import numpy as np
from scipy.sparse.csgraph import floyd_warshall
from scipy.sparse import csr_matrix
arr = np.array([
[0, 1, 2],
[1, 0, 0],
[2, 0, 0]
])
newarr = csr_matrix(arr)
print(floyd_warshall(newarr, return_predecessors=True))
(array([[ 0., 1., 2.], [ 1., 0., 3.], [ 2., 3., 0.]]), array([[-9999, 0, 0], [ 1, -9999, 0], [ 2, 0, -9999]], dtype=int32))