Commit 76b5ebee authored by Taddeus Kroes's avatar Taddeus Kroes

Removed redundant polynome rules.

parent 6e8d6345
from itertools import combinations
from ..node import Scope, OP_ADD
from ..possibilities import Possibility as P, MESSAGES
from .numerics import add_numerics
def match_combine_polynomes(node, verbose=False):
"""
n + exp + m -> exp + (n + m)
k0 * v ^ n + exp + k1 * v ^ n -> exp + (k0 + k1) * v ^ n
"""
assert node.is_op(OP_ADD)
p = []
# Collect all nodes that can be combined:
# a ^ e = 1 * a ^ e
# c * a = c * a ^ 1
# c * a ^ e
# a = 1 * a ^ 1
#
# Identifier nodes of all polynomes, tuple format is:
# (root, exponent, coefficient, literal_coefficient)
polys = []
if verbose: # pragma: nocover
print 'match combine factors:', node
scope = Scope(node)
for n in scope:
polynome = n.extract_polynome_properties()
if verbose: # pragma: nocover
print 'n:', n, 'polynome:', polynome
if polynome:
polys.append((n, polynome))
# Each combination of powers of the same value and polynome can be added
if len(polys) >= 2:
for left, right in combinations(polys, 2):
n0, p0 = left
n1, p1 = right
c0, r0, e0 = p0
c1, r1, e1 = p1
# Both numeric root and same exponent -> combine coefficients and
# roots, or: same root and exponent -> combine coefficients.
# TODO: Addition with zero, e.g. a + 0 -> a
#if c0 == 1 and c1 == 1 and e0 == 1 and e1 == 1 \
# and all(map(lambda n: n.is_numeric(), [r0, r1])):
# # 2 + 3 -> 5
# # 2 + -3 -> -1
# # -2 + 3 -> 1
# # -2 + -3 -> -5
# p.append(P(node, add_numerics, (scope, n0, n1, r0, r1)))
#el
if c0.is_numeric() and c1.is_numeric() and r0 == r1 and e0 == e1:
# 2a + 2a -> 4a
# a + 2a -> 3a
# 2a + a -> 3a
# a + a -> 2a
p.append(P(node, combine_polynomes, (scope, n0, n1,
c0, c1, r0, e0)))
return p
def combine_polynomes(root, args):
"""
Combine two multiplications of any polynome in an n-ary plus.
Synopsis:
c0 * a ^ b + c1 * a ^ b -> (c0 + c1) * a ^ b
"""
scope, n0, n1, c0, c1, r, e = args
# a ^ 1 -> a
if e == 1:
power = r
else:
power = r ** e
# Replace the left node with the new expression:
# (c0 + c1) * a ^ b
# a, b and c are from 'left', d is from 'right'.
scope.replace(n0, (c0 + c1) * power)
# Remove the right node
scope.remove(n1)
return scope.as_nary_node()
from src.rules.poly import match_combine_polynomes, combine_polynomes
from src.rules.numerics import add_numerics
from src.node import Scope
from src.possibilities import Possibility as P
from tests.rulestestcase import RulesTestCase, tree
class TestRulesPoly(RulesTestCase):
def test_identifiers_basic(self):
a1, a2 = root = tree('a+a')
possibilities = match_combine_polynomes(root)
self.assertEqualPos(possibilities,
[P(root, combine_polynomes, (Scope(root), a1, a2,
1, 1, 'a', 1))])
def test_identifiers_normal(self):
a1, a2 = root = tree('a+2a')
possibilities = match_combine_polynomes(root)
self.assertEqualPos(possibilities,
[P(root, combine_polynomes, (Scope(root), a1, a2,
1, 2, 'a', 1))])
def test_identifiers_reverse(self):
a1, a2 = root = tree('a+a*2')
possibilities = match_combine_polynomes(root)
self.assertEqualPos(possibilities,
[P(root, combine_polynomes, (Scope(root), a1, a2,
1, 2, a1, 1))])
def test_identifiers_exponent(self):
a1, a2 = root = tree('a2+a2')
possibilities = match_combine_polynomes(root)
self.assertEqualPos(possibilities,
[P(root, combine_polynomes, (Scope(root), a1, a2,
1, 1, 'a', 2))])
def test_identifiers_coeff_exponent_left(self):
a1, a2 = root = tree('2a3+a3')
possibilities = match_combine_polynomes(root)
self.assertEqualPos(possibilities,
[P(root, combine_polynomes, (Scope(root), a1, a2,
2, 1, 'a', 3))])
def test_identifiers_coeff_exponent_both(self):
a1, a2 = root = tree('2a3+2a3')
possibilities = match_combine_polynomes(root)
self.assertEqualPos(possibilities,
[P(root, combine_polynomes, (Scope(root), a1, a2,
2, 2, 'a', 3))])
def test_basic_subexpressions(self):
a_b, c, d = tree('a+b,c,d')
left, right = root = tree('(a+b)^d + (a+b)^d')
self.assertEqual(left, right)
possibilities = match_combine_polynomes(root)
self.assertEqualPos(possibilities,
[P(root, combine_polynomes, (Scope(root), left, right,
1, 1, a_b, d))])
left, right = root = tree('5(a+b)^d + 7(a+b)^d')
possibilities = match_combine_polynomes(root)
self.assertEqualPos(possibilities,
[P(root, combine_polynomes, (Scope(root), left, right,
5, 7, a_b, d))])
# TODO: Move to other strategy
#left, right = root = tree('c(a+b)^d + c(a+b)^d')
#self.assertEqual(left, right)
#possibilities = match_combine_polynomes(root)
#self.assertEqualPos(possibilities,
# [P(root, combine_polynomes, (Scope(root), left, right,
# c, c, a_b, d))])
def test_match_add_numerics(self):
l0, l1, l2 = tree('0,1,2')
root = l0 + l1 + l2
possibilities = match_combine_polynomes(root)
self.assertEqualPos(possibilities,
[P(root, add_numerics, (Scope(root), l0, l1, l0, l1)),
P(root, add_numerics, (Scope(root), l0, l2, l0, l2)),
P(root, add_numerics, (Scope(root), l1, l2, l1, l2))])
def test_match_add_numerics_explicit_powers(self):
l0, l1, l2 = tree('0^1,1*1,1*2^1')
root = l0 + l1 + l2
possibilities = match_combine_polynomes(root)
self.assertEqualPos(possibilities,
[P(root, add_numerics, (Scope(root), l0, l1, l0[0], l1[1])),
P(root, add_numerics, (Scope(root), l0, l2, l0[0], l2[1][0])),
P(root, add_numerics, (Scope(root), l1, l2,
l1[1], l2[1][0]))])
def test_combine_polynomes(self):
# 2a + 3a -> (2 + 3) * a
l0, a, l1, l2 = tree('2,a,3,1')
root = l0 * a + l1 * a
left, right = root
replacement = combine_polynomes(root, (Scope(root), left, right,
l0, l1, a, 1))
self.assertEqualNodes(replacement, (l0 + l1) * a)
# a + 3a -> (1 + 3) * a
root = a + l1 * a
left, right = root
replacement = combine_polynomes(root, (Scope(root), left, right,
l2, l1, a, 1))
self.assertEqualNodes(replacement, (l2 + l1) * a)
# 2a + a -> (2 + 1) * a
root = l0 * a + a
left, right = root
replacement = combine_polynomes(root, (Scope(root), left, right,
l0, l2, a, 1))
self.assertEqualNodes(replacement, (l0 + 1) * a)
# a + a -> (1 + 1) * a
root = a + a
left, right = root
replacement = combine_polynomes(root, (Scope(root), left, right, l2, l2, a, 1))
self.assertEqualNodes(replacement, (l2 + 1) * a)
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