`scipy.sparse.csgraph._reordering:reverse_cuthill_mckee`

Signature

def reverse_cuthill_mckee(graph, symmetric_mode = False)

Summary

Returns the permutation array that orders a sparse CSR or CSC matrix in Reverse-Cuthill McKee ordering.

Extended Summary

It is assumed by default, symmetric_mode=False, that the input matrix is not symmetric and works on the matrix A+A.T. If you are guaranteed that the matrix is symmetric in structure (values of matrix elements do not matter) then set symmetric_mode=True.

Parameters

graph : sparse array or matrix: Input sparse in CSC or CSR sparse array or matrix format.
symmetric_mode : bool, optional: Is input matrix guaranteed to be symmetric.

Returns

perm : ndarray: Array of permuted row and column indices.

Notes

Examples

from scipy.sparse import csr_array
from scipy.sparse.csgraph import reverse_cuthill_mckee

✓

graph = [
[0, 1, 2, 0],
[0, 0, 0, 1],
[2, 0, 0, 3],
[0, 0, 0, 0]
]
graph = csr_array(graph)

✓

print(graph)

✗

<Compressed Sparse Row sparse array of dtype 'int64'
	with 5 stored elements and shape (4, 4)>
  Coords	Values
  (0, 1)	1
  (0, 2)	2
  (1, 3)	1
  (2, 0)	2
  (2, 3)	3

reverse_cuthill_mckee(graph)

✓

array([3, 2, 1, 0], dtype=int32)

Aliases

scipy.sparse.csgraph.reverse_cuthill_mckee