def test_sympyissue_from_PR1599():
n1, n2, n3, n4 = symbols('n1 n2 n3 n4', negative=True)
assert simplify(I*sqrt(n1)) == -sqrt(-n1)
assert (powsimp(sqrt(n1)*sqrt(n2)*sqrt(n3)) ==
-I*sqrt(-n1)*sqrt(-n2)*sqrt(-n3))
assert (powsimp(root(n1, 3)*root(n2, 3)*root(n3, 3)*root(n4, 3)) ==
-cbrt(-1)*cbrt(-n1)*cbrt(-n2)*cbrt(-n3)*cbrt(-n4))
def test_combsimp_gamma():
R = Rational
assert combsimp(gamma(x)) == gamma(x)
assert combsimp(gamma(x + 1)/x) == gamma(x)
assert combsimp(gamma(x)/(x - 1)) == gamma(x - 1)
assert combsimp(x*gamma(x)) == gamma(x + 1)
assert combsimp((x + 1)*gamma(x + 1)) == gamma(x + 2)
assert combsimp(gamma(x + y)*(x + y)) == gamma(x + y + 1)
assert combsimp(x/gamma(x + 1)) == 1/gamma(x)
assert combsimp((x + 1)**2/gamma(x + 2)) == (x + 1)/gamma(x + 1)
assert combsimp(x*gamma(x) + gamma(x + 3)/(x + 2)) == \
(x + 2)*gamma(x + 1)
assert combsimp(gamma(2*x)*x) == gamma(2*x + 1)/2
assert combsimp(gamma(2*x)/(x - Rational(1, 2))) == 2*gamma(2*x - 1)
assert combsimp(gamma(x)*gamma(1 - x)) == pi/sin(pi*x)
assert combsimp(gamma(x)*gamma(-x)) == -pi/(x*sin(pi*x))
assert combsimp(1/gamma(x + 3)/gamma(1 - x)) == \
sin(pi*x)/(pi*x*(x + 1)*(x + 2))
assert powsimp(combsimp(
gamma(x)*gamma(x + Rational(1, 2))*gamma(y)/gamma(x + y))) == \
2**(-2*x + 1)*sqrt(pi)*gamma(2*x)*gamma(y)/gamma(x + y)
assert combsimp(1/gamma(x)/gamma(x - Rational(1, 3))/gamma(x + Rational(1, 3))) == \
3**(3*x - Rational(3, 2))/(2*pi*gamma(3*x - 1))
assert simplify(
gamma(Rational(1, 2) + x/2)*gamma(1 + x/2)/gamma(1 + x)/sqrt(pi)*2**x) == 1
assert combsimp(gamma(Rational(-1, 4))*gamma(Rational(-3, 4))) == 16*sqrt(2)*pi/3
assert powsimp(combsimp(gamma(2*x)/gamma(x))) == \
2**(2*x - 1)*gamma(x + Rational(1, 2))/sqrt(pi)
# issue sympy/sympy#6792
e = (-gamma(k)*gamma(k + 2) + gamma(k + 1)**2)/gamma(k)**2
assert combsimp(e) == -k
assert combsimp(1/e) == -1/k
e = (gamma(x) + gamma(x + 1))/gamma(x)
assert combsimp(e) == x + 1
assert combsimp(1/e) == 1/(x + 1)
e = (gamma(x) + gamma(x + 2))*(gamma(x - 1) + gamma(x))/gamma(x)
assert combsimp(e) == (x**2 + x + 1)*gamma(x + 1)/(x - 1)
e = (-gamma(k)*gamma(k + 2) + gamma(k + 1)**2)/gamma(k)**2
assert combsimp(e**2) == k**2
assert combsimp(e**2/gamma(k + 1)) == k/gamma(k)
a = R(1, 2) + R(1, 3)
b = a + R(1, 3)
assert combsimp(gamma(2*k)/gamma(k)*gamma(k + a)*gamma(k + b))
3*2**(2*k + 1)*3**(-3*k - 2)*sqrt(pi)*gamma(3*k + R(3, 2))/2
A, B = symbols('A B', commutative=False)
assert combsimp(e*B*A) == combsimp(e)*B*A
# check iteration
assert combsimp(gamma(2*k)/gamma(k)*gamma(-k - R(1, 2))) == (
-2**(2*k + 1)*sqrt(pi)/(2*((2*k + 1)*cos(pi*k))))
assert combsimp(
gamma(k)*gamma(k + R(1, 3))*gamma(k + R(2, 3))/gamma(3*k/2)) == (
3*2**(3*k + 1)*3**(-3*k - Rational(1, 2))*sqrt(pi)*gamma(3*k/2 + Rational(1, 2))/2)
def test_roots_binomial():
assert roots_binomial(Poly(5*x, x)) == [0]
assert roots_binomial(Poly(5*x**4, x)) == [0, 0, 0, 0]
assert roots_binomial(Poly(5*x + 2, x)) == [-Rational(2, 5)]
A = 10**Rational(3, 4)/10
assert roots_binomial(Poly(5*x**4 + 2, x)) == \
[-A - A*I, -A + A*I, A - A*I, A + A*I]
a1 = Symbol('a1', nonnegative=True)
b1 = Symbol('b1', nonnegative=True)
r0 = roots_quadratic(Poly(a1*x**2 + b1, x))
r1 = roots_binomial(Poly(a1*x**2 + b1, x))
assert powsimp(r0[0]) == powsimp(r1[0])
assert powsimp(r0[1]) == powsimp(r1[1])
for a, b, s, n in itertools.product((1, 2), (1, 2), (-1, 1), (2, 3, 4, 5)):
if a == b and a != 1: # a == b == 1 is sufficient
continue
p = Poly(a*x**n + s*b)
ans = roots_binomial(p)
assert ans == _nsort(ans)
# issue sympy/sympy#8813
assert roots(Poly(2*x**3 - 16*y**3, x)) == {
2*y*(-Rational(1, 2) - sqrt(3)*I/2): 1,
2*y: 1,
2*y*(-Rational(1, 2) + sqrt(3)*I/2): 1}
def test_sympyissue_6367():
z = -5*sqrt(2)/(2*sqrt(2*sqrt(29) + 29)) + sqrt(-sqrt(29)/29 + Rational(1, 2))
assert Mul(*[powsimp(a) for a in Mul.make_args(z.normal())]) == 0
assert powsimp(z.normal()) == 0
assert simplify(z) == 0
assert powsimp(sqrt(2 + sqrt(3))*sqrt(2 - sqrt(3)) + 1) == 2
assert powsimp(z) != 0
def test_powsimp_negated_base():
assert powsimp((-x + y)/sqrt(x - y)) == -sqrt(x - y)
assert powsimp((-x + y)*(-z + y)/sqrt(x - y)/sqrt(z - y)) == sqrt(x - y)*sqrt(z - y)
p = symbols('p', positive=True)
assert powsimp((-p)**a/p**a) == (-1)**a
n = symbols('n', negative=True)
assert powsimp((-n)**a/n**a) == (-1)**a
# if x is 0 then the lhs is 0**a*oo**a which is not (-1)**a
assert powsimp((-x)**a/x**a) != (-1)**a
def test_powsimp_negated_base():
assert powsimp((-x + y) / sqrt(x - y)) == -sqrt(x - y)
assert powsimp((-x + y) * (-z + y) / sqrt(x - y) /
sqrt(z - y)) == sqrt(x - y) * sqrt(z - y)
p = symbols('p', positive=True)
assert powsimp((-p)**a / p**a) == (-1)**a
n = symbols('n', negative=True)
assert powsimp((-n)**a / n**a) == (-1)**a
# if x is 0 then the lhs is 0**a*oo**a which is not (-1)**a
assert powsimp((-x)**a / x**a) != (-1)**a
def test_TR2i():
# just a reminder that ratios of powers only simplify if both
# numerator and denominator satisfy the condition that each
# has a positive base or an integer exponent; e.g. the following,
# at y=-1, x=1/2 gives sqrt(2)*I != -sqrt(2)*I
assert powsimp(2**x/y**x) != (2/y)**x
assert TR2i(sin(x)/cos(x)) == tan(x)
assert TR2i(sin(x)*sin(y)/cos(x)) == tan(x)*sin(y)
assert TR2i(1/(sin(x)/cos(x))) == 1/tan(x)
assert TR2i(1/(sin(x)*sin(y)/cos(x))) == 1/tan(x)/sin(y)
assert TR2i(sin(x)/2/(cos(x) + 1)) == sin(x)/(cos(x) + 1)/2
assert TR2i(sin(x)/2/(cos(x) + 1), half=True) == tan(x/2)/2
assert TR2i(sin(1)/(cos(1) + 1), half=True) == tan(S.Half)
assert TR2i(sin(2)/(cos(2) + 1), half=True) == tan(1)
assert TR2i(sin(4)/(cos(4) + 1), half=True) == tan(2)
assert TR2i(sin(5)/(cos(5) + 1), half=True) == tan(5*S.Half)
assert TR2i((cos(1) + 1)/sin(1), half=True) == 1/tan(S.Half)
assert TR2i((cos(2) + 1)/sin(2), half=True) == 1/tan(1)
assert TR2i((cos(4) + 1)/sin(4), half=True) == 1/tan(2)
assert TR2i((cos(5) + 1)/sin(5), half=True) == 1/tan(5*S.Half)
assert TR2i((cos(1) + 1)**(-a)*sin(1)**a, half=True) == tan(S.Half)**a
assert TR2i((cos(2) + 1)**(-a)*sin(2)**a, half=True) == tan(1)**a
assert TR2i((cos(4) + 1)**(-a)*sin(4)**a, half=True) == (cos(4) + 1)**(-a)*sin(4)**a
assert TR2i((cos(5) + 1)**(-a)*sin(5)**a, half=True) == (cos(5) + 1)**(-a)*sin(5)**a
assert TR2i((cos(1) + 1)**a*sin(1)**(-a), half=True) == tan(S.Half)**(-a)
assert TR2i((cos(2) + 1)**a*sin(2)**(-a), half=True) == tan(1)**(-a)
assert TR2i((cos(4) + 1)**a*sin(4)**(-a), half=True) == (cos(4) + 1)**a*sin(4)**(-a)
assert TR2i((cos(5) + 1)**a*sin(5)**(-a), half=True) == (cos(5) + 1)**a*sin(5)**(-a)
i = symbols('i', integer=True)
assert TR2i(((cos(5) + 1)**i*sin(5)**(-i)), half=True) == tan(5*S.Half)**(-i)
assert TR2i(1/((cos(5) + 1)**i*sin(5)**(-i)), half=True) == tan(5*S.Half)**i
def test_TR2i():
# just a reminder that ratios of powers only simplify if both
# numerator and denominator satisfy the condition that each
# has a positive base or an integer exponent; e.g. the following,
# at y=-1, x=1/2 gives sqrt(2)*I != -sqrt(2)*I
assert powsimp(2**x/y**x) != (2/y)**x
assert TR2i(sin(x)/cos(x)) == tan(x)
assert TR2i(sin(x)*sin(y)/cos(x)) == tan(x)*sin(y)
assert TR2i(1/(sin(x)/cos(x))) == 1/tan(x)
assert TR2i(1/(sin(x)*sin(y)/cos(x))) == 1/tan(x)/sin(y)
assert TR2i(sin(x)/2/(cos(x) + 1)) == sin(x)/(cos(x) + 1)/2
assert TR2i(sin(x)/2/(cos(x) + 1), half=True) == tan(x/2)/2
assert TR2i(sin(1)/(cos(1) + 1), half=True) == tan(Rational(1, 2))
assert TR2i(sin(2)/(cos(2) + 1), half=True) == tan(1)
assert TR2i(sin(4)/(cos(4) + 1), half=True) == tan(2)
assert TR2i(sin(5)/(cos(5) + 1), half=True) == tan(Rational(5, 2))
assert TR2i((cos(1) + 1)/sin(1), half=True) == 1/tan(Rational(1, 2))
assert TR2i((cos(2) + 1)/sin(2), half=True) == 1/tan(1)
assert TR2i((cos(4) + 1)/sin(4), half=True) == 1/tan(2)
assert TR2i((cos(5) + 1)/sin(5), half=True) == 1/tan(Rational(5, 2))
assert TR2i((cos(1) + 1)**(-a)*sin(1)**a, half=True) == tan(Rational(1, 2))**a
assert TR2i((cos(2) + 1)**(-a)*sin(2)**a, half=True) == tan(1)**a
assert TR2i((cos(4) + 1)**(-a)*sin(4)**a, half=True) == (cos(4) + 1)**(-a)*sin(4)**a
assert TR2i((cos(5) + 1)**(-a)*sin(5)**a, half=True) == (cos(5) + 1)**(-a)*sin(5)**a
assert TR2i((cos(1) + 1)**a*sin(1)**(-a), half=True) == tan(Rational(1, 2))**(-a)
assert TR2i((cos(2) + 1)**a*sin(2)**(-a), half=True) == tan(1)**(-a)
assert TR2i((cos(4) + 1)**a*sin(4)**(-a), half=True) == (cos(4) + 1)**a*sin(4)**(-a)
assert TR2i((cos(5) + 1)**a*sin(5)**(-a), half=True) == (cos(5) + 1)**a*sin(5)**(-a)
i = symbols('i', integer=True)
assert TR2i(((cos(5) + 1)**i*sin(5)**(-i)), half=True) == tan(Rational(5, 2))**(-i)
assert TR2i(1/((cos(5) + 1)**i*sin(5)**(-i)), half=True) == tan(Rational(5, 2))**i
def test_sympyissue_9324():
def count(val):
return count_ops(val, visual=False)
M = MatrixSymbol('M', 10, 10)
assert count(M[0, 0]) == 0
assert count(2 * M[0, 0] + M[5, 7]) == 2
P = MatrixSymbol('P', 3, 3)
Q = MatrixSymbol('Q', 3, 3)
assert count(P + Q) == 9
expr = powsimp(M, deep=True)
assert expr == M
assert expr.name == 'M'
m = Symbol('m', integer=True)
n = Symbol('n', integer=True)
M = MatrixSymbol('M', m + n, m * m)
assert count(M[0, 1]) == 0
def test_powsimp_polar():
p, q = symbols('p q', polar=True)
assert (polar_lift(-1))**(2 * x) == exp_polar(2 * pi * I * x)
assert powsimp(p**x * q**x) == (p * q)**x
assert p**x * (1 / p)**x == 1
assert (1 / p)**x == p**(-x)
assert exp_polar(x) * exp_polar(y) == exp_polar(x) * exp_polar(y)
assert powsimp(exp_polar(x) * exp_polar(y)) == exp_polar(x + y)
assert powsimp(exp_polar(x)*exp_polar(y)*p**x*p**y) == \
(p*exp_polar(1))**(x + y)
assert powsimp(exp_polar(x)*exp_polar(y)*p**x*p**y, combine='exp') == \
exp_polar(x + y)*p**(x + y)
assert powsimp(
exp_polar(x)*exp_polar(y)*exp_polar(2)*sin(x) + sin(y) + p**x*p**y) \
== p**(x + y) + sin(x)*exp_polar(2 + x + y) + sin(y)
assert powsimp(sin(exp_polar(x)*exp_polar(y))) == \
sin(exp_polar(x)*exp_polar(y))
assert powsimp(sin(exp_polar(x)*exp_polar(y)), deep=True) == \
sin(exp_polar(x + y))
def test_powsimp_polar():
p, q, r = symbols('p q r', polar=True)
assert (polar_lift(-1))**(2*x) == exp_polar(2*pi*I*x)
assert powsimp(p**x * q**x) == (p*q)**x
assert p**x * (1/p)**x == 1
assert (1/p)**x == p**(-x)
assert exp_polar(x)*exp_polar(y) == exp_polar(x)*exp_polar(y)
assert powsimp(exp_polar(x)*exp_polar(y)) == exp_polar(x + y)
assert powsimp(exp_polar(x)*exp_polar(y)*p**x*p**y) == \
(p*exp_polar(1))**(x + y)
assert powsimp(exp_polar(x)*exp_polar(y)*p**x*p**y, combine='exp') == \
exp_polar(x + y)*p**(x + y)
assert powsimp(
exp_polar(x)*exp_polar(y)*exp_polar(2)*sin(x) + sin(y) + p**x*p**y) \
== p**(x + y) + sin(x)*exp_polar(2 + x + y) + sin(y)
assert powsimp(sin(exp_polar(x)*exp_polar(y))) == \
sin(exp_polar(x)*exp_polar(y))
assert powsimp(sin(exp_polar(x)*exp_polar(y)), deep=True) == \
sin(exp_polar(x + y))
def test_issue_5728():
b = x * sqrt(y)
a = sqrt(b)
c = sqrt(sqrt(x) * y)
assert powsimp(a * b) == sqrt(b)**3
assert powsimp(a * b**2 * sqrt(y)) == sqrt(y) * a**5
assert powsimp(a * x**2 * c**3 * y) == c**3 * a**5
assert powsimp(a * x * c**3 * y**2) == c**7 * a
assert powsimp(x * c**3 * y**2) == c**7
assert powsimp(x * c**3 * y) == x * y * c**3
assert powsimp(sqrt(x) * c**3 * y) == c**5
assert powsimp(sqrt(x) * a**3 * sqrt(y)) == sqrt(x) * sqrt(y) * a**3
assert powsimp(Mul(sqrt(x)*c**3*sqrt(y), y, evaluate=False)) == \
sqrt(x)*sqrt(y)**3*c**3
assert powsimp(a**2 * a * x**2 * y) == a**7
# symbolic powers work, too
b = x**y * y
a = b * sqrt(b)
assert a.is_Mul is True
assert powsimp(a) == sqrt(b)**3
# as does exp
a = x * exp(2 * y / 3)
assert powsimp(a * sqrt(a)) == sqrt(a)**3
assert powsimp(a**2 * sqrt(a)) == sqrt(a)**5
assert powsimp(a**2 * sqrt(sqrt(a))) == sqrt(sqrt(a))**9
def test_issue_9324_powsimp_on_matrix_symbol():
M = MatrixSymbol('M', 10, 10)
expr = powsimp(M, deep=True)
assert expr == M
assert expr.args[0] == 'M'
def test_issue_6440():
assert powsimp(16 * 2**a * 8**b) == 2**(a + 3 * b + 4)
def test_sympyissue_9324_powsimp_on_matrix_symbol():
M = MatrixSymbol('M', 10, 10)
expr = powsimp(M, deep=True)
assert expr == M
assert expr.name == 'M'
def mysimp(expr):
return expand(powsimp(logcombine(expr, force=True),
force=True,
deep=True),
force=True).replace(exp_polar, exp)
def test_combsimp_gamma():
R = Rational
assert combsimp(gamma(x)) == gamma(x)
assert combsimp(gamma(x + 1) / x) == gamma(x)
assert combsimp(gamma(x) / (x - 1)) == gamma(x - 1)
assert combsimp(x * gamma(x)) == gamma(x + 1)
assert combsimp((x + 1) * gamma(x + 1)) == gamma(x + 2)
assert combsimp(gamma(x + y) * (x + y)) == gamma(x + y + 1)
assert combsimp(x / gamma(x + 1)) == 1 / gamma(x)
assert combsimp((x + 1)**2 / gamma(x + 2)) == (x + 1) / gamma(x + 1)
assert combsimp(x*gamma(x) + gamma(x + 3)/(x + 2)) == \
(x + 2)*gamma(x + 1)
assert combsimp(gamma(2 * x) * x) == gamma(2 * x + 1) / 2
assert combsimp(gamma(2 * x) /
(x - Rational(1, 2))) == 2 * gamma(2 * x - 1)
assert combsimp(gamma(x) * gamma(1 - x)) == pi / sin(pi * x)
assert combsimp(gamma(x) * gamma(-x)) == -pi / (x * sin(pi * x))
assert combsimp(1/gamma(x + 3)/gamma(1 - x)) == \
sin(pi*x)/(pi*x*(x + 1)*(x + 2))
assert powsimp(combsimp(
gamma(x)*gamma(x + Rational(1, 2))*gamma(y)/gamma(x + y))) == \
2**(-2*x + 1)*sqrt(pi)*gamma(2*x)*gamma(y)/gamma(x + y)
assert combsimp(1/gamma(x)/gamma(x - Rational(1, 3))/gamma(x + Rational(1, 3))) == \
3**(3*x - Rational(3, 2))/(2*pi*gamma(3*x - 1))
assert simplify(
gamma(Rational(1, 2) + x / 2) * gamma(1 + x / 2) / gamma(1 + x) /
sqrt(pi) * 2**x) == 1
assert combsimp(gamma(Rational(-1, 4)) *
gamma(Rational(-3, 4))) == 16 * sqrt(2) * pi / 3
assert powsimp(combsimp(gamma(2*x)/gamma(x))) == \
2**(2*x - 1)*gamma(x + Rational(1, 2))/sqrt(pi)
# issue sympy/sympy#6792
e = (-gamma(k) * gamma(k + 2) + gamma(k + 1)**2) / gamma(k)**2
assert combsimp(e) == -k
assert combsimp(1 / e) == -1 / k
e = (gamma(x) + gamma(x + 1)) / gamma(x)
assert combsimp(e) == x + 1
assert combsimp(1 / e) == 1 / (x + 1)
e = (gamma(x) + gamma(x + 2)) * (gamma(x - 1) + gamma(x)) / gamma(x)
assert combsimp(e) == (x**2 + x + 1) * gamma(x + 1) / (x - 1)
e = (-gamma(k) * gamma(k + 2) + gamma(k + 1)**2) / gamma(k)**2
assert combsimp(e**2) == k**2
assert combsimp(e**2 / gamma(k + 1)) == k / gamma(k)
a = R(1, 2) + R(1, 3)
b = a + R(1, 3)
assert combsimp(gamma(2 * k) / gamma(k) * gamma(k + a) * gamma(k + b))
3 * 2**(2 * k + 1) * 3**(-3 * k - 2) * sqrt(pi) * gamma(3 * k +
R(3, 2)) / 2
A, B = symbols('A B', commutative=False)
assert combsimp(e * B * A) == combsimp(e) * B * A
# check iteration
assert combsimp(gamma(2 * k) / gamma(k) *
gamma(-k - R(1, 2))) == (-2**(2 * k + 1) * sqrt(pi) /
(2 * ((2 * k + 1) * cos(pi * k))))
assert combsimp(
gamma(k) * gamma(k + R(1, 3)) * gamma(k + R(2, 3)) /
gamma(3 * k / 2)) == (3 * 2**(3 * k + 1) * 3**(-3 * k - S.Half) *
sqrt(pi) * gamma(3 * k / 2 + S.Half) / 2)
def diop_simplify(eq):
return _mexpand(powsimp(_mexpand(eq)))
def mysimp(expr):
return expand(
powsimp(logcombine(expr, force=True), force=True, deep=True),
force=True).replace(exp_polar, exp)
def mysimp(expr):
from diofant import expand, logcombine, powsimp
return expand(powsimp(logcombine(expr, force=True),
force=True,
deep=True),
force=True).replace(exp_polar, exp)
def test_diofantissue_124():
n = Symbol('n', odd=True)
assert powsimp((-1)**(n/2)) in ((-1)**(n/2), I**n)
assert powsimp((-1)**(n/2 - Rational(1, 2)) -
(-1)**(3*n/2 - Rational(1, 2))) != 2 # sympy/sympy#10195
def test_powsimp():
x, y, z, n = symbols('x,y,z,n')
f = Function('f')
assert powsimp( 4**x * 2**(-x) * 2**(-x) ) == 1
assert powsimp( (-4)**x * (-2)**(-x) * 2**(-x) ) == 1
assert powsimp(
f(4**x * 2**(-x) * 2**(-x)) ) == f(4**x * 2**(-x) * 2**(-x))
assert powsimp( f(4**x * 2**(-x) * 2**(-x)), deep=True ) == f(1)
assert exp(x)*exp(y) == exp(x)*exp(y)
assert powsimp(exp(x)*exp(y)) == exp(x + y)
assert powsimp(exp(x)*exp(y)*2**x*2**y) == (2*E)**(x + y)
assert powsimp(exp(x)*exp(y)*2**x*2**y, combine='exp') == \
exp(x + y)*2**(x + y)
assert powsimp(exp(x)*exp(y)*exp(2)*sin(x) + sin(y) + 2**x*2**y) == \
exp(2 + x + y)*sin(x) + sin(y) + 2**(x + y)
assert powsimp(sin(exp(x)*exp(y))) == sin(exp(x)*exp(y))
assert powsimp(sin(exp(x)*exp(y)), deep=True) == sin(exp(x + y))
assert powsimp(x**2*x**y) == x**(2 + y)
# This should remain factored, because 'exp' with deep=True is supposed
# to act like old automatic exponent combining.
assert powsimp((1 + E*exp(E))*exp(-E), combine='exp', deep=True) == \
(1 + exp(1 + E))*exp(-E)
assert powsimp((1 + E*exp(E))*exp(-E), deep=True) == \
(1 + exp(1 + E))*exp(-E)
assert powsimp((1 + E*exp(E))*exp(-E)) == (1 + exp(1 + E))*exp(-E)
assert powsimp((1 + E*exp(E))*exp(-E), combine='exp') == \
(1 + exp(1 + E))*exp(-E)
assert powsimp((1 + E*exp(E))*exp(-E), combine='base') == \
(1 + E*exp(E))*exp(-E)
x, y = symbols('x,y', nonnegative=True)
n = Symbol('n', extended_real=True)
assert powsimp(y**n * (y/x)**(-n)) == x**n
assert powsimp(x**(x**(x*y)*y**(x*y))*y**(x**(x*y)*y**(x*y)), deep=True) \
== (x*y)**(x*y)**(x*y)
assert powsimp(2**(2**(2*x)*x), deep=False) == 2**(2**(2*x)*x)
assert powsimp(2**(2**(2*x)*x), deep=True) == 2**(x*4**x)
assert powsimp(
exp(-x + exp(-x)*exp(-x*log(x))), deep=False, combine='exp') == \
exp(-x + exp(-x)*exp(-x*log(x)))
assert powsimp(
exp(-x + exp(-x)*exp(-x*log(x))), deep=False, combine='exp') == \
exp(-x + exp(-x)*exp(-x*log(x)))
assert powsimp((x + y)/(3*z), deep=False, combine='exp') == (x + y)/(3*z)
assert powsimp((x/3 + y/3)/z, deep=True, combine='exp') == (x/3 + y/3)/z
assert powsimp(exp(x)/(1 + exp(x)*exp(y)), deep=True) == \
exp(x)/(1 + exp(x + y))
assert powsimp(x*y**(z**x*z**y), deep=True) == x*y**(z**(x + y))
assert powsimp((z**x*z**y)**x, deep=True) == (z**(x + y))**x
assert powsimp(x*(z**x*z**y)**x, deep=True) == x*(z**(x + y))**x
p = symbols('p', positive=True)
assert powsimp((1/x)**log(2)/x) == (1/x)**(1 + log(2))
assert powsimp((1/p)**log(2)/p) == p**(-1 - log(2))
# coefficient of exponent can only be simplified for positive bases
assert powsimp(2**(2*x)) == 4**x
assert powsimp((-1)**(2*x)) == (-1)**(2*x)
i = symbols('i', integer=True)
assert powsimp((-1)**(2*i)) == 1
assert powsimp((-1)**(-x)) != (-1)**x # could be 1/((-1)**x), but is not
# force=True overrides assumptions
assert powsimp((-1)**(2*x), force=True) == 1
# rational exponents allow combining of negative terms
w, n, m = symbols('w n m', negative=True)
e = i/a # not a rational exponent if `a` is unknown
ex = w**e*n**e*m**e
assert powsimp(ex) == m**(i/a)*n**(i/a)*w**(i/a)
e = i/3
ex = w**e*n**e*m**e
assert powsimp(ex) == (-1)**i*(-m*n*w)**(i/3)
e = (3 + i)/i
ex = w**e*n**e*m**e
assert powsimp(ex) == (-1)**(3*e)*(-m*n*w)**e
eq = x**(2*a/3)
# eq != (x**a)**(2/3) (try x = -1 and a = 3 to see)
assert powsimp(eq).exp == eq.exp == 2*a/3
# powdenest goes the other direction
assert powsimp(2**(2*x)) == 4**x
assert powsimp(exp(p/2)) == exp(p/2)
# issue sympy/sympy#6368
eq = Mul(*[sqrt(Dummy(imaginary=True)) for i in range(3)])
assert powsimp(eq) == eq and eq.is_Mul
assert all(powsimp(e) == e for e in (sqrt(x**a), sqrt(x**2)))
# issue sympy/sympy#8836
assert str( powsimp(exp(I*pi/3)*root(-1, 3)) ) == '(-1)**(2/3)'
def test_sympyissue_5728():
b = x*sqrt(y)
a = sqrt(b)
c = sqrt(sqrt(x)*y)
assert powsimp(a*b) == sqrt(b)**3
assert powsimp(a*b**2*sqrt(y)) == sqrt(y)*a**5
assert powsimp(a*x**2*c**3*y) == c**3*a**5
assert powsimp(a*x*c**3*y**2) == c**7*a
assert powsimp(x*c**3*y**2) == c**7
assert powsimp(x*c**3*y) == x*y*c**3
assert powsimp(sqrt(x)*c**3*y) == c**5
assert powsimp(sqrt(x)*a**3*sqrt(y)) == sqrt(x)*sqrt(y)*a**3
assert powsimp(Mul(sqrt(x)*c**3*sqrt(y), y, evaluate=False)) == \
sqrt(x)*sqrt(y)**3*c**3
assert powsimp(a**2*a*x**2*y) == a**7
# symbolic powers work, too
b = x**y*y
a = b*sqrt(b)
assert a.is_Mul is True
assert powsimp(a) == sqrt(b)**3
# as does exp
a = x*exp(2*y/3)
assert powsimp(a*sqrt(a)) == sqrt(a)**3
assert powsimp(a**2*sqrt(a)) == sqrt(a)**5
assert powsimp(a**2*sqrt(sqrt(a))) == sqrt(sqrt(a))**9
def test_powsimp_nc():
A, B, C = symbols('A B C', commutative=False)
assert powsimp(A**x*A**y, combine='all') == A**(x + y)
assert powsimp(A**x*A**y, combine='base') == A**x*A**y
assert powsimp(A**x*A**y, combine='exp') == A**(x + y)
assert powsimp(A**x*B**x, combine='all') == (A*B)**x
assert powsimp(A**x*B**x, combine='base') == (A*B)**x
assert powsimp(A**x*B**x, combine='exp') == A**x*B**x
assert powsimp(B**x*A**x, combine='all') == (B*A)**x
assert powsimp(B**x*A**x, combine='base') == (B*A)**x
assert powsimp(B**x*A**x, combine='exp') == B**x*A**x
assert powsimp(A**x*A**y*A**z, combine='all') == A**(x + y + z)
assert powsimp(A**x*A**y*A**z, combine='base') == A**x*A**y*A**z
assert powsimp(A**x*A**y*A**z, combine='exp') == A**(x + y + z)
assert powsimp(A**x*B**x*C**x, combine='all') == (A*B*C)**x
assert powsimp(A**x*B**x*C**x, combine='base') == (A*B*C)**x
assert powsimp(A**x*B**x*C**x, combine='exp') == A**x*B**x*C**x
assert powsimp(B**x*A**x*C**x, combine='all') == (B*A*C)**x
assert powsimp(B**x*A**x*C**x, combine='base') == (B*A*C)**x
assert powsimp(B**x*A**x*C**x, combine='exp') == B**x*A**x*C**x
def test_diofantissue_124():
n = Symbol('n', odd=True)
assert powsimp((-1)**(n / 2)) in ((-1)**(n / 2), I**n)
assert powsimp((-1)**(n / 2 - Rational(1, 2)) - (-1)**
(3 * n / 2 - Rational(1, 2))) != 2 # sympy/sympy#10195
def test_issue_143():
n = Symbol('n', odd=True)
assert powsimp((-1)**(n / 2)) == (-1)**(n / 2)
assert powsimp((-1)**(n / 2 - Rational(1, 2)) - (-1)**
(3 * n / 2 - Rational(1, 2))) != 2 # sympy/sympy#10195
def test_powsimp():
x, y, z, n = symbols('x,y,z,n')
f = Function('f')
assert powsimp(4**x * 2**(-x) * 2**(-x)) == 1
assert powsimp((-4)**x * (-2)**(-x) * 2**(-x)) == 1
assert powsimp(f(4**x * 2**(-x) * 2**(-x))) == f(4**x * 2**(-x) * 2**(-x))
assert powsimp(f(4**x * 2**(-x) * 2**(-x)), deep=True) == f(1)
assert exp(x) * exp(y) == exp(x) * exp(y)
assert powsimp(exp(x) * exp(y)) == exp(x + y)
assert powsimp(exp(x) * exp(y) * 2**x * 2**y) == (2 * E)**(x + y)
assert powsimp(exp(x)*exp(y)*2**x*2**y, combine='exp') == \
exp(x + y)*2**(x + y)
assert powsimp(exp(x)*exp(y)*exp(2)*sin(x) + sin(y) + 2**x*2**y) == \
exp(2 + x + y)*sin(x) + sin(y) + 2**(x + y)
assert powsimp(sin(exp(x) * exp(y))) == sin(exp(x) * exp(y))
assert powsimp(sin(exp(x) * exp(y)), deep=True) == sin(exp(x + y))
assert powsimp(x**2 * x**y) == x**(2 + y)
# This should remain factored, because 'exp' with deep=True is supposed
# to act like old automatic exponent combining.
assert powsimp((1 + E*exp(E))*exp(-E), combine='exp', deep=True) == \
(1 + exp(1 + E))*exp(-E)
assert powsimp((1 + E*exp(E))*exp(-E), deep=True) == \
(1 + exp(1 + E))*exp(-E)
assert powsimp((1 + E * exp(E)) * exp(-E)) == (1 + exp(1 + E)) * exp(-E)
assert powsimp((1 + E*exp(E))*exp(-E), combine='exp') == \
(1 + exp(1 + E))*exp(-E)
assert powsimp((1 + E*exp(E))*exp(-E), combine='base') == \
(1 + E*exp(E))*exp(-E)
x, y = symbols('x,y', nonnegative=True)
n = Symbol('n', extended_real=True)
assert powsimp(y**n * (y / x)**(-n)) == x**n
assert powsimp(x**(x**(x*y)*y**(x*y))*y**(x**(x*y)*y**(x*y)), deep=True) \
== (x*y)**(x*y)**(x*y)
assert powsimp(2**(2**(2 * x) * x), deep=False) == 2**(2**(2 * x) * x)
assert powsimp(2**(2**(2 * x) * x), deep=True) == 2**(x * 4**x)
assert powsimp(
exp(-x + exp(-x)*exp(-x*log(x))), deep=False, combine='exp') == \
exp(-x + exp(-x)*exp(-x*log(x)))
assert powsimp(
exp(-x + exp(-x)*exp(-x*log(x))), deep=False, combine='exp') == \
exp(-x + exp(-x)*exp(-x*log(x)))
assert powsimp((x + y) / (3 * z), deep=False,
combine='exp') == (x + y) / (3 * z)
assert powsimp((x / 3 + y / 3) / z, deep=True,
combine='exp') == (x / 3 + y / 3) / z
assert powsimp(exp(x)/(1 + exp(x)*exp(y)), deep=True) == \
exp(x)/(1 + exp(x + y))
assert powsimp(x * y**(z**x * z**y), deep=True) == x * y**(z**(x + y))
assert powsimp((z**x * z**y)**x, deep=True) == (z**(x + y))**x
assert powsimp(x * (z**x * z**y)**x, deep=True) == x * (z**(x + y))**x
p = symbols('p', positive=True)
assert powsimp((1 / x)**log(2) / x) == (1 / x)**(1 + log(2))
assert powsimp((1 / p)**log(2) / p) == p**(-1 - log(2))
# coefficient of exponent can only be simplified for positive bases
assert powsimp(2**(2 * x)) == 4**x
assert powsimp((-1)**(2 * x)) == (-1)**(2 * x)
i = symbols('i', integer=True)
assert powsimp((-1)**(2 * i)) == 1
assert powsimp((-1)**(-x)) != (-1)**x # could be 1/((-1)**x), but is not
# force=True overrides assumptions
assert powsimp((-1)**(2 * x), force=True) == 1
# rational exponents allow combining of negative terms
w, n, m = symbols('w n m', negative=True)
e = i / a # not a rational exponent if `a` is unknown
ex = w**e * n**e * m**e
assert powsimp(ex) == m**(i / a) * n**(i / a) * w**(i / a)
e = i / 3
ex = w**e * n**e * m**e
assert powsimp(ex) == (-1)**i * (-m * n * w)**(i / 3)
e = (3 + i) / i
ex = w**e * n**e * m**e
assert powsimp(ex) == (-1)**(3 * e) * (-m * n * w)**e
eq = x**(2 * a / 3)
# eq != (x**a)**(2/3) (try x = -1 and a = 3 to see)
assert powsimp(eq).exp == eq.exp == 2 * a / 3
# powdenest goes the other direction
assert powsimp(2**(2 * x)) == 4**x
assert powsimp(exp(p / 2)) == exp(p / 2)
# issue 6368
eq = Mul(*[sqrt(Dummy(imaginary=True)) for i in range(3)])
assert powsimp(eq) == eq and eq.is_Mul
assert all(powsimp(e) == e for e in (sqrt(x**a), sqrt(x**2)))
# issue 8836
assert str(powsimp(exp(I * pi / 3) * root(-1, 3))) == '(-1)**(2/3)'
def test_sympyissue_11981():
x, y = symbols('x y', commutative=False)
assert powsimp((x * y)**2 * (y * x)**2) == (x * y)**2 * (y * x)**2
def contains(self, expr):
"""Membership test.
Returns
=======
Boolean or None
Return True if ``expr`` belongs to ``self``. Return False if
``self`` belongs to ``expr``. Return None if the inclusion
relation cannot be determined.
"""
from diofant import powsimp
from diofant.series.limits import Limit
if expr is S.Zero:
return True
if expr is S.NaN:
return False
if expr.is_Order:
if (not all(p == expr.point[0] for p in expr.point) and
not all(p == self.point[0] for p in self.point)): # pragma: no cover
raise NotImplementedError('Order at points other than 0 '
'or oo not supported, got %s as a point.' % point)
else:
# self and/or expr is O(1):
if any(not p for p in [expr.point, self.point]):
point = self.point + expr.point
if point:
point = point[0]
else:
point = S.Zero
else:
point = self.point[0]
if expr.expr == self.expr:
# O(1) + O(1), O(1) + O(1, x), etc.
return all([x in self.args[1:] for x in expr.args[1:]])
if expr.expr.is_Add:
return all([self.contains(x) for x in expr.expr.args])
if self.expr.is_Add and point == S.Zero:
return any([self.func(x, *self.args[1:]).contains(expr)
for x in self.expr.args])
if self.variables and expr.variables:
common_symbols = tuple(
[s for s in self.variables if s in expr.variables])
elif self.variables:
common_symbols = self.variables
else:
common_symbols = expr.variables
if not common_symbols:
return
r = None
ratio = self.expr/expr.expr
ratio = powsimp(ratio, deep=True, combine='exp')
for s in common_symbols:
l = Limit(ratio, s, point).doit(heuristics=False)
if not isinstance(l, Limit):
l = l != 0
else:
l = None
if r is None:
r = l
else:
if r != l:
return
return r
obj = self.func(expr, *self.args[1:])
return self.contains(obj)
def test_probability():
# various integrals from probability theory
mu1, mu2 = symbols('mu1 mu2', real=True, nonzero=True)
sigma1, sigma2 = symbols('sigma1 sigma2', real=True,
nonzero=True, positive=True)
rate = Symbol('lambda', real=True, positive=True)
def normal(x, mu, sigma):
return 1/sqrt(2*pi*sigma**2)*exp(-(x - mu)**2/2/sigma**2)
def exponential(x, rate):
return rate*exp(-rate*x)
assert integrate(normal(x, mu1, sigma1), (x, -oo, oo), meijerg=True) == 1
assert integrate(x*normal(x, mu1, sigma1), (x, -oo, oo), meijerg=True) == \
mu1
assert integrate(x**2*normal(x, mu1, sigma1), (x, -oo, oo), meijerg=True) \
== mu1**2 + sigma1**2
assert integrate(x**3*normal(x, mu1, sigma1), (x, -oo, oo), meijerg=True) \
== mu1**3 + 3*mu1*sigma1**2
assert integrate(normal(x, mu1, sigma1)*normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo), meijerg=True) == 1
assert integrate(x*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo), meijerg=True) == mu1
assert integrate(y*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo), meijerg=True) == mu2
assert integrate(x*y*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo), meijerg=True) == mu1*mu2
assert integrate((x + y + 1)*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo), meijerg=True) == 1 + mu1 + mu2
assert integrate((x + y - 1)*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo), meijerg=True) == \
-1 + mu1 + mu2
i = integrate(x**2*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo), meijerg=True)
assert not i.has(Abs)
assert simplify(i) == mu1**2 + sigma1**2
assert integrate(y**2*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo), meijerg=True) == \
sigma2**2 + mu2**2
assert integrate(exponential(x, rate), (x, 0, oo), meijerg=True) == 1
assert integrate(x*exponential(x, rate), (x, 0, oo), meijerg=True) == \
1/rate
assert integrate(x**2*exponential(x, rate), (x, 0, oo), meijerg=True) == \
2/rate**2
def E(expr):
res1 = integrate(expr*exponential(x, rate)*normal(y, mu1, sigma1),
(x, 0, oo), (y, -oo, oo), meijerg=True)
res2 = integrate(expr*exponential(x, rate)*normal(y, mu1, sigma1),
(y, -oo, oo), (x, 0, oo), meijerg=True)
assert expand_mul(res1) == expand_mul(res2)
return res1
assert E(1) == 1
assert E(x*y) == mu1/rate
assert E(x*y**2) == mu1**2/rate + sigma1**2/rate
ans = sigma1**2 + 1/rate**2
assert simplify(E((x + y + 1)**2) - E(x + y + 1)**2) == ans
assert simplify(E((x + y - 1)**2) - E(x + y - 1)**2) == ans
assert simplify(E((x + y)**2) - E(x + y)**2) == ans
# Beta' distribution
alpha, beta = symbols('alpha beta', positive=True)
betadist = x**(alpha - 1)*(1 + x)**(-alpha - beta)*gamma(alpha + beta) \
/ gamma(alpha)/gamma(beta)
assert integrate(betadist, (x, 0, oo), meijerg=True) == 1
i = integrate(x*betadist, (x, 0, oo), meijerg=True, conds='separate')
assert (combsimp(i[0]), i[1]) == (alpha/(beta - 1), 1 < beta)
j = integrate(x**2*betadist, (x, 0, oo), meijerg=True, conds='separate')
assert j[1] == (1 < beta - 1)
assert combsimp(j[0] - i[0]**2) == (alpha + beta - 1)*alpha \
/ (beta - 2)/(beta - 1)**2
# Beta distribution
# NOTE: this is evaluated using antiderivatives. It also tests that
# meijerint_indefinite returns the simplest possible answer.
a, b = symbols('a b', positive=True)
betadist = x**(a - 1)*(-x + 1)**(b - 1)*gamma(a + b)/(gamma(a)*gamma(b))
assert simplify(integrate(betadist, (x, 0, 1), meijerg=True)) == 1
assert simplify(integrate(x*betadist, (x, 0, 1), meijerg=True)) == \
a/(a + b)
assert simplify(integrate(x**2*betadist, (x, 0, 1), meijerg=True)) == \
a*(a + 1)/(a + b)/(a + b + 1)
assert simplify(integrate(x**y*betadist, (x, 0, 1), meijerg=True)) == \
gamma(a + b)*gamma(a + y)/gamma(a)/gamma(a + b + y)
# Chi distribution
k = Symbol('k', integer=True, positive=True)
chi = 2**(1 - k/2)*x**(k - 1)*exp(-x**2/2)/gamma(k/2)
assert powsimp(integrate(chi, (x, 0, oo), meijerg=True)) == 1
assert simplify(integrate(x*chi, (x, 0, oo), meijerg=True)) == \
sqrt(2)*gamma((k + 1)/2)/gamma(k/2)
assert simplify(integrate(x**2*chi, (x, 0, oo), meijerg=True)) == k
# Chi^2 distribution
chisquared = 2**(-k/2)/gamma(k/2)*x**(k/2 - 1)*exp(-x/2)
assert powsimp(integrate(chisquared, (x, 0, oo), meijerg=True)) == 1
assert simplify(integrate(x*chisquared, (x, 0, oo), meijerg=True)) == k
assert simplify(integrate(x**2*chisquared, (x, 0, oo), meijerg=True)) == \
k*(k + 2)
assert combsimp(integrate(((x - k)/sqrt(2*k))**3*chisquared, (x, 0, oo),
meijerg=True)) == 2*sqrt(2)/sqrt(k)
# Dagum distribution
a, b, p = symbols('a b p', positive=True)
# XXX (x/b)**a does not work
dagum = a*p/x*(x/b)**(a*p)/(1 + x**a/b**a)**(p + 1)
assert simplify(integrate(dagum, (x, 0, oo), meijerg=True)) == 1
# XXX conditions are a mess
arg = x*dagum
assert simplify(integrate(arg, (x, 0, oo), meijerg=True, conds='none')
) == a*b*gamma(1 - 1/a)*gamma(p + 1 + 1/a)/(
(a*p + 1)*gamma(p))
assert simplify(integrate(x*arg, (x, 0, oo), meijerg=True, conds='none')
) == a*b**2*gamma(1 - 2/a)*gamma(p + 1 + 2/a)/(
(a*p + 2)*gamma(p))
# F-distribution
d1, d2 = symbols('d1 d2', positive=True)
f = sqrt(((d1*x)**d1 * d2**d2)/(d1*x + d2)**(d1 + d2))/x \
/ gamma(d1/2)/gamma(d2/2)*gamma((d1 + d2)/2)
assert simplify(integrate(f, (x, 0, oo), meijerg=True)) == 1
# TODO conditions are a mess
assert simplify(integrate(x*f, (x, 0, oo), meijerg=True, conds='none')
) == d2/(d2 - 2)
assert simplify(integrate(x**2*f, (x, 0, oo), meijerg=True, conds='none')
) == d2**2*(d1 + 2)/d1/(d2 - 4)/(d2 - 2)
# TODO gamma, rayleigh
# inverse gaussian
lamda, mu = symbols('lamda mu', positive=True)
dist = sqrt(lamda/2/pi)*x**(-Rational(3, 2))*exp(-lamda*(x - mu)**2/x/2/mu**2)
def mysimp(expr):
return simplify(expr.rewrite(exp))
assert mysimp(integrate(dist, (x, 0, oo))) == 1
assert mysimp(integrate(x*dist, (x, 0, oo))) == mu
assert mysimp(integrate((x - mu)**2*dist, (x, 0, oo))) == mu**3/lamda
assert mysimp(integrate((x - mu)**3*dist, (x, 0, oo))) == 3*mu**5/lamda**2
# Levi
c = Symbol('c', positive=True)
assert integrate(sqrt(c/2/pi)*exp(-c/2/(x - mu))/(x - mu)**Rational(3, 2),
(x, mu, oo)) == 1
# higher moments oo
# log-logistic
distn = (beta/alpha)*x**(beta - 1)/alpha**(beta - 1) / \
(1 + x**beta/alpha**beta)**2
assert simplify(integrate(distn, (x, 0, oo))) == 1
# NOTE the conditions are a mess, but correctly state beta > 1
assert simplify(integrate(x*distn, (x, 0, oo), conds='none')) == \
pi*alpha/beta/sin(pi/beta)
# (similar comment for conditions applies)
assert simplify(integrate(x**y*distn, (x, 0, oo), conds='none')) == \
pi*alpha**y*y/beta/sin(pi*y/beta)
# weibull
k = Symbol('k', positive=True)
n = Symbol('n', positive=True)
distn = k/lamda*(x/lamda)**(k - 1)*exp(-(x/lamda)**k)
assert simplify(integrate(distn, (x, 0, oo))) == 1
assert simplify(integrate(x**n*distn, (x, 0, oo))) == \
lamda**n*gamma(1 + n/k)
# rice distribution
nu, sigma = symbols('nu sigma', positive=True)
rice = x/sigma**2*exp(-(x**2 + nu**2)/2/sigma**2)*besseli(0, x*nu/sigma**2)
assert integrate(rice, (x, 0, oo), meijerg=True) == 1
# can someone verify higher moments?
# Laplace distribution
mu = Symbol('mu', extended_real=True)
b = Symbol('b', positive=True)
laplace = exp(-abs(x - mu)/b)/2/b
assert integrate(laplace, (x, -oo, oo), meijerg=True) == 1
assert integrate(x*laplace, (x, -oo, oo), meijerg=True) == mu
assert integrate(x**2*laplace, (x, -oo, oo), meijerg=True) == \
2*b**2 + mu**2
# TODO are there other distributions supported on (-oo, oo) that we can do?
# misc tests
k = Symbol('k', positive=True)
assert combsimp(expand_mul(integrate(log(x)*x**(k - 1)*exp(-x)/gamma(k),
(x, 0, oo)))) == polygamma(0, k)
def test_probability():
# various integrals from probability theory
mu1, mu2 = symbols('mu1 mu2', real=True, nonzero=True)
sigma1, sigma2 = symbols('sigma1 sigma2',
real=True,
nonzero=True,
positive=True)
rate = Symbol('lambda', real=True, positive=True)
def normal(x, mu, sigma):
return 1 / sqrt(2 * pi * sigma**2) * exp(-(x - mu)**2 / 2 / sigma**2)
def exponential(x, rate):
return rate * exp(-rate * x)
assert integrate(normal(x, mu1, sigma1), (x, -oo, oo), meijerg=True) == 1
assert integrate(x*normal(x, mu1, sigma1), (x, -oo, oo), meijerg=True) == \
mu1
assert integrate(x**2*normal(x, mu1, sigma1), (x, -oo, oo), meijerg=True) \
== mu1**2 + sigma1**2
assert integrate(x**3*normal(x, mu1, sigma1), (x, -oo, oo), meijerg=True) \
== mu1**3 + 3*mu1*sigma1**2
assert integrate(normal(x, mu1, sigma1) * normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo),
meijerg=True) == 1
assert integrate(x * normal(x, mu1, sigma1) * normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo),
meijerg=True) == mu1
assert integrate(y * normal(x, mu1, sigma1) * normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo),
meijerg=True) == mu2
assert integrate(x * y * normal(x, mu1, sigma1) * normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo),
meijerg=True) == mu1 * mu2
assert integrate(
(x + y + 1) * normal(x, mu1, sigma1) * normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo),
meijerg=True) == 1 + mu1 + mu2
assert integrate((x + y - 1)*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo), meijerg=True) == \
-1 + mu1 + mu2
i = integrate(x**2 * normal(x, mu1, sigma1) * normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo),
meijerg=True)
assert not i.has(Abs)
assert simplify(i) == mu1**2 + sigma1**2
assert integrate(y**2*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),
(x, -oo, oo), (y, -oo, oo), meijerg=True) == \
sigma2**2 + mu2**2
assert integrate(exponential(x, rate), (x, 0, oo), meijerg=True) == 1
assert integrate(x*exponential(x, rate), (x, 0, oo), meijerg=True) == \
1/rate
assert integrate(x**2*exponential(x, rate), (x, 0, oo), meijerg=True) == \
2/rate**2
def E(expr):
res1 = integrate(expr * exponential(x, rate) * normal(y, mu1, sigma1),
(x, 0, oo), (y, -oo, oo),
meijerg=True)
res2 = integrate(expr * exponential(x, rate) * normal(y, mu1, sigma1),
(y, -oo, oo), (x, 0, oo),
meijerg=True)
assert expand_mul(res1) == expand_mul(res2)
return res1
assert E(1) == 1
assert E(x * y) == mu1 / rate
assert E(x * y**2) == mu1**2 / rate + sigma1**2 / rate
ans = sigma1**2 + 1 / rate**2
assert simplify(E((x + y + 1)**2) - E(x + y + 1)**2) == ans
assert simplify(E((x + y - 1)**2) - E(x + y - 1)**2) == ans
assert simplify(E((x + y)**2) - E(x + y)**2) == ans
# Beta' distribution
alpha, beta = symbols('alpha beta', positive=True, real=True)
betadist = x**(alpha - 1)*(1 + x)**(-alpha - beta)*gamma(alpha + beta) \
/ gamma(alpha)/gamma(beta)
assert integrate(betadist, (x, 0, oo), meijerg=True) == 1
i = integrate(x * betadist, (x, 0, oo), meijerg=True, conds='separate')
assert (combsimp(i[0]), i[1]) == (alpha / (beta - 1), 1 < beta)
j = integrate(x**2 * betadist, (x, 0, oo), meijerg=True, conds='separate')
assert j[1] == (1 < beta - 1)
assert combsimp(j[0] - i[0]**2) == (alpha + beta - 1)*alpha \
/ (beta - 2)/(beta - 1)**2
# Beta distribution
# NOTE: this is evaluated using antiderivatives. It also tests that
# meijerint_indefinite returns the simplest possible answer.
a, b = symbols('a b', positive=True)
betadist = x**(a - 1) * (-x + 1)**(b - 1) * gamma(a + b) / (gamma(a) *
gamma(b))
assert simplify(integrate(betadist, (x, 0, 1), meijerg=True)) == 1
assert simplify(integrate(x*betadist, (x, 0, 1), meijerg=True)) == \
a/(a + b)
assert simplify(integrate(x**2*betadist, (x, 0, 1), meijerg=True)) == \
a*(a + 1)/(a + b)/(a + b + 1)
assert simplify(integrate(x**y*betadist, (x, 0, 1), meijerg=True)) == \
Piecewise((gamma(a + b)*gamma(a + y)/(gamma(a)*gamma(a + b + y)),
-a - re(y) + 1 < 1),
(Integral(x**(a + y - 1)*(-x + 1)**(b - 1)*gamma(a + b)/(gamma(a)*gamma(b)),
(x, 0, 1)), True))
# Chi distribution
k = Symbol('k', integer=True, positive=True)
chi = 2**(1 - k / 2) * x**(k - 1) * exp(-x**2 / 2) / gamma(k / 2)
assert powsimp(integrate(chi, (x, 0, oo), meijerg=True)) == 1
assert simplify(integrate(x*chi, (x, 0, oo), meijerg=True)) == \
sqrt(2)*gamma((k + 1)/2)/gamma(k/2)
assert simplify(integrate(x**2 * chi, (x, 0, oo), meijerg=True)) == k
# Chi^2 distribution
chisquared = 2**(-k / 2) / gamma(k / 2) * x**(k / 2 - 1) * exp(-x / 2)
assert powsimp(integrate(chisquared, (x, 0, oo), meijerg=True)) == 1
assert simplify(integrate(x * chisquared, (x, 0, oo), meijerg=True)) == k
assert simplify(integrate(x**2*chisquared, (x, 0, oo), meijerg=True)) == \
k*(k + 2)
assert combsimp(
integrate(((x - k) / sqrt(2 * k))**3 * chisquared, (x, 0, oo),
meijerg=True)) == 2 * sqrt(2) / sqrt(k)
# Dagum distribution
a, b, p = symbols('a b p', positive=True, real=True)
# XXX (x/b)**a does not work
dagum = a * p / x * (x / b)**(a * p) / (1 + x**a / b**a)**(p + 1)
assert simplify(integrate(dagum, (x, 0, oo), meijerg=True)) == 1
# XXX conditions are a mess
arg = x * dagum
assert simplify(integrate(
arg, (x, 0, oo), meijerg=True,
conds='none')) == a * b * gamma(1 - 1 / a) * gamma(p + 1 + 1 / a) / (
(a * p + 1) * gamma(p))
assert simplify(integrate(
x * arg, (x, 0, oo), meijerg=True,
conds='none')) == a * b**2 * gamma(1 -
2 / a) * gamma(p + 1 + 2 / a) / (
(a * p + 2) * gamma(p))
# F-distribution
d1, d2 = symbols('d1 d2', positive=True)
f = sqrt(((d1*x)**d1 * d2**d2)/(d1*x + d2)**(d1 + d2))/x \
/ gamma(d1/2)/gamma(d2/2)*gamma((d1 + d2)/2)
assert simplify(integrate(f, (x, 0, oo), meijerg=True)) == 1
# TODO conditions are a mess
assert simplify(integrate(x * f, (x, 0, oo), meijerg=True,
conds='none')) == d2 / (d2 - 2)
assert simplify(
integrate(x**2 * f, (x, 0, oo), meijerg=True,
conds='none')) == d2**2 * (d1 + 2) / d1 / (d2 - 4) / (d2 - 2)
# TODO gamma, rayleigh
# inverse gaussian
lamda, mu = symbols('lamda mu', positive=True)
dist = sqrt(lamda / 2 / pi) * x**(-Rational(3, 2)) * exp(
-lamda * (x - mu)**2 / x / 2 / mu**2)
def mysimp(expr):
return simplify(expr.rewrite(exp))
assert mysimp(integrate(dist, (x, 0, oo))) == 1
assert mysimp(integrate(x * dist, (x, 0, oo))) == mu
assert mysimp(integrate((x - mu)**2 * dist, (x, 0, oo))) == mu**3 / lamda
assert mysimp(integrate((x - mu)**3 * dist,
(x, 0, oo))) == 3 * mu**5 / lamda**2
# Levi
c = Symbol('c', positive=True)
assert integrate(
sqrt(c / 2 / pi) * exp(-c / 2 / (x - mu)) / (x - mu)**Rational(3, 2),
(x, mu, oo)) == 1
# higher moments oo
# log-logistic
distn = (beta/alpha)*x**(beta - 1)/alpha**(beta - 1) / \
(1 + x**beta/alpha**beta)**2
assert simplify(integrate(distn, (x, 0, oo))) == 1
# NOTE the conditions are a mess, but correctly state beta > 1
assert simplify(integrate(x*distn, (x, 0, oo), conds='none')) == \
pi*alpha/beta/sin(pi/beta)
# (similar comment for conditions applies)
assert simplify(integrate(x**y*distn, (x, 0, oo), conds='none')) == \
pi*alpha**y*y/beta/sin(pi*y/beta)
# weibull
k = Symbol('k', positive=True, real=True)
n = Symbol('n', positive=True)
distn = k / lamda * (x / lamda)**(k - 1) * exp(-(x / lamda)**k)
assert simplify(integrate(distn, (x, 0, oo))) == 1
assert simplify(integrate(x**n*distn, (x, 0, oo))) == \
lamda**n*gamma(1 + n/k)
# rice distribution
nu, sigma = symbols('nu sigma', positive=True)
rice = x / sigma**2 * exp(-(x**2 + nu**2) / 2 / sigma**2) * besseli(
0, x * nu / sigma**2)
assert integrate(rice, (x, 0, oo), meijerg=True) == 1
# can someone verify higher moments?
# Laplace distribution
mu = Symbol('mu', extended_real=True)
b = Symbol('b', positive=True)
laplace = exp(-abs(x - mu) / b) / 2 / b
assert integrate(laplace, (x, -oo, oo), meijerg=True) == 1
assert integrate(x * laplace, (x, -oo, oo), meijerg=True) == mu
assert integrate(x**2*laplace, (x, -oo, oo), meijerg=True) == \
2*b**2 + mu**2
# TODO are there other distributions supported on (-oo, oo) that we can do?
# misc tests
k = Symbol('k', positive=True)
assert combsimp(
expand_mul(
integrate(log(x) * x**(k - 1) * exp(-x) / gamma(k),
(x, 0, oo)))) == polygamma(0, k)
def test_powsimp_nc():
A, B, C = symbols('A B C', commutative=False)
assert powsimp(A**x * A**y, combine='all') == A**(x + y)
assert powsimp(A**x * A**y, combine='base') == A**x * A**y
assert powsimp(A**x * A**y, combine='exp') == A**(x + y)
assert powsimp(A**x * B**x, combine='all') == (A * B)**x
assert powsimp(A**x * B**x, combine='base') == (A * B)**x
assert powsimp(A**x * B**x, combine='exp') == A**x * B**x
assert powsimp(B**x * A**x, combine='all') == (B * A)**x
assert powsimp(B**x * A**x, combine='base') == (B * A)**x
assert powsimp(B**x * A**x, combine='exp') == B**x * A**x
assert powsimp(A**x * A**y * A**z, combine='all') == A**(x + y + z)
assert powsimp(A**x * A**y * A**z, combine='base') == A**x * A**y * A**z
assert powsimp(A**x * A**y * A**z, combine='exp') == A**(x + y + z)
assert powsimp(A**x * B**x * C**x, combine='all') == (A * B * C)**x
assert powsimp(A**x * B**x * C**x, combine='base') == (A * B * C)**x
assert powsimp(A**x * B**x * C**x, combine='exp') == A**x * B**x * C**x
assert powsimp(B**x * A**x * C**x, combine='all') == (B * A * C)**x
assert powsimp(B**x * A**x * C**x, combine='base') == (B * A * C)**x
assert powsimp(B**x * A**x * C**x, combine='exp') == B**x * A**x * C**x
def simp_pows(expr):
return simplify(powsimp(expand_mul(expr, deep=False),
force=True)).replace(exp_polar, exp)
def test_sympyissue_6440():
assert powsimp(16*2**a*8**b) == 2**(a + 3*b + 4)
def diop_simplify(eq):
return _mexpand(powsimp(_mexpand(eq)))
def simp_pows(expr):
return simplify(powsimp(expand_mul(expr, deep=False), force=True)).replace(exp_polar, exp)