derivative(form, u, du=None, coefficient_derivatives=None)¶
UFL form operator: Compute the Gateaux derivative of form w.r.t. coefficient in direction of argument.
If the argument is omitted, a new
Argumentis created in the same space as the coefficient, with argument number one higher than the highest one in the form.
The resulting form has one additional
Argumentin 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
Argumentargument is based on a
MixedElementcreated from this tuple.
Coefficientfrom a mixed space may be provided, in which case the argument should be in the corresponding subspace of the coefficient space.
If provided, coefficient_derivatives should be a mapping from
Coefficientinstances to their derivatives w.r.t. coefficient.
A tuple of Coefficients in place of a single Coefficient is not supported in DOLFIN. Supply rather a Function on a mixed space in place of a Coefficient.