Implement PetscTaoSolver in dolfinx

dolfinx
1

Hello everyone,

I have implemented the PetscTaoSolver in the dolfin and it works perfectly for me. For that I used OptimisationProblem class inbuild class of the dolfin. It has three functions to define the problem: objective function, its gradient and Hessian matrix as shown below.

class ContactProblem(OptimisationProblem):

    def __init__(self):
        OptimisationProblem.__init__(self)

    # Objective function
    def f(self, x):
        u.vector()[:] = x
        return assemble(objective_function)

    # Gradient of the objective function
    def F(self, b, x):
        u.vector()[:] = x
        return assemble(derivative(objective_function), tensor=b)

    # Hessian of the objective function
    def J(self, A, x):
        u.vector()[:] = x
        return assemble(derivative(derivative(objective_function)), tensor=A)

Now, I am trying to implement PetscTaoSolver in dolfinx for which there is no inbuild class. Therefore, I am following this approach,

The function f of class OptimisationProblem return a scalar value. I am not able to figure out how to define a Petsc scalar. Please help to solve the issue.

Thank you,
Manish