dolfin.fem.formmanipulations.derivative(form, u, du=None)

UFL form operator: Given any form, compute the linearization of the form with respect to the given Coefficient. The resulting form has one additional Argument in the same finite element space as the coefficient. A tuple of Coefficients may be provided in place of a single Coefficient, in which case the new Argument argument is based on a MixedElement created from this tuple.