Intersection error

[rbe051]

`frac1 = np.array([[1,2,4], [1,4,1], [2,2,2]])

frac2 = np.array([[2,2,2], [2,4,1], [1,2,4]])

fracs = [frac1, frac2]

domain = {'xmin': 0, 'ymin': 0, 'zmin': 0,
'xmax': 5, 'ymax': 5, 'zmax': 5,}

path_to_gmsh = .... # Set the sytem path to gmsh

gb = tetrahedral_grid(fracs, domain, gmsh_path = path_to_gms)`

which gives following error:
Find intersections between fractures
Traceback (most recent call last):
File "", line 1, in
File "/home/runar/uib/porepy/src/porepy/fracs/simplex.py", line 92, in tetrahedral_grid
if not network.has_checked_intersections:
File "/home/runar/uib/porepy/src/porepy/fracs/fractures.py", line 869, in find_intersections
isect, _, _ = first.intersects(second, self.tol)
File "/home/runar/uib/porepy/src/porepy/fracs/fractures.py", line 345, in intersects
assert u_bound_pt.shape[1] == 1
IndexError: tuple index out of range

[keileg]

This is the case of fractures meeting in a single point. Up to now, it has not been thought of at all; mainly because it will never happen in practice.

The best option seems to be to treat this as no intersection; the two identical points should then be merged during splitting of the fractures.

Does this sound reasonable?