How can I get the information of edges on each cell ( triangle ) ?

Question

Using " mesh.cells() " can only get the information about cells and vertices, but I want to know the connections about cells and edges.
In another word, I want to know the global ID of the three edges on a given cell(triangle).
I tried Pydoc dolfin.Mesh ,but no answer.

Thanks !

Answer 1

Hi, here are 2 ways how you can get the cell->edge connectivity

from dolfin import *

mesh = UnitSquareMesh(2, 2)

# 'long' version
for cell in cells(mesh):
  print "cell", cell.index(), "has edges :",
  for edge in edges(cell):
    print edge.index(),
  print

print 

# 'short' version
for cell in cells(mesh):
  print "cell", cell.index(), "has edges :", cell.entities(1) 

Comments

Thank you ！： ）

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There's a chance that you rather want facets(cell) instead of edges(cell) (which makes no difference in 2D).

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Thanks a lot ! ：）