate_2ndInvariant = sqrt(inv2) uw.function.evaluate(strainRate_2ndInvariant, mesh.data) ``` ``` RuntimeError: Derivatives functions are not handled...