## [32a023]: obsolete / test / test_bc.m  Maximize  Restore  History

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 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40``` ```# We follow the dolfin example for the Poisson problem # -div ( grad (u) ) = f on omega # u = h on gamma_d; # du/dn = g on gamma_n; # See (http://fenicsproject.org/documentation/dolfin/1.2.0/cpp/demo/pde/poisson/cpp/documentation.html#index-0) # we check if: # 1) the classes created within fem-fenics # like "mesh" and "functionspace" hold correctly the dolfin data # 2) the class "expression", which we derived from dolfin::Expression # correctly sets up the value for the bc using a function_handle # 3) the class "boundarycondition", which handle a vecotr of pointer # to dolfin::DirichletBC correctly stores the value for the bc pkg load msh addpath ("../src/") # create a unit square mesh using msh: labels for the boundary sides are 1,2,3,4 # we can use only 2D mesh for the moment # if you want to try with a 3D mesh, you need to use tetrahedron instead of # triangle inside Laplace.ufl and recompile fem_fs.cpp msho = msh2m_structured_mesh (0:0.05:1, 0:0.05:1, 1, 1:4); mshd = fem_init_mesh (msho); V = fem_fs (mshd); f = @(x,y) 0; # fem_bc take as input the functionspace V, a function handler f, # and the sides where we want to apply the condition # The value on each point of the boundary is computed using # the eval method available inside expression.h # if a side is not specified, Neumann conditions are applied # with g = sin(5*x) bc = fem_bc (V, f, [2, 4]); # test_bc take as input the functionspace V, and the # boundarycondition bc and solve the Poisson problem with # f = 10*exp(-(dx*dx + dy*dy) / 0.02); test_bc (V, bc); ```