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#!/usr/bin/python3
# -*- coding: utf-8 -*-
# Copyright (C) 2009-2020 Authors of CryptoMiniSat, see AUTHORS file
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; version 2
# of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.
import unittest
def inv(l):
assert len(l) > 0
if l[0] == "-":
return l[1:]
else:
return "-"+l
def check_clause_sanity(c):
for i1 in range(len(c)):
l1 = c[i1]
for i2 in range(i1+1, len(c)):
l2 = c[i2]
if l1 == l2:
print("ERROR: Same literal twice in clause: %s", l1)
assert False
if l1 == inv(l2):
print("ERROR: Inverted literal in clause: %s ", l1)
assert False
return True
def can_resolve(c1, c2):
check_clause_sanity(c1)
check_clause_sanity(c2)
# find inverted
resolve_on = None
for a in c1:
for b in c2:
if a==inv(b):
if resolve_on is not None:
return None
resolve_on = a
return resolve_on
def resolve(c1, c2):
resolve_on = can_resolve(c1,c2)
assert resolve_on is not None, "Cannot resolve the two clauses!"
ret = []
for a in c1:
if a != resolve_on:
ret.append(a)
for b in c2:
if b != inv(resolve_on) and b not in ret:
ret.append(b)
ret = sorted(ret)
return ret
def ham_w(num):
w = 0
for i in range(16):
w += (num>>i)&1
return w
def gen_cls(x):
check_clause_sanity(x)
ret = []
for i in range(1<<len(x)):
if ham_w(i)%2 == (len(x)%2):
continue
cl = []
for i2 in range(len(x)):
l = x[i2]
if i>>i2&1 == 1:
cl.append(inv(l))
else:
cl.append(l)
ret.append(cl)
return ret
class TestMethods(unittest.TestCase):
def test_inv(self):
self.assertEqual(inv("a"), "-a")
self.assertEqual(inv("-a"), "a")
self.assertEqual(inv("x1"), "-x1")
self.assertEqual(inv("-x1"), "x1")
def test_sanity_good(self):
self.assertTrue(check_clause_sanity(["a"]))
self.assertTrue(check_clause_sanity(["a", "b"]))
self.assertTrue(check_clause_sanity(["a", "-b"]))
def test_sanity(self):
with self.assertRaises(AssertionError):
check_clause_sanity(["a", "a"])
with self.assertRaises(AssertionError):
check_clause_sanity(["a", "-a"])
def tets_gen_cls(self):
self.assertEqual(gen_cls(["a"]), [["a"]])
self.assertEqual(gen_cls(["-a"]), [["-a"]])
self.assertEqual(gen_cls(["a", "b"]), [["a", "b"], ["-a", "-b"]])
self.assertEqual(gen_cls(["a", "-b"]), [["a", "-b"], ["-a", "b"]])
self.assertEqual(
gen_cls(["a", "b", "c"]),
[["a", "b", "c"], ["-a", "-b", "c"], ["-a", "b", "-c"], ["a", "-b", "-c"]])
def test_ham_w(self):
self.assertEqual(ham_w(1), 1)
self.assertEqual(ham_w(0), 0)
self.assertEqual(ham_w(2), 1)
self.assertEqual(ham_w(3), 2)
self.assertEqual(ham_w(9), 2)
self.assertEqual(ham_w(8), 1)
self.assertEqual(ham_w(11), 3)
def test_resolve(self):
with self.assertRaises(AssertionError):
resolve(["-a", "b"], ["-a", "c"])
with self.assertRaises(AssertionError):
resolve(["-a", "-b"], ["a", "b"])
self.assertEqual(resolve(["a", "b", "c"], ["-a", "b"]), ["b", "c"])
def num_inside(cl,lits):
num = 0
for l in cl:
for l2 in lits:
if l == l2:
num+=1
return num
def find_most_inside(xors, to_prove):
most_inside = 0
most_inside_cl = None
for i_x in range(len(xors)):
x = xors[i_x]
cls = gen_cls(x)
for i_c in range(len(cls)):
cl = cls[i_c]
n = num_inside(cl, to_prove)
if n > most_inside:
most_inside = n
most_inside_cl = cl
most_inside_at = i_x
return most_inside, most_inside_cl, most_inside_at
def find_resolvent_most_inside(xors, cl_other, to_prove):
most_inside = 0
most_inside_cl = None
for i_x in range(len(xors)):
x = xors[i_x]
cls = gen_cls(x)
for i in range(len(cls)):
cl = cls[i]
if can_resolve(cl,cl_other) is None:
continue
n = num_inside(cl, to_prove)
if n > most_inside:
most_inside = n
most_inside_cl = cl
most_inside_at = i_x
return most_inside, most_inside_cl, most_inside_at
def prove(xors, to_prove):
to_prove = sorted(to_prove)
ret = []
most_inside, cl, most_inside_at = find_most_inside(xors, to_prove)
assert most_inside > 0
print("cl picked:", cl)
xors.remove(xors[most_inside_at])
while cl != to_prove:
most_inside, cl2, most_inside_at = find_resolvent_most_inside(xors, cl, to_prove)
assert most_inside > 0
print("cl picked:", cl2)
cl = resolve(cl, cl2)
cl = sorted(cl)
print("resolvent:", cl)
if __name__ == '__main__':
# XORs to add together (we know this)
xors = [
["a", "b", "c"],
["a", "b", "d"]
]
# so c+d = 0
# so c=1 d=0 must be banned
# generate clause
to_prove = ["-c", "d"]
print("xors:", xors)
print("to_prove:", to_prove)
prove(xors, to_prove)
print("----------------")
print("----------------")
print(gen_cls(["v1", "-v2"]))
print(gen_cls(["v1", "v2", "v3"]))
print("----------------")
print("----------------")
unittest.main()
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