def join_split_tree(mesh, height_func, split=False):
join_tree = DiGraph()
# map of nodes to union-find set that it's in
uf_map = {}
# map of union-find set id to lowest node in the set.
lowest_node_map = {}
# a list of (height, node) tuples
height_and_nodes = [(height_func(node), node) for node in mesh.nodes()]
height_and_nodes.sort(reverse=not split)
for h, n in height_and_nodes:
uf_map[n] = set([n])
lowest_node_map[id(uf_map[n])] = n
for nbr in mesh.neighbors_iter(n):
nbr_h = height_func(nbr)
if nbr_h == h:
raise ValueError("nbr_h == h!!!")
if (split and nbr_h > h) or (not split and nbr_h < h) or (uf_map[nbr] is uf_map[n]):
continue
# uf_merge() can change the uf_map[nbr], and hence, the lowest
# point in nbr's union-find set. So we add the edge first before doing the
# union-find merge.
lowest_in_nbr_uf = lowest_node_map[id(uf_map[nbr])]
join_tree.add_edge(lowest_in_nbr_uf, n)
uf_merge(uf_map, n, nbr)
lowest_node_map[id(uf_map[nbr])] = n
return join_tree
def growth_tree(mesh, seed_pts):
raise RuntimeError("I think I'm untested and unfinished, check to see...")
growth_tree = DiGraph()
regions = [(set([seed_pt]), set([seed_pt])) for seed_pt in seed_pts]
last_region_pt = {}
# pt2frontier = {}
# for seed_pt in seed_pts:
# pt2frontier[seed_pt] = set([seed_pt])
region_queue = heapq.heapify([(len(reg), reg, front) for reg,front in regions])
for tt in region_queue:
_, reg, front = tt
last_region_pt[id(reg)] = list(reg)[0]
while len(region_queue) > 1:
# get the smallest frontier from the frontier_queue
rsize, region, frontier = heapq.heappop(region_queue)
new_frontier = set()
for pt in frontier:
# add pt to growth_tree's edge.
last_reg_pt = last_region_pt[id(region)]
growth_tree.add_edge(last_region_pt, pt)
def contour_tree_from_join_split(join, split, height_func):
c_tree = DiGraph()
leaves = join_split_peak_pit_nodes(join) + join_split_peak_pit_nodes(split)
while len(leaves) > 1:
leaf = leaves.pop()
if is_upper_leaf(leaf, join, split):
this = join
other = split
else:
this = split
other = join
this_succ = this.successors(leaf)
assert len(this_succ) == 1
nbr = this_succ[0]
if height_func(leaf) > height_func(nbr):
c_tree.add_edge(leaf, nbr)
else:
c_tree.add_edge(nbr, leaf)
reduce_graph(this, leaf)
reduce_graph(other, leaf)
if is_leaf(nbr, join, split):
leaves.append(nbr)
return c_tree