porepy.utils.sort_points module

Functions to sort points and edges belonging to geometric objects.

sort_multiple_point_pairs(lines)[source]

Function to sort multiple pairs of points to form circular chains.

The routine contains essentially the same functionality as sort_point_pairs, but stripped down to the special case of circular chains. Differently to sort_point_pairs, this variant sorts an arbitrary amount of independent point pairs. The chains are restricted by the assumption that each contains equally many line segments. Finally, this routine uses numba.

Parameters

lines (np.ndarray) – Array of size 2 * num_chains x num_lines_per_chain, containing node indices. For each pair of two rows, each column represents a line segment connectng the two nodes in the two entries of this column.

Returns

Sorted version of lines, where for each chain, the collection: of l

Return type

np.ndarray

Raises

ImportError ifine segments has been potentially flipped and sorted. –

sort_point_pairs(lines, check_circular=True, is_circular=True)[source]

Sort pairs of numbers to form a chain.

The target application is to sort lines, defined by their start end endpoints, so that they form a continuous polyline.

The algorithm is brute-force, using a double for-loop. This can surely be improved.

Parameters

lines (np.ndarray, 2xn) – the line pairs. If lines has more than 2 rows, we assume that the points are stored in the first two rows.
check_circular (bool) – Verify that the sorted polyline form a circle.
is_circular (bool) – if the lines form a closed set. Default is True.

Returns

sorted line pairs. If lines had more than 2 rows,: the extra are sorted accordingly.
np.ndarray, n: Sorted column indices, so that: sorted_lines = lines[:, sort_ind], modulo flipping of rows in individual columns

Return type

np.ndarray, 2xn

sort_point_plane(pts, centre, normal=None, tol=1e-5)[source]

Sort the points which lie on a plane.

The algorithm assumes a star-shaped disposition of the points with respect the centre.

Parameters

pts (ndarray) – np.ndarray, 3xn, the points.
centre (ndarray) – np.ndarray, 3x1, the face centre.
normal (Optional[ndarray]) – (optional) the normal of the plane, otherwise three points are required.
tol (float) – Absolute tolerance used to identify active (non-constant) dimensions.

Returns

np.array, 1xn, sorted point ids.

Return type

map_pts

sort_triangle_edges(t)[source]

Sort a set of triangles so that no edges occur twice with the same ordering.

For a planar triangulation, this will end up with all the triangles being ordered CW or CCW. In cases where the triangulated surface(s) do not share a common plane, methods based on geometry are at best cumbersome. This approach should work also in those cases.

Parameters: t (np.ndarray, 3 x n_tri) – Triangulation to have vertexes ordered.
Returns: With the vertexes ordered.
Return type: np.ndarray, 3 x n_tri

Example

>>> t = np.array([[0, 1, 2], [1, 2, 3]]).T
>>> sort_triangle_edges(t)
np.array([[0, 2], [1, 1], [2, 3]])