You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

93 lines
2.3 KiB

from sympy.strategies.tree import treeapply, greedy, allresults, brute
from functools import partial, reduce
def inc(x):
return x + 1
def dec(x):
return x - 1
def double(x):
return 2 * x
def square(x):
return x**2
def add(*args):
return sum(args)
def mul(*args):
return reduce(lambda a, b: a * b, args, 1)
def test_treeapply():
tree = ([3, 3], [4, 1], 2)
assert treeapply(tree, {list: min, tuple: max}) == 3
assert treeapply(tree, {list: add, tuple: mul}) == 60
def test_treeapply_leaf():
assert treeapply(3, {}, leaf=lambda x: x**2) == 9
tree = ([3, 3], [4, 1], 2)
treep1 = ([4, 4], [5, 2], 3)
assert treeapply(tree, {list: min, tuple: max}, leaf=lambda x: x + 1) == \
treeapply(treep1, {list: min, tuple: max})
def test_treeapply_strategies():
from sympy.strategies import chain, minimize
join = {list: chain, tuple: minimize}
assert treeapply(inc, join) == inc
assert treeapply((inc, dec), join)(5) == minimize(inc, dec)(5)
assert treeapply([inc, dec], join)(5) == chain(inc, dec)(5)
tree = (inc, [dec, double]) # either inc or dec-then-double
assert treeapply(tree, join)(5) == 6
assert treeapply(tree, join)(1) == 0
maximize = partial(minimize, objective=lambda x: -x)
join = {list: chain, tuple: maximize}
fn = treeapply(tree, join)
assert fn(4) == 6 # highest value comes from the dec then double
assert fn(1) == 2 # highest value comes from the inc
def test_greedy():
tree = [inc, (dec, double)] # either inc or dec-then-double
fn = greedy(tree, objective=lambda x: -x)
assert fn(4) == 6 # highest value comes from the dec then double
assert fn(1) == 2 # highest value comes from the inc
tree = [inc, dec, [inc, dec, [(inc, inc), (dec, dec)]]]
lowest = greedy(tree)
assert lowest(10) == 8
highest = greedy(tree, objective=lambda x: -x)
assert highest(10) == 12
def test_allresults():
# square = lambda x: x**2
assert set(allresults(inc)(3)) == {inc(3)}
assert set(allresults([inc, dec])(3)) == {2, 4}
assert set(allresults((inc, dec))(3)) == {3}
assert set(allresults([inc, (dec, double)])(4)) == {5, 6}
def test_brute():
tree = ([inc, dec], square)
fn = brute(tree, lambda x: -x)
assert fn(2) == (2 + 1)**2
assert fn(-2) == (-2 - 1)**2
assert brute(inc)(1) == 2