Exemple #1
0
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
Exemple #2
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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)
Exemple #3
0
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