Solve poisson equation just add a source term - CFD Online Discussion Forums The documentation is quite good when you know that you need to search for the MeshEditor class. If anyone finds this by searching the web for how to build a mesh programmatically in FEniCS/dolfin, then I hope the above was understandable. close () print 'Created mesh with %d vertices and %d cells' % ( nvert, ncell ) if show : df. add_cell ( i_cell, i_vert0, i_vert1, i_vert2 ) i_cell += 1 # Close the mesh for editing editor. add_cell ( i_cell, i_vert0, i_vert1, i_vert2 ) i_cell += 1 # Lower right triangle in this square i_vert0 = ix * ny + iy i_vert1 = ( ix + 1 ) * ny + iy + 1 i_vert2 = ( ix + 1 ) * ny + iy editor. init_cells ( ncell ) i_cell = 0 for ix in xrange ( nx - 1 ): for iy in xrange ( ny - 1 ): # Upper left triangle in this square i_vert0 = ix * ny + iy i_vert1 = ix * ny + iy + 1 i_vert2 = ( ix + 1 ) * ny + iy + 1 editor. add_vertex ( i_vert, x, y ) i_vert += 1 # Add the cells (triangular elements) # Loop over the vertices and build two cells for each square # where the selected vertex is in the lower left corner editor. init_vertices ( nvert ) i_vert = 0 for x in xpos : for y in ypos : editor. open ( mesh, 2, 2 ) # Add the vertices (nodes) editor. linspace ( 0, height, ny ) # Create the mesh and open for editing mesh = df. linspace ( 0, length, nx ) ypos = numpy. """ # The number of mesh entities nvert = nx * ny ncell = 2 * ( nx - 1 ) * ( ny - 1 ) # Positions of the vertices xpos = numpy. Should give exactly the same results as using the built in dolfin.RectangleMesh() class So, for posterity, here is a reimplementation of dolfin.RectangleMesh in a much more cumbersome (and flexible) way: import numpy import dolfin as df def create_mesh ( length, height, nx, ny, show = False ): """ While playing with implementing a simple solver for fluid flow in a tank by use of FEniCS to solve the Laplace equation I needed to create my own mesh in code.įEniCS is quite well documented, but I had to look at the source code for some of the mesh conversion routines to find out how to build a mesh from scratch. I may end up doing a large project using FEniCS which is a collection of tools for automated, efficient solution of differential equations using the finite element method.
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