def test_add_expr():
bdd = sylvan.BDD()
for var in ['x', 'y']:
bdd.add_var(var)
# ((0 \/ 1) /\ x) \equiv x
s = '(TRUE \/ FALSE) /\ x'
u = bdd.add_expr(s)
x = bdd.var('x')
assert u == x, (u, x)
# ((x \/ ~ y) /\ x) \equiv x
s = '(x \/ ~ y) /\ x'
u = bdd.add_expr(s)
assert u == x, (u, x)
# x /\ y /\ z
bdd.add_var('z')
z = bdd.var('z')
u = bdd.add_expr('x /\ y /\ z')
u_ = bdd.cube(dict(x=True, y=True, z=True))
assert u == u_, (u, u_)
# x /\ ~ y /\ z
u = bdd.add_expr('x /\ ~ y /\ z')
u_ = bdd.cube(dict(x=True, y=False, z=True))
assert u == u_, (u, u_)
# (\E x: x /\ y) \equiv y
y = bdd.var('y')
u = bdd.add_expr('\E x: x /\ y')
assert u == y, (str(u), str(y))
# (\A x: x \/ ~ x) \equiv TRUE
u = bdd.add_expr('\A x: ~ x \/ x')
assert u == bdd.true, u
del x, y, z, u, u_
def test_add_expr():
bdd = sylvan.BDD()
for var in ['x', 'y']:
bdd.add_var(var)
# (0 | 1) & x = x
s = '(True | False) & x'
u = bdd.add_expr(s)
x = bdd.var('x')
assert u == x, (u, x)
# (x | !y) & x = x
s = '(x | !y) & x'
u = bdd.add_expr(s)
assert u == x, (u, x)
# x & y & z
bdd.add_var('z')
z = bdd.var('z')
u = bdd.add_expr('x & y & z')
u_ = bdd.cube(dict(x=True, y=True, z=True))
assert u == u_, (u, u_)
# x & !y & z
u = bdd.add_expr('x & !y & z')
u_ = bdd.cube(dict(x=True, y=False, z=True))
assert u == u_, (u, u_)
# ? x. x & y = y
y = bdd.var('y')
u = bdd.add_expr('\E x: x & y')
assert u == y, (str(u), str(y))
# ! x. x | !x = 1
u = bdd.add_expr('\A x: !x | x')
assert u == bdd.true, u
del x, y, z, u, u_
def test_true_false():
b = sylvan.BDD()
false = b.false
true = b.true
assert false != true
assert false == ~true
assert false == false & true
assert true == true | false
del true, false
def test_compose():
bdd = sylvan.BDD()
bdd.add_var('x')
bdd.add_var('y')
x = bdd.var('x')
y = bdd.var('y')
var_sub = dict(x=y)
y_ = bdd.let(var_sub, x)
assert y == y_, bdd.to_expr(y_)
del x, y, y_, var_sub
def test_insert_var():
bdd = sylvan.BDD()
level = 0
j = bdd.add_var('x', index=level)
assert j == 0, j # initially indices = levels
x = bdd.var_at_level(level)
assert x == 'x', x
level = 101
bdd.add_var('y', index=level)
y = bdd.var_at_level(level)
assert y == 'y', y
def test_pick_iter():
b = sylvan.BDD()
b.add_var('x')
b.add_var('y')
# FALSE
u = b.false
m = list(b.pick_iter(u))
assert not m, m
# TRUE, no care vars
u = b.true
m = list(b.pick_iter(u))
assert m == [{}], m
# x
u = b.add_expr('x')
m = list(b.pick_iter(u))
m_ = [dict(x=True)]
assert m == m_, (m, m_)
# ~ x /\ y
s = '~ x /\ y'
u = b.add_expr(s)
g = b.pick_iter(u, care_vars=set())
m = list(g)
m_ = [dict(x=False, y=True)]
assert m == m_, (m, m_)
u = b.add_expr(s)
g = b.pick_iter(u)
m = list(g)
assert m == m_, (m, m_)
# x /\ y
u = b.add_expr('x /\ y')
m = list(b.pick_iter(u))
m_ = [dict(x=True, y=True)]
assert m == m_, m
# x
s = '~ y'
u = b.add_expr(s)
# partial
g = b.pick_iter(u)
m = list(g)
m_ = [dict(y=False)]
equal_list_contents(m, m_)
# partial
g = b.pick_iter(u, care_vars=['x', 'y'])
m = list(g)
m_ = [dict(x=True, y=False), dict(x=False, y=False)]
equal_list_contents(m, m_)
# care bits x, y
b.add_var('z')
s = 'x \/ y'
u = b.add_expr(s)
g = b.pick_iter(u, care_vars=['x', 'y'])
m = list(g)
m_ = [dict(x=True, y=False), dict(x=False, y=True), dict(x=True, y=True)]
equal_list_contents(m, m_)
def test_support():
bdd = sylvan.BDD()
bdd.add_var('x')
bdd.add_var('y')
u = bdd.var('x')
supp = bdd.support(u)
assert supp == {'x'}, supp
u = bdd.var('y')
supp = bdd.support(u)
assert supp == {'y'}, supp
u = bdd.add_expr('x /\ y')
supp = bdd.support(u)
assert supp == {'x', 'y'}, supp
del u
def test_len():
b = sylvan.BDD()
# constant
assert len(b) == 0, len(b)
u = b.false
assert len(b) == 0, len(b)
del u
assert len(b) == 0, len(b)
# var node
b.add_var('x')
u = b.var('x')
assert len(b) == 1, len(b)
del u
assert len(b) == 0, len(b)
def test_cofactor():
bdd = sylvan.BDD()
bdd.add_var('x')
x = bdd.var('x')
# u = bdd.let(dict(x=True), x)
# assert u == bdd.true, u
# u = bdd.let(dict(x=False), x)
# u = bdd.true
# u_ = bdd.false
# assert u == ~u_
assert x == bdd.add_expr('x')
u = bdd.let(dict(x=bdd.false), x)
u_ = bdd.false
assert u == u_, (u, u_)
del x, u, u_
def test_add_var():
bdd = sylvan.BDD()
bdd.add_var('x')
bdd.add_var('y')
jx = bdd._index_of_var['x']
jy = bdd._index_of_var['y']
assert jx == 0, jx
assert jy == 1, jy
x = bdd._var_with_index[0]
y = bdd._var_with_index[1]
assert x == 'x', x
assert y == 'y', y
assert bdd.vars == {'x', 'y'}, bdd.vars
x = bdd.var('x')
y = bdd.var('y')
assert x != y, (x, y)
del x, y
def test_rename():
bdd = sylvan.BDD()
# single variable
bdd.add_var('x')
bdd.add_var('y')
x = bdd.var('x')
y = bdd.var('y')
rename = dict(x='y')
y_ = bdd.let(rename, x)
assert y == y_, bdd.to_expr(y_)
# multiple variables
bdd.add_var('z')
bdd.add_var('w')
s = '(x /\ ~ y) \/ w'
u = bdd.add_expr(s)
rename = dict(x='w', y='z', w='y')
v = bdd.let(rename, u)
s = '(w /\ ~ z) \/ y'
v_ = bdd.add_expr(s)
assert v == v_, bdd.to_expr(v)
del x, y, y_, u, v, v_
