KernelGrad
Derive from this base class if your residual is of the form
i.e. if the test function  (_grad_test[_i][_qp]) can be factored out.
Derived classes
Override
- precomputeQpResidual()instead of- computeQpResidual()(do not multiply by- _grad_test[_i][_qp]).
- precomputeQpJacobian()instead of- computeQpJacobian()(do not multiply by- _grad_test[_i][_qp])
- computeOffDiagJacobianstill has to be implemented as if deriving from- Kernel.
Note that precomputeQpResidual() and precomputeQpJacobian() return a RealGradient type.