def eval(cls, n, z):
n, z = list(map(sympify, (n, z)))
from sympy import unpolarify
if n.is_integer:
if n.is_nonnegative:
nz = unpolarify(z)
if z != nz:
return polygamma(n, nz)
if n == -1:
return loggamma(z)
else:
if z.is_Number:
if z is S.NaN:
return S.NaN
elif z is S.Infinity:
if n.is_Number:
if n is S.Zero:
return S.Infinity
else:
return S.Zero
elif z.is_Integer:
if z.is_nonpositive:
return S.ComplexInfinity
else:
if n is S.Zero:
return -S.EulerGamma + C.harmonic(z - 1, 1)
elif n.is_odd:
return (-1) ** (n + 1) * C.factorial(n) * zeta(n + 1, z)
if n == 0:
if z is S.NaN:
return S.NaN
elif z.is_Rational:
# TODO actually *any* n/m can be done, but that is messy
lookup = {
S(1) / 2: -2 * log(2) - S.EulerGamma,
S(1) / 3: -S.Pi / 2 / sqrt(3) - 3 * log(3) / 2 - S.EulerGamma,
S(1) / 4: -S.Pi / 2 - 3 * log(2) - S.EulerGamma,
S(3) / 4: -3 * log(2) - S.EulerGamma + S.Pi / 2,
S(2) / 3: -3 * log(3) / 2 + S.Pi / 2 / sqrt(3) - S.EulerGamma,
}
if z > 0:
n = floor(z)
z0 = z - n
if z0 in lookup:
return lookup[z0] + Add(*[1 / (z0 + k) for k in range(n)])
elif z < 0:
n = floor(1 - z)
z0 = z + n
if z0 in lookup:
return lookup[z0] - Add(*[1 / (z0 - 1 - k) for k in range(n)])
elif z in (S.Infinity, S.NegativeInfinity):
return S.Infinity
else:
t = z.extract_multiplicatively(S.ImaginaryUnit)
if t in (S.Infinity, S.NegativeInfinity):
return S.Infinity
def test_issue_8413():
x = Symbol('x', real=True)
# we can't evaluate in general because non-reals are not
# comparable: Min(floor(3.2 + I), 3.2 + I) -> ValueError
assert Min(floor(x), x) == floor(x)
assert Min(ceiling(x), x) == x
assert Max(floor(x), x) == x
assert Max(ceiling(x), x) == ceiling(x)
def test_slicing():
assert X[1:5, 2:4] == MatrixSlice(X, (1, 5), (2, 4))
assert X[1, 2:4] == MatrixSlice(X, 1, (2, 4))
assert X[1:5, :].shape == (4, X.shape[1])
assert X[:, 1:5].shape == (X.shape[0], 4)
assert X[::2, ::2].shape == (floor(n/2), floor(m/2))
assert X[2, :] == MatrixSlice(X, 2, (0, m))
def as_relational(self, x):
"""Rewrite a Range in terms of equalities and logic operators. """
from sympy.functions.elementary.integers import floor
return And(
Eq(x, floor(x)),
x >= self.inf if self.inf in self else x > self.inf,
x <= self.sup if self.sup in self else x < self.sup)
def real_root(arg, n=None):
"""Return the real nth-root of arg if possible. If n is omitted then
all instances of (-n)**(1/odd) will be changed to -n**(1/odd); this
will only create a real root of a principle root -- the presence of
other factors may cause the result to not be real.
Examples
========
>>> from sympy import root, real_root, Rational
>>> from sympy.abc import x, n
>>> real_root(-8, 3)
-2
>>> root(-8, 3)
2*(-1)**(1/3)
>>> real_root(_)
-2
If one creates a non-principle root and applies real_root, the
result will not be real (so use with caution):
>>> root(-8, 3, 2)
-2*(-1)**(2/3)
>>> real_root(_)
-2*(-1)**(2/3)
See Also
========
sympy.polys.rootoftools.rootof
sympy.core.power.integer_nthroot
root, sqrt
"""
from sympy import im, Piecewise
if n is not None:
try:
n = as_int(n)
arg = sympify(arg)
if arg.is_positive or arg.is_negative:
rv = root(arg, n)
else:
raise ValueError
except ValueError:
return root(arg, n)*Piecewise(
(S.One, ~Equality(im(arg), 0)),
(Pow(S.NegativeOne, S.One/n)**(2*floor(n/2)), And(
Equality(n % 2, 1),
arg < 0)),
(S.One, True))
else:
rv = sympify(arg)
n1pow = Transform(lambda x: -(-x.base)**x.exp,
lambda x:
x.is_Pow and
x.base.is_negative and
x.exp.is_Rational and
x.exp.p == 1 and x.exp.q % 2)
return rv.xreplace(n1pow)
def _eval_rewrite_as_polynomial(self, n, m, x, **kwargs):
from sympy import Sum
k = Dummy("k")
kern = factorial(2 * n - 2 * k) / (
2**n * factorial(n - k) * factorial(k) *
factorial(n - 2 * k - m)) * (-1)**k * x**(n - m - 2 * k)
return (1 - x**2)**(m / 2) * Sum(kern, (k, 0, floor((n - m) * S.Half)))
def test_tribonacci():
assert [tribonacci(n) for n in range(8)] == [0, 1, 1, 2, 4, 7, 13, 24]
assert tribonacci(100) == 98079530178586034536500564
assert tribonacci(0, x) == 0
assert tribonacci(1, x) == 1
assert tribonacci(2, x) == x**2
assert tribonacci(3, x) == x**4 + x
assert tribonacci(4, x) == x**6 + 2 * x**3 + 1
assert tribonacci(5, x) == x**8 + 3 * x**5 + 3 * x**2
n = Dummy('n')
assert tribonacci(n).limit(n, S.Infinity) is S.Infinity
w = (-1 + S.ImaginaryUnit * sqrt(3)) / 2
a = (1 + cbrt(19 + 3 * sqrt(33)) + cbrt(19 - 3 * sqrt(33))) / 3
b = (1 + w * cbrt(19 + 3 * sqrt(33)) + w**2 * cbrt(19 - 3 * sqrt(33))) / 3
c = (1 + w**2 * cbrt(19 + 3 * sqrt(33)) + w * cbrt(19 - 3 * sqrt(33))) / 3
assert tribonacci(n).rewrite(sqrt) == \
(a**(n + 1)/((a - b)*(a - c))
+ b**(n + 1)/((b - a)*(b - c))
+ c**(n + 1)/((c - a)*(c - b)))
assert tribonacci(n).rewrite(sqrt).subs(n, 4).simplify() == tribonacci(4)
assert tribonacci(n).rewrite(GoldenRatio).subs(n,10).evalf() == \
tribonacci(10)
assert tribonacci(n).rewrite(TribonacciConstant) == floor(
3 * TribonacciConstant**n * (102 * sqrt(33) + 586)**Rational(1, 3) /
(-2 * (102 * sqrt(33) + 586)**Rational(1, 3) + 4 +
(102 * sqrt(33) + 586)**Rational(2, 3)) + S.Half)
raises(ValueError, lambda: tribonacci(-1, x))
def _eval_expand_func(self, **hints):
from sympy import Sum
n = self.args[0]
m = self.args[1] if len(self.args) == 2 else 1
if m == S.One:
if n.is_Add:
off = n.args[0]
nnew = n - off
if off.is_Integer and off.is_positive:
result = [S.One/(nnew + i) for i in range(off, 0, -1)] + [harmonic(nnew)]
return Add(*result)
elif off.is_Integer and off.is_negative:
result = [-S.One/(nnew + i) for i in range(0, off, -1)] + [harmonic(nnew)]
return Add(*result)
if n.is_Rational:
# Expansions for harmonic numbers at general rational arguments (u + p/q)
# Split n as u + p/q with p < q
p, q = n.as_numer_denom()
u = p // q
p = p - u * q
if u.is_nonnegative and p.is_positive and q.is_positive and p < q:
k = Dummy("k")
t1 = q * Sum(1 / (q * k + p), (k, 0, u))
t2 = 2 * Sum(cos((2 * pi * p * k) / S(q)) *
log(sin((pi * k) / S(q))),
(k, 1, floor((q - 1) / S(2))))
t3 = (pi / 2) * cot((pi * p) / q) + log(2 * q)
return t1 + t2 - t3
return self
def _eval_expand_func(self, **hints):
from sympy import Sum
n = self.args[0]
m = self.args[1] if len(self.args) == 2 else 1
if m == S.One:
if n.is_Add:
off = n.args[0]
nnew = n - off
if off.is_Integer and off.is_positive:
result = [S.One / (nnew + i)
for i in range(off, 0, -1)] + [harmonic(nnew)]
return Add(*result)
elif off.is_Integer and off.is_negative:
result = [-S.One / (nnew + i)
for i in range(0, off, -1)] + [harmonic(nnew)]
return Add(*result)
if n.is_Rational:
# Expansions for harmonic numbers at general rational arguments (u + p/q)
# Split n as u + p/q with p < q
p, q = n.as_numer_denom()
u = p // q
p = p - u * q
if u.is_nonnegative and p.is_positive and q.is_positive and p < q:
k = Dummy("k")
t1 = q * Sum(1 / (q * k + p), (k, 0, u))
t2 = 2 * Sum(
cos((2 * pi * p * k) / S(q)) * log(sin(
(pi * k) / S(q))), (k, 1, floor((q - 1) / S(2))))
t3 = (pi / 2) * cot((pi * p) / q) + log(2 * q)
return t1 + t2 - t3
return self
def real_root(arg, n=None):
"""Return the real nth-root of arg if possible. If n is omitted then
all instances of (-n)**(1/odd) will be changed to -n**(1/odd); this
will only create a real root of a principle root -- the presence of
other factors may cause the result to not be real.
Examples
========
>>> from sympy import root, real_root, Rational
>>> from sympy.abc import x, n
>>> real_root(-8, 3)
-2
>>> root(-8, 3)
2*(-1)**(1/3)
>>> real_root(_)
-2
If one creates a non-principle root and applies real_root, the
result will not be real (so use with caution):
>>> root(-8, 3, 2)
-2*(-1)**(2/3)
>>> real_root(_)
-2*(-1)**(2/3)
See Also
========
sympy.polys.rootoftools.RootOf
sympy.core.power.integer_nthroot
root, sqrt
"""
from sympy import im, Piecewise
if n is not None:
try:
n = as_int(n)
arg = sympify(arg)
if arg.is_positive or arg.is_negative:
rv = root(arg, n)
else:
raise ValueError
except ValueError:
return root(arg, n)*Piecewise(
(S.One, ~Equality(im(arg), 0)),
(Pow(S.NegativeOne, S.One/n)**(2*floor(n/2)), And(
Equality(n % 2, 1),
arg < 0)),
(S.One, True))
else:
rv = sympify(arg)
n1pow = Transform(lambda x: -(-x.base)**x.exp,
lambda x:
x.is_Pow and
x.base.is_negative and
x.exp.is_Rational and
x.exp.p == 1 and x.exp.q % 2)
return rv.xreplace(n1pow)
def _intersect(self, other):
from sympy.functions.elementary.integers import floor, ceiling
from sympy.functions.elementary.miscellaneous import Min, Max
if other.is_Interval:
osup = other.sup
oinf = other.inf
# if other is [0, 10) we can only go up to 9
if osup.is_integer and other.right_open:
osup -= 1
if oinf.is_integer and other.left_open:
oinf += 1
# Take the most restrictive of the bounds set by the two sets
# round inwards
inf = ceiling(Max(self.inf, oinf))
sup = floor(Min(self.sup, osup))
# if we are off the sequence, get back on
if inf.is_finite and self.inf.is_finite:
off = (inf - self.inf) % self.step
else:
off = S.Zero
if off:
inf += self.step - off
return Range(inf, sup + 1, self.step)
if other == S.Naturals:
return self._intersect(Interval(1, S.Infinity))
if other == S.Integers:
return self
return None
def sample(self):
""" A random realization from the distribution """
icdf = self._inverse_cdf_expression()
while True:
sample_ = floor(list(icdf(random.uniform(0, 1)))[0])
if sample_ >= self.set.inf:
return sample_
def sample(self):
""" A random realization from the distribution """
icdf = self._inverse_cdf_expression()
while True:
sample_ = floor(list(icdf(random.uniform(0, 1)))[0])
if sample_ >= self.set.inf:
return sample_
def test_issue_17681():
class identity_func(Function):
def _eval_evalf(self, *args, **kwargs):
return self.args[0].evalf(*args, **kwargs)
assert floor(identity_func(S(0))) == 0
assert get_integer_part(S(0), 1, {}, True) == (0, 0)
def _intersect(self, other):
from sympy.functions.elementary.integers import floor, ceiling
from sympy.functions.elementary.miscellaneous import Min, Max
if other.is_Interval:
osup = other.sup
oinf = other.inf
# if other is [0, 10) we can only go up to 9
if osup.is_integer and other.right_open:
osup -= 1
if oinf.is_integer and other.left_open:
oinf += 1
# Take the most restrictive of the bounds set by the two sets
# round inwards
inf = ceiling(Max(self.inf, oinf))
sup = floor(Min(self.sup, osup))
# if we are off the sequence, get back on
off = (inf - self.inf) % self.step
if off:
inf += self.step - off
return Range(inf, sup + 1, self.step)
if other == S.Naturals:
return self._intersect(Interval(1, S.Infinity))
if other == S.Integers:
return self
return None
def _intersect(self, other):
if other.is_Interval:
osup = other.sup
oinf = other.inf
# if other is [0, 10) we can only go up to 9
if osup.is_integer and other.right_open:
osup -= 1
if oinf.is_integer and other.left_open:
oinf += 1
# Take the most restrictive of the bounds set by the two sets
# round inwards
inf = ceiling(Max(self.inf, oinf))
sup = floor(Min(self.sup, osup))
# if we are off the sequence, get back on
off = (inf - self.inf) % self.step
if off:
inf += self.step - off
return Range(inf, sup + 1, self.step)
if other == S.Naturals:
return self._intersect(Interval(1, oo))
if other == S.Integers:
return self
return None
def test_floor_requires_robust_assumptions():
assert limit(floor(sin(x)), x, 0, "+") == 0
assert limit(floor(sin(x)), x, 0, "-") == -1
assert limit(floor(cos(x)), x, 0, "+") == 0
assert limit(floor(cos(x)), x, 0, "-") == 0
assert limit(floor(5 + sin(x)), x, 0, "+") == 5
assert limit(floor(5 + sin(x)), x, 0, "-") == 4
assert limit(floor(5 + cos(x)), x, 0, "+") == 5
assert limit(floor(5 + cos(x)), x, 0, "-") == 5
def _intersect(self, other):
from sympy.functions.elementary.integers import floor, ceiling
if other is Interval(S.NegativeInfinity, S.Infinity) or other is S.Reals:
return self
elif other.is_Interval:
s = Range(ceiling(other.left), floor(other.right) + 1)
return s.intersect(other) # take out endpoints if open interval
return None
def _eval_rewrite_as_polynomial(self, n, x, **kwargs):
from sympy import Sum
k = Dummy("k")
kern = (
(-1) ** k / (factorial(k) * factorial(n - 2 * k)) * (2 * x) ** (n - 2 * k)
)
return factorial(n) * Sum(kern, (k, 0, floor(n / 2)))
def _intlike_interval(a, b):
try:
if b._inf is S.NegativeInfinity and b._sup is S.Infinity:
return a
s = Range(max(a.inf, ceiling(b.left)), floor(b.right) + 1)
return intersection_sets(s, b) # take out endpoints if open interval
except ValueError:
return None
def _intersect(self, other):
from sympy.functions.elementary.integers import floor, ceiling
if other is Interval(S.NegativeInfinity, S.Infinity) or other is S.Reals:
return self
elif other.is_Interval:
s = Range(ceiling(other.left), floor(other.right) + 1)
return s.intersect(other) # take out endpoints if open interval
return None
def _eval_expand_func(self, **hints):
n, z = self.args
if n.is_Integer and n.is_nonnegative:
if z.is_Add:
coeff = z.args[0]
if coeff.is_Integer:
e = -(n + 1)
if coeff > 0:
tail = Add(*[Pow(
z - i, e) for i in range(1, int(coeff) + 1)])
else:
tail = -Add(*[Pow(
z + i, e) for i in range(0, int(-coeff))])
return polygamma(n, z - coeff) + (-1)**n*factorial(n)*tail
elif z.is_Mul:
coeff, z = z.as_two_terms()
if coeff.is_Integer and coeff.is_positive:
tail = [ polygamma(n, z + Rational(
i, coeff)) for i in range(0, int(coeff)) ]
if n == 0:
return Add(*tail)/coeff + log(coeff)
else:
return Add(*tail)/coeff**(n + 1)
z *= coeff
if n == 0 and z.is_Rational:
p, q = z.as_numer_denom()
# Reference:
# Values of the polygamma functions at rational arguments, J. Choi, 2007
part_1 = -S.EulerGamma - pi * cot(p * pi / q) / 2 - log(q) + Add(
*[cos(2 * k * pi * p / q) * log(2 * sin(k * pi / q)) for k in range(1, q)])
if z > 0:
n = floor(z)
z0 = z - n
return part_1 + Add(*[1 / (z0 + k) for k in range(n)])
elif z < 0:
n = floor(1 - z)
z0 = z + n
return part_1 - Add(*[1 / (z0 - 1 - k) for k in range(n)])
return polygamma(n, z)
def _eval_expand_func(self, **hints):
n, z = self.args
if n.is_Integer and n.is_nonnegative:
if z.is_Add:
coeff = z.args[0]
if coeff.is_Integer:
e = -(n + 1)
if coeff > 0:
tail = Add(*[Pow(
z - i, e) for i in range(1, int(coeff) + 1)])
else:
tail = -Add(*[Pow(
z + i, e) for i in range(0, int(-coeff))])
return polygamma(n, z - coeff) + (-1)**n*factorial(n)*tail
elif z.is_Mul:
coeff, z = z.as_two_terms()
if coeff.is_Integer and coeff.is_positive:
tail = [ polygamma(n, z + Rational(
i, coeff)) for i in range(0, int(coeff)) ]
if n == 0:
return Add(*tail)/coeff + log(coeff)
else:
return Add(*tail)/coeff**(n + 1)
z *= coeff
if n == 0 and z.is_Rational:
p, q = z.as_numer_denom()
# Reference:
# Values of the polygamma functions at rational arguments, J. Choi, 2007
part_1 = -S.EulerGamma - pi * cot(p * pi / q) / 2 - log(q) + Add(
*[cos(2 * k * pi * p / q) * log(2 * sin(k * pi / q)) for k in range(1, q)])
if z > 0:
n = floor(z)
z0 = z - n
return part_1 + Add(*[1 / (z0 + k) for k in range(n)])
elif z < 0:
n = floor(1 - z)
z0 = z + n
return part_1 - Add(*[1 / (z0 - 1 - k) for k in range(n)])
return polygamma(n, z)
def intersection_sets(a, b):
try:
from sympy.functions.elementary.integers import floor, ceiling
if b._inf is S.NegativeInfinity and b._sup is S.Infinity:
return a
s = Range(ceiling(b.left), floor(b.right) + 1)
return intersection_sets(s, b) # take out endpoints if open interval
except ValueError:
return None
def size(self):
if self.start == self.stop:
return S.Zero
dif = self.stop - self.start
n = dif / self.step
if n.is_infinite:
return S.Infinity
if n.is_extended_nonnegative and all(i.is_integer for i in self.args):
return abs(floor(n))
raise ValueError('Invalid method for symbolic Range')
def apply(n):
X = Symbol.X(integer=True, random=True)
if n.is_even:
return Equality(Expectation[X:DieDistribution(n)](X | (X > n / 2)),
(3 * n + 2) / 4)
elif n.is_odd:
return Equality(Expectation[X:DieDistribution(n)](X | (X > n / 2)),
(3 * n + 1) / 4)
else:
return Equality(Expectation[X:DieDistribution(n)](X | (X > n / 2)),
n / 2 + floor(n / 2) / 2)
def _eval_rewrite_as_polynomial(self, n, x, **kwargs):
from sympy import Sum
k = Dummy("k")
kern = (
S.NegativeOne ** k
* factorial(n - k)
* (2 * x) ** (n - 2 * k)
/ (factorial(k) * factorial(n - 2 * k))
)
return Sum(kern, (k, 0, floor(n / 2)))
def sample(self, size=(1, ), library='scipy'):
""" A random realization from the distribution"""
if hasattr(self, '_sample_scipy') and import_module('scipy'):
return self._sample_scipy(size=size)
icdf = self._inverse_cdf_expression()
samp_list = []
while True:
sample_ = floor(list(icdf(random.uniform(0, 1)))[0])
if sample_ >= self.set.inf:
samp_list.append(sample_)
if len(samp_list) == size:
return samp_list
def test_gegenbauer():
n = Symbol("n")
a = Symbol("a")
assert gegenbauer(0, a, x) == 1
assert gegenbauer(1, a, x) == 2 * a * x
assert gegenbauer(2, a, x) == -a + x**2 * (2 * a**2 + 2 * a)
assert gegenbauer(3, a, x) == \
x**3*(4*a**3/3 + 4*a**2 + a*Rational(8, 3)) + x*(-2*a**2 - 2*a)
assert gegenbauer(-1, a, x) == 0
assert gegenbauer(n, S.Half, x) == legendre(n, x)
assert gegenbauer(n, 1, x) == chebyshevu(n, x)
assert gegenbauer(n, -1, x) == 0
X = gegenbauer(n, a, x)
assert isinstance(X, gegenbauer)
assert gegenbauer(n, a, -x) == (-1)**n * gegenbauer(n, a, x)
assert gegenbauer(n, a, 0) == 2**n*sqrt(pi) * \
gamma(a + n/2)/(gamma(a)*gamma(-n/2 + S.Half)*gamma(n + 1))
assert gegenbauer(n, a,
1) == gamma(2 * a + n) / (gamma(2 * a) * gamma(n + 1))
assert gegenbauer(n, Rational(3, 4), -1) is zoo
assert gegenbauer(n, Rational(1, 4),
-1) == (sqrt(2) * cos(pi * (n + S.One / 4)) *
gamma(n + S.Half) / (sqrt(pi) * gamma(n + 1)))
m = Symbol("m", positive=True)
assert gegenbauer(m, a, oo) == oo * RisingFactorial(a, m)
assert unchanged(gegenbauer, n, a, oo)
assert conjugate(gegenbauer(n,
a, x)) == gegenbauer(n, conjugate(a),
conjugate(x))
_k = Dummy('k')
assert diff(gegenbauer(n, a, x), n) == Derivative(gegenbauer(n, a, x), n)
assert diff(gegenbauer(n, a, x), a).dummy_eq(
Sum((2 * (-1)**(-_k + n) + 2) * (_k + a) * gegenbauer(_k, a, x) /
((-_k + n) * (_k + 2 * a + n)) +
((2 * _k + 2) / ((_k + 2 * a) * (2 * _k + 2 * a + 1)) + 2 /
(_k + 2 * a + n)) * gegenbauer(n, a, x), (_k, 0, n - 1)))
assert diff(gegenbauer(n, a, x), x) == 2 * a * gegenbauer(n - 1, a + 1, x)
assert gegenbauer(n, a, x).rewrite('polynomial').dummy_eq(
Sum((-1)**_k * (2 * x)**(-2 * _k + n) * RisingFactorial(a, -_k + n) /
(factorial(_k) * factorial(-2 * _k + n)), (_k, 0, floor(n / 2))))
raises(ArgumentIndexError, lambda: gegenbauer(n, a, x).fdiff(4))
def _compute_slice_size(idx: Any, axis_size: Any) -> Any: # noqa: R701
if idx is None:
return axis_size
if not isinstance(idx, sp.Tuple):
return 1
start, stop, step = idx
if stop is None and axis_size is None:
return None
size = stop - start
size = size if step == 1 or step is None else floor(size / step)
if axis_size is not None and (size > axis_size) == True: # noqa: E712
return axis_size
return size
def test_assoc_legendre():
Plm = assoc_legendre
Q = sqrt(1 - x**2)
assert Plm(0, 0, x) == 1
assert Plm(1, 0, x) == x
assert Plm(1, 1, x) == -Q
assert Plm(2, 0, x) == (3 * x**2 - 1) / 2
assert Plm(2, 1, x) == -3 * x * Q
assert Plm(2, 2, x) == 3 * Q**2
assert Plm(3, 0, x) == (5 * x**3 - 3 * x) / 2
assert Plm(3, 1,
x).expand() == ((3 * (1 - 5 * x**2) / 2).expand() * Q).expand()
assert Plm(3, 2, x) == 15 * x * Q**2
assert Plm(3, 3, x) == -15 * Q**3
# negative m
assert Plm(1, -1, x) == -Plm(1, 1, x) / 2
assert Plm(2, -2, x) == Plm(2, 2, x) / 24
assert Plm(2, -1, x) == -Plm(2, 1, x) / 6
assert Plm(3, -3, x) == -Plm(3, 3, x) / 720
assert Plm(3, -2, x) == Plm(3, 2, x) / 120
assert Plm(3, -1, x) == -Plm(3, 1, x) / 12
n = Symbol("n")
m = Symbol("m")
X = Plm(n, m, x)
assert isinstance(X, assoc_legendre)
assert Plm(n, 0, x) == legendre(n, x)
assert Plm(n, m, 0) == 2**m * sqrt(pi) / (gamma(-m / 2 - n / 2 + S.Half) *
gamma(-m / 2 + n / 2 + 1))
assert diff(Plm(m, n, x),
x) == (m * x * assoc_legendre(m, n, x) -
(m + n) * assoc_legendre(m - 1, n, x)) / (x**2 - 1)
_k = Dummy('k')
assert Plm(m, n, x).rewrite("polynomial").dummy_eq(
(1 - x**2)**(n / 2) * Sum(
(-1)**_k * 2**(-m) * x**(-2 * _k + m - n) *
factorial(-2 * _k + 2 * m) /
(factorial(_k) * factorial(-_k + m) * factorial(-2 * _k + m - n)),
(_k, 0, floor(m / 2 - n / 2))))
assert conjugate(assoc_legendre(n, m, x)) == \
assoc_legendre(n, conjugate(m), conjugate(x))
raises(ValueError, lambda: Plm(0, 1, x))
raises(ValueError, lambda: Plm(-1, 1, x))
raises(ArgumentIndexError, lambda: Plm(n, m, x).fdiff(1))
raises(ArgumentIndexError, lambda: Plm(n, m, x).fdiff(2))
raises(ArgumentIndexError, lambda: Plm(n, m, x).fdiff(4))
def eval(cls, arg):
from sympy import atan
arg = sympify(arg)
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg.is_zero:
return S.Zero
elif arg is S.One:
return S.Infinity
elif arg is S.NegativeOne:
return S.NegativeInfinity
elif arg is S.Infinity:
return -S.ImaginaryUnit * atan(arg)
elif arg is S.NegativeInfinity:
return S.ImaginaryUnit * atan(-arg)
elif arg.is_negative:
return -cls(-arg)
else:
if arg is S.ComplexInfinity:
from sympy.calculus.util import AccumBounds
return S.ImaginaryUnit * AccumBounds(-S.Pi / 2, S.Pi / 2)
i_coeff = arg.as_coefficient(S.ImaginaryUnit)
if i_coeff is not None:
return S.ImaginaryUnit * atan(i_coeff)
else:
if _coeff_isneg(arg):
return -cls(-arg)
if arg.is_zero:
return S.Zero
if isinstance(arg, tanh) and arg.args[0].is_number:
z = arg.args[0]
if z.is_real:
return z
r, i = match_real_imag(z)
if r is not None and i is not None:
f = floor(2 * i / pi)
even = f.is_even
m = z - I * f * pi / 2
if even is True:
return m
elif even is False:
return m - I * pi / 2
def eval_prob(self, _domain):
if isinstance(_domain, Range):
n = symbols('n')
inf, sup, step = (r for r in _domain.args)
summand = ((self.pdf).replace(self.symbol, inf + n * step))
rv = summation(summand,
(n, 0, floor((sup - inf) / step - 1))).doit()
return rv
elif isinstance(_domain, FiniteSet):
pdf = Lambda(self.symbol, self.pdf)
rv = sum(pdf(x) for x in _domain)
return rv
elif isinstance(_domain, Union):
rv = sum(self.eval_prob(x) for x in _domain.args)
return rv
def _eval_expand_func(self, deep=True, **hints):
if deep:
arg = self.args[0].expand(deep, **hints)
else:
arg = self.args[0]
if arg.is_Add:
coeff, tail = arg.as_coeff_add()
if coeff and coeff.q != 1:
tail = (C.Rational(1, coeff.q), ) + tail
coeff = floor(coeff)
tail = arg._new_rawargs(*tail, **dict(reeval=False))
return gamma(tail) * C.RisingFactorial(tail, coeff)
return self.func(*self.args)
def compute_cdf(self, **kwargs):
""" Compute the CDF from the PDF.
Returns a Lambda.
"""
x = symbols('x', integer=True, cls=Dummy)
z = symbols('z', real=True, cls=Dummy)
left_bound = self.set.inf
# CDF is integral of PDF from left bound to z
pdf = self.pdf(x)
cdf = summation(pdf, (x, left_bound, floor(z)), **kwargs)
# CDF Ensure that CDF left of left_bound is zero
cdf = Piecewise((cdf, z >= left_bound), (0, True))
return Lambda(z, cdf)
def _eval_expand_func(self, deep=True, **hints):
if deep:
arg = self.args[0].expand(deep, **hints)
else:
arg = self.args[0]
if arg.is_Add:
coeff, tail = arg.as_coeff_add()
if coeff and coeff.q != 1:
tail = (C.Rational(1, coeff.q),) + tail
coeff = floor(coeff)
tail = arg._new_rawargs(*tail, **dict(reeval=False))
return gamma(tail)*C.RisingFactorial(tail, coeff)
return self.func(*self.args)
def test_evalf_integer_parts():
a = floor(log(8) / log(2) - exp(-1000), evaluate=False)
b = floor(log(8) / log(2), evaluate=False)
assert a.evalf() == 3
assert b.evalf() == 3
# equals, as a fallback, can still fail but it might succeed as here
assert ceiling(10 * (sin(1)**2 + cos(1)**2)) == 10
assert int(floor(factorial(50)/E, evaluate=False).evalf(70)) == \
int(11188719610782480504630258070757734324011354208865721592720336800)
assert int(ceiling(factorial(50)/E, evaluate=False).evalf(70)) == \
int(11188719610782480504630258070757734324011354208865721592720336801)
assert int(floor(GoldenRatio**999 / sqrt(5) +
S.Half).evalf(1000)) == fibonacci(999)
assert int(floor(GoldenRatio**1000 / sqrt(5) +
S.Half).evalf(1000)) == fibonacci(1000)
assert ceiling(x).evalf(subs={x: 3}) == 3
assert ceiling(x).evalf(subs={x: 3 * I}) == 3.0 * I
assert ceiling(x).evalf(subs={x: 2 + 3 * I}) == 2.0 + 3.0 * I
assert ceiling(x).evalf(subs={x: 3.}) == 3
assert ceiling(x).evalf(subs={x: 3. * I}) == 3.0 * I
assert ceiling(x).evalf(subs={x: 2. + 3 * I}) == 2.0 + 3.0 * I
assert float((floor(1.5, evaluate=False) + 1 / 9).evalf()) == 1 + 1 / 9
assert float((floor(0.5, evaluate=False) + 20).evalf()) == 20
# issue 19991
n = 1169809367327212570704813632106852886389036911
r = 744723773141314414542111064094745678855643068
assert floor(n / (pi / 2)) == r
assert floor(80782 * sqrt(2)) == 114242
# issue 20076
assert 260515 - floor(260515 / pi + 1 / 2) * pi == atan(tan(260515))
def eval(cls, arg):
from sympy import asin
arg = sympify(arg)
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.Infinity
elif arg is S.NegativeInfinity:
return S.NegativeInfinity
elif arg.is_zero:
return S.Zero
elif arg is S.One:
return log(sqrt(2) + 1)
elif arg is S.NegativeOne:
return log(sqrt(2) - 1)
elif arg.is_negative:
return -cls(-arg)
else:
if arg is S.ComplexInfinity:
return S.ComplexInfinity
if arg.is_zero:
return S.Zero
i_coeff = arg.as_coefficient(S.ImaginaryUnit)
if i_coeff is not None:
return S.ImaginaryUnit * asin(i_coeff)
else:
if _coeff_isneg(arg):
return -cls(-arg)
if isinstance(arg, sinh) and arg.args[0].is_number:
z = arg.args[0]
if z.is_real:
return z
r, i = match_real_imag(z)
if r is not None and i is not None:
f = floor((i + pi / 2) / pi)
m = z - I * pi * f
even = f.is_even
if even is True:
return m
elif even is False:
return -m
def eval_prob(self, _domain):
if isinstance(_domain, Range):
n = symbols('n')
inf, sup, step = (r for r in _domain.args)
summand = ((self.pdf).replace(
self.symbol, inf + n*step))
rv = summation(summand,
(n, 0, floor((sup - inf)/step - 1))).doit()
return rv
elif isinstance(_domain, FiniteSet):
pdf = Lambda(self.symbol, self.pdf)
rv = sum(pdf(x) for x in _domain)
return rv
elif isinstance(_domain, Union):
rv = sum(self.eval_prob(x) for x in _domain.args)
return rv
def test_issue9474():
mods = [None, 'math']
if numpy:
mods.append('numpy')
if mpmath:
mods.append('mpmath')
for mod in mods:
f = lambdify(x, S.One / x, modules=mod)
assert f(2) == 0.5
f = lambdify(x, floor(S.One / x), modules=mod)
assert f(2) == 0
for absfunc, modules in product([Abs, abs], mods):
f = lambdify(x, absfunc(x), modules=modules)
assert f(-1) == 1
assert f(1) == 1
assert f(3 + 4j) == 5
def intersection_sets(a, b): # noqa:F811
from sympy.functions.elementary.integers import floor, ceiling
if not all(i.is_number for i in b.args[:2]):
return
# In case of null Range, return an EmptySet.
if a.size == 0:
return S.EmptySet
# trim down to self's size, and represent
# as a Range with step 1.
start = ceiling(max(b.inf, a.inf))
if start not in b:
start += 1
end = floor(min(b.sup, a.sup))
if end not in b:
end -= 1
return intersection_sets(a, Range(start, end + 1))
def eval_prob(self, _domain):
if isinstance(_domain, Range):
n = symbols('n')
inf, sup, step = (r for r in _domain.args)
summand = ((self.pdf).replace(
self.symbol, inf + n*step))
rv = summation(summand,
(n, 0, floor((sup - inf)/step - 1))).doit()
return rv
elif isinstance(_domain, FiniteSet):
pdf = Lambda(self.symbol, self.pdf)
rv = sum(pdf(x) for x in _domain)
return rv
elif isinstance(_domain, Union):
rv = sum(self.eval_prob(x) for x in _domain.args)
return rv
else:
raise NotImplementedError(filldedent('''Probability for
the domain %s cannot be calculated.'''%(_domain)))
def _eval_expand_func(self, **hints):
arg = self.args[0]
if arg.is_Rational:
if abs(arg.p) > arg.q:
x = Dummy("x")
n = arg.p // arg.q
p = arg.p - n * arg.q
return gamma(x + n)._eval_expand_func().subs(x, Rational(p, arg.q))
if arg.is_Add:
coeff, tail = arg.as_coeff_add()
if coeff and coeff.q != 1:
intpart = floor(coeff)
tail = (coeff - intpart,) + tail
coeff = intpart
tail = arg._new_rawargs(*tail, reeval=False)
return gamma(tail) * C.RisingFactorial(tail, coeff)
return self.func(*self.args)
def intersection_sets(a, b):
from sympy.functions.elementary.integers import floor, ceiling
from sympy.functions.elementary.miscellaneous import Min, Max
if not all(i.is_number for i in b.args[:2]):
return
# In case of null Range, return an EmptySet.
if a.size == 0:
return S.EmptySet
# trim down to self's size, and represent
# as a Range with step 1.
start = ceiling(max(b.inf, a.inf))
if start not in b:
start += 1
end = floor(min(b.sup, a.sup))
if end not in b:
end -= 1
return intersection_sets(a, Range(start, end + 1))
def update(self):
filled_length = round(self.width * self.progress, self.tenths)
filled_length_int = floor(self.width * self.progress)
_int = round(filled_length - filled_length_int, self.tenths)
phase = self.nphases[_int]
#print(filled_length)
#print(filled_length_int)
#print(_int)
#print(phase)
percent = "{:.0%} ".format(self.progress)
empty_length = round(self.width - filled_length, 1)
message = self.message
if filled_length == 0:
bar = ' '
else:
bar = self.COLOR.format('█'* int(filled_length)+ phase)
empty = ' ' * int(empty_length)
#suffix = self.suffix
line = ''.join([message, percent, self.bar_prefix, bar, empty, self.bar_prefix])
self.file.writelines(line)
self.file.flush()
def _eval_is_positive(self):
x = self.args[0]
if x.is_positive:
return True
elif x.is_noninteger:
return floor(x).is_even
def _eval_rewrite_as_polynomial(self, n, x):
from sympy import Sum
k = Dummy("k")
kern = (-1)**k / (factorial(k)*factorial(n - 2*k)) * (2*x)**(n - 2*k)
return factorial(n)*Sum(kern, (k, 0, floor(n/2)))
def test_issue_8623():
assert integrate((1 + cos(2*x)) / (3 - 2*cos(2*x)), (x, 0, pi)) == -pi/2 + sqrt(5)*pi/2
assert integrate((1 + cos(2*x))/(3 - 2*cos(2*x))) == -x/2 + sqrt(5)*(atan(sqrt(5)*tan(x)) + \
pi*floor((x - pi/2)/pi))/2
def _intersect(self, other):
if other.is_Interval:
s = FiniteSet(range(ceiling(other.left), floor(other.right) + 1))
return s.intersect(other) # take out endpoints if open interval
return None
def _eval_rewrite_as_polynomial(self, n, x):
from sympy import Sum
k = Dummy("k")
kern = S.NegativeOne**k * factorial(
n - k) * (2*x)**(n - 2*k) / (factorial(k) * factorial(n - 2*k))
return Sum(kern, (k, 0, floor(n/2)))
def _eval_rewrite_as_polynomial(self, n, m, x):
from sympy import Sum
k = Dummy("k")
kern = factorial(2*n - 2*k)/(2**n*factorial(n - k)*factorial(
k)*factorial(n - 2*k - m))*(-1)**k*x**(n - m - 2*k)
return (1 - x**2)**(m/2) * Sum(kern, (k, 0, floor((n - m)*S.Half)))
def shape(self):
rows = self.rowslice[1] - self.rowslice[0]
rows = rows if self.rowslice[2] == 1 else floor(rows/self.rowslice[2])
cols = self.colslice[1] - self.colslice[0]
cols = cols if self.colslice[2] == 1 else floor(cols/self.colslice[2])
return rows, cols
def _eval_rewrite_as_polynomial(self, n, x):
from sympy import Sum
k = Dummy("k")
kern = binomial(n, 2*k) * (x**2 - 1)**k * x**(n - 2*k)
return Sum(kern, (k, 0, floor(n/2)))
def rsolve_hypergeometric(f, x, P, Q, k, m):
"""Solves RE of hypergeometric type.
Attempts to solve RE of the form
Q(k)*a(k + m) - P(k)*a(k)
Transformations that preserve Hypergeometric type:
a. x**n*f(x): b(k + m) = R(k - n)*b(k)
b. f(A*x): b(k + m) = A**m*R(k)*b(k)
c. f(x**n): b(k + n*m) = R(k/n)*b(k)
d. f(x**(1/m)): b(k + 1) = R(k*m)*b(k)
e. f'(x): b(k + m) = ((k + m + 1)/(k + 1))*R(k + 1)*b(k)
Some of these transformations have been used to solve the RE.
Returns
=======
formula : Expr
ind : Expr
Independent terms.
order : int
Examples
========
>>> from sympy import exp, ln, S
>>> from sympy.series.formal import rsolve_hypergeometric as rh
>>> from sympy.abc import x, k
>>> rh(exp(x), x, -S.One, (k + 1), k, 1)
(Piecewise((1/factorial(k), Eq(Mod(k, 1), 0)), (0, True)), 1, 1)
>>> rh(ln(1 + x), x, k**2, k*(k + 1), k, 1)
(Piecewise(((-1)**(k - 1)*factorial(k - 1)/RisingFactorial(2, k - 1),
Eq(Mod(k, 1), 0)), (0, True)), x, 2)
References
==========
.. [1] Formal Power Series - Dominik Gruntz, Wolfram Koepf
.. [2] Power Series in Computer Algebra - Wolfram Koepf
"""
result = _rsolve_hypergeometric(f, x, P, Q, k, m)
if result is None:
return None
sol_list, ind, mp = result
sol_dict = defaultdict(lambda: S.Zero)
for res, cond in sol_list:
j, mk = cond.as_coeff_Add()
c = mk.coeff(k)
if j.is_integer is False:
res *= x**frac(j)
j = floor(j)
res = res.subs(k, (k - j) / c)
cond = Eq(k % c, j % c)
sol_dict[cond] += res # Group together formula for same conditions
sol = []
for cond, res in sol_dict.items():
sol.append((res, cond))
sol.append((S.Zero, True))
sol = Piecewise(*sol)
if mp is -oo:
s = S.Zero
elif mp.is_integer is False:
s = ceiling(mp)
else:
s = mp + 1
# save all the terms of
# form 1/x**k in ind
if s < 0:
ind += sum(sequence(sol * x**k, (k, s, -1)))
s = S.Zero
return (sol, ind, s)
def _intersect(self, other):
if other.is_Interval and other.measure < oo:
s = Range(ceiling(other.left), floor(other.right) + 1)
return s.intersect(other) # take out endpoints if open interval
return None
def _intersect(self, other):
from sympy.functions.elementary.integers import floor, ceiling
if other.is_Interval and other.measure < S.Infinity:
s = Range(ceiling(other.left), floor(other.right) + 1)
return s.intersect(other) # take out endpoints if open interval
return None
def test_sympy__functions__elementary__integers__floor():
from sympy.functions.elementary.integers import floor
assert _test_args(floor(x))
def test_issue_13749():
assert integrate(1 / (2 + cos(x)), (x, 0, pi)) == pi/sqrt(3)
assert integrate(1/(2 + cos(x))) == 2*sqrt(3)*(atan(sqrt(3)*tan(x/2)/3) + pi*floor((x/2 - pi/2)/pi))/3
def _intersect(self, other):
from sympy.functions.elementary.integers import ceiling, floor
from sympy.functions.elementary.complexes import sign
if other is S.Naturals:
return self._intersect(Interval(1, S.Infinity))
if other is S.Integers:
return self
if other.is_Interval:
if not all(i.is_number for i in other.args[:2]):
return
# In case of null Range, return an EmptySet.
if self.size == 0:
return S.EmptySet
# trim down to self's size, and represent
# as a Range with step 1.
start = ceiling(max(other.inf, self.inf))
if start not in other:
start += 1
end = floor(min(other.sup, self.sup))
if end not in other:
end -= 1
return self.intersect(Range(start, end + 1))
if isinstance(other, Range):
from sympy.solvers.diophantine import diop_linear
from sympy.core.numbers import ilcm
# non-overlap quick exits
if not other:
return S.EmptySet
if not self:
return S.EmptySet
if other.sup < self.inf:
return S.EmptySet
if other.inf > self.sup:
return S.EmptySet
# work with finite end at the start
r1 = self
if r1.start.is_infinite:
r1 = r1.reversed
r2 = other
if r2.start.is_infinite:
r2 = r2.reversed
# this equation represents the values of the Range;
# it's a linear equation
eq = lambda r, i: r.start + i*r.step
# we want to know when the two equations might
# have integer solutions so we use the diophantine
# solver
a, b = diop_linear(eq(r1, Dummy()) - eq(r2, Dummy()))
# check for no solution
no_solution = a is None and b is None
if no_solution:
return S.EmptySet
# there is a solution
# -------------------
# find the coincident point, c
a0 = a.as_coeff_Add()[0]
c = eq(r1, a0)
# find the first point, if possible, in each range
# since c may not be that point
def _first_finite_point(r1, c):
if c == r1.start:
return c
# st is the signed step we need to take to
# get from c to r1.start
st = sign(r1.start - c)*step
# use Range to calculate the first point:
# we want to get as close as possible to
# r1.start; the Range will not be null since
# it will at least contain c
s1 = Range(c, r1.start + st, st)[-1]
if s1 == r1.start:
pass
else:
# if we didn't hit r1.start then, if the
# sign of st didn't match the sign of r1.step
# we are off by one and s1 is not in r1
if sign(r1.step) != sign(st):
s1 -= st
if s1 not in r1:
return
return s1
# calculate the step size of the new Range
step = abs(ilcm(r1.step, r2.step))
s1 = _first_finite_point(r1, c)
if s1 is None:
return S.EmptySet
s2 = _first_finite_point(r2, c)
if s2 is None:
return S.EmptySet
# replace the corresponding start or stop in
# the original Ranges with these points; the
# result must have at least one point since
# we know that s1 and s2 are in the Ranges
def _updated_range(r, first):
st = sign(r.step)*step
if r.start.is_finite:
rv = Range(first, r.stop, st)
else:
rv = Range(r.start, first + st, st)
return rv
r1 = _updated_range(self, s1)
r2 = _updated_range(other, s2)
# work with them both in the increasing direction
if sign(r1.step) < 0:
r1 = r1.reversed
if sign(r2.step) < 0:
r2 = r2.reversed
# return clipped Range with positive step; it
# can't be empty at this point
start = max(r1.start, r2.start)
stop = min(r1.stop, r2.stop)
return Range(start, stop, step)
else:
return
def _eval_rewrite_as_polynomial(self, n, a, x):
from sympy import Sum
k = Dummy("k")
kern = ((-1)**k * RisingFactorial(a, n - k) * (2*x)**(n - 2*k) /
(factorial(k) * factorial(n - 2*k)))
return Sum(kern, (k, 0, floor(n/2)))
