def get_path_cover_multi_src(adj, src_list, dst, bfs_cache=None):
"""Generates a list of nodes that contains all the nodes in between
multiple sources and a destination (endpoints included).
Args:
adj: Adjacency matrix.
src: Source node index list, 0-based.
dst: Destination node index, 0-based.
Returns:
cover: List of node indices, in traversal order.
"""
num_nodes = adj.shape[0]
if bfs_cache is None:
bfs_cache = np.zeros([num_nodes, num_nodes], dtype=np.int8)
cover = []
for src in src_list:
if src == dst:
return cover
if src > dst:
raise Exception("Source must be smaller than destination.")
if src >= num_nodes or dst >= num_nodes:
raise Exception("Node index must be smaller than number of nodes.")
if not bfs(adj, src, dst, cache=bfs_cache):
log.error("Source is not connected to destination.")
cover.extend(src_list)
start = min(src_list) + 1
for idx in range(start, dst):
# If the node is connected to both source and destination, add.
if idx in src_list:
continue
connect_dst = bfs(adj, idx, dst, cache=bfs_cache)
if not connect_dst:
continue
for src in src_list:
connect_src = bfs(adj, src, idx, cache=bfs_cache)
if connect_src:
break
if connect_src and connect_dst:
cover.append(idx)
cover.append(dst)
return cover
def test_bfs_performance(self):
adj = np.random.uniform(0, 1, [1000, 1000])
adj = (adj > 0.3).astype(np.int8)
for ii in range(10):
bfs(adj, 0, 999, None)
def test_bfs_cache(self): adj = np.zeros([3, 3], dtype=np.int8) self.assertTrue(bfs(adj, 0, 2, cache=np.ones([3, 3], dtype=np.int8))) self.assertFalse(bfs(adj, 0, 2, cache=np.zeros([3, 3], dtype=np.int8)))
def test_bfs(self): adj = np.array([[1, 1, 0], [0, 0, 1], [0, 0, 0]], dtype=np.int8) self.assertTrue(bfs(adj, 0, 2, None)) self.assertFalse(bfs(adj, 2, 0, None))