def test_Factors():
assert Factors() == Factors({}) == Factors(Integer(1))
assert Factors(Integer(1)) == Factors(Factors(Integer(1)))
assert Factors().as_expr() == 1
assert Factors({x: 2, y: 3, sin(x): 4}).as_expr() == x**2*y**3*sin(x)**4
assert Factors(+oo) == Factors({oo: 1})
assert Factors(-oo) == Factors({oo: 1, -1: 1})
f1 = Factors({oo: 1})
f2 = Factors({oo: 1})
assert hash(f1) == hash(f2)
a = Factors({x: 5, y: 3, z: 7})
b = Factors({ y: 4, z: 3, t: 10})
assert a.mul(b) == a*b == Factors({x: 5, y: 7, z: 10, t: 10})
assert a.div(b) == divmod(a, b) == \
(Factors({x: 5, z: 4}), Factors({y: 1, t: 10}))
assert a.quo(b) == a/b == Factors({x: 5, z: 4})
assert a.rem(b) == a % b == Factors({y: 1, t: 10})
assert a.pow(3) == a**3 == Factors({x: 15, y: 9, z: 21})
assert b.pow(3) == b**3 == Factors({y: 12, z: 9, t: 30})
pytest.raises(ValueError, lambda: a.pow(3.1))
pytest.raises(ValueError, lambda: a.pow(Factors(3.1)))
assert a.pow(0) == Factors()
assert a.gcd(b) == Factors({y: 3, z: 3})
assert a.lcm(b) == a.lcm(b.as_expr()) == Factors({x: 5, y: 4, z: 7, t: 10})
a = Factors({x: 4, y: 7, t: 7})
b = Factors({z: 1, t: 3})
assert a.normal(b) == (Factors({x: 4, y: 7, t: 4}), Factors({z: 1}))
assert Factors(sqrt(2)*x).as_expr() == sqrt(2)*x
assert Factors(-I)*I == Factors()
assert Factors({Integer(-1): Integer(3)})*Factors({Integer(-1): Integer(1), I: Integer(5)}) == \
Factors(I)
assert Factors(Integer(2)**x).div(Integer(3)**x) == \
(Factors({Integer(2): x}), Factors({Integer(3): x}))
assert Factors(2**(2*x + 2)).div(Integer(8)) == \
(Factors({Integer(2): 2*x + 2}), Factors({Integer(8): Integer(1)}))
# coverage
# /!\ things break if this is not True
assert Factors({Integer(-1): Rational(3, 2)}) == Factors({I: 1, -1: 1})
assert Factors({I: Integer(1), Integer(-1): Rational(1, 3)}).as_expr() == I*cbrt(-1)
assert Factors(-1.) == Factors({Integer(-1): Integer(1), Float(1.): 1})
assert Factors(-2.) == Factors({Integer(-1): Integer(1), Float(2.): 1})
assert Factors((-2.)**x) == Factors({Float(-2.): x})
assert Factors(Integer(-2)) == Factors({Integer(-1): Integer(1), Integer(2): 1})
assert Factors(Rational(1, 2)) == Factors({Integer(2): -1})
assert Factors(Rational(3, 2)) == Factors({Integer(3): 1, Integer(2): Integer(-1)})
assert Factors({I: Integer(1)}) == Factors(I)
assert Factors({-1.0: 2, I: 1}) == Factors({Float(1.0): 1, I: 1})
assert Factors({-1: -Rational(3, 2)}).as_expr() == I
A = symbols('A', commutative=False)
assert Factors(2*A**2) == Factors({Integer(2): 1, A**2: 1})
assert Factors(I) == Factors({I: 1})
assert Factors(x).normal(Integer(2)) == (Factors(x), Factors(Integer(2)))
assert Factors(x).normal(Integer(0)) == (Factors(), Factors(Integer(0)))
pytest.raises(ZeroDivisionError, lambda: Factors(x).div(Integer(0)))
assert Factors(x).mul(Integer(2)) == Factors(2*x)
assert Factors(x).mul(Integer(0)).is_zero
assert Factors(x).mul(1/x).is_one
assert Factors(x**sqrt(8)).as_expr() == x**(2*sqrt(2))
assert Factors(x)**Factors(Integer(2)) == Factors(x**2)
assert Factors(x).gcd(Integer(0)) == Factors(x)
assert Factors(x).lcm(Integer(0)).is_zero
assert Factors(Integer(0)).div(x) == (Factors(Integer(0)), Factors())
assert Factors(x).div(x) == (Factors(), Factors())
assert Factors({x: .2})/Factors({x: .2}) == Factors()
assert Factors(x) != Factors()
assert Factors(x) == x
assert Factors(Integer(0)).normal(x) == (Factors(Integer(0)), Factors())
n, d = x**(2 + y), x**2
f = Factors(n)
assert f.div(d) == f.normal(d) == (Factors(x**y), Factors())
assert f.gcd(d) == Factors()
d = x**y
assert f.div(d) == f.normal(d) == (Factors(x**2), Factors())
assert f.gcd(d) == Factors(d)
n = d = 2**x
f = Factors(n)
assert f.div(d) == f.normal(d) == (Factors(), Factors())
assert f.gcd(d) == Factors(d)
n, d = 2**x, 2**y
f = Factors(n)
assert f.div(d) == f.normal(d) == (Factors({Integer(2): x}), Factors({Integer(2): y}))
assert f.gcd(d) == Factors()
assert f.div(f) == (Factors(), Factors())
# extraction of constant only
n = x**(x + 3)
assert Factors(n).normal(x**-3) == (Factors({x: x + 6}), Factors({}))
assert Factors(n).normal(x**3) == (Factors({x: x}), Factors({}))
assert Factors(n).normal(x**4) == (Factors({x: x}), Factors({x: 1}))
assert Factors(n).normal(x**(y - 3)) == \
(Factors({x: x + 6}), Factors({x: y}))
assert Factors(n).normal(x**(y + 3)) == (Factors({x: x}), Factors({x: y}))
assert Factors(n).normal(x**(y + 4)) == \
(Factors({x: x}), Factors({x: y + 1}))
assert Factors(n).div(x**-3) == (Factors({x: x + 6}), Factors({}))
assert Factors(n).div(x**3) == (Factors({x: x}), Factors({}))
assert Factors(n).div(x**4) == (Factors({x: x}), Factors({x: 1}))
assert Factors(n).div(x**(y - 3)) == \
(Factors({x: x + 6}), Factors({x: y}))
assert Factors(n).div(x**(y + 3)) == (Factors({x: x}), Factors({x: y}))
assert Factors(n).div(x**(y + 4)) == \
(Factors({x: x}), Factors({x: y + 1}))
assert Factors({I: I}).as_expr() == (-1)**(I/2)
assert Factors({-1: Rational(4, 3)}).as_expr() == -cbrt(-1)
def test_Factors():
assert Factors() == Factors({}) == Factors(Integer(1))
assert Factors(Integer(1)) == Factors(Factors(Integer(1)))
assert Factors().as_expr() == 1
assert Factors({
x: 2,
y: 3,
sin(x): 4
}).as_expr() == x**2 * y**3 * sin(x)**4
assert Factors(+oo) == Factors({oo: 1})
assert Factors(-oo) == Factors({oo: 1, -1: 1})
f1 = Factors({oo: 1})
f2 = Factors({oo: 1})
assert hash(f1) == hash(f2)
a = Factors({x: 5, y: 3, z: 7})
b = Factors({y: 4, z: 3, t: 10})
assert a.mul(b) == a * b == Factors({x: 5, y: 7, z: 10, t: 10})
assert a.div(b) == divmod(a, b) == \
(Factors({x: 5, z: 4}), Factors({y: 1, t: 10}))
assert a.quo(b) == a / b == Factors({x: 5, z: 4})
assert a.rem(b) == a % b == Factors({y: 1, t: 10})
assert a.pow(3) == a**3 == Factors({x: 15, y: 9, z: 21})
assert b.pow(3) == b**3 == Factors({y: 12, z: 9, t: 30})
pytest.raises(ValueError, lambda: a.pow(3.1))
pytest.raises(ValueError, lambda: a.pow(Factors(3.1)))
assert a.pow(0) == Factors()
assert a.gcd(b) == Factors({y: 3, z: 3})
assert a.lcm(b) == a.lcm(b.as_expr()) == Factors({x: 5, y: 4, z: 7, t: 10})
a = Factors({x: 4, y: 7, t: 7})
b = Factors({z: 1, t: 3})
assert a.normal(b) == (Factors({x: 4, y: 7, t: 4}), Factors({z: 1}))
assert Factors(sqrt(2) * x).as_expr() == sqrt(2) * x
assert Factors(-I) * I == Factors()
assert Factors({Integer(-1): Integer(3)})*Factors({Integer(-1): Integer(1), I: Integer(5)}) == \
Factors(I)
assert Factors(Integer(2)**x).div(Integer(3)**x) == \
(Factors({Integer(2): x}), Factors({Integer(3): x}))
assert Factors(2**(2*x + 2)).div(Integer(8)) == \
(Factors({Integer(2): 2*x + 2}), Factors({Integer(8): Integer(1)}))
# coverage
# /!\ things break if this is not True
assert Factors({Integer(-1): Rational(3, 2)}) == Factors({I: 1, -1: 1})
assert Factors({
I: Integer(1),
Integer(-1): Rational(1, 3)
}).as_expr() == I * cbrt(-1)
assert Factors(-1.) == Factors({Integer(-1): Integer(1), Float(1.): 1})
assert Factors(-2.) == Factors({Integer(-1): Integer(1), Float(2.): 1})
assert Factors((-2.)**x) == Factors({Float(-2.): x})
assert Factors(Integer(-2)) == Factors({
Integer(-1): Integer(1),
Integer(2): 1
})
assert Factors(Rational(1, 2)) == Factors({Integer(2): -1})
assert Factors(Rational(3, 2)) == Factors({
Integer(3): 1,
Integer(2): Integer(-1)
})
assert Factors({I: Integer(1)}) == Factors(I)
assert Factors({-1.0: 2, I: 1}) == Factors({Float(1.0): 1, I: 1})
assert Factors({-1: -Rational(3, 2)}).as_expr() == I
A = symbols('A', commutative=False)
assert Factors(2 * A**2) == Factors({Integer(2): 1, A**2: 1})
assert Factors(I) == Factors({I: 1})
assert Factors(x).normal(Integer(2)) == (Factors(x), Factors(Integer(2)))
assert Factors(x).normal(Integer(0)) == (Factors(), Factors(Integer(0)))
pytest.raises(ZeroDivisionError, lambda: Factors(x).div(Integer(0)))
assert Factors(x).mul(Integer(2)) == Factors(2 * x)
assert Factors(x).mul(Integer(0)).is_zero
assert Factors(x).mul(1 / x).is_one
assert Factors(x**sqrt(8)).as_expr() == x**(2 * sqrt(2))
assert Factors(x)**Factors(Integer(2)) == Factors(x**2)
assert Factors(x).gcd(Integer(0)) == Factors(x)
assert Factors(x).lcm(Integer(0)).is_zero
assert Factors(Integer(0)).div(x) == (Factors(Integer(0)), Factors())
assert Factors(x).div(x) == (Factors(), Factors())
assert Factors({x: .2}) / Factors({x: .2}) == Factors()
assert Factors(x) != Factors()
assert Factors(x) == x
assert Factors(Integer(0)).normal(x) == (Factors(Integer(0)), Factors())
n, d = x**(2 + y), x**2
f = Factors(n)
assert f.div(d) == f.normal(d) == (Factors(x**y), Factors())
assert f.gcd(d) == Factors()
d = x**y
assert f.div(d) == f.normal(d) == (Factors(x**2), Factors())
assert f.gcd(d) == Factors(d)
n = d = 2**x
f = Factors(n)
assert f.div(d) == f.normal(d) == (Factors(), Factors())
assert f.gcd(d) == Factors(d)
n, d = 2**x, 2**y
f = Factors(n)
assert f.div(d) == f.normal(d) == (Factors({Integer(2): x
}), Factors({Integer(2): y}))
assert f.gcd(d) == Factors()
assert f.div(f) == (Factors(), Factors())
# extraction of constant only
n = x**(x + 3)
assert Factors(n).normal(x**-3) == (Factors({x: x + 6}), Factors({}))
assert Factors(n).normal(x**3) == (Factors({x: x}), Factors({}))
assert Factors(n).normal(x**4) == (Factors({x: x}), Factors({x: 1}))
assert Factors(n).normal(x**(y - 3)) == \
(Factors({x: x + 6}), Factors({x: y}))
assert Factors(n).normal(x**(y + 3)) == (Factors({x: x}), Factors({x: y}))
assert Factors(n).normal(x**(y + 4)) == \
(Factors({x: x}), Factors({x: y + 1}))
assert Factors(n).div(x**-3) == (Factors({x: x + 6}), Factors({}))
assert Factors(n).div(x**3) == (Factors({x: x}), Factors({}))
assert Factors(n).div(x**4) == (Factors({x: x}), Factors({x: 1}))
assert Factors(n).div(x**(y - 3)) == \
(Factors({x: x + 6}), Factors({x: y}))
assert Factors(n).div(x**(y + 3)) == (Factors({x: x}), Factors({x: y}))
assert Factors(n).div(x**(y + 4)) == \
(Factors({x: x}), Factors({x: y + 1}))
assert Factors({I: I}).as_expr() == (-1)**(I / 2)
assert Factors({-1: Rational(4, 3)}).as_expr() == -cbrt(-1)
def collect_const(expr, *vars, **kwargs):
"""A non-greedy collection of terms with similar number coefficients in
an Add expr. If ``vars`` is given then only those constants will be
targeted. Although any Number can also be targeted, if this is not
desired set ``Numbers=False`` and no Float or Rational will be collected.
Examples
========
>>> from diofant import sqrt
>>> from diofant.abc import a, s, x, y, z
>>> from diofant.simplify.radsimp import collect_const
>>> collect_const(sqrt(3) + sqrt(3)*(1 + sqrt(2)))
sqrt(3)*(sqrt(2) + 2)
>>> collect_const(sqrt(3)*s + sqrt(7)*s + sqrt(3) + sqrt(7))
(sqrt(3) + sqrt(7))*(s + 1)
>>> s = sqrt(2) + 2
>>> collect_const(sqrt(3)*s + sqrt(3) + sqrt(7)*s + sqrt(7))
(sqrt(2) + 3)*(sqrt(3) + sqrt(7))
>>> collect_const(sqrt(3)*s + sqrt(3) + sqrt(7)*s + sqrt(7), sqrt(3))
sqrt(7) + sqrt(3)*(sqrt(2) + 3) + sqrt(7)*(sqrt(2) + 2)
The collection is sign-sensitive, giving higher precedence to the
unsigned values:
>>> collect_const(x - y - z)
x - (y + z)
>>> collect_const(-y - z)
-(y + z)
>>> collect_const(2*x - 2*y - 2*z, 2)
2*(x - y - z)
>>> collect_const(2*x - 2*y - 2*z, -2)
2*x - 2*(y + z)
See Also
========
collect, collect_sqrt, rcollect
"""
if not expr.is_Add:
return expr
recurse = False
Numbers = kwargs.get('Numbers', True)
if not vars:
recurse = True
vars = set()
for a in expr.args:
for m in Mul.make_args(a):
if m.is_number:
vars.add(m)
else:
vars = sympify(vars)
if not Numbers:
vars = [v for v in vars if not v.is_Number]
vars = list(ordered(vars))
for v in vars:
terms = defaultdict(list)
Fv = Factors(v)
for m in Add.make_args(expr):
f = Factors(m)
q, r = f.div(Fv)
if r.is_one:
# only accept this as a true factor if
# it didn't change an exponent from an Integer
# to a non-Integer, e.g. 2/sqrt(2) -> sqrt(2)
# -- we aren't looking for this sort of change
fwas = f.factors.copy()
fnow = q.factors
if not any(k in fwas and fwas[k].is_Integer
and not fnow[k].is_Integer for k in fnow):
terms[v].append(q.as_expr())
continue
terms[S.One].append(m)
args = []
hit = False
uneval = False
for k in ordered(terms):
v = terms[k]
if k is S.One:
args.extend(v)
continue
if len(v) > 1:
v = Add(*v)
hit = True
if recurse and v != expr:
vars.append(v)
else:
v = v[0]
# be careful not to let uneval become True unless
# it must be because it's going to be more expensive
# to rebuild the expression as an unevaluated one
if Numbers and k.is_Number and v.is_Add:
args.append(_keep_coeff(k, v, sign=True))
uneval = True
else:
args.append(k * v)
if hit:
if uneval:
expr = _unevaluated_Add(*args)
else:
expr = Add(*args)
if not expr.is_Add:
break
return expr