Exemplo n.º 1
0
    def solve(self, dt):
        self.u = Function(self.V0)
        self.w = TestFunction(self.V0)
        self.du = TrialFunction(self.V0)

        x = SpatialCoordinate(self.mesh0)

        L = inner( self.S(), self.eps(self.w) )*dx(degree=4)\
        - inner( self.b, self.w )*dx(degree=4)\
        - inner( self.h, self.w )*ds(degree=4)\
        + inner( 1e-6*self.u, self.w )*ds(degree=4)\
        - inner( min_value(x[2]+self.ut[2]+self.u[2], 0) * Constant((0,0,-1.0)), self.w )*ds(degree=4)

        a = derivative(L, self.u, self.du)

        problem = NonlinearVariationalProblem(L, self.u, bcs=[], J=a)
        solver = NonlinearVariationalSolver(problem)

        solver.solve()

        self.ut.vector()[:] = self.ut.vector()[:] + self.u.vector()[:]

        ALE.move(self.mesh, Function(self.V, self.u.vector()))

        self.v.vector()[:] = self.u.vector()[:] / dt
        self.n = FacetNormal(self.mesh)
Exemplo n.º 2
0
    def set_solver_alpha_snes2(self):
        V = self.alpha.function_space()
        denergy = derivative(self.energy, self.alpha, TestFunction(V))
        ddenergy = derivative(denergy, self.alpha, TrialFunction(V))
        self.lb = self.alpha_init  # interpolate(Constant("0."), V)
        ub = interpolate(Constant("1."), V)
        self.problem_alpha = NonlinearVariationalProblem(denergy,
                                                         self.alpha,
                                                         self.bcs_alpha,
                                                         J=ddenergy)
        self.problem_alpha.set_bounds(self.lb, ub)
        self.problem_alpha.lb = self.lb
        # set up the solver
        solver = NonlinearVariationalSolver(self.problem_alpha)

        snes_solver_parameters_bounds = {
            "nonlinear_solver": "snes",
            "snes_solver": {
                "linear_solver": "mumps",
                "maximum_iterations": 300,
                "report": True,
                "line_search": "basic",
                "method": "vinewtonrsls",
                "absolute_tolerance": 1e-5,
                "relative_tolerance": 1e-5,
                "solution_tolerance": 1e-5
            }
        }
        solver.parameters.update(snes_solver_parameters_bounds)
        #solver.solve()
        self.solver = solver
Exemplo n.º 3
0
    def _set_solid_default_parameters(self):
        solid = df.Parameters(Physics.SOLID.value)
        solid.add("dt", 1e-3)
        solid.add("dummy_parameter", False)

        # Add boundary condtion parameters
        solid.add(df.Parameters("BoundaryConditions"))
        solid["BoundaryConditions"].add("base_bc", "fixed")
        solid["BoundaryConditions"].add("lv_pressure", 10.0)
        solid["BoundaryConditions"].add("rv_pressure", 0.0)
        solid["BoundaryConditions"].add("pericardium_spring", 0.0)
        solid["BoundaryConditions"].add("base_spring", 0.0)

        # Add default parameters from both LU and Krylov solvers
        solid.add(NonlinearVariationalSolver.default_parameters())
        solid.add(LUSolver.default_parameters())
        solid.add(PETScKrylovSolver.default_parameters())

        # Add solver parameters
        solid.add(df.Parameters("Solver"))
        solid["Solver"].add("dummy_parameter", False)

        self.add(solid)
an, ca, psi = split(u)
van, vca, vpsi = TestFunctions(ME)

Fan = D_an * (-inner(grad(an), grad(van)) * dx -
              Farad / R / Temp * z_an * an * inner(grad(psi), grad(van)) * dx)
Fca = D_ca * (-inner(grad(ca), grad(vca)) * dx -
              Farad / R / Temp * z_ca * ca * inner(grad(psi), grad(vca)) * dx)
Fpsi = inner(grad(psi), grad(vpsi)) * dx - (Farad / (eps0 * epsR)) * (
    z_an * an + z_ca * ca + z_fc * fc_function) * vpsi * dx

F = Fpsi + Fan + Fca

J = derivative(F, u)
problem = NonlinearVariationalProblem(F, u, bcs=bcs, J=J)
solver = NonlinearVariationalSolver(problem)
prm = solver.parameters
#print(solver.default_parameters().items())
prm["newton_solver"]["linear_solver"] = 'mumps'
solver.solve()

#########################  Post - Processing  #################################
an, ca, psi = u.split()

aftersolveT = timer()

first = plot(an, title="Anion concentration, $c^-$")
plt.xlim(0.0, 0.015)
plt.xticks([0.0, 0.005, 0.01, 0.015])
plt.ylim(0.0, 0.015)
plt.yticks([0.0, 0.005, 0.01, 0.015])
Exemplo n.º 5
0
    def solve(self, problem):
        self.problem = problem
        doSave = problem.doSave
        save_this_step = False
        onlyVel = problem.saveOnlyVel
        dt = self.metadata['dt']

        nu = Constant(self.problem.nu)
        self.tc.init_watch('init', 'Initialization', True, count_to_percent=False)
        self.tc.init_watch('solve', 'Running nonlinear solver', True, count_to_percent=True)
        self.tc.init_watch('next', 'Next step assignments', True, count_to_percent=True)
        self.tc.init_watch('saveVel', 'Saved velocity', True)

        self.tc.start('init')

        mesh = self.problem.mesh

        # Define function spaces (P2-P1)
        self.V = VectorFunctionSpace(mesh, "Lagrange", 2)  # velocity
        self.Q = FunctionSpace(mesh, "Lagrange", 1)  # pressure
        self.W = MixedFunctionSpace([self.V, self.Q])
        self.PS = FunctionSpace(mesh, "Lagrange", 2)  # partial solution (must be same order as V)
        self.D = FunctionSpace(mesh, "Lagrange", 1)   # velocity divergence space

        # to assign solution in space W.sub(0) to Function(V) we need FunctionAssigner (cannot be assigned directly)
        fa = FunctionAssigner(self.V, self.W.sub(0))
        velSp = Function(self.V)

        problem.initialize(self.V, self.Q, self.PS, self.D)

        # Define unknown and test function(s) NS
        v, q = TestFunctions(self.W)
        w = Function(self.W)
        dw = TrialFunction(self.W)
        u, p = split(w)

        # Define fields
        n = FacetNormal(mesh)
        I = Identity(u.geometric_dimension())
        theta = 0.5  # Crank-Nicholson
        k = Constant(self.metadata['dt'])

        # Initial conditions: u0 velocity at previous time step u1 velocity two time steps back p0 previous pressure
        [u0, p0] = self.problem.get_initial_conditions([{'type': 'v', 'time': 0.0}, {'type': 'p', 'time': 0.0}])

        if doSave:
            problem.save_vel(False, u0, 0.0)

        # boundary conditions
        bcu, bcp = problem.get_boundary_conditions(self.bc == 'outflow', self.W.sub(0), self.W.sub(1))
        # NT bcp is not used

        # Define steady part of the equation
        def T(u):
            return -p * I + 2.0 * nu * sym(grad(u))

        def F(u, v, q):
            return (inner(T(u), grad(v)) - q * div(u)) * dx + inner(grad(u) * u, v) * dx

        # Define variational forms
        F_ns = (inner((u - u0), v) / k) * dx + (1.0 - theta) * F(u0, v, q) + theta * F(u, v, q)
        J_ns = derivative(F_ns, w, dw)
        # J_ns = derivative(F_ns, w)  # did not work

        # NS_problem = NonlinearVariationalProblem(F_ns, w, bcu, J_ns, form_compiler_parameters=ffc_options)
        NS_problem = NonlinearVariationalProblem(F_ns, w, bcu, J_ns)
        # (var. formulation, unknown, Dir. BC, jacobian, optional)
        NS_solver = NonlinearVariationalSolver(NS_problem)

        prm = NS_solver.parameters
        prm['newton_solver']['absolute_tolerance'] = 1E-08
        prm['newton_solver']['relative_tolerance'] = 1E-08
        # prm['newton_solver']['maximum_iterations'] = 45
        # prm['newton_solver']['relaxation_parameter'] = 1.0
        prm['newton_solver']['linear_solver'] = 'mumps'

        info(NS_solver.parameters, True)

        self.tc.end('init')

        # Time-stepping
        info("Running of direct method")
        ttime = self.metadata['time']
        t = dt
        step = 1
        while t < (ttime + dt/2.0):
            info("t = %f" % t)
            self.problem.update_time(t, step)
            if self.MPI_rank == 0:
                problem.write_status_file(t)

            if doSave:
                save_this_step = problem.save_this_step

            # Compute
            begin("Solving NS ....")
            try:
                self.tc.start('solve')
                NS_solver.solve()
                self.tc.end('solve')
            except RuntimeError as inst:
                problem.report_fail(t)
                return 1
            end()

            # Extract solutions:
            (u, p) = w.split()
            fa.assign(velSp, u)
            # we are assigning twice (now and inside save_vel), but it works with one method save_vel for direct and
            #   projection (we could split save_vel to save one assign)

            if save_this_step:
                self.tc.start('saveVel')
                problem.save_vel(False, velSp, t)
                self.tc.end('saveVel')
            if save_this_step and not onlyVel:
                problem.save_div(False, u)
            problem.compute_err(False, u, t)
            problem.compute_div(False, u)

            # foo = Function(self.Q)
            # foo.assign(p)
            # problem.averaging_pressure(foo)
            # if save_this_step and not onlyVel:
            #     problem.save_pressure(False, foo)

            if save_this_step and not onlyVel:
                problem.save_pressure(False, p)

            # compute functionals (e. g. forces)
            problem.compute_functionals(u, p, t)

            # Move to next time step
            self.tc.start('next')
            u0.assign(velSp)
            t = round(t + dt, 6)  # round time step to 0.000001
            step += 1
            self.tc.end('next')

        info("Finished: direct method")
        problem.report()
        return 0
Exemplo n.º 6
0
def cmscr1d_weak_solution(V: VectorFunctionSpace,
                          f: Function, ft: Function, fx: Function,
                          alpha0: float, alpha1: float,
                          alpha2: float, alpha3: float,
                          beta: float, bcs=[]) \
                          -> (Function, Function, float, float, bool):
    """Solves the weak formulation of the Euler-Lagrange equations of the L2-H1
    mass conserving flow functional with source and with spatio-temporal and
    convective regularisation for a 1D image sequence with natural boundary
    conditions.

    Args:
        V (VectorFunctionSpace): The function space.
        f (Function): A 1D image sequence.
        ft (Function): Partial derivative of f wrt. time.
        fx (Function): Partial derivative of f wrt. space.
        alpha0 (float): The spatial regularisation parameter for v.
        alpha1 (float): The temporal regularisation parameter for v.
        alpha2 (float): The spatial regularisation parameter for k.
        alpha3 (float): The temporal regularisation parameter for k.
        beta (float): The convective regularisation parameter for.
        bcs: boundary conditions (optional).

    Returns:
        v (Function): The velocity.
        k (Function): The source.
        res (float): The residual.
        fun (float): The function value.
        status (bool): True if Newton's method converged.
    """
    # Define trial and test functions.
    w = Function(V)
    v, k = split(w)
    w1, w2 = TestFunctions(V)

    # Define weak formulation.
    A = (- (ft + fx * v + f * v.dx(1) - k) * (fx * w1 + f * w1.dx(1))
         - alpha0 * v.dx(1) * w1.dx(1)
         - alpha1 * v.dx(0) * w1.dx(0)
         - beta * k.dx(1) * (k.dx(0) + k.dx(1) * v) * w1) * dx \
        + ((ft + fx * v + f * v.dx(1) - k) * w2
           - alpha2 * k.dx(1) * w2.dx(1)
           - alpha3 * k.dx(0) * w2.dx(0)
           - beta * (k.dx(0) * w2.dx(0) + k.dx(1) * v * w2.dx(0)
                     + k.dx(0) * v * w2.dx(1)
                     + k.dx(1) * v * v * w2.dx(1))) * dx

    # Compute Gateaux derivative.
    DA = derivative(A, w)

    # Set up solver.
    problem = NonlinearVariationalProblem(A, w, bcs, DA)
    solver = NonlinearVariationalSolver(problem)

    # Set solver parameters.
    prm = solver.parameters
    prm['newton_solver']['error_on_nonconvergence'] = False
    prm['newton_solver']['maximum_iterations'] = 15
    prm['newton_solver']['absolute_tolerance'] = 1e-10
    prm['newton_solver']['relative_tolerance'] = 1e-10

    # Compute solution via Newton method.
    itern, status = solver.solve()
    if not bool(status):
        print("Newton's method did not converge within {0} ".format(itern) +
              "iterations for parameters alpha0={0}, ".format(alpha0) +
              "alpha1={0}, alpha3={1}, ".format(alpha1, alpha2) +
              "alpha4={0}, beta={1}".format(alpha3, beta))

    # Recover solution.
    v, k = w.split(deepcopy=True)

    # Evaluate and print residual and functional value.
    res = abs(ft + fx * v + f * v.dx(1) - k)
    fun = 0.5 * (res**2 + alpha0 * v.dx(1)**2 + alpha1 * v.dx(0)**2 +
                 alpha2 * k.dx(1)**2 + alpha3 * k.dx(0)**2 + beta *
                 (k.dx(0) + k.dx(1) * v)**2)
    print('Res={0}, Func={1}'.format(assemble(res * dx), assemble(fun * dx)))
    return v, k, assemble(res * dx), assemble(fun * dx), bool(status)
# def value_shape(self):
#   return (3,)
# u.interpolate(InitialConditions(degree=1))

an, ca, psi = split(u)
van, vca, vpsi = TestFunctions(ME)

Fan = D_an*(-inner(grad(an), grad(van))*dx - Farad / R / Temp * z_an*an*inner(grad(psi), grad(van))*dx)
Fca = D_ca*(-inner(grad(ca), grad(vca))*dx - Farad / R / Temp * z_ca*ca*inner(grad(psi), grad(vca))*dx)
Fpsi = inner(grad(psi), grad(vpsi))*dx - (Farad/(eps0*epsR))*(z_an*an + z_ca*ca + z_fc*fc_function)*vpsi*dx

F = Fpsi + Fan + Fca

J = derivative(F, u)
problem = NonlinearVariationalProblem(F, u, bcs = bcs, J = J)
solver = NonlinearVariationalSolver(problem)
#solver = AdaptiveNonlinearVariationalSolver(problem, M)

#print(solver.default_parameters().items())
solver.parameters["newton_solver"]["linear_solver"] = "mumps"
solver.solve()

#########################  Post - Processing  #################################
an, ca, psi = u.split()

aftersolveT = timer() 

first = plot(an, title = "Anion concentration, $c^-$")
plt.colorbar(first)
plt.xlim(0.0, 0.015)
plt.xticks([0.0, 0.005, 0.01, 0.015])
Exemplo n.º 8
0
    def solve(self, problem):
        self.problem = problem
        doSave = problem.doSave
        save_this_step = False
        onlyVel = problem.saveOnlyVel
        dt = self.metadata['dt']

        nu = Constant(self.problem.nu)
        self.tc.init_watch('init',
                           'Initialization',
                           True,
                           count_to_percent=False)
        self.tc.init_watch('solve',
                           'Running nonlinear solver',
                           True,
                           count_to_percent=True)
        self.tc.init_watch('next',
                           'Next step assignments',
                           True,
                           count_to_percent=True)
        self.tc.init_watch('saveVel', 'Saved velocity', True)

        self.tc.start('init')

        mesh = self.problem.mesh

        # Define function spaces (P2-P1)
        self.V = VectorFunctionSpace(mesh, "Lagrange", 2)  # velocity
        self.Q = FunctionSpace(mesh, "Lagrange", 1)  # pressure
        self.W = MixedFunctionSpace([self.V, self.Q])
        self.PS = FunctionSpace(
            mesh, "Lagrange", 2)  # partial solution (must be same order as V)
        self.D = FunctionSpace(mesh, "Lagrange",
                               1)  # velocity divergence space

        # to assign solution in space W.sub(0) to Function(V) we need FunctionAssigner (cannot be assigned directly)
        fa = FunctionAssigner(self.V, self.W.sub(0))
        velSp = Function(self.V)

        problem.initialize(self.V, self.Q, self.PS, self.D)

        # Define unknown and test function(s) NS
        v, q = TestFunctions(self.W)
        w = Function(self.W)
        dw = TrialFunction(self.W)
        u, p = split(w)

        # Define fields
        n = FacetNormal(mesh)
        I = Identity(u.geometric_dimension())
        theta = 0.5  # Crank-Nicholson
        k = Constant(self.metadata['dt'])

        # Initial conditions: u0 velocity at previous time step u1 velocity two time steps back p0 previous pressure
        [u0, p0] = self.problem.get_initial_conditions([{
            'type': 'v',
            'time': 0.0
        }, {
            'type': 'p',
            'time': 0.0
        }])

        if doSave:
            problem.save_vel(False, u0)

        # boundary conditions
        bcu, bcp = problem.get_boundary_conditions(False, self.W.sub(0),
                                                   self.W.sub(1))

        # Define steady part of the equation
        def T(u):
            return -p * I + 2.0 * nu * sym(grad(u))

        def F(u, v, q):
            return (inner(T(u), grad(v)) - q * div(u)) * dx + inner(
                grad(u) * u, v) * dx

        # Define variational forms
        F_ns = (inner(
            (u - u0), v) / k) * dx + (1.0 - theta) * F(u0, v, q) + theta * F(
                u, v, q)
        J_ns = derivative(F_ns, w, dw)
        # J_ns = derivative(F_ns, w)  # did not work

        # NS_problem = NonlinearVariationalProblem(F_ns, w, bcu, J_ns, form_compiler_parameters=ffc_options)
        NS_problem = NonlinearVariationalProblem(F_ns, w, bcu, J_ns)
        # (var. formulation, unknown, Dir. BC, jacobian, optional)
        NS_solver = NonlinearVariationalSolver(NS_problem)

        prm = NS_solver.parameters
        prm['newton_solver']['absolute_tolerance'] = 1E-08
        prm['newton_solver']['relative_tolerance'] = 1E-08
        # prm['newton_solver']['maximum_iterations'] = 45
        # prm['newton_solver']['relaxation_parameter'] = 1.0
        prm['newton_solver']['linear_solver'] = 'mumps'
        # prm['newton_solver']['lu_solver']['same_nonzero_pattern'] = True

        info(NS_solver.parameters, True)

        self.tc.end('init')

        # Time-stepping
        info("Running of direct method")
        ttime = self.metadata['time']
        t = dt
        step = 1
        while t < (ttime + dt / 2.0):
            self.problem.update_time(t, step)
            if self.MPI_rank == 0:
                problem.write_status_file(t)

            if doSave:
                save_this_step = problem.save_this_step

            # Compute
            begin("Solving NS ....")
            try:
                self.tc.start('solve')
                NS_solver.solve()
                self.tc.end('solve')
            except RuntimeError as inst:
                problem.report_fail(t)
                return 1
            end()

            # Extract solutions:
            (u, p) = w.split()
            fa.assign(velSp, u)
            # we are assigning twice (now and inside save_vel), but it works with one method save_vel for direct and
            #   projection (we could split save_vel to save one assign)

            if save_this_step:
                self.tc.start('saveVel')
                problem.save_vel(False, velSp)
                self.tc.end('saveVel')
            if save_this_step and not onlyVel:
                problem.save_div(False, u)
            problem.compute_err(False, u, t)
            problem.compute_div(False, u)

            # foo = Function(self.Q)
            # foo.assign(p)
            # problem.averaging_pressure(foo)
            # if save_this_step and not onlyVel:
            #     problem.save_pressure(False, foo)

            if save_this_step and not onlyVel:
                problem.save_pressure(False, p)

            # compute functionals (e. g. forces)
            problem.compute_functionals(u, p, t, step)

            # Move to next time step
            self.tc.start('next')
            u0.assign(velSp)
            t = round(t + dt, 6)  # round time step to 0.000001
            step += 1
            self.tc.end('next')

        info("Finished: direct method")
        problem.report()
        return 0
Exemplo n.º 9
0
    def model(self, parameters=None, logger=None):
        def format(arr):
            return np.array(arr)

        # Setup parameters, logger
        self.set_parameters(parameters)
        self.set_logger(logger)

        # Get parameters
        parameters = self.get_parameters()

        #SS#if not parameters.get('simulate'):
        #SS#	return

        # Setup data
        self.set_data(reset=True)
        self.set_observables(reset=True)

        # Show simulation settings
        self.get_logger()('\n\t'.join([
            'Simulating:', *[
                '%s : %r' % (param, parameters[param] if not isinstance(
                    parameters[param], dict) else list(parameters[param]))
                for param in
                ['fields', 'num_elem', 'N', 'dt', 'D', 'alpha', 'tol']
            ]
        ]))

        # Data mesh
        mesh = IntervalMesh(MPI.comm_world, parameters['num_elem'],
                            parameters['L_0'], parameters['L_1'])

        # Fields
        V = {}
        W = {}
        fields_n = {}
        fields = {}
        w = {}
        fields_0 = {}
        potential = {}
        potential_derivative = {}
        bcs = {}
        R = {}
        J = {}
        # v2d_vector = {}
        observables = {}
        for field in parameters['fields']:

            # Define functions
            V[field] = {}
            w[field] = {}
            for space in parameters['spaces']:
                V[field][space] = getattr(
                    dolfin, parameters['spaces'][space]['type'])(
                        mesh, parameters['spaces'][space]['family'],
                        parameters['spaces'][space]['degree'])
                w[field][space] = TestFunction(V[field][space])

            space = V[field][parameters['fields'][field]['space']]
            test = w[field][parameters['fields'][field]['space']]

            fields_n[field] = Function(space, name='%sn' % (field))
            fields[field] = Function(space, name=field)

            # Inital condition
            fields_0[field] = Expression(
                parameters['fields'][field]['initial'],
                element=space.ufl_element())
            fields_n[field] = project(fields_0[field], space)
            fields[field].assign(fields_n[field])

            # Define potential
            if parameters['potential'].get('kwargs') is None:
                parameters['potential']['kwargs'] = {}
            for k in parameters['potential']['kwargs']:
                if parameters['potential']['kwargs'][k] is None:
                    parameters['potential']['kwargs'][k] = fields[k]

            potential[field] = Expression(
                parameters['potential']['expression'],
                degree=parameters['potential']['degree'],
                **parameters['potential']['kwargs'])
            potential_derivative[field] = Expression(
                parameters['potential']['derivative'],
                degree=parameters['potential']['degree'] - 1,
                **parameters['potential']['kwargs'])

            #Subdomain for defining Positive grain
            sub_domains = MeshFunction('size_t', mesh,
                                       mesh.topology().dim(), 0)

            #BC condition
            bcs[field] = []
            if parameters['fields'][field]['bcs'] == 'dirichlet':
                BC_l = CompiledSubDomain('near(x[0], side) && on_boundary',
                                         side=parameters['L_0'])
                BC_r = CompiledSubDomain('near(x[0], side) && on_boundary',
                                         side=parameters['L_1'])
                bcl = DirichletBC(V, fields_n[field], BC_l)
                bcr = DirichletBC(V, fields_n[field], BC_r)
                bcs[field].extend([bcl, bcr])
            elif parameters['fields'][field]['bcs'] == 'neumann':
                bcs[field].extend([])

            # Residual and Jacobian
            R[field] = (
                ((fields[field] - fields_n[field]) / parameters['dt'] * test *
                 dx) +
                (inner(parameters['D'] * grad(test), grad(fields[field])) * dx)
                + (parameters['alpha'] * potential_derivative[field] * test *
                   dx))

            J[field] = derivative(R[field], fields[field])

            # Observables
            observables[field] = {}

        files = {
            'xdmf': XDMFFile(MPI.comm_world,
                             self.get_paths()['xdmf']),
            'hdf5': HDF5File(MPI.comm_world,
                             self.get_paths()['hdf5'], 'w'),
        }

        files['hdf5'].write(mesh, '/mesh')
        eps = lambda n, key, field, observables, tol: (
            n == 0) or (abs(observables[key]['total_energy'][n] - observables[
                key]['total_energy'][n - 1]) /
                        (observables[key]['total_energy'][0]) > tol)
        flag = {field: True for field in parameters['fields']}
        tol = {
            field: parameters['tol'][field] if isinstance(
                parameters['tol'], dict) else parameters['tol']
            for field in parameters['fields']
        }
        phases = {'p': 1, 'm': 2}
        n = 0
        problem = {}
        solver = {}
        while (n < parameters['N']
               and any([flag[field] for field in parameters['fields']])):

            self.get_logger()('Time: %d' % (n))

            for field in parameters['fields']:

                if not flag[field]:
                    continue

                # Solve
                problem[field] = NonlinearVariationalProblem(
                    R[field], fields[field], bcs[field], J[field])
                solver[field] = NonlinearVariationalSolver(problem[field])
                solver[field].solve()

                # Get field array
                array = assemble(
                    (1 / CellVolume(mesh)) *
                    inner(fields[field], w[field]['Z']) * dx).get_local()

                # Observables
                observables[field]['Time'] = parameters['dt'] * n

                # observables[field]['energy_density'] = format(0.5*dot(grad(fields[field]),grad(fields[field]))*dx)
                observables[field]['gradient_energy'] = format(
                    assemble(0.5 *
                             dot(grad(fields[field]), grad(fields[field])) *
                             dx(domain=mesh)))
                observables[field]['landau_energy'] = format(
                    assemble(potential[field] * dx(domain=mesh)))
                observables[field]['diffusion_energy'] = format(
                    assemble(
                        project(
                            div(project(grad(fields[field]), V[field]['W'])),
                            V[field]['Z']) * dx(domain=mesh))
                )  #Diffusion part of chemical potential
                observables[field]['spinodal_energy'] = format(
                    assemble(
                        potential_derivative[field] *
                        dx(domain=mesh)))  #Spinodal part of chemical potential

                observables[field]['total_energy'] = parameters[
                    'D'] * observables[field]['gradient_energy'] + parameters[
                        'alpha'] * observables[field]['landau_energy']
                observables[field]['chi'] = parameters['alpha'] * observables[
                    field]['diffusion_energy'] - parameters['D'] * observables[
                        field]['spinodal_energy']

                # Phase observables
                sub_domains.set_all(0)
                sub_domains.array()[:] = np.where(array > 0.0, phases['p'],
                                                  phases['m'])

                phases_dxp = Measure('dx',
                                     domain=mesh,
                                     subdomain_data=sub_domains)
                for phase in phases:
                    dxp = phases_dxp(phases[phase])

                    observables[field]['Phi_0%s' % (phase)] = format(
                        assemble(1 * dxp))
                    observables[field]['Phi_1%s' % (phase)] = format(
                        assemble(fields[field] * dxp))
                    observables[field]['Phi_2%s' % (phase)] = format(
                        assemble(fields[field] * fields[field] * dxp))
                    observables[field]['Phi_3%s' % (phase)] = format(
                        assemble(fields[field] * fields[field] *
                                 fields[field] * dxp))
                    observables[field]['Phi_4%s' % (phase)] = format(
                        assemble(fields[field] * fields[field] *
                                 fields[field] * fields[field] * dxp))
                    observables[field]['Phi_5%s' % (phase)] = format(
                        assemble(fields[field] * fields[field] *
                                 fields[field] * fields[field] *
                                 fields[field] * dxp))

                    observables[field]['gradient_energy_%s' %
                                       (phase)] = format(
                                           assemble(
                                               0.5 *
                                               dot(grad(fields[field]),
                                                   grad(fields[field])) * dxp))
                    observables[field]['landau_energy_%s' % (phase)] = format(
                        assemble(potential[field] * dxp))
                    observables[field][
                        'total_energy_%s' %
                        (phase)] = parameters['D'] * observables[field][
                            'gradient_energy_%s' %
                            (phase)] + parameters['alpha'] * observables[
                                field]['landau_energy_%s' % (phase)]

                    observables[field][
                        'diffusion_energy_%s' % (phase)] = format(
                            assemble(
                                project(
                                    div(
                                        project(grad(fields[field]),
                                                V[field]['W'])), V[field]['Z'])
                                * dxp))  #Diffusion part of chemical potential
                    observables[field][
                        'spinodal_energy_%s' % (phase)] = format(
                            assemble(
                                potential_derivative[field] *
                                dxp))  #Spinodal part of chemical potential

                    observables[field][
                        'chi_%s' %
                        (phase)] = parameters['alpha'] * observables[field][
                            'spinodal_energy_%s' %
                            (phase)] - parameters['D'] * observables[field][
                                'diffusion_energy_%s' % (phase)]

                files['hdf5'].write(fields[field], '/%s' % (field), n)
                files['xdmf'].write(fields[field], n)

                fields_n[field].assign(fields[field])

                self.set_data({field: array})
                self.set_observables({field: observables[field]})

                flag[field] = eps(n, field, fields[field],
                                  self.get_observables(), tol[field])

            n += 1

        for file in files:
            files[file].close()

        return