49 lines
1.4 KiB
Python
49 lines
1.4 KiB
Python
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import numpy as np
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import pytest
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from sklearn.tree._reingold_tilford import buchheim, Tree
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simple_tree = Tree("", 0, Tree("", 1), Tree("", 2))
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bigger_tree = Tree(
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"",
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0,
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Tree(
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"",
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1,
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Tree("", 3),
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Tree("", 4, Tree("", 7), Tree("", 8)),
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),
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Tree("", 2, Tree("", 5), Tree("", 6)),
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)
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@pytest.mark.parametrize("tree, n_nodes", [(simple_tree, 3), (bigger_tree, 9)])
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def test_buchheim(tree, n_nodes):
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def walk_tree(draw_tree):
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res = [(draw_tree.x, draw_tree.y)]
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for child in draw_tree.children:
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# parents higher than children:
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assert child.y == draw_tree.y + 1
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res.extend(walk_tree(child))
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if len(draw_tree.children):
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# these trees are always binary
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# parents are centered above children
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assert (
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draw_tree.x == (draw_tree.children[0].x + draw_tree.children[1].x) / 2
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)
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return res
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layout = buchheim(tree)
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coordinates = walk_tree(layout)
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assert len(coordinates) == n_nodes
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# test that x values are unique per depth / level
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# we could also do it quicker using defaultdicts..
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depth = 0
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while True:
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x_at_this_depth = [node[0] for node in coordinates if node[1] == depth]
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if not x_at_this_depth:
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# reached all leafs
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break
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assert len(np.unique(x_at_this_depth)) == len(x_at_this_depth)
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depth += 1
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