def test_point3D():
p1 = Point3D(x1, x2, x3)
p2 = Point3D(y1, y2, y3)
p3 = Point3D(0, 0, 0)
p4 = Point3D(1, 1, 1)
p5 = Point3D(0, 1, 2)
assert p1 in p1
assert p1 not in p2
assert p2.y == y2
assert (p3 + p4) == p4
assert (p2 - p1) == Point3D(y1 - x1, y2 - x2, y3 - x3)
assert p4*5 == Point3D(5, 5, 5)
assert -p2 == Point3D(-y1, -y2, -y3)
assert Point(34.05, sqrt(3)) == Point(Rational(681, 20), sqrt(3))
assert Point3D.midpoint(p3, p4) == Point3D(half, half, half)
assert Point3D.midpoint(p1, p4) == Point3D(half + half*x1, half + half*x2,
half + half*x3)
assert Point3D.midpoint(p2, p2) == p2
assert p2.midpoint(p2) == p2
assert Point3D.distance(p3, p4) == sqrt(3)
assert Point3D.distance(p1, p1) == 0
assert Point3D.distance(p3, p2) == sqrt(p2.x**2 + p2.y**2 + p2.z**2)
p1_1 = Point3D(x1, x1, x1)
p1_2 = Point3D(y2, y2, y2)
p1_3 = Point3D(x1 + 1, x1, x1)
# according to the description in the docs, points are collinear
# if they like on a single line. Thus a single point should always
# be collinear
assert Point3D.are_collinear(p3)
assert Point3D.are_collinear(p3, p4)
assert Point3D.are_collinear(p3, p4, p1_1, p1_2)
assert Point3D.are_collinear(p3, p4, p1_1, p1_3) is False
assert Point3D.are_collinear(p3, p3, p4, p5) is False
assert p3.intersection(Point3D(0, 0, 0)) == [p3]
assert p3.intersection(p4) == []
assert p4 * 5 == Point3D(5, 5, 5)
assert p4 / 5 == Point3D(0.2, 0.2, 0.2)
pytest.raises(ValueError, lambda: Point3D(0, 0, 0) + 10)
# Point differences should be simplified
assert Point3D(x*(x - 1), y, 2) - Point3D(x**2 - x, y + 1, 1) == \
Point3D(0, -1, 1)
a, b = Rational(1, 2), Rational(1, 3)
assert Point(a, b).evalf(2) == \
Point(a.evalf(2), b.evalf(2))
pytest.raises(ValueError, lambda: Point(1, 2) + 1)
# test transformations
p = Point3D(1, 1, 1)
assert p.scale(2, 3) == Point3D(2, 3, 1)
assert p.translate(1, 2) == Point3D(2, 3, 1)
assert p.translate(1) == Point3D(2, 1, 1)
assert p.translate(z=1) == Point3D(1, 1, 2)
assert p.translate(*p.args) == Point3D(2, 2, 2)
# Test __new__
assert Point3D(Point3D(1, 2, 3), 4, 5, evaluate=False) == Point3D(1, 2, 3)
# Test length property returns correctly
assert p.length == 0
assert p1_1.length == 0
assert p1_2.length == 0
# Test are_colinear type error
pytest.raises(TypeError, lambda: Point3D.are_collinear(p, x))
# Test are_coplanar
planar2 = Point3D(1, -1, 1)
planar3 = Point3D(-1, 1, 1)
assert Point3D.are_coplanar(p, planar2, planar3) is True
assert Point3D.are_coplanar(p, planar2, planar3, p3) is False
pytest.raises(ValueError, lambda: Point3D.are_coplanar(p, planar2))
planar2 = Point3D(1, 1, 2)
planar3 = Point3D(1, 1, 3)
pytest.raises(ValueError, lambda: Point3D.are_coplanar(p, planar2, planar3))
# Test Intersection
assert planar2.intersection(Line3D(p, planar3)) == [Point3D(1, 1, 2)]
# Test Scale
assert planar2.scale(1, 1, 1) == planar2
assert planar2.scale(2, 2, 2, planar3) == Point3D(1, 1, 1)
assert planar2.scale(1, 1, 1, p3) == planar2
# Test Transform
identity = Matrix([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]])
assert p.transform(identity) == p
trans = Matrix([[1, 0, 0, 1], [0, 1, 0, 1], [0, 0, 1, 1], [0, 0, 0, 1]])
assert p.transform(trans) == Point3D(2, 2, 2)
pytest.raises(ValueError, lambda: p.transform(p))
pytest.raises(ValueError, lambda: p.transform(Matrix([[1, 0], [0, 1]])))
# Test Equals
assert p.equals(x1) is False
# Test __sub__
p_2d = Point(0, 0)
pytest.raises(ValueError, lambda: (p - p_2d))
def test_integrate_DiracDelta_fails():
# issue 6427
assert integrate(
integrate(integrate(DiracDelta(x - y - z), (z, 0, oo)), (y, 0, 1)),
(x, 0, 1)) == Rational(1, 2)
def test_sympyissue_14811():
assert limit(((1 + Rational(2, 3)**(x + 1))**2**x)/(2**Rational(4, 3)**(x - 1)), x, oo) == oo
def test_sympyissue_8245():
a = Rational(6506833320952669167898688709329, 5070602400912917605986812821504)
q = a.evalf(10)
assert (a == q) is True
assert (a != q) is False
assert (a > q) is false
assert (a < q) is false
assert (a >= q) is true
assert (a <= q) is true
a = sqrt(2)
r = Rational(str(a.evalf(30)))
assert (r == a) is False
assert (r != a) is True
assert (r > a) is true
assert (r < a) is false
assert (r >= a) is true
assert (r <= a) is false
a = sqrt(2)
r = Rational(str(a.evalf(29)))
assert (r == a) is False
assert (r != a) is True
assert (r > a) is false
assert (r < a) is true
assert (r >= a) is false
assert (r <= a) is true
def test_composite_sums():
f = Rational(1, 2)*(7 - 6*n + Rational(1, 7)*n**3)
s = summation(f, (n, a, b))
assert not isinstance(s, Sum)
A = 0
for i in range(-3, 5):
A += f.subs({n: i})
B = s.subs({a: -3, b: 4})
assert A == B
def test_large_rational():
e = cbrt(Rational(123712**12 - 1, 7) + Rational(1, 7))
assert e == 234232585392159195136 * cbrt(Rational(1, 7))
def test_sympyissue_3792():
assert limit( (1 - cos(x))/x**2, x, Rational(1, 2)) == 4 - 4*cos(Rational(1, 2))
assert limit(sin(sin(x + 1) + 1), x, 0) == sin(1 + sin(1))
assert limit(abs(sin(x + 1) + 1), x, 0) == 1 + sin(1)
def test_point():
p1 = Point(x1, x2)
p2 = Point(y1, y2)
p3 = Point(0, 0)
p4 = Point(1, 1)
p5 = Point(0, 1)
assert p1.origin == p3
assert p1.ambient_dimension == 2
assert p1 in p1
assert p1 not in p2
assert p2.y == y2
assert (p3 + p4) == p4
assert (p2 - p1) == Point(y1 - x1, y2 - x2)
assert p4*5 == Point(5, 5)
assert -p2 == Point(-y1, -y2)
pytest.raises(ValueError, lambda: Point(3, I))
pytest.raises(ValueError, lambda: Point(2*I, I))
pytest.raises(ValueError, lambda: Point(3 + I, I))
assert Point(34.05, sqrt(3)) == Point(Rational(681, 20), sqrt(3))
assert Point.midpoint(p3, p4) == Point(half, half)
assert Point.midpoint(p1, p4) == Point(half + half*x1, half + half*x2)
assert Point.midpoint(p2, p2) == p2
assert p2.midpoint(p2) == p2
assert Point.distance(p3, p4) == sqrt(2)
assert Point.distance(p1, p1) == 0
assert Point.distance(p3, p2) == sqrt(p2.x**2 + p2.y**2)
p1_1 = Point(x1, x1)
p1_2 = Point(y2, y2)
p1_3 = Point(x1 + 1, x1)
assert Point.is_collinear() is False
assert Point.is_collinear(p3)
assert Point.is_collinear(p3, p4)
assert Point.is_collinear(p3, p4, p1_1, p1_2)
assert Point.is_collinear(p3, p4, p1_1, p1_3) is False
assert Point.is_collinear(p3, p3, p4, p5) is False
line = Line(Point(1, 0), slope=1)
pytest.raises(TypeError, lambda: Point.is_collinear(line))
pytest.raises(TypeError, lambda: p1_1.is_collinear(line))
assert p3.intersection(Point(0, 0)) == [p3]
assert p3.intersection(p4) == []
x_pos = Symbol('x', real=True, positive=True)
p2_1 = Point(x_pos, 0)
p2_2 = Point(0, x_pos)
p2_3 = Point(-x_pos, 0)
p2_4 = Point(0, -x_pos)
p2_5 = Point(x_pos, 5)
assert Point.is_concyclic(p2_1)
assert Point.is_concyclic(p2_1, p2_2)
assert Point.is_concyclic(p2_1, p2_2, p2_3, p2_4)
assert Point.is_concyclic(p2_1, p2_2, p2_3, p2_5) is False
assert Point.is_concyclic(p4, p4 * 2, p4 * 3) is False
pytest.raises(TypeError, lambda: Point.is_concyclic(p2_1, "123"))
assert p4.scale(2, 3) == Point(2, 3)
assert p3.scale(2, 3) == p3
assert p4.rotate(pi, Point(0.5, 0.5)) == p3
assert p1.__radd__(p2) == p1.midpoint(p2).scale(2, 2)
assert (-p3).__rsub__(p4) == p3.midpoint(p4).scale(2, 2)
assert p4 * 5 == Point(5, 5)
assert p4 / 5 == Point(0.2, 0.2)
pytest.raises(ValueError, lambda: Point(0, 0) + 10)
# Point differences should be simplified
assert Point(x*(x - 1), y) - Point(x**2 - x, y + 1) == Point(0, -1)
a, b = Rational(1, 2), Rational(1, 3)
assert Point(a, b).evalf(2) == \
Point(a.evalf(2), b.evalf(2))
pytest.raises(ValueError, lambda: Point(1, 2) + 1)
# test transformations
p = Point(1, 0)
assert p.rotate(pi/2) == Point(0, 1)
assert p.rotate(pi/2, p) == p
p = Point(1, 1)
assert p.scale(2, 3) == Point(2, 3)
assert p.translate(1, 2) == Point(2, 3)
assert p.translate(1) == Point(2, 1)
assert p.translate(y=1) == Point(1, 2)
assert p.translate(*p.args) == Point(2, 2)
# Check invalid input for transform
pytest.raises(ValueError, lambda: p3.transform(p3))
pytest.raises(ValueError, lambda: p.transform(Matrix([[1, 0], [0, 1]])))
def test_issue_3664():
n = Symbol('n', integer=True, nonzero=True)
assert integrate(-1./2 * x * sin(n * pi * x/2), [x, -2, 0]) == \
2*cos(pi*n)/(pi*n)
assert integrate(-Rational(1)/2 * x * sin(n * pi * x/2), [x, -2, 0]) == \
2*cos(pi*n)/(pi*n)
def test_logexppow(): # no eval()
x = Symbol('x', extended_real=True)
w = Symbol('w')
e = (3**(1 + x) + 2**(1 + x)) / (3**x + 2**x)
assert e.subs(2**x, w) != e
assert e.subs(exp(x * log(Rational(2))), w) != e
def test_cosine_transform():
f = Function("f")
# Test unevaluated form
assert cosine_transform(f(t), t, w) == CosineTransform(f(t), t, w)
assert inverse_cosine_transform(f(w), w,
t) == InverseCosineTransform(f(w), w, t)
assert cosine_transform(1 / sqrt(t), t, w) == 1 / sqrt(w)
assert inverse_cosine_transform(1 / sqrt(w), w, t) == 1 / sqrt(t)
assert cosine_transform(1 / (a**2 + t**2), t,
w) == sqrt(2) * sqrt(pi) * exp(-a * w) / (2 * a)
assert cosine_transform(
t**(-a), t, w) == 2**(-a + Rational(1, 2)) * w**(a - 1) * gamma(
(-a + 1) / 2) / gamma(a / 2)
assert inverse_cosine_transform(
2**(-a + Rational(1, 2)) * w**(a - 1) *
gamma(-a / 2 + Rational(1, 2)) / gamma(a / 2), w, t) == t**(-a)
assert cosine_transform(exp(-a * t), t,
w) == sqrt(2) * a / (sqrt(pi) * (a**2 + w**2))
assert inverse_cosine_transform(
sqrt(2) * a / (sqrt(pi) * (a**2 + w**2)), w, t) == exp(-a * t)
assert cosine_transform(exp(-a * sqrt(t)) * cos(a * sqrt(t)), t,
w) == a * exp(-a**2 /
(2 * w)) / (2 * w**Rational(3, 2))
assert cosine_transform(
1 / (a + t), t,
w) == sqrt(2) * ((-2 * Si(a * w) + pi) * sin(a * w) / 2 -
cos(a * w) * Ci(a * w)) / sqrt(pi)
assert inverse_cosine_transform(
sqrt(2) * meijerg(((Rational(1, 2), 0), ()),
((Rational(1, 2), 0, 0),
(Rational(1, 2), )), a**2 * w**2 / 4) / (2 * pi), w,
t) == 1 / (a + t)
assert cosine_transform(1 / sqrt(a**2 + t**2), t, w) == sqrt(2) * meijerg(
((Rational(1, 2), ), ()),
((0, 0), (Rational(1, 2), )), a**2 * w**2 / 4) / (2 * sqrt(pi))
assert inverse_cosine_transform(
sqrt(2) * meijerg(
((Rational(1, 2), ), ()),
((0, 0), (Rational(1, 2), )), a**2 * w**2 / 4) / (2 * sqrt(pi)), w,
t) == 1 / (a * sqrt(1 + t**2 / a**2))
def test_mellin_transform_bessel():
MT = mellin_transform
# 8.4.19
assert MT(besselj(a, 2*sqrt(x)), x, s) == \
(gamma(a/2 + s)/gamma(a/2 - s + 1), (-re(a)/2, Rational(3, 4)), True)
assert MT(sin(sqrt(x))*besselj(a, sqrt(x)), x, s) == \
(2**a*gamma(-2*s + Rational(1, 2))*gamma(a/2 + s + Rational(1, 2))/(
gamma(-a/2 - s + 1)*gamma(a - 2*s + 1)), (
-re(a)/2 - Rational(1, 2), Rational(1, 4)), True)
assert MT(cos(sqrt(x))*besselj(a, sqrt(x)), x, s) == \
(2**a*gamma(a/2 + s)*gamma(-2*s + Rational(1, 2))/(
gamma(-a/2 - s + Rational(1, 2))*gamma(a - 2*s + 1)), (
-re(a)/2, Rational(1, 4)), True)
assert MT(besselj(a, sqrt(x))**2, x, s) == \
(gamma(a + s)*gamma(Rational(1, 2) - s)
/ (sqrt(pi)*gamma(1 - s)*gamma(1 + a - s)),
(-re(a), Rational(1, 2)), True)
assert MT(besselj(a, sqrt(x))*besselj(-a, sqrt(x)), x, s) == \
(gamma(s)*gamma(Rational(1, 2) - s)
/ (sqrt(pi)*gamma(1 - a - s)*gamma(1 + a - s)),
(0, Rational(1, 2)), True)
# NOTE: prudnikov gives the strip below as (1/2 - re(a), 1). As far as
# I can see this is wrong (since besselj(z) ~ 1/sqrt(z) for z large)
assert MT(besselj(a - 1, sqrt(x))*besselj(a, sqrt(x)), x, s) == \
(gamma(1 - s)*gamma(a + s - Rational(1, 2))
/ (sqrt(pi)*gamma(Rational(3, 2) - s)*gamma(a - s + Rational(1, 2))),
(Rational(1, 2) - re(a), Rational(1, 2)), True)
assert MT(besselj(a, sqrt(x))*besselj(b, sqrt(x)), x, s) == \
(4**s*gamma(1 - 2*s)*gamma((a + b)/2 + s)
/ (gamma(1 - s + (b - a)/2)*gamma(1 - s + (a - b)/2)
* gamma( 1 - s + (a + b)/2)),
(-(re(a) + re(b))/2, Rational(1, 2)), True)
assert MT(besselj(a, sqrt(x))**2 + besselj(-a, sqrt(x))**2, x, s)[1:] == \
((Max(re(a), -re(a)), Rational(1, 2)), True)
# Section 8.4.20
assert MT(bessely(a, 2*sqrt(x)), x, s) == \
(-cos(pi*(a/2 - s))*gamma(s - a/2)*gamma(s + a/2)/pi,
(Max(-re(a)/2, re(a)/2), Rational(3, 4)), True)
assert MT(sin(sqrt(x))*bessely(a, sqrt(x)), x, s) == \
(-4**s*sin(pi*(a/2 - s))*gamma(Rational(1, 2) - 2*s)
* gamma((1 - a)/2 + s)*gamma((1 + a)/2 + s)
/ (sqrt(pi)*gamma(1 - s - a/2)*gamma(1 - s + a/2)),
(Max(-(re(a) + 1)/2, (re(a) - 1)/2), Rational(1, 4)), True)
assert MT(cos(sqrt(x))*bessely(a, sqrt(x)), x, s) == \
(-4**s*cos(pi*(a/2 - s))*gamma(s - a/2)*gamma(s + a/2)*gamma(Rational(1, 2) - 2*s)
/ (sqrt(pi)*gamma(Rational(1, 2) - s - a/2)*gamma(Rational(1, 2) - s + a/2)),
(Max(-re(a)/2, re(a)/2), Rational(1, 4)), True)
assert MT(besselj(a, sqrt(x))*bessely(a, sqrt(x)), x, s) == \
(-cos(pi*s)*gamma(s)*gamma(a + s)*gamma(Rational(1, 2) - s)
/ (pi**Rational(3, 2)*gamma(1 + a - s)),
(Max(-re(a), 0), Rational(1, 2)), True)
assert MT(besselj(a, sqrt(x))*bessely(b, sqrt(x)), x, s) == \
(-4**s*cos(pi*(a/2 - b/2 + s))*gamma(1 - 2*s)
* gamma(a/2 - b/2 + s)*gamma(a/2 + b/2 + s)
/ (pi*gamma(a/2 - b/2 - s + 1)*gamma(a/2 + b/2 - s + 1)),
(Max((-re(a) + re(b))/2, (-re(a) - re(b))/2), Rational(1, 2)), True)
# NOTE bessely(a, sqrt(x))**2 and bessely(a, sqrt(x))*bessely(b, sqrt(x))
# are a mess (no matter what way you look at it ...)
assert MT(bessely(a, sqrt(x))**2, x, s)[1:] == \
((Max(-re(a), 0, re(a)), Rational(1, 2)), True)
# Section 8.4.22
# TODO we can't do any of these (delicate cancellation)
# Section 8.4.23
assert MT(besselk(a, 2*sqrt(x)), x, s) == \
(gamma(
s - a/2)*gamma(s + a/2)/2, (Max(-re(a)/2, re(a)/2), oo), True)
assert MT(
besselj(a, 2 * sqrt(2 * sqrt(x))) * besselk(a, 2 * sqrt(2 * sqrt(x))),
x, s) == (4**(-s) * gamma(2 * s) * gamma(a / 2 + s) /
(2 * gamma(a / 2 - s + 1)), (Max(0, -re(a) / 2), oo), True)
# TODO bessely(a, x)*besselk(a, x) is a mess
assert MT(besseli(a, sqrt(x))*besselk(a, sqrt(x)), x, s) == \
(gamma(s)*gamma(
a + s)*gamma(-s + Rational(1, 2))/(2*sqrt(pi)*gamma(a - s + 1)),
(Max(-re(a), 0), Rational(1, 2)), True)
assert MT(besseli(b, sqrt(x))*besselk(a, sqrt(x)), x, s) == \
(2**(2*s - 1)*gamma(-2*s + 1)*gamma(-a/2 + b/2 + s) *
gamma(a/2 + b/2 + s)/(gamma(-a/2 + b/2 - s + 1) *
gamma(a/2 + b/2 - s + 1)), (Max(-re(a)/2 - re(b)/2,
re(a)/2 - re(b)/2), Rational(1, 2)), True)
# TODO products of besselk are a mess
mt = MT(exp(-x / 2) * besselk(a, x / 2), x, s)
mt0 = combsimp((trigsimp(combsimp(mt[0].expand(func=True)))))
assert mt0 == 2 * pi**Rational(3, 2) * cos(
pi * s) * gamma(-s + Rational(1, 2)) / (
(cos(2 * pi * a) - cos(2 * pi * s)) * gamma(-a - s + 1) *
gamma(a - s + 1))
assert mt[1:] == ((Max(-re(a), re(a)), oo), True)
def test_sympyissue_8229():
assert limit((root(x, 4) - 2)/(sqrt(x) - 4)**Rational(2, 3),
x, 16) == 0
def test_sympyissue_6560():
e = 5*x**3/4 - 3*x/4 + (y*(3*x**2/2 - Rational(1, 2)) +
35*x**4/8 - 15*x**2/4 + Rational(3, 8))/(2*(y + 1))
assert limit(e, y, oo) == (5*x**3 + 3*x**2 - 3*x - 1)/4
def test_compute_leading_term():
assert limit(x**Rational(77, 3)/(1 + x**Rational(77, 3)), x, oo) == 1
assert limit(x**Rational('101.1')/(1 + x**Rational('101.1')), x, oo) == 1
def test_sympyissue_4090():
assert limit(1/(x + 3), x, 2) == Rational(1, 5)
assert limit(1/(x + pi), x, 2) == 1/(2 + pi)
assert limit(log(x)/(x**2 + 3), x, 2) == log(2)/7
assert limit(log(x)/(x**2 + pi), x, 2) == log(2)/(4 + pi)
def test_sympyissue_4362():
neg = Symbol('neg', negative=True)
nonneg = Symbol('nonneg', nonnegative=True)
any = Symbol('any')
num, den = sqrt(1 / neg).as_numer_denom()
assert num == sqrt(-1)
assert den == sqrt(-neg)
num, den = sqrt(1 / nonneg).as_numer_denom()
assert num == 1
assert den == sqrt(nonneg)
num, den = sqrt(1 / any).as_numer_denom()
assert num == sqrt(1 / any)
assert den == 1
def eqn(num, den, pow):
return (num / den)**pow
npos = 1
nneg = -1
dpos = 2 - sqrt(3)
dneg = 1 - sqrt(3)
assert dpos > 0 and dneg < 0 and npos > 0 and nneg < 0
# pos or neg integer
eq = eqn(npos, dpos, 2)
assert eq.is_Pow and eq.as_numer_denom() == (1, dpos**2)
eq = eqn(npos, dneg, 2)
assert eq.is_Pow and eq.as_numer_denom() == (1, dneg**2)
eq = eqn(nneg, dpos, 2)
assert eq.is_Pow and eq.as_numer_denom() == (1, dpos**2)
eq = eqn(nneg, dneg, 2)
assert eq.is_Pow and eq.as_numer_denom() == (1, dneg**2)
eq = eqn(npos, dpos, -2)
assert eq.is_Pow and eq.as_numer_denom() == (dpos**2, 1)
eq = eqn(npos, dneg, -2)
assert eq.is_Pow and eq.as_numer_denom() == (dneg**2, 1)
eq = eqn(nneg, dpos, -2)
assert eq.is_Pow and eq.as_numer_denom() == (dpos**2, 1)
eq = eqn(nneg, dneg, -2)
assert eq.is_Pow and eq.as_numer_denom() == (dneg**2, 1)
# pos or neg rational
pow = Rational(1, 2)
eq = eqn(npos, dpos, pow)
assert eq.is_Pow and eq.as_numer_denom() == (npos**pow, dpos**pow)
eq = eqn(npos, dneg, pow)
assert eq.is_Pow is False and eq.as_numer_denom() == ((-npos)**pow,
(-dneg)**pow)
eq = eqn(nneg, dpos, pow)
assert not eq.is_Pow or eq.as_numer_denom() == (nneg**pow, dpos**pow)
eq = eqn(nneg, dneg, pow)
assert eq.is_Pow and eq.as_numer_denom() == ((-nneg)**pow, (-dneg)**pow)
eq = eqn(npos, dpos, -pow)
assert eq.is_Pow and eq.as_numer_denom() == (dpos**pow, npos**pow)
eq = eqn(npos, dneg, -pow)
assert eq.is_Pow is False and eq.as_numer_denom() == (-(-npos)**pow *
(-dneg)**pow, npos)
eq = eqn(nneg, dpos, -pow)
assert not eq.is_Pow or eq.as_numer_denom() == (dpos**pow, nneg**pow)
eq = eqn(nneg, dneg, -pow)
assert eq.is_Pow and eq.as_numer_denom() == ((-dneg)**pow, (-nneg)**pow)
# unknown exponent
pow = 2 * any
eq = eqn(npos, dpos, pow)
assert eq.is_Pow and eq.as_numer_denom() == (npos**pow, dpos**pow)
eq = eqn(npos, dneg, pow)
assert eq.is_Pow and eq.as_numer_denom() == ((-npos)**pow, (-dneg)**pow)
eq = eqn(nneg, dpos, pow)
assert eq.is_Pow and eq.as_numer_denom() == (nneg**pow, dpos**pow)
eq = eqn(nneg, dneg, pow)
assert eq.is_Pow and eq.as_numer_denom() == ((-nneg)**pow, (-dneg)**pow)
eq = eqn(npos, dpos, -pow)
assert eq.as_numer_denom() == (dpos**pow, npos**pow)
eq = eqn(npos, dneg, -pow)
assert eq.is_Pow and eq.as_numer_denom() == ((-dneg)**pow, (-npos)**pow)
eq = eqn(nneg, dpos, -pow)
assert eq.is_Pow and eq.as_numer_denom() == (dpos**pow, nneg**pow)
eq = eqn(nneg, dneg, -pow)
assert eq.is_Pow and eq.as_numer_denom() == ((-dneg)**pow, (-nneg)**pow)
assert ((1 / (1 + x / 3))**-1).as_numer_denom() == (3 + x, 3)
notp = Symbol('notp', positive=False) # not positive does not imply real
b = ((1 + x / notp)**-2)
assert (b**(-y)).as_numer_denom() == (1, b**y)
assert (b**-1).as_numer_denom() == ((notp + x)**2, notp**2)
nonp = Symbol('nonp', nonpositive=True)
assert (((1 + x / nonp)**-2)**-1).as_numer_denom() == ((-nonp - x)**2,
nonp**2)
n = Symbol('n', negative=True)
assert (x**n).as_numer_denom() == (1, x**-n)
assert sqrt(1 / n).as_numer_denom() == (I, sqrt(-n))
n = Symbol('0 or neg', nonpositive=True)
# if x and n are split up without negating each term and n is negative
# then the answer might be wrong; if n is 0 it won't matter since
# 1/oo and 1/zoo are both zero as is sqrt(0)/sqrt(-x) unless x is also
# zero (in which case the negative sign doesn't matter):
# 1/sqrt(1/-1) = -I but sqrt(-1)/sqrt(1) = I
assert (1 / sqrt(x / n)).as_numer_denom() == (sqrt(-n), sqrt(-x))
c = Symbol('c', complex=True)
e = sqrt(1 / c)
assert e.as_numer_denom() == (e, 1)
i = Symbol('i', integer=True)
assert (((1 + x / y)**i)).as_numer_denom() == ((x + y)**i, y**i)
def test_expand():
assert (2**(-1 - x)).expand() == Rational(1, 2) * 2**(-x)
def test_sympyissue_6782():
assert sqrt(sin(x**3)).series(x, 0, 7) == x**Rational(3, 2) + O(x**7)
assert sqrt(sin(x**4)).series(x, 0, 3) == x**2 + O(x**3)
def test_gamma():
assert gamma(nan) == nan
assert gamma(oo) == oo
assert gamma(-100) == zoo
assert gamma(0) == zoo
assert gamma(1) == 1
assert gamma(2) == 1
assert gamma(3) == 2
assert gamma(102) == factorial(101)
assert gamma(Rational(1, 2)) == sqrt(pi)
assert gamma(Rational(3, 2)) == Rational(1, 2)*sqrt(pi)
assert gamma(Rational(5, 2)) == Rational(3, 4)*sqrt(pi)
assert gamma(Rational(7, 2)) == Rational(15, 8)*sqrt(pi)
assert gamma(Rational(-1, 2)) == -2*sqrt(pi)
assert gamma(Rational(-3, 2)) == Rational(4, 3)*sqrt(pi)
assert gamma(Rational(-5, 2)) == -Rational(8, 15)*sqrt(pi)
assert gamma(Rational(-15, 2)) == Rational(256, 2027025)*sqrt(pi)
assert gamma(Rational(
-11, 8)).expand(func=True) == Rational(64, 33)*gamma(Rational(5, 8))
assert gamma(Rational(
-10, 3)).expand(func=True) == Rational(81, 280)*gamma(Rational(2, 3))
assert gamma(Rational(
14, 3)).expand(func=True) == Rational(880, 81)*gamma(Rational(2, 3))
assert gamma(Rational(
17, 7)).expand(func=True) == Rational(30, 49)*gamma(Rational(3, 7))
assert gamma(Rational(
19, 8)).expand(func=True) == Rational(33, 64)*gamma(Rational(3, 8))
assert gamma(x).diff(x) == gamma(x)*polygamma(0, x)
pytest.raises(ArgumentIndexError, lambda: gamma(x).fdiff(2))
assert gamma(x - 1).expand(func=True) == gamma(x)/(x - 1)
assert gamma(x + 2).expand(func=True, mul=False) == x*(x + 1)*gamma(x)
assert conjugate(gamma(x)) == gamma(conjugate(x))
assert expand_func(gamma(x + Rational(3, 2))) == \
(x + Rational(1, 2))*gamma(x + Rational(1, 2))
assert expand_func(gamma(x - Rational(1, 2))) == \
gamma(Rational(1, 2) + x)/(x - Rational(1, 2))
# Test a bug:
assert expand_func(gamma(x + Rational(3, 4))) == gamma(x + Rational(3, 4))
assert gamma(3*exp_polar(I*pi)/4).is_nonnegative is False
assert gamma(3*exp_polar(I*pi)/4).is_nonpositive is True
# Issue sympy/sympy#8526
k = Symbol('k', integer=True, nonnegative=True)
assert isinstance(gamma(k), gamma)
assert gamma(-k) == zoo
def test_loggamma():
pytest.raises(TypeError, lambda: loggamma(2, 3))
pytest.raises(ArgumentIndexError, lambda: loggamma(x).fdiff(2))
assert loggamma(-1) == oo
assert loggamma(-2) == oo
assert loggamma(0) == oo
assert loggamma(1) == 0
assert loggamma(2) == 0
assert loggamma(3) == log(2)
assert loggamma(4) == log(6)
n = Symbol('n', integer=True, positive=True)
assert loggamma(n) == log(gamma(n))
assert loggamma(-n) == oo
assert loggamma(n/2) == log(2**(-n + 1)*sqrt(pi)*gamma(n)/gamma(n/2 + Rational(1, 2)))
assert loggamma(oo) == oo
assert loggamma(-oo) == zoo
assert loggamma(I*oo) == zoo
assert loggamma(-I*oo) == zoo
assert loggamma(zoo) == zoo
assert loggamma(nan) == nan
L = loggamma(Rational(16, 3))
E = -5*log(3) + loggamma(Rational(1, 3)) + log(4) + log(7) + log(10) + log(13)
assert expand_func(L).doit() == E
assert L.evalf() == E.evalf()
L = loggamma(Rational(19, 4))
E = -4*log(4) + loggamma(Rational(3, 4)) + log(3) + log(7) + log(11) + log(15)
assert expand_func(L).doit() == E
assert L.evalf() == E.evalf()
L = loggamma(Rational(23, 7))
E = -3*log(7) + log(2) + loggamma(Rational(2, 7)) + log(9) + log(16)
assert expand_func(L).doit() == E
assert L.evalf() == E.evalf()
L = loggamma(Rational(19, 4) - 7)
E = -log(9) - log(5) + loggamma(Rational(3, 4)) + 3*log(4) - 3*I*pi
assert expand_func(L).doit() == E
assert L.evalf() == E.evalf()
L = loggamma(Rational(23, 7) - 6)
E = -log(19) - log(12) - log(5) + loggamma(Rational(2, 7)) + 3*log(7) - 3*I*pi
assert expand_func(L).doit() == E
assert L.evalf() == E.evalf()
assert expand_func(loggamma(x)) == loggamma(x)
assert expand_func(loggamma(Rational(1, 3))) == loggamma(Rational(1, 3))
assert loggamma(x).diff(x) == polygamma(0, x)
s1 = loggamma(1/(x + sin(x)) + cos(x)).series(x, n=4)
s2 = (-log(2*x) - 1)/(2*x) - log(x/pi)/2 + (4 - log(2*x))*x/24 + O(x**2) + \
log(x)*x**2/2
assert (s1 - s2).expand(force=True).removeO() == 0
s1 = loggamma(1/x).series(x)
s2 = (1/x - Rational(1, 2))*log(1/x) - 1/x + log(2*pi)/2 + \
x/12 - x**3/360 + x**5/1260 + O(x**7)
assert ((s1 - s2).expand(force=True)).removeO() == 0
assert loggamma(x).rewrite('intractable') == log(gamma(x))
s1 = loggamma(x).series(x)
assert s1 == -log(x) - EulerGamma*x + pi**2*x**2/12 + x**3*polygamma(2, 1)/6 + \
pi**4*x**4/360 + x**5*polygamma(4, 1)/120 + O(x**6)
assert s1 == loggamma(x).rewrite('intractable').series(x)
assert conjugate(loggamma(x)) == conjugate(loggamma(x), evaluate=False)
p = Symbol('p', positive=True)
c = Symbol('c', complex=True, extended_real=False)
assert conjugate(loggamma(p)) == loggamma(p)
assert conjugate(loggamma(c)) == loggamma(conjugate(c))
assert conjugate(loggamma(0)) == conjugate(loggamma(0))
assert conjugate(loggamma(1)) == loggamma(conjugate(1))
assert conjugate(loggamma(-oo)) == conjugate(loggamma(-oo))
assert loggamma(x).is_extended_real is None
y = Symbol('y', nonnegative=True)
assert loggamma(y).is_extended_real
assert loggamma(w).is_extended_real is None
def tN(N, M):
assert loggamma(1/x)._eval_nseries(x, n=N).getn() == M
tN(0, 0)
tN(1, 1)
tN(2, 3)
tN(3, 3)
tN(4, 5)
tN(5, 5)
def test_sympyissue_10610():
assert limit(3**x*3**(-x - 1)*(x + 1)**2/x**2, x, oo) == Rational(1, 3)
assert limit(2**x*2**(-x - 1)*(x + 1)*(y - 1)**(-x) *
(y - 1)**(x + 1)/(x + 2), x, oo) == y/2 - Rational(1, 2)
def test_inverse_mellin_transform():
IMT = inverse_mellin_transform
assert IMT(gamma(s), s, x, (0, oo)) == exp(-x)
assert IMT(gamma(-s), s, x, (-oo, 0)) == exp(-1 / x)
assert simplify(IMT(s/(2*s**2 - 2), s, x, (2, oo))) == \
(x**2 + 1)*Heaviside(1 - x)/(4*x)
# test passing "None"
assert IMT(1/(s**2 - 1), s, x, (-1, None)) == \
-x*Heaviside(-x + 1)/2 - Heaviside(x - 1)/(2*x)
assert IMT(1/(s**2 - 1), s, x, (None, 1)) == \
(-x/2 + 1/(2*x))*Heaviside(-x + 1)
# test expansion of sums
assert IMT(gamma(s) + gamma(s - 1), s, x, (1, oo)) == (x + 1) * exp(-x) / x
# test factorisation of polys
r = symbols('r', extended_real=True)
assert (IMT(1 / (s**2 + 1), s, exp(-x), (None, oo)).subs(
x, r).rewrite(sin).simplify() == sin(r) * Heaviside(1 - exp(-r)))
# test multiplicative substitution
_a, _b = symbols('a b', positive=True)
assert IMT(_b**(-s / _a) * factorial(s / _a) / s, s, x,
(0, oo)) == exp(-_b * x**_a)
assert IMT(factorial(_a / _b + s / _b) / (_a + s), s, x,
(-_a, oo)) == x**_a * exp(-x**_b)
def simp_pows(expr):
return simplify(powsimp(expand_mul(expr, deep=False),
force=True)).replace(exp_polar, exp)
# Now test the inverses of all direct transforms tested above
# Section 8.4.2
nu = symbols('nu', real=True)
assert IMT(-1 / (nu + s), s, x, (-oo, None)) == x**nu * Heaviside(x - 1)
assert IMT(1 / (nu + s), s, x, (None, oo)) == x**nu * Heaviside(1 - x)
assert simp_pows(IMT(gamma(beta)*gamma(s)/gamma(s + beta), s, x, (0, oo))) \
== (1 - x)**(beta - 1)*Heaviside(1 - x)
assert simp_pows(IMT(gamma(beta)*gamma(1 - beta - s)/gamma(1 - s),
s, x, (-oo, None))) \
== (x - 1)**(beta - 1)*Heaviside(x - 1)
assert simp_pows(IMT(gamma(s)*gamma(rho - s)/gamma(rho), s, x, (0, None))) \
== (1/(x + 1))**rho
assert simp_pows(IMT(d**c*d**(s - 1)*sin(pi*c)
* gamma(s)*gamma(s + c)*gamma(1 - s)*gamma(1 - s - c)/pi,
s, x, (Max(-re(c), 0), Min(1 - re(c), 1)))) \
== (x**c - d**c)/(x - d)
assert simplify(IMT(1/sqrt(pi)*(-c/2)*gamma(s)*gamma((1 - c)/2 - s)
* gamma(-c/2 - s)/gamma(1 - c - s),
s, x, (0, -re(c)/2))) == \
(1 + sqrt(x + 1))**c
assert simplify(IMT(2**(a + 2*s)*b**(a + 2*s - 1)*gamma(s)*gamma(1 - a - 2*s)
/ gamma(1 - a - s), s, x, (0, (-re(a) + 1)/2))) == \
b**(a - 1)*(sqrt(1 + x/b**2) + 1)**(a - 1)*(b**2*sqrt(1 + x/b**2) +
b**2 + x)/(b**2 + x)
assert simplify(IMT(-2**(c + 2*s)*c*b**(c + 2*s)*gamma(s)*gamma(-c - 2*s)
/ gamma(-c - s + 1), s, x, (0, -re(c)/2))) == \
b**c*(sqrt(1 + x/b**2) + 1)**c
# Section 8.4.5
assert IMT(24 / s**5, s, x, (0, oo)) == log(x)**4 * Heaviside(1 - x)
assert expand(IMT(6/s**4, s, x, (-oo, 0)), force=True) == \
log(x)**3*Heaviside(x - 1)
assert IMT(pi / (s * sin(pi * s)), s, x, (-1, 0)) == log(x + 1)
assert IMT(pi / (s * sin(pi * s / 2)), s, x, (-2, 0)) == log(x**2 + 1)
assert IMT(pi / (s * sin(2 * pi * s)), s, x,
(-Rational(1, 2), 0)) == log(sqrt(x) + 1)
assert IMT(pi / (s * sin(pi * s)), s, x, (0, 1)) == log(1 + 1 / x)
# TODO
def mysimp(expr):
return expand(powsimp(logcombine(expr, force=True),
force=True,
deep=True),
force=True).replace(exp_polar, exp)
assert mysimp(mysimp(IMT(pi / (s * tan(pi * s)), s, x, (-1, 0)))) in [
log(1 - x) * Heaviside(1 - x) + log(x - 1) * Heaviside(x - 1),
log(x) * Heaviside(x - 1) + log(1 - 1 / x) * Heaviside(x - 1) +
log(-x + 1) * Heaviside(-x + 1)
]
# test passing cot
assert mysimp(IMT(pi * cot(pi * s) / s, s, x, (0, 1))) in [
log(1 / x - 1) * Heaviside(1 - x) + log(1 - 1 / x) * Heaviside(x - 1),
-log(x) * Heaviside(-x + 1) + log(1 - 1 / x) * Heaviside(x - 1) +
log(-x + 1) * Heaviside(-x + 1),
]
# 8.4.14
assert IMT(-gamma(s + Rational(1, 2))/(sqrt(pi)*s), s, x, (-Rational(1, 2), 0)) == \
erf(sqrt(x))
# 8.4.19
assert simplify(IMT(gamma(a/2 + s)/gamma(a/2 - s + 1), s, x, (-re(a)/2, Rational(3, 4)))) \
== besselj(a, 2*sqrt(x))
assert simplify(IMT(2**a*gamma(Rational(1, 2) - 2*s)*gamma(s + (a + 1)/2)
/ (gamma(1 - s - a/2)*gamma(1 - 2*s + a)),
s, x, (-(re(a) + 1)/2, Rational(1, 4)))) == \
sin(sqrt(x))*besselj(a, sqrt(x))
assert simplify(IMT(2**a*gamma(a/2 + s)*gamma(Rational(1, 2) - 2*s)
/ (gamma(Rational(1, 2) - s - a/2)*gamma(1 - 2*s + a)),
s, x, (-re(a)/2, Rational(1, 4)))) == \
cos(sqrt(x))*besselj(a, sqrt(x))
# TODO this comes out as an amazing mess, but simplifies nicely
assert simplify(IMT(gamma(a + s)*gamma(Rational(1, 2) - s)
/ (sqrt(pi)*gamma(1 - s)*gamma(1 + a - s)),
s, x, (-re(a), Rational(1, 2)))) == \
besselj(a, sqrt(x))**2
assert simplify(IMT(gamma(s)*gamma(Rational(1, 2) - s)
/ (sqrt(pi)*gamma(1 - s - a)*gamma(1 + a - s)),
s, x, (0, Rational(1, 2)))) == \
besselj(-a, sqrt(x))*besselj(a, sqrt(x))
assert simplify(IMT(4**s*gamma(-2*s + 1)*gamma(a/2 + b/2 + s)
/ (gamma(-a/2 + b/2 - s + 1)*gamma(a/2 - b/2 - s + 1)
* gamma(a/2 + b/2 - s + 1)),
s, x, (-(re(a) + re(b))/2, Rational(1, 2)))) == \
besselj(a, sqrt(x))*besselj(b, sqrt(x))
# Section 8.4.20
# TODO this can be further simplified!
assert simplify(IMT(-2**(2*s)*cos(pi*a/2 - pi*b/2 + pi*s)*gamma(-2*s + 1) *
gamma(a/2 - b/2 + s)*gamma(a/2 + b/2 + s) /
(pi*gamma(a/2 - b/2 - s + 1)*gamma(a/2 + b/2 - s + 1)),
s, x,
(Max(-re(a)/2 - re(b)/2, -re(a)/2 + re(b)/2), Rational(1, 2)))) == \
besselj(a, sqrt(x))*-(besselj(-b, sqrt(x)) -
besselj(b, sqrt(x))*cos(pi*b))/sin(pi*b)
# TODO more
# for coverage
assert IMT(pi / cos(pi * s), s, x,
(0, Rational(1, 2))) == sqrt(x) / (x + 1)
def test_sympyissue_11672():
assert limit(Rational(-1, 2)**x, x, oo) == 0
assert limit(1/(-2)**x, x, oo) == 0
def test_mellin_transform():
MT = mellin_transform
bpos = symbols('b', positive=True)
# 8.4.2
assert MT(x**nu*Heaviside(x - 1), x, s) == \
(-1/(nu + s), (-oo, -re(nu)), True)
assert MT(x**nu*Heaviside(1 - x), x, s) == \
(1/(nu + s), (-re(nu), oo), True)
assert MT((1 - x)**(beta - 1)*Heaviside(1 - x), x, s) == \
(gamma(beta)*gamma(s)/gamma(beta + s), (0, oo), re(-beta) < 0)
assert MT((x - 1)**(beta - 1)*Heaviside(x - 1), x, s) == \
(gamma(beta)*gamma(1 - beta - s)/gamma(1 - s),
(-oo, -re(beta) + 1), re(-beta) < 0)
assert MT((1 + x)**(-rho), x, s) == \
(gamma(s)*gamma(rho - s)/gamma(rho), (0, re(rho)), True)
# TODO also the conditions should be simplified
assert MT(abs(1 - x)**(-rho), x,
s) == (2 * sin(pi * rho / 2) * gamma(1 - rho) *
cos(pi * (rho / 2 - s)) * gamma(s) * gamma(rho - s) / pi,
(0, re(rho)), And(re(rho) - 1 < 0,
re(rho) < 1))
mt = MT((1 - x)**(beta - 1) * Heaviside(1 - x) + a *
(x - 1)**(beta - 1) * Heaviside(x - 1), x, s)
assert mt[1], mt[2] == ((0, -re(beta) + 1), True)
assert MT((x**a - b**a)/(x - b), x, s)[0] == \
pi*b**(a + s - 1)*sin(pi*a)/(sin(pi*s)*sin(pi*(a + s)))
assert MT((x**a - bpos**a)/(x - bpos), x, s) == \
(pi*bpos**(a + s - 1)*sin(pi*a)/(sin(pi*s)*sin(pi*(a + s))),
(Max(-re(a), 0), Min(1 - re(a), 1)), True)
expr = (sqrt(x + b**2) + b)**a
assert MT(expr.subs(b, bpos), x, s) == \
(-a*(2*bpos)**(a + 2*s)*gamma(s)*gamma(-a - 2*s)/gamma(-a - s + 1),
(0, -re(a)/2), True)
expr = (sqrt(x + b**2) + b)**a / sqrt(x + b**2)
assert MT(expr.subs(b, bpos), x, s) == \
(2**(a + 2*s)*bpos**(a + 2*s - 1)*gamma(s)
* gamma(1 - a - 2*s)/gamma(1 - a - s),
(0, -re(a)/2 + Rational(1, 2)), True)
# 8.4.2
assert MT(exp(-x), x, s) == (gamma(s), (0, oo), True)
assert MT(exp(-1 / x), x, s) == (gamma(-s), (-oo, 0), True)
# 8.4.5
assert MT(log(x)**4 * Heaviside(1 - x), x, s) == (24 / s**5, (0, oo), True)
assert MT(log(x)**3 * Heaviside(x - 1), x, s) == (6 / s**4, (-oo, 0), True)
assert MT(log(x + 1), x, s) == (pi / (s * sin(pi * s)), (-1, 0), True)
assert MT(log(1 / x + 1), x, s) == (pi / (s * sin(pi * s)), (0, 1), True)
assert MT(log(abs(1 - x)), x, s) == (pi / (s * tan(pi * s)), (-1, 0), True)
assert MT(log(abs(1 - 1 / x)), x,
s) == (pi / (s * tan(pi * s)), (0, 1), True)
# TODO we cannot currently do these (needs summation of 3F2(-1))
# this also implies that they cannot be written as a single g-function
# (although this is possible)
mt = MT(log(x) / (x + 1), x, s)
assert mt[1:] == ((0, 1), True)
assert not hyperexpand(mt[0], allow_hyper=True).has(meijerg)
mt = MT(log(x)**2 / (x + 1), x, s)
assert mt[1:] == ((0, 1), True)
assert not hyperexpand(mt[0], allow_hyper=True).has(meijerg)
mt = MT(log(x) / (x + 1)**2, x, s)
assert mt[1:] == ((0, 2), True)
assert not hyperexpand(mt[0], allow_hyper=True).has(meijerg)
# 8.4.14
assert MT(erf(sqrt(x)), x, s) == \
(-gamma(s + Rational(1, 2))/(sqrt(pi)*s), (-Rational(1, 2), 0), True)
def test_sympyissue_13332():
assert limit(sqrt(30)*5**(-5*n - 1)*(46656*n)**n *
(5*n + 2)**(5*n + Rational(5, 2)) *
(6*n + 2)**(-6*n - Rational(5, 2)), n, oo) == Rational(25, 36)
def test_multiple_integration():
assert integrate((x**2) * (y**2), (x, 0, 1), (y, -1, 2)) == Rational(1)
assert integrate((y**2) * (x**2), x, y) == Rational(1, 9) * (x**3) * (y**3)
assert integrate(1/(x + 3)/(1 + x)**3, x) == \
-Rational(1, 8)*log(3 + x) + Rational(1, 8)*log(1 + x) + x/(4 + 8*x + 4*x**2)
def test_sympyissue_14793():
e = ((x + Rational(1, 2))*log(x) - x +
log(2*pi)/2 - log(factorial(x)) + 1/(12*x))*x**3
assert limit(e, x, oo) == Rational(1, 360)
def test_issue_4052():
f = Rational(1, 2) * asin(x) + x * sqrt(1 - x**2) / 2
assert integrate(cos(asin(x)), x) == f
assert integrate(sin(acos(x)), x) == f
def test_sympyissue_6990():
assert (sqrt(a + b*x + x**2)).series(x, 0, 3).removeO() == \
b*x/(2*sqrt(a)) + x**2*(1/(2*sqrt(a)) -
b**2/(8*a**Rational(3, 2))) + sqrt(a)
def test_issue_4517():
assert integrate((sqrt(x) - x**3)/x**Rational(1, 3), x) == \
6*x**Rational(7, 6)/7 - 3*x**Rational(11, 3)/11
def test_sympyissue_15146():
assert limit((n/2)*(-2*n**3 - 2*(n**3 - 1)*n**2*digamma(n**3 + 1) +
2*(n**3 - 1)*n**2*digamma(n**3 + n + 1) +
n + 3), n, oo) == Rational(1, 3)
def test_polygamma():
assert polygamma(n, nan) == nan
assert polygamma(0, oo) == oo
assert polygamma(0, -oo) == oo
assert polygamma(0, I*oo) == oo
assert polygamma(0, -I*oo) == oo
assert polygamma(1, oo) == 0
assert polygamma(5, oo) == 0
assert polygamma(n, oo) == polygamma(n, oo, evaluate=False)
assert polygamma(0, -9) == zoo
assert polygamma(0, -9) == zoo
assert polygamma(0, -1) == zoo
assert polygamma(0, 0) == zoo
assert polygamma(0, 1) == -EulerGamma
assert polygamma(0, 7) == Rational(49, 20) - EulerGamma
assert polygamma(0, -Rational(3, 11)) == polygamma(0, -Rational(3, 11),
evaluate=False)
assert polygamma(1, 1) == pi**2/6
assert polygamma(1, 2) == pi**2/6 - 1
assert polygamma(1, 3) == pi**2/6 - Rational(5, 4)
assert polygamma(3, 1) == pi**4 / 15
assert polygamma(3, 5) == 6*(Rational(-22369, 20736) + pi**4/90)
assert polygamma(5, 1) == 8 * pi**6 / 63
assert trigamma(x) == polygamma(1, x)
def t(m, n):
x = Integer(m)/n
r = polygamma(0, x)
if r.has(polygamma):
return False
return abs(polygamma(0, x.evalf()).evalf(strict=False) - r.evalf()).evalf(strict=False) < 1e-10
assert t(1, 2)
assert t(3, 2)
assert t(-1, 2)
assert t(1, 4)
assert t(-3, 4)
assert t(1, 3)
assert t(4, 3)
assert t(3, 4)
assert t(2, 3)
assert polygamma(0, x).rewrite(zeta) == polygamma(0, x)
assert polygamma(1, x).rewrite(zeta) == zeta(2, x)
assert polygamma(2, x).rewrite(zeta) == -2*zeta(3, x)
assert polygamma(3, 7*x).diff(x) == 7*polygamma(4, 7*x)
pytest.raises(ArgumentIndexError, lambda: polygamma(3, 7*x).fdiff(3))
assert polygamma(0, x).rewrite(harmonic) == harmonic(x - 1) - EulerGamma
assert polygamma(2, x).rewrite(harmonic) == 2*harmonic(x - 1, 3) - 2*zeta(3)
ni = Symbol('n', integer=True)
assert polygamma(ni, x).rewrite(harmonic) == (-1)**(ni + 1)*(-harmonic(x - 1, ni + 1)
+ zeta(ni + 1))*factorial(ni)
assert polygamma(x, y).rewrite(harmonic) == polygamma(x, y)
# Polygamma of non-negative integer order is unbranched:
k = Symbol('n', integer=True, nonnegative=True)
assert polygamma(k, exp_polar(2*I*pi)*x) == polygamma(k, x)
# but negative integers are branched!
k = Symbol('n', integer=True)
assert polygamma(k, exp_polar(2*I*pi)*x).args == (k, exp_polar(2*I*pi)*x)
# Polygamma of order -1 is loggamma:
assert polygamma(-1, x) == loggamma(x)
# But smaller orders are iterated integrals and don't have a special name
assert isinstance(polygamma(-2, x), polygamma)
# Test a bug
assert polygamma(0, -x).expand(func=True) == polygamma(0, -x)
assert polygamma(1, x).as_leading_term(x) == polygamma(1, x)
def test_sympyissue_6068():
assert sqrt(sin(x)).series(x, 0, 8) == \
sqrt(x) - x**Rational(5, 2)/12 + x**Rational(9, 2)/1440 - \
x**Rational(13, 2)/24192 + O(x**8)
assert sqrt(sin(x)).series(x, 0, 10) == \
sqrt(x) - x**Rational(5, 2)/12 + x**Rational(9, 2)/1440 - \
x**Rational(13, 2)/24192 - 67*x**Rational(17, 2)/29030400 + O(x**10)
assert sqrt(sin(x**3)).series(x, 0, 19) == \
x**Rational(3, 2) - x**Rational(15, 2)/12 + x**Rational(27, 2)/1440 + O(x**19)
assert sqrt(sin(x**3)).series(x, 0, 20) == \
x**Rational(3, 2) - x**Rational(15, 2)/12 + x**Rational(27, 2)/1440 - \
x**Rational(39, 2)/24192 + O(x**20)