mesh.Mesh.lengths

Mesh.lengths()

Return element or perimeter lengths for a Mesh of level 1 or 2.

Returns

array | None

For a level 1 Mesh, the length of the elements. For a level 2 Mesh, the length of the elements’ perimeter. If the elements or its edges are of eltype ‘line2’, the lengths are exact. For other eltypes, a conversion to ‘line2’ is done before computing the lengths. This can produce an exact result, an approximate result or no result (if the conversion fails). If successful, returns an (n_elems,) float array with the lengths.

Returns None if the Mesh level is not 1 or 2, or the conversion to ‘line2’ does not succeed.

Examples

>>> nx = 4
>>> M = Mesh(eltype='line2').subdivide(nx)
>>> a = M.lengths()
>>> print(a)        # each equals 1. / nx
[0.25 0.25 0.25 0.25]
>>> print(a.sum())
1.0

>>> nx, ny = 3, 2
>>> M = Mesh(eltype='quad4').subdivide(nx, ny)
>>> a = M.lengths()
>>> print(a)        # each equals (nx + ny) * 2 / (nx * ny)
[1.6667 1.6667 1.6667 1.6667 1.6667 1.6667]
>>> print(a.sum())  # equals (nx + ny) * 2
10.0...