Localized mesh refinement using a CellFunction

plottingMeshes_CellFunction.py

from dolfin import *
import numpy

mesh = UnitSquare(8,8)

mesh = refine(mesh)

# editor = MeshEditor()
# editor.open(mesh,2,2)
# editor.add_cell(0,0,1,2)
# editor.add_cell(1,0,2,3)
# editor.close()

# plot(mesh, interactive = True)    # uncomment to plot

#######################################################################
## One way of creating a mesh function
#######################################################################

# create a mesh function
# mesh_function = MeshFunction(mesh, 2)
# initialize it all to False

cell_marker = CellFunction("bool", mesh)
cell_marker.set_all(False)
# mesh_function.set_all(0)

origin=Point(0,0,0)

for cell in cells(mesh):
	p=cell.midpoint()
	if p.distance(origin) < 0.1:
		cell_marker[cell]=True
#		mesh_function[cell]=1
		
#refine the mesh in the sub domain where meshFunction is True
mesh=refine(mesh, cell_marker)

#plot(mesh_function, mesh=mesh, rescale=True, title="Vector function")

plot(mesh, interactive=True)