### oriented-goal adaptive solve

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Hollo everyone!

I am solving the oriented-goal adaptive solve.

The test code is following

from dolfin import *

#encoding=utf-8

# Define mesh

mesh = UnitSquareMesh(8, 8)

# Create classes for defining parts of the boundaries

class Left(SubDomain):

def inside(self, x, on_boundary):

return near(x[0], 0.0)

class Right(SubDomain):

def inside(self, x, on_boundary):

return near(x[0], 1.0)

class Bottom(SubDomain):

def inside(self, x, on_boundary):

return near(x[1], 0.0)

class Top(SubDomain):

def inside(self, x, on_boundary):

return near(x[1], 1.0)

# Initialize sub-domain instances

left = Left()

top = Top()

right = Right()

bottom = Bottom()

# Initialize mesh function for boundary domains

boundaries = FacetFunction("size_t", mesh)

boundaries.set_all(0)

left.mark(boundaries, 1)

top.mark(boundaries, 2)

right.mark(boundaries, 3)

bottom.mark(boundaries, 4)

# Define function space and basis functions

V = FunctionSpace(mesh, "CG", 2)

u = TrialFunction(V)

v = TestFunction(V)

# Define input data

a0 = Constant(1.0)

a1 = Constant(0.01)

g_L = Expression("- 10*exp(- pow(x[1] - 0.5, 2))")

g_R = Constant("1.0")

f = Constant(1.0)

# Initialize mesh function for interior domains

class Obstacle(SubDomain):

def inside(self, x, on_boundary):

return (between(x[1], (0.5, 0.7)) and between(x[0], (0.2, 1.0)))

obstacle = Obstacle()

domains = CellFunction("size_t", mesh)

domains.set_all(0)

obstacle.mark(domains, 1)

# Define Dirichlet boundary conditions at top and bottom boundaries

bcs = [DirichletBC(V, 5.0, boundaries, 2),

DirichletBC(V, 0.0, boundaries, 4)]

# Define new measures associated with the interior domains and

# exterior boundaries

dx = Measure("dx")[domains]

ds = Measure("ds")[boundaries]

# Define variational form

F = (inner(a0*grad(u), grad(v))*dx(0) + inner(a1*grad(u), grad(v))*dx(1)

- g_L*v*ds(1) - g_R*v*ds(3)

- f*v*dx(0) - f*v*dx(1))

# Separate left and right hand sides of equation

a, L = lhs(F), rhs(F)

tol=1e-4

# Solve problem

u = Function(V)

M=u*dx(1)

problem=LinearVariationalProblem(a,L,u,bcs)

solver=AdaptiveLinearVariationalSolver(problem,M)

solver.solve(tol)

solver.summary()

# Plot solution

plot(u, title="u")

interactive()

why is the code running wrong?

Generating forms required for error control, this may take some time...

Solving variational problem adaptively

Adaptive iteration 0

Solving linear variational problem.

Value of goal functional is 1.71367.

Solving linear variational problem.

5 cells out of 128 marked for refinement (3.9%).

Number of cells increased from 128 to 169 (32.0% increase).

Traceback (most recent call last):

File "b.py", line 97, in <module>

solver.solve(tol)

File "/usr/lib/python2.7/dist-packages/dolfin/fem/adaptivesolving.py", line 80, in solve

cpp.AdaptiveLinearVariationalSolver.solve(self, tol)

RuntimeError:

*** -------------------------------------------------------------------------

*** DOLFIN encountered an error. If you are not able to resolve this issue

*** using the information listed below, you can ask for help at

***

*** fenics@fenicsproject.org

How should i solve it?

Best wishes!

I am solving the oriented-goal adaptive solve.

The test code is following

from dolfin import *

#encoding=utf-8

# Define mesh

mesh = UnitSquareMesh(8, 8)

# Create classes for defining parts of the boundaries

class Left(SubDomain):

def inside(self, x, on_boundary):

return near(x[0], 0.0)

class Right(SubDomain):

def inside(self, x, on_boundary):

return near(x[0], 1.0)

class Bottom(SubDomain):

def inside(self, x, on_boundary):

return near(x[1], 0.0)

class Top(SubDomain):

def inside(self, x, on_boundary):

return near(x[1], 1.0)

# Initialize sub-domain instances

left = Left()

top = Top()

right = Right()

bottom = Bottom()

# Initialize mesh function for boundary domains

boundaries = FacetFunction("size_t", mesh)

boundaries.set_all(0)

left.mark(boundaries, 1)

top.mark(boundaries, 2)

right.mark(boundaries, 3)

bottom.mark(boundaries, 4)

# Define function space and basis functions

V = FunctionSpace(mesh, "CG", 2)

u = TrialFunction(V)

v = TestFunction(V)

# Define input data

a0 = Constant(1.0)

a1 = Constant(0.01)

g_L = Expression("- 10*exp(- pow(x[1] - 0.5, 2))")

g_R = Constant("1.0")

f = Constant(1.0)

# Initialize mesh function for interior domains

class Obstacle(SubDomain):

def inside(self, x, on_boundary):

return (between(x[1], (0.5, 0.7)) and between(x[0], (0.2, 1.0)))

obstacle = Obstacle()

domains = CellFunction("size_t", mesh)

domains.set_all(0)

obstacle.mark(domains, 1)

# Define Dirichlet boundary conditions at top and bottom boundaries

bcs = [DirichletBC(V, 5.0, boundaries, 2),

DirichletBC(V, 0.0, boundaries, 4)]

# Define new measures associated with the interior domains and

# exterior boundaries

dx = Measure("dx")[domains]

ds = Measure("ds")[boundaries]

# Define variational form

F = (inner(a0*grad(u), grad(v))*dx(0) + inner(a1*grad(u), grad(v))*dx(1)

- g_L*v*ds(1) - g_R*v*ds(3)

- f*v*dx(0) - f*v*dx(1))

# Separate left and right hand sides of equation

a, L = lhs(F), rhs(F)

tol=1e-4

# Solve problem

u = Function(V)

M=u*dx(1)

problem=LinearVariationalProblem(a,L,u,bcs)

solver=AdaptiveLinearVariationalSolver(problem,M)

solver.solve(tol)

solver.summary()

# Plot solution

plot(u, title="u")

interactive()

why is the code running wrong?

Generating forms required for error control, this may take some time...

Solving variational problem adaptively

Adaptive iteration 0

Solving linear variational problem.

Value of goal functional is 1.71367.

Solving linear variational problem.

5 cells out of 128 marked for refinement (3.9%).

Number of cells increased from 128 to 169 (32.0% increase).

Traceback (most recent call last):

File "b.py", line 97, in <module>

solver.solve(tol)

File "/usr/lib/python2.7/dist-packages/dolfin/fem/adaptivesolving.py", line 80, in solve

cpp.AdaptiveLinearVariationalSolver.solve(self, tol)

RuntimeError:

*** -------------------------------------------------------------------------

*** DOLFIN encountered an error. If you are not able to resolve this issue

*** using the information listed below, you can ask for help at

***

*** fenics@fenicsproject.org

How should i solve it?

Best wishes!

Community: FEniCS Project

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It works using the solution posted here: https://fenicsproject.org/qa/6719/using-adapt-on-a-meshfunction-looking-for-a-working-example