def sympy_atoms_namespace(expr):
"""For no real reason this function is separated from
sympy_expression_namespace. It can be moved to it."""
atoms = expr.atoms(Symbol, NumberSymbol, I, zoo, oo)
d = {}
for a in atoms:
# XXX debug: print 'atom:' + str(a)
d[str(a)] = a
return d
python类oo()的实例源码
def test_L2():
b1 = L2(Interval(-oo, 1))
assert isinstance(b1, L2)
assert b1.dimension == oo
assert b1.interval == Interval(-oo, 1)
x = Symbol('x', real=True)
y = Symbol('y', real=True)
b2 = L2(Interval(x, y))
assert b2.dimension == oo
assert b2.interval == Interval(x, y)
assert b2.subs(x, -1) == L2(Interval(-1, y))
def test_fock_space():
f1 = FockSpace()
f2 = FockSpace()
assert isinstance(f1, FockSpace)
assert f1.dimension == oo
assert f1 == f2
def eval(cls, dimension):
if len(dimension.atoms()) == 1:
if not (dimension.is_Integer and dimension > 0 or dimension is oo
or dimension.is_Symbol):
raise TypeError('The dimension of a ComplexSpace can only'
'be a positive integer, oo, or a Symbol: %r'
% dimension)
else:
for dim in dimension.atoms():
if not (dim.is_Integer or dim is oo or dim.is_Symbol):
raise TypeError('The dimension of a ComplexSpace can only'
' contain integers, oo, or a Symbol: %r'
% dim)
def dimension(self):
arg_list = [arg.dimension for arg in self.args]
if oo in arg_list:
return oo
else:
return reduce(lambda x, y: x*y, arg_list)
def dimension(self):
arg_list = [arg.dimension for arg in self.args]
if oo in arg_list:
return oo
else:
return reduce(lambda x, y: x + y, arg_list)
def dimension(self):
if self.base.dimension == oo:
return oo
else:
return self.base.dimension**self.exp
def default_args(self):
return (oo,)
def test_norm():
# Maximum "n" which is tested:
n_max = 2
# you can test any n and it works, but it's slow, so it's commented out:
#n_max = 4
for n in range(n_max + 1):
for l in range(n):
assert integrate(R_nl(n, l, r)**2 * r**2, (r, 0, oo)) == 1
def test_norm(n=1):
# Maximum "n" which is tested:
for i in range(n + 1):
assert integrate(psi_n(i, x, 1, 1)**2, (x, -oo, oo)) == 1
def test_orthogonality(n=1):
# Maximum "n" which is tested:
for i in range(n + 1):
for j in range(i + 1, n + 1):
assert integrate(
psi_n(i, x, 1, 1)*psi_n(j, x, 1, 1), (x, -oo, oo)) == 0
def _eval_rewrite_as_Sum(self, ap, bq, z):
from sympy.functions import factorial, RisingFactorial, Piecewise
n = C.Dummy("n", integer=True)
rfap = Tuple(*[RisingFactorial(a, n) for a in ap])
rfbq = Tuple(*[RisingFactorial(b, n) for b in bq])
coeff = Mul(*rfap) / Mul(*rfbq)
return Piecewise((C.Sum(coeff * z**n / factorial(n), (n, 0, oo)),
self.convergence_statement), (self, True))
def convergence_statement(self):
""" Return a condition on z under which the series converges. """
from sympy import And, Or, re, Ne, oo
R = self.radius_of_convergence
if R == 0:
return False
if R == oo:
return True
# The special functions and their approximations, page 44
e = self.eta
z = self.argument
c1 = And(re(e) < 0, abs(z) <= 1)
c2 = And(0 <= re(e), re(e) < 1, abs(z) <= 1, Ne(z, 1))
c3 = And(re(e) >= 1, abs(z) < 1)
return Or(c1, c2, c3)
def get_period(self):
"""
Return a number P such that G(x*exp(I*P)) == G(x).
>>> from sympy.functions.special.hyper import meijerg
>>> from sympy.abc import z
>>> from sympy import pi, S
>>> meijerg([1], [], [], [], z).get_period()
2*pi
>>> meijerg([pi], [], [], [], z).get_period()
oo
>>> meijerg([1, 2], [], [], [], z).get_period()
oo
>>> meijerg([1,1], [2], [1, S(1)/2, S(1)/3], [1], z).get_period()
12*pi
"""
# This follows from slater's theorem.
def compute(l):
# first check that no two differ by an integer
for i, b in enumerate(l):
if not b.is_Rational:
return oo
for j in range(i + 1, len(l)):
if not Mod((b - l[j]).simplify(), 1):
return oo
return reduce(ilcm, (x.q for x in l), 1)
beta = compute(self.bm)
alpha = compute(self.an)
p, q = len(self.ap), len(self.bq)
if p == q:
if beta == oo or alpha == oo:
return oo
return 2*pi*ilcm(alpha, beta)
elif p < q:
return 2*pi*beta
else:
return 2*pi*alpha
def eval(cls, ar, period):
# Our strategy is to evaluate the argument on the riemann surface of the
# logarithm, and then reduce.
# NOTE evidently this means it is a rather bad idea to use this with
# period != 2*pi and non-polar numbers.
from sympy import ceiling, oo, atan2, atan, polar_lift, pi, Mul
if not period.is_positive:
return None
if period == oo and isinstance(ar, principal_branch):
return periodic_argument(*ar.args)
if ar.func is polar_lift and period >= 2*pi:
return periodic_argument(ar.args[0], period)
if ar.is_Mul:
newargs = [x for x in ar.args if not x.is_positive]
if len(newargs) != len(ar.args):
return periodic_argument(Mul(*newargs), period)
unbranched = cls._getunbranched(ar)
if unbranched is None:
return None
if unbranched.has(periodic_argument, atan2, arg, atan):
return None
if period == oo:
return unbranched
if period != oo:
n = ceiling(unbranched/period - S(1)/2)*period
if not n.has(ceiling):
return unbranched - n
def _eval_evalf(self, prec):
from sympy import ceiling, oo
z, period = self.args
if period == oo:
unbranched = periodic_argument._getunbranched(z)
if unbranched is None:
return self
return unbranched._eval_evalf(prec)
ub = periodic_argument(z, oo)._eval_evalf(prec)
return (ub - ceiling(ub/period - S(1)/2)*period)._eval_evalf(prec)
def _default_integrator(f, x):
return integrate(f, (x, 0, oo))
def _as_integral(self, f, x, s):
from sympy import Integral
return Integral(f*x**(s - 1), (x, 0, oo))
def mellin_transform(f, x, s, **hints):
r"""
Compute the Mellin transform `F(s)` of `f(x)`,
.. math :: F(s) = \int_0^\infty x^{s-1} f(x) \mathrm{d}x.
For all "sensible" functions, this converges absolutely in a strip
`a < \operatorname{Re}(s) < b`.
The Mellin transform is related via change of variables to the Fourier
transform, and also to the (bilateral) Laplace transform.
This function returns ``(F, (a, b), cond)``
where ``F`` is the Mellin transform of ``f``, ``(a, b)`` is the fundamental strip
(as above), and ``cond`` are auxiliary convergence conditions.
If the integral cannot be computed in closed form, this function returns
an unevaluated :class:`MellinTransform` object.
For a description of possible hints, refer to the docstring of
:func:`sympy.integrals.transforms.IntegralTransform.doit`. If ``noconds=False``,
then only `F` will be returned (i.e. not ``cond``, and also not the strip
``(a, b)``).
>>> from sympy.integrals.transforms import mellin_transform
>>> from sympy import exp
>>> from sympy.abc import x, s
>>> mellin_transform(exp(-x), x, s)
(gamma(s), (0, oo), True)
See Also
========
inverse_mellin_transform, laplace_transform, fourier_transform
hankel_transform, inverse_hankel_transform
"""
return MellinTransform(f, x, s).doit(**hints)
def _as_integral(self, F, s, x):
from sympy import Integral, I, oo
c = self.__class__._c
return Integral(F*x**(-s), (s, c - I*oo, c + I*oo))
