Description

GRADIENT_RECOVERY Gradient recovery with L2 projection.

[ U_XJ ] = GRADIENT_RECOVERY( PROB, I_DVAR, J_DERIV, U, IND_C, I_CUB, I_MASS, XI, AINVJAC )

Computes the gradient J_DERIV (2 = x, 3 = y, 4 = z) for dependent variable I_DVAR in the degrees of freedom. U is an optional solution vector (default PROB.SOL.U(:,end)). IND_C specifies cells to evaluate (default all), I_CUB the numerical quadrature rule. I_MASS prescribes mass matrix lumping 1 = full (default for higher order elements), 2 = row sum (default for linear elements), 3 = diagonal, 4 = HRZ lumping. When given, the optional arguments XI and AINVJAC computes the derivative in local coordinates XI for cells in IND_C.

See also: evalexpr0