def fdiff(self, argindex=1):
if len(self.args) == 3:
n, z, m = self.args
fm, fn = sqrt(1 - m * sin(z) ** 2), 1 - n * sin(z) ** 2
if argindex == 1:
return (
elliptic_e(z, m)
+ (m - n) * elliptic_f(z, m) / n
+ (n ** 2 - m) * elliptic_pi(n, z, m) / n
- n * fm * sin(2 * z) / (2 * fn)
) / (2 * (m - n) * (n - 1))
elif argindex == 2:
return 1 / (fm * fn)
elif argindex == 3:
return (elliptic_e(z, m) / (m - 1) + elliptic_pi(n, z, m) - m * sin(2 * z) / (2 * (m - 1) * fm)) / (
2 * (n - m)
)
else:
n, m = self.args
if argindex == 1:
return (elliptic_e(m) + (m - n) * elliptic_k(m) / n + (n ** 2 - m) * elliptic_pi(n, m) / n) / (
2 * (m - n) * (n - 1)
)
elif argindex == 2:
return (elliptic_e(m) / (m - 1) + elliptic_pi(n, m)) / (2 * (n - m))
raise ArgumentIndexError(self, argindex)
def test_singular_values():
x = Symbol('x', real=True)
A = EigenOnlyMatrix([[0, 1*I], [2, 0]])
# if singular values can be sorted, they should be in decreasing order
assert A.singular_values() == [2, 1]
A = eye(3)
A[1, 1] = x
A[2, 2] = 5
vals = A.singular_values()
# since Abs(x) cannot be sorted, test set equality
assert set(vals) == set([5, 1, Abs(x)])
A = EigenOnlyMatrix([[sin(x), cos(x)], [-cos(x), sin(x)]])
vals = [sv.trigsimp() for sv in A.singular_values()]
assert vals == [S(1), S(1)]
A = EigenOnlyMatrix([
[2, 4],
[1, 3],
[0, 0],
[0, 0]
])
assert A.singular_values() == \
[sqrt(sqrt(221) + 15), sqrt(15 - sqrt(221))]
assert A.T.singular_values() == \
[sqrt(sqrt(221) + 15), sqrt(15 - sqrt(221)), 0, 0]
def taylor_term(n, x, *previous_terms):
if n < 0:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) > 1:
p = previous_terms[-1]
return (
(3 ** (S(1) / 3) * x) ** (-n)
* (3 ** (S(1) / 3) * x) ** (n + 1)
* sin(pi * (2 * n / 3 + S(4) / 3))
* factorial(n)
* gamma(n / 3 + S(2) / 3)
/ (sin(pi * (2 * n / 3 + S(2) / 3)) * factorial(n + 1) * gamma(n / 3 + S(1) / 3))
* p
)
else:
return (
S.One
/ (3 ** (S(2) / 3) * pi)
* gamma((n + S.One) / S(3))
* sin(2 * pi * (n + S.One) / S(3))
/ factorial(n)
* (root(3, 3) * x) ** n
)
def test_issue_3554():
x = Symbol("x")
assert (1 / sqrt(1 + cos(x) * sin(x ** 2))).series(x, 0, 7) == 1 - x ** 2 / 2 + 5 * x ** 4 / 8 - 5 * x ** 6 / 8 + O(
x ** 7
)
assert (1 / sqrt(1 + cos(x) * sin(x ** 2))).series(x, 0, 8) == 1 - x ** 2 / 2 + 5 * x ** 4 / 8 - 5 * x ** 6 / 8 + O(
x ** 8
)
def fdiff(self, argindex=1):
z, m = self.args
fm = sqrt(1 - m*sin(z)**2)
if argindex == 1:
return 1/fm
elif argindex == 2:
return (elliptic_e(z, m)/(2*m*(1 - m)) - elliptic_f(z, m)/(2*m) -
sin(2*z)/(4*(1 - m)*fm))
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_cos(self, n, m, theta, phi):
# This method can be expensive due to extensive use of simplification!
from sympy.simplify import simplify, trigsimp
# TODO: Make sure n \in N
# TODO: Assert |m| <= n ortherwise we should return 0
term = simplify(self.expand(func=True))
# We can do this because of the range of theta
term = term.xreplace({Abs(sin(theta)):sin(theta)})
return simplify(trigsimp(term))
def arbitrary_point(self, u=None, v=None):
""" Returns an arbitrary point on the Plane. If given two
parameters, the point ranges over the entire plane. If given 1
or no parameters, returns a point with one parameter which,
when varying from 0 to 2*pi, moves the point in a circle of
radius 1 about p1 of the Plane.
Examples
========
>>> from sympy.geometry import Plane, Ray
>>> from sympy.abc import u, v, t, r
>>> p = Plane((1, 1, 1), normal_vector=(1, 0, 0))
>>> p.arbitrary_point(u, v)
Point3D(1, u + 1, v + 1)
>>> p.arbitrary_point(t)
Point3D(1, cos(t) + 1, sin(t) + 1)
While arbitrary values of u and v can move the point anywhere in
the plane, the single-parameter point can be used to construct a
ray whose arbitrary point can be located at angle t and radius
r from p.p1:
>>> Ray(p.p1, _).arbitrary_point(r)
Point3D(1, r*cos(t) + 1, r*sin(t) + 1)
Returns
=======
Point3D
"""
circle = v is None
if circle:
u = _symbol(u or 't', real=True)
else:
u = _symbol(u or 'u', real=True)
v = _symbol(v or 'v', real=True)
x, y, z = self.normal_vector
a, b, c = self.p1.args
# x1, y1, z1 is a nonzero vector parallel to the plane
if x.is_zero and y.is_zero:
x1, y1, z1 = S.One, S.Zero, S.Zero
else:
x1, y1, z1 = -y, x, S.Zero
# x2, y2, z2 is also parallel to the plane, and orthogonal to x1, y1, z1
x2, y2, z2 = tuple(Matrix((x, y, z)).cross(Matrix((x1, y1, z1))))
if circle:
x1, y1, z1 = (w/sqrt(x1**2 + y1**2 + z1**2) for w in (x1, y1, z1))
x2, y2, z2 = (w/sqrt(x2**2 + y2**2 + z2**2) for w in (x2, y2, z2))
p = Point3D(a + x1*cos(u) + x2*sin(u), \
b + y1*cos(u) + y2*sin(u), \
c + z1*cos(u) + z2*sin(u))
else:
p = Point3D(a + x1*u + x2*v, b + y1*u + y2*v, c + z1*u + z2*v)
return p
def taylor_term(n, x, *previous_terms):
if n < 0:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) > 1:
p = previous_terms[-1]
return (3**(S(1)/3)*x * Abs(sin(2*pi*(n + S.One)/S(3))) * C.factorial((n - S.One)/S(3)) /
((n + S.One) * Abs(cos(2*pi*(n + S.Half)/S(3))) * C.factorial((n - 2)/S(3))) * p)
else:
return (S.One/(root(3, 6)*pi) * gamma((n + S.One)/S(3)) * Abs(sin(2*pi*(n + S.One)/S(3))) /
C.factorial(n) * (root(3, 3)*x)**n)
def test_issue_6068():
x = Symbol('x')
assert sqrt(sin(x)).series(x, 0, 7) == \
sqrt(x) - x**(S(5)/2)/12 + x**(S(9)/2)/1440 - \
x**(S(13)/2)/24192 + O(x**7)
assert sqrt(sin(x)).series(x, 0, 9) == \
sqrt(x) - x**(S(5)/2)/12 + x**(S(9)/2)/1440 - \
x**(S(13)/2)/24192 - 67*x**(S(17)/2)/29030400 + O(x**9)
assert sqrt(sin(x**3)).series(x, 0, 19) == \
x**(S(3)/2) - x**(S(15)/2)/12 + x**(S(27)/2)/1440 + O(x**19)
assert sqrt(sin(x**3)).series(x, 0, 20) == \
x**(S(3)/2) - x**(S(15)/2)/12 + x**(S(27)/2)/1440 - \
x**(S(39)/2)/24192 + O(x**20)
def test_bool_as_set():
assert ITE(y <= 0, False, y >= 1).as_set() == Interval(1, oo)
assert And(x <= 2, x >= -2).as_set() == Interval(-2, 2)
assert Or(x >= 2, x <= -2).as_set() == Interval(-oo, -2) + Interval(2, oo)
assert Not(x > 2).as_set() == Interval(-oo, 2)
# issue 10240
assert Not(And(x > 2, x < 3)).as_set() == \
Union(Interval(-oo, 2), Interval(3, oo))
assert true.as_set() == S.UniversalSet
assert false.as_set() == EmptySet()
assert x.as_set() == S.UniversalSet
assert And(Or(x < 1, x > 3), x < 2).as_set() == Interval.open(-oo, 1)
assert And(x < 1, sin(x) < 3).as_set() == (x < 1).as_set()
raises(NotImplementedError, lambda: (sin(x) < 1).as_set())
def test_issue_2969():
x = Symbol("x")
assert sqrt(sin(x)).series(x, 0, 7) == sqrt(x) - x ** (S(5) / 2) / 12 + x ** (S(9) / 2) / 1440 - x ** (
S(13) / 2
) / 24192 + O(x ** 7)
assert sqrt(sin(x)).series(x, 0, 9) == sqrt(x) - x ** (S(5) / 2) / 12 + x ** (S(9) / 2) / 1440 - x ** (
S(13) / 2
) / 24192 - 67 * x ** (S(17) / 2) / 29030400 + O(x ** 9)
assert sqrt(sin(x ** 3)).series(x, 0, 19) == sqrt(x ** 3) - x ** 6 * sqrt(x ** 3) / 12 + x ** 12 * sqrt(
x ** 3
) / 1440 + O(x ** 19)
assert sqrt(sin(x ** 3)).series(x, 0, 20) == sqrt(x ** 3) - x ** 6 * sqrt(x ** 3) / 12 + x ** 12 * sqrt(
x ** 3
) / 1440 - x ** 18 * sqrt(x ** 3) / 24192 + O(x ** 20)
def test_jacobian2():
rho, phi = symbols("rho,phi")
X = CalculusOnlyMatrix(3, 1, [rho*cos(phi), rho*sin(phi), rho**2])
Y = CalculusOnlyMatrix(2, 1, [rho, phi])
J = Matrix([
[cos(phi), -rho*sin(phi)],
[sin(phi), rho*cos(phi)],
[ 2*rho, 0],
])
assert X.jacobian(Y) == J
m = CalculusOnlyMatrix(2, 2, [1, 2, 3, 4])
m2 = CalculusOnlyMatrix(4, 1, [1, 2, 3, 4])
raises(TypeError, lambda: m.jacobian(Matrix([1,2])))
raises(TypeError, lambda: m2.jacobian(m))
def jn(n, z):
"""
Spherical Bessel function of the first kind.
Examples:
>>> from sympy import Symbol, jn, sin, cos
>>> z = Symbol("z")
>>> print jn(0, z)
sin(z)/z
>>> jn(1, z) == sin(z)/z**2 - cos(z)/z
True
>>> jn(3, z) ==(1/z - 15/z**3)*cos(z) + (15/z**4 - 6/z**2)*sin(z)
True
The spherical Bessel functions are calculated using the formula:
jn(n, z) == fn(n, z) * sin(z) + (-1)**(n+1) * fn(-n-1, z) * cos(z)
where fn(n, z) are the coefficients, see fn()'s sourcecode for more
information.
"""
n = sympify(n)
z = sympify(z)
return fn(n, z) * sin(z) + (-1)**(n+1) * fn(-n-1, z) * cos(z)
def test_issue_7638():
f = pi/log(sqrt(2))
assert ((1 + I)**(I*f/2))**0.3 == (1 + I)**(0.15*I*f)
# if 1/3 -> 1.0/3 this should fail since it cannot be shown that the
# sign will be +/-1; for the previous "small arg" case, it didn't matter
# that this could not be proved
assert (1 + I)**(4*I*f) == ((1 + I)**(12*I*f))**(S(1)/3)
assert (((1 + I)**(I*(1 + 7*f)))**(S(1)/3)).exp == S(1)/3
r = symbols('r', real=True)
assert sqrt(r**2) == abs(r)
assert cbrt(r**3) != r
assert sqrt(Pow(2*I, 5*S.Half)) != (2*I)**(5/S(4))
p = symbols('p', positive=True)
assert cbrt(p**2) == p**(2/S(3))
assert NS(((0.2 + 0.7*I)**(0.7 + 1.0*I))**(0.5 - 0.1*I), 1) == '0.4 + 0.2*I'
assert sqrt(1/(1 + I)) == sqrt(1 - I)/sqrt(2) # or 1/sqrt(1 + I)
e = 1/(1 - sqrt(2))
assert sqrt(e) == I/sqrt(-1 + sqrt(2))
assert e**-S.Half == -I*sqrt(-1 + sqrt(2))
assert sqrt((cos(1)**2 + sin(1)**2 - 1)**(3 + I)).exp == S.Half
assert sqrt(r**(4/S(3))) != r**(2/S(3))
assert sqrt((p + I)**(4/S(3))) == (p + I)**(2/S(3))
assert sqrt((p - p**2*I)**2) == p - p**2*I
assert sqrt((p + r*I)**2) != p + r*I
e = (1 + I/5)
assert sqrt(e**5) == e**(5*S.Half)
assert sqrt(e**6) == e**3
assert sqrt((1 + I*r)**6) != (1 + I*r)**3
def _test():
'''runs module unit tests'''
# Test below - tries every supported subexpression - takes a few seconds
x = symbols('x')
eq = sin(x + 0.01)
#eq = 1*x*x + (0.2-x) / x + sin(x+0.01) + sqrt(x + 1) + cos(x + 0.01) + tan(x + 0.01) - (x+0.1)**(x+0.1)
print eval_eq(eq, {'x':interval(0.20, 0.21)})
########################################################################
# Test below - makes sure evalEqMulti works as expected
x = symbols('x')
eq = x + interval(0.1)
range1 = {'x':interval(0, 1)}
range2 = {'x':interval(1, 2)}
for i in eval_eq_multi(eq, [range1, range2]):
print i
########################################################################
# Test below - makes sure eval_eq_multi_branch_bound works as expected
x = symbols('x')
eq = x*x - 2*x
range1 = {'x':interval(0, 2)}
for i in eval_eq_multi_branch_bound(eq, [range1], 0.1):
print i
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 test_issue_3554s():
x = Symbol("x")
assert (1 / sqrt(1 + cos(x) * sin(x ** 2))).series(
x, 0, 15
) == 1 - x ** 2 / 2 + 5 * x ** 4 / 8 - 5 * x ** 6 / 8 + 4039 * x ** 8 / 5760 - 5393 * x ** 10 / 6720 + 13607537 * x ** 12 / 14515200 - 532056047 * x ** 14 / 479001600 + O(
x ** 15
)
def finite_check(f, x, L):
def check_fx(exprs, x):
return x not in exprs.free_symbols
def check_sincos(expr, x, L):
if type(expr) == sin or type(expr) == cos:
sincos_args = expr.args[0]
if sincos_args.match(a*(pi/L)*x + b) is not None:
return True
else:
return False
expr = sincos_to_sum(TR2(TR1(f)))
res_expr = S.Zero
add_coeff = expr.as_coeff_add()
res_expr += add_coeff[0]
a = Wild('a', properties=[lambda k: k.is_Integer, lambda k: k != S.Zero, ])
b = Wild('b', properties=[lambda k: x not in k.free_symbols or k == S.Zero, ])
for s in add_coeff[1]:
mul_coeffs = s.as_coeff_mul()[1]
for t in mul_coeffs:
if not (check_fx(t, x) or check_sincos(t, x, L)):
return False, f
res_expr += TR10(s)
return True, res_expr.collect([sin(a*(pi/L)*x), cos(a*(pi/L)*x)])
def _print_sinc(self, expr):
from sympy.functions.elementary.trigonometric import sin
from sympy.core.relational import Ne
from sympy.functions import Piecewise
_piecewise = Piecewise(
(sin(expr.args[0]) / expr.args[0], Ne(expr.args[0], 0)), (1, True))
return self._print(_piecewise)
def fourier_sin_seq(func, limits, n):
"""Returns the sin sequence in a Fourier series"""
from sympy.integrals import integrate
x, L = limits[0], limits[2] - limits[1]
sin_term = sin(2*n*pi*x / L)
return SeqFormula(2 * sin_term * integrate(func * sin_term, limits)
/ L, (n, 1, oo))
def __new__(cls, f, limits, exprs):
if not (type(exprs) == tuple and len(exprs) == 3): # exprs is not of form (a0, an, bn)
# Converts the expression to fourier form
c, e = exprs.as_coeff_add()
rexpr = c + Add(*[TR10(i) for i in e])
a0, exp_ls = rexpr.expand(trig=False, power_base=False, power_exp=False, log=False).as_coeff_add()
x = limits[0]
L = abs(limits[2] - limits[1]) / 2
a = Wild('a', properties=[lambda k: k.is_Integer, lambda k: k is not S.Zero, ])
b = Wild('b', properties=[lambda k: x not in k.free_symbols, ])
an = dict()
bn = dict()
# separates the coefficients of sin and cos terms in dictionaries an, and bn
for p in exp_ls:
t = p.match(b * cos(a * (pi / L) * x))
q = p.match(b * sin(a * (pi / L) * x))
if t:
an[t[a]] = t[b] + an.get(t[a], S.Zero)
elif q:
bn[q[a]] = q[b] + bn.get(q[a], S.Zero)
else:
a0 += p
exprs = (a0, an, bn)
args = map(sympify, (f, limits, exprs))
return Expr.__new__(cls, *args)
def _eval_term(self, pt):
if pt == 0:
return self.a0
_term = self.an.get(pt, S.Zero) * cos(pt * (pi / self.L) * self.x) \
+ self.bn.get(pt, S.Zero) * sin(pt * (pi / self.L) * self.x)
return _term
def eval(cls, n, m, z=None):
if z is not None:
n, z, m = n, m, z
k = 2 * z / pi
if n == S.Zero:
return elliptic_f(z, m)
elif n == S.One:
return elliptic_f(z, m) + (sqrt(1 - m * sin(z) ** 2) * tan(z) - elliptic_e(z, m)) / (1 - m)
elif k.is_integer:
return k * elliptic_pi(n, m)
elif m == S.Zero:
return atanh(sqrt(n - 1) * tan(z)) / sqrt(n - 1)
elif n == m:
return elliptic_f(z, n) - elliptic_pi(1, z, n) + tan(z) / sqrt(1 - n * sin(z) ** 2)
elif n in (S.Infinity, S.NegativeInfinity):
return S.Zero
elif m in (S.Infinity, S.NegativeInfinity):
return S.Zero
elif z.could_extract_minus_sign():
return -elliptic_pi(n, -z, m)
else:
if n == S.Zero:
return elliptic_k(m)
elif n == S.One:
return S.ComplexInfinity
elif m == S.Zero:
return pi / (2 * sqrt(1 - n))
elif m == S.One:
return -S.Infinity / sign(n - 1)
elif n == m:
return elliptic_e(n) / (1 - n)
elif n in (S.Infinity, S.NegativeInfinity):
return S.Zero
elif m in (S.Infinity, S.NegativeInfinity):
return S.Zero
def as_real_imag(self, deep=True, **hints):
# TODO: Handle deep and hints
n, m, theta, phi = self.args
re = (sqrt((2*n + 1)/(4*pi) * factorial(n - m)/factorial(n + m)) *
cos(m*phi) * assoc_legendre(n, m, cos(theta)))
im = (sqrt((2*n + 1)/(4*pi) * factorial(n - m)/factorial(n + m)) *
sin(m*phi) * assoc_legendre(n, m, cos(theta)))
return (re, im)
def _eval_expand_func(self, **hints):
n, m, theta, phi = self.args
rv = (
sqrt((2 * n + 1) / (4 * pi) * C.factorial(n - m) / C.factorial(n + m))
* C.exp(I * m * phi)
* assoc_legendre(n, m, C.cos(theta))
)
# We can do this because of the range of theta
return rv.subs(sqrt(-cos(theta) ** 2 + 1), sin(theta))
def random_point(self, seed=None):
"""A random point on the ellipse.
Returns
=======
point : Point
Examples
========
>>> from sympy import Point, Ellipse, Segment
>>> e1 = Ellipse(Point(0, 0), 3, 2)
>>> e1.random_point() # gives some random point
Point2D(...)
>>> p1 = e1.random_point(seed=0); p1.n(2)
Point2D(2.1, 1.4)
Notes
=====
When creating a random point, one may simply replace the
parameter with a random number. When doing so, however, the
random number should be made a Rational or else the point
may not test as being in the ellipse:
>>> from sympy.abc import t
>>> from sympy import Rational
>>> arb = e1.arbitrary_point(t); arb
Point2D(3*cos(t), 2*sin(t))
>>> arb.subs(t, .1) in e1
False
>>> arb.subs(t, Rational(.1)) in e1
True
>>> arb.subs(t, Rational('.1')) in e1
True
See Also
========
sympy.geometry.point.Point
arbitrary_point : Returns parameterized point on ellipse
"""
from sympy import sin, cos, Rational
t = _symbol('t', real=True)
x, y = self.arbitrary_point(t).args
# get a random value in [-1, 1) corresponding to cos(t)
# and confirm that it will test as being in the ellipse
if seed is not None:
rng = random.Random(seed)
else:
rng = random
# simplify this now or else the Float will turn s into a Float
r = Rational(rng.random())
c = 2*r - 1
s = sqrt(1 - c**2)
return Point(x.subs(cos(t), c), y.subs(sin(t), s))
def test_expand():
m0 = OperationsOnlyMatrix([[x*(x + y), 2], [((x + y)*y)*x, x*(y + x*(x + y))]])
# Test if expand() returns a matrix
m1 = m0.expand()
assert m1 == Matrix(
[[x*y + x**2, 2], [x*y**2 + y*x**2, x*y + y*x**2 + x**3]])
a = Symbol('a', real=True)
assert OperationsOnlyMatrix(1, 1, [exp(I*a)]).expand(complex=True) == \
Matrix([cos(a) + I*sin(a)])
def fdiff(self, argindex=1):
if len(self.args) == 2:
z, m = self.args
if argindex == 1:
return sqrt(1 - m*sin(z)**2)
elif argindex == 2:
return (elliptic_e(z, m) - elliptic_f(z, m))/(2*m)
else:
m = self.args[0]
if argindex == 1:
return (elliptic_e(m) - elliptic_k(m))/(2*m)
raise ArgumentIndexError(self, argindex)
def _fourier_transform(seq, dps, inverse=False):
"""Utility function for the Discrete Fourier Transform"""
if not iterable(seq):
raise TypeError("Expected a sequence of numeric coefficients "
"for Fourier Transform")
a = [sympify(arg) for arg in seq]
if any(x.has(Symbol) for x in a):
raise ValueError("Expected non-symbolic coefficients")
n = len(a)
if n < 2:
return a
b = n.bit_length() - 1
if n&(n - 1): # not a power of 2
b += 1
n = 2**b
a += [S.Zero]*(n - len(a))
for i in range(1, n):
j = int(ibin(i, b, str=True)[::-1], 2)
if i < j:
a[i], a[j] = a[j], a[i]
ang = -2*pi/n if inverse else 2*pi/n
if dps is not None:
ang = ang.evalf(dps + 2)
w = [cos(ang*i) + I*sin(ang*i) for i in range(n // 2)]
h = 2
while h <= n:
hf, ut = h // 2, n // h
for i in range(0, n, h):
for j in range(hf):
u, v = a[i + j], expand_mul(a[i + j + hf]*w[ut * j])
a[i + j], a[i + j + hf] = u + v, u - v
h *= 2
if inverse:
a = [(x/n).evalf(dps) for x in a] if dps is not None \
else [x/n for x in a]
return a
def test_Max():
from sympy.abc import x, y, z
n = Symbol('n', negative=True)
n_ = Symbol('n_', negative=True)
nn = Symbol('nn', nonnegative=True)
nn_ = Symbol('nn_', nonnegative=True)
p = Symbol('p', positive=True)
p_ = Symbol('p_', positive=True)
np = Symbol('np', nonpositive=True)
np_ = Symbol('np_', nonpositive=True)
r = Symbol('r', real=True)
assert Max(5, 4) == 5
# lists
raises(ValueError, lambda: Max())
assert Max(x, y) == Max(y, x)
assert Max(x, y, z) == Max(z, y, x)
assert Max(x, Max(y, z)) == Max(z, y, x)
assert Max(x, Min(y, oo)) == Max(x, y)
assert Max(n, -oo, n_, p, 2) == Max(p, 2)
assert Max(n, -oo, n_, p) == p
assert Max(2, x, p, n, -oo, S.NegativeInfinity, n_, p, 2) == Max(2, x, p)
assert Max(0, x, 1, y) == Max(1, x, y)
assert Max(r, r + 1, r - 1) == 1 + r
assert Max(1000, 100, -100, x, p, n) == Max(p, x, 1000)
assert Max(cos(x), sin(x)) == Max(sin(x), cos(x))
assert Max(cos(x), sin(x)).subs(x, 1) == sin(1)
assert Max(cos(x), sin(x)).subs(x, S(1)/2) == cos(S(1)/2)
raises(ValueError, lambda: Max(cos(x), sin(x)).subs(x, I))
raises(ValueError, lambda: Max(I))
raises(ValueError, lambda: Max(I, x))
raises(ValueError, lambda: Max(S.ComplexInfinity, 1))
# interesting:
# Max(n, -oo, n_, p, 2) == Max(p, 2)
# True
# Max(n, -oo, n_, p, 1000) == Max(p, 1000)
# False
assert Max(1, x).diff(x) == Heaviside(x - 1)
assert Max(x, 1).diff(x) == Heaviside(x - 1)
assert Max(x**2, 1 + x, 1).diff(x) == \
2*x*Heaviside(x**2 - Max(1, x + 1)) \
+ Heaviside(x - Max(1, x**2) + 1)
a, b = Symbol('a', real=True), Symbol('b', real=True)
# a and b are both real, Max(a, b) should be real
assert Max(a, b).is_real
# issue 7233
e = Max(0, x)
assert e.evalf == e.n
assert e.n().args == (0, x)
def expr(self):
from sympy.functions.elementary.trigonometric import sin, cos
r, theta = self.variables
return r * (cos(theta) + S.ImaginaryUnit * sin(theta))
def test_issue_8821_highprec_from_str():
s = str(pi.evalf(128))
p = sympify(s)
assert Abs(sin(p)) < 1e-127
def test_issue_6782():
x = Symbol('x')
assert sqrt(sin(x**3)).series(x, 0, 7) == x**(S(3) / 2) + O(x**7)
assert sqrt(sin(x**4)).series(x, 0, 3) == x**2 + O(x**3)
def test_shifted_sum():
from sympy.simplify.simplify import simplify
assert simplify(hyperexpand(z**4*hyper([2], [3, S('3/2')], -z**2))) \
== z*sin(2*z) + (-z**2 + S.Half)*cos(2*z) - S.Half
def test_sin():
e = sin(x).lseries(x)
assert next(e) == x
assert next(e) == -x**3 / 6
assert next(e) == x**5 / 120
def _yn(n, z):
# (-1)**(n + 1) * _jn(-n - 1, z)
return (-1)**(n + 1) * fn(-n - 1, z)*sin(z) - fn(n, z)*cos(z)
def periodicity(f, symbol, check=False):
"""
Tests the given function for periodicity in the given symbol.
Parameters
==========
f : :py:class:`~.Expr`.
The concerned function.
symbol : :py:class:`~.Symbol`
The variable for which the period is to be determined.
check : bool, optional
The flag to verify whether the value being returned is a period or not.
Returns
=======
period
The period of the function is returned.
``None`` is returned when the function is aperiodic or has a complex period.
The value of $0$ is returned as the period of a constant function.
Raises
======
NotImplementedError
The value of the period computed cannot be verified.
Notes
=====
Currently, we do not support functions with a complex period.
The period of functions having complex periodic values such
as ``exp``, ``sinh`` is evaluated to ``None``.
The value returned might not be the "fundamental" period of the given
function i.e. it may not be the smallest periodic value of the function.
The verification of the period through the ``check`` flag is not reliable
due to internal simplification of the given expression. Hence, it is set
to ``False`` by default.
Examples
========
>>> from sympy import periodicity, Symbol, sin, cos, tan, exp
>>> x = Symbol('x')
>>> f = sin(x) + sin(2*x) + sin(3*x)
>>> periodicity(f, x)
2*pi
>>> periodicity(sin(x)*cos(x), x)
pi
>>> periodicity(exp(tan(2*x) - 1), x)
pi/2
>>> periodicity(sin(4*x)**cos(2*x), x)
pi
>>> periodicity(exp(x), x)
"""
if symbol.kind is not NumberKind:
raise NotImplementedError("Cannot use symbol of kind %s" % symbol.kind)
temp = Dummy('x', real=True)
f = f.subs(symbol, temp)
symbol = temp
def _check(orig_f, period):
'''Return the checked period or raise an error.'''
new_f = orig_f.subs(symbol, symbol + period)
if new_f.equals(orig_f):
return period
else:
raise NotImplementedError(
filldedent('''
The period of the given function cannot be verified.
When `%s` was replaced with `%s + %s` in `%s`, the result
was `%s` which was not recognized as being the same as
the original function.
So either the period was wrong or the two forms were
not recognized as being equal.
Set check=False to obtain the value.''' %
(symbol, symbol, period, orig_f, new_f)))
orig_f = f
period = None
if isinstance(f, Relational):
f = f.lhs - f.rhs
f = simplify(f)
if symbol not in f.free_symbols:
return S.Zero
if isinstance(f, TrigonometricFunction):
try:
period = f.period(symbol)
except NotImplementedError:
pass
if isinstance(f, Abs):
arg = f.args[0]
if isinstance(arg, (sec, csc, cos)):
# all but tan and cot might have a
# a period that is half as large
# so recast as sin
arg = sin(arg.args[0])
period = periodicity(arg, symbol)
if period is not None and isinstance(arg, sin):
# the argument of Abs was a trigonometric other than
# cot or tan; test to see if the half-period
# is valid. Abs(arg) has behaviour equivalent to
# orig_f, so use that for test:
orig_f = Abs(arg)
try:
return _check(orig_f, period / 2)
except NotImplementedError as err:
if check:
raise NotImplementedError(err)
# else let new orig_f and period be
# checked below
if isinstance(f, exp) or (f.is_Pow and f.base == S.Exp1):
f = Pow(S.Exp1, expand_mul(f.exp))
if im(f) != 0:
period_real = periodicity(re(f), symbol)
period_imag = periodicity(im(f), symbol)
if period_real is not None and period_imag is not None:
period = lcim([period_real, period_imag])
if f.is_Pow and f.base != S.Exp1:
base, expo = f.args
base_has_sym = base.has(symbol)
expo_has_sym = expo.has(symbol)
if base_has_sym and not expo_has_sym:
period = periodicity(base, symbol)
elif expo_has_sym and not base_has_sym:
period = periodicity(expo, symbol)
else:
period = _periodicity(f.args, symbol)
elif f.is_Mul:
coeff, g = f.as_independent(symbol, as_Add=False)
if isinstance(g, TrigonometricFunction) or coeff is not S.One:
period = periodicity(g, symbol)
else:
period = _periodicity(g.args, symbol)
elif f.is_Add:
k, g = f.as_independent(symbol)
if k is not S.Zero:
return periodicity(g, symbol)
period = _periodicity(g.args, symbol)
elif isinstance(f, Mod):
a, n = f.args
if a == symbol:
period = n
elif isinstance(a, TrigonometricFunction):
period = periodicity(a, symbol)
#check if 'f' is linear in 'symbol'
elif (a.is_polynomial(symbol) and degree(a, symbol) == 1
and symbol not in n.free_symbols):
period = Abs(n / a.diff(symbol))
elif isinstance(f, Piecewise):
pass # not handling Piecewise yet as the return type is not favorable
elif period is None:
from sympy.solvers.decompogen import compogen, decompogen
g_s = decompogen(f, symbol)
num_of_gs = len(g_s)
if num_of_gs > 1:
for index, g in enumerate(reversed(g_s)):
start_index = num_of_gs - 1 - index
g = compogen(g_s[start_index:], symbol)
if g not in (orig_f, f): # Fix for issue 12620
period = periodicity(g, symbol)
if period is not None:
break
if period is not None:
if check:
return _check(orig_f, period)
return period
return None
def _eval_rewrite_as_sin(self, arg, **kwargs):
from sympy.functions.elementary.trigonometric import sin
I = S.ImaginaryUnit
return sin(I * arg + S.Pi / 2) - I * sin(I * arg)
def test_minimum():
x, y = symbols('x y')
assert minimum(sin(x), x) is S.NegativeOne
assert minimum(sin(x), x, Interval(1, 4)) == sin(4)
assert minimum(tan(x), x) is -oo
assert minimum(tan(x), x, Interval(-pi/4, pi/4)) is S.NegativeOne
assert minimum(sin(x)*cos(x), x, S.Reals) == Rational(-1, 2)
assert simplify(minimum(sin(x)*cos(x), x, Interval(pi*Rational(3, 8), pi*Rational(5, 8)))
) == -sqrt(2)/4
assert minimum((x+3)*(x-2), x) == Rational(-25, 4)
assert minimum((x+3)/(x-2), x, Interval(-5, 0)) == Rational(-3, 2)
assert minimum(x**4-x**3+x**2+10, x) == S(10)
assert minimum(exp(x), x, Interval(-2, oo)) == exp(-2)
assert minimum(log(x) - x, x, S.Reals) is -oo
assert minimum(cos(x), x, Union(Interval(0, 5), Interval(-6, -3))
) is S.NegativeOne
assert minimum(cos(x)-sin(x), x, S.Reals) == -sqrt(2)
assert minimum(y, x, S.Reals) == y
assert minimum(x/sqrt(x**2+1), x, S.Reals) == -1
raises(ValueError, lambda : minimum(sin(x), x, S.EmptySet))
raises(ValueError, lambda : minimum(log(cos(x)), x, S.EmptySet))
raises(ValueError, lambda : minimum(1/(x**2 + y**2 + 1), x, S.EmptySet))
raises(ValueError, lambda : minimum(sin(x), sin(x)))
raises(ValueError, lambda : minimum(sin(x), x*y, S.EmptySet))
raises(ValueError, lambda : minimum(sin(x), S.One))
def test_TableForm_latex():
s = latex(
TableForm(
[[0, x**3], ["c", S.One / 4], [sqrt(x), sin(x**2)]],
wipe_zeros=True,
headings=("automatic", "automatic"),
))
assert s == ("\\begin{tabular}{r l l}\n"
" & 1 & 2 \\\\\n"
"\\hline\n"
"1 & & $x^{3}$ \\\\\n"
"2 & $c$ & $\\frac{1}{4}$ \\\\\n"
"3 & $\\sqrt{x}$ & $\\sin{\\left(x^{2} \\right)}$ \\\\\n"
"\\end{tabular}")
s = latex(
TableForm(
[[0, x**3], ["c", S.One / 4], [sqrt(x), sin(x**2)]],
wipe_zeros=True,
headings=("automatic", "automatic"),
alignments="l",
))
assert s == ("\\begin{tabular}{r l l}\n"
" & 1 & 2 \\\\\n"
"\\hline\n"
"1 & & $x^{3}$ \\\\\n"
"2 & $c$ & $\\frac{1}{4}$ \\\\\n"
"3 & $\\sqrt{x}$ & $\\sin{\\left(x^{2} \\right)}$ \\\\\n"
"\\end{tabular}")
s = latex(
TableForm(
[[0, x**3], ["c", S.One / 4], [sqrt(x), sin(x**2)]],
wipe_zeros=True,
headings=("automatic", "automatic"),
alignments="l" * 3,
))
assert s == ("\\begin{tabular}{l l l}\n"
" & 1 & 2 \\\\\n"
"\\hline\n"
"1 & & $x^{3}$ \\\\\n"
"2 & $c$ & $\\frac{1}{4}$ \\\\\n"
"3 & $\\sqrt{x}$ & $\\sin{\\left(x^{2} \\right)}$ \\\\\n"
"\\end{tabular}")
s = latex(
TableForm(
[["a", x**3], ["c", S.One / 4], [sqrt(x), sin(x**2)]],
headings=("automatic", "automatic"),
))
assert s == ("\\begin{tabular}{r l l}\n"
" & 1 & 2 \\\\\n"
"\\hline\n"
"1 & $a$ & $x^{3}$ \\\\\n"
"2 & $c$ & $\\frac{1}{4}$ \\\\\n"
"3 & $\\sqrt{x}$ & $\\sin{\\left(x^{2} \\right)}$ \\\\\n"
"\\end{tabular}")
s = latex(
TableForm(
[["a", x**3], ["c", S.One / 4], [sqrt(x), sin(x**2)]],
formats=["(%s)", None],
headings=("automatic", "automatic"),
))
assert s == ("\\begin{tabular}{r l l}\n"
" & 1 & 2 \\\\\n"
"\\hline\n"
"1 & (a) & $x^{3}$ \\\\\n"
"2 & (c) & $\\frac{1}{4}$ \\\\\n"
"3 & (sqrt(x)) & $\\sin{\\left(x^{2} \\right)}$ \\\\\n"
"\\end{tabular}")
def neg_in_paren(x, i, j):
if i % 2:
return ("(%s)" if x < 0 else "%s") % x
else:
pass # use default print
s = latex(
TableForm(
[[-1, 2], [-3, 4]],
formats=[neg_in_paren] * 2,
headings=("automatic", "automatic"),
))
assert s == ("\\begin{tabular}{r l l}\n"
" & 1 & 2 \\\\\n"
"\\hline\n"
"1 & -1 & 2 \\\\\n"
"2 & (-3) & 4 \\\\\n"
"\\end{tabular}")
s = latex(TableForm([["a", x**3], ["c", S.One / 4], [sqrt(x), sin(x**2)]]))
assert s == ("\\begin{tabular}{l l}\n"
"$a$ & $x^{3}$ \\\\\n"
"$c$ & $\\frac{1}{4}$ \\\\\n"
"$\\sqrt{x}$ & $\\sin{\\left(x^{2} \\right)}$ \\\\\n"
"\\end{tabular}")
def test_issue_3554():
x = Symbol('x')
assert (1 / sqrt(1 + cos(x) * sin(x**2))).series(x, 0, 7) == \
1 - x**2/2 + 5*x**4/8 - 5*x**6/8 + O(x**7)
assert (1 / sqrt(1 + cos(x) * sin(x**2))).series(x, 0, 8) == \
1 - x**2/2 + 5*x**4/8 - 5*x**6/8 + O(x**8)
def test_issue_3554s():
x = Symbol('x')
assert (1 / sqrt(1 + cos(x) * sin(x**2))).series(x, 0, 15) == \
1 - x**2/2 + 5*x**4/8 - 5*x**6/8 + 4039*x**8/5760 - 5393*x**10/6720 + \
13607537*x**12/14515200 - 532056047*x**14/479001600 + O(x**15)
def test_Min():
from sympy.abc import x, y, z
n = Symbol('n', negative=True)
n_ = Symbol('n_', negative=True)
nn = Symbol('nn', nonnegative=True)
nn_ = Symbol('nn_', nonnegative=True)
p = Symbol('p', positive=True)
p_ = Symbol('p_', positive=True)
np = Symbol('np', nonpositive=True)
np_ = Symbol('np_', nonpositive=True)
assert Min(5, 4) == 4
assert Min(-oo, -oo) == -oo
assert Min(-oo, n) == -oo
assert Min(n, -oo) == -oo
assert Min(-oo, np) == -oo
assert Min(np, -oo) == -oo
assert Min(-oo, 0) == -oo
assert Min(0, -oo) == -oo
assert Min(-oo, nn) == -oo
assert Min(nn, -oo) == -oo
assert Min(-oo, p) == -oo
assert Min(p, -oo) == -oo
assert Min(-oo, oo) == -oo
assert Min(oo, -oo) == -oo
assert Min(n, n) == n
assert Min(n, np) == Min(n, np)
assert Min(np, n) == Min(np, n)
assert Min(n, 0) == n
assert Min(0, n) == n
assert Min(n, nn) == n
assert Min(nn, n) == n
assert Min(n, p) == n
assert Min(p, n) == n
assert Min(n, oo) == n
assert Min(oo, n) == n
assert Min(np, np) == np
assert Min(np, 0) == np
assert Min(0, np) == np
assert Min(np, nn) == np
assert Min(nn, np) == np
assert Min(np, p) == np
assert Min(p, np) == np
assert Min(np, oo) == np
assert Min(oo, np) == np
assert Min(0, 0) == 0
assert Min(0, nn) == 0
assert Min(nn, 0) == 0
assert Min(0, p) == 0
assert Min(p, 0) == 0
assert Min(0, oo) == 0
assert Min(oo, 0) == 0
assert Min(nn, nn) == nn
assert Min(nn, p) == Min(nn, p)
assert Min(p, nn) == Min(p, nn)
assert Min(nn, oo) == nn
assert Min(oo, nn) == nn
assert Min(p, p) == p
assert Min(p, oo) == p
assert Min(oo, p) == p
assert Min(oo, oo) == oo
assert Min(n, n_).func is Min
assert Min(nn, nn_).func is Min
assert Min(np, np_).func is Min
assert Min(p, p_).func is Min
# lists
raises(ValueError, lambda: Min())
assert Min(x, y) == Min(y, x)
assert Min(x, y, z) == Min(z, y, x)
assert Min(x, Min(y, z)) == Min(z, y, x)
assert Min(x, Max(y, -oo)) == Min(x, y)
assert Min(p, oo, n, p, p, p_) == n
assert Min(p_, n_, p) == n_
assert Min(n, oo, -7, p, p, 2) == Min(n, -7)
assert Min(2, x, p, n, oo, n_, p, 2, -2, -2) == Min(-2, x, n, n_)
assert Min(0, x, 1, y) == Min(0, x, y)
assert Min(1000, 100, -100, x, p, n) == Min(n, x, -100)
assert Min(cos(x), sin(x)) == Min(cos(x), sin(x))
assert Min(cos(x), sin(x)).subs(x, 1) == cos(1)
assert Min(cos(x), sin(x)).subs(x, S(1)/2) == sin(S(1)/2)
raises(ValueError, lambda: Min(cos(x), sin(x)).subs(x, I))
raises(ValueError, lambda: Min(I))
raises(ValueError, lambda: Min(I, x))
raises(ValueError, lambda: Min(S.ComplexInfinity, x))
assert Min(1,x).diff(x) == Heaviside(1-x)
assert Min(x,1).diff(x) == Heaviside(1-x)
assert Min(0,-x,1-2*x).diff(x) == -Heaviside(x + Min(0, -2*x + 1)) \
- 2*Heaviside(2*x + Min(0, -x) - 1)
a, b = Symbol('a', real=True), Symbol('b', real=True)
# a and b are both real, Min(a, b) should be real
assert Min(a, b).is_real
# issue 7619
f = Function('f')
assert Min(1, 2*Min(f(1), 2)) # doesn't fail
# issue 7233
e = Min(0, x)
assert e.evalf == e.n
assert e.n().args == (0, x)
def test_maximum():
x, y = symbols('x y')
assert maximum(sin(x), x) is S.One
assert maximum(sin(x), x, Interval(0, 1)) == sin(1)
assert maximum(tan(x), x) is oo
assert maximum(tan(x), x, Interval(-pi/4, pi/4)) is S.One
assert maximum(sin(x)*cos(x), x, S.Reals) == S.Half
assert simplify(maximum(sin(x)*cos(x), x, Interval(pi*Rational(3, 8), pi*Rational(5, 8)))
) == sqrt(2)/4
assert maximum((x+3)*(x-2), x) is oo
assert maximum((x+3)*(x-2), x, Interval(-5, 0)) == S(14)
assert maximum((x+3)/(x-2), x, Interval(-5, 0)) == Rational(2, 7)
assert simplify(maximum(-x**4-x**3+x**2+10, x)
) == 41*sqrt(41)/512 + Rational(5419, 512)
assert maximum(exp(x), x, Interval(-oo, 2)) == exp(2)
assert maximum(log(x) - x, x, S.Reals) is S.NegativeOne
assert maximum(cos(x), x, Union(Interval(0, 5), Interval(-6, -3))
) is S.One
assert maximum(cos(x)-sin(x), x, S.Reals) == sqrt(2)
assert maximum(y, x, S.Reals) == y
assert maximum(abs(a**3 + a), a, Interval(0, 2)) == 10
assert maximum(abs(60*a**3 + 24*a), a, Interval(0, 2)) == 528
assert maximum(abs(12*a*(5*a**2 + 2)), a, Interval(0, 2)) == 528
assert maximum(x/sqrt(x**2+1), x, S.Reals) == 1
raises(ValueError, lambda : maximum(sin(x), x, S.EmptySet))
raises(ValueError, lambda : maximum(log(cos(x)), x, S.EmptySet))
raises(ValueError, lambda : maximum(1/(x**2 + y**2 + 1), x, S.EmptySet))
raises(ValueError, lambda : maximum(sin(x), sin(x)))
raises(ValueError, lambda : maximum(sin(x), x*y, S.EmptySet))
raises(ValueError, lambda : maximum(sin(x), S.One))
expr = new_expr
else:
expr = optim.cheapest(expr, new_expr)
return expr
exp2_opt = ReplaceOptim(lambda p: p.is_Pow and p.base == 2,
lambda p: exp2(p.exp))
_d = Wild('d', properties=[lambda x: x.is_Dummy])
_u = Wild('u', properties=[lambda x: not x.is_number and not x.is_Add])
_v = Wild('v')
_w = Wild('w')
_n = Wild('n', properties=[lambda x: x.is_number])
sinc_opt1 = ReplaceOptim(sin(_w) / _w, sinc(_w))
sinc_opt2 = ReplaceOptim(sin(_n * _w) / _w, _n * sinc(_n * _w))
sinc_opts = (sinc_opt1, sinc_opt2)
log2_opt = ReplaceOptim(
_v * log(_w) / log(2),
_v * log2(_w),
cost_function=lambda expr: expr.count(
lambda e:
( # division & eval of transcendentals are expensive floating point operations...
e.is_Pow and e.exp.is_negative # division
or (isinstance(e, (log, log2)) and not e.args[0].is_number)
) # transcendental
))
log2const_opt = ReplaceOptim(log(2) * log2(_w), log(_w))
def gauss_chebyshev_u(n, n_digits):
r"""
Computes the Gauss-Chebyshev quadrature [1]_ points and weights of
the second kind.
The Gauss-Chebyshev quadrature of the second kind approximates the
integral:
.. math::
\int_{-1}^{1} \sqrt{1-x^2} f(x)\,dx \approx \sum_{i=1}^n w_i f(x_i)
The nodes `x_i` of an order `n` quadrature rule are the roots of `U_n`
and the weights `w_i` are given by:
.. math::
w_i = \frac{\pi}{n+1} \sin^2 \left(\frac{i}{n+1}\pi\right)
Parameters
==========
n : the order of quadrature
n_digits : number of significant digits of the points and weights to return
Returns
=======
(x, w) : the ``x`` and ``w`` are lists of points and weights as Floats.
The points `x_i` and weights `w_i` are returned as ``(x, w)``
tuple of lists.
Examples
========
>>> from sympy import S
>>> from sympy.integrals.quadrature import gauss_chebyshev_u
>>> x, w = gauss_chebyshev_u(3, 5)
>>> x
[0.70711, 0, -0.70711]
>>> w
[0.3927, 0.7854, 0.3927]
>>> x, w = gauss_chebyshev_u(6, 5)
>>> x
[0.90097, 0.62349, 0.22252, -0.22252, -0.62349, -0.90097]
>>> w
[0.084489, 0.27433, 0.42658, 0.42658, 0.27433, 0.084489]
See Also
========
gauss_legendre, gauss_laguerre, gauss_hermite, gauss_gen_laguerre, gauss_chebyshev_t, gauss_jacobi, gauss_lobatto
References
==========
.. [1] http://en.wikipedia.org/wiki/Chebyshev%E2%80%93Gauss_quadrature
.. [2] http://people.sc.fsu.edu/~jburkardt/cpp_src/chebyshev2_rule/chebyshev2_rule.html
"""
xi = []
w = []
for i in range(1, n + 1):
xi.append((cos(i / (n + S.One) * S.Pi)).n(n_digits))
w.append(
(S.Pi / (n + S.One) * sin(i * S.Pi / (n + S.One))**2).n(n_digits))
return xi, w
def test_input_format():
raises(TypeError, lambda: diophantine(sin(x)))
raises(TypeError, lambda: diophantine(3))
raises(TypeError, lambda: diophantine(x/pi - 3))
def test_gamma_as_leading_term():
assert gamma(x).as_leading_term(x) == 1/x
assert gamma(2 + x).as_leading_term(x) == S(1)
assert gamma(cos(x)).as_leading_term(x) == S(1)
assert gamma(sin(x)).as_leading_term(x) == 1/x
def periodicity(f, symbol, check=False):
"""
Tests the given function for periodicity in the given symbol.
Parameters
==========
f : Expr.
The concerned function.
symbol : Symbol
The variable for which the period is to be determined.
check : Boolean
The flag to verify whether the value being returned is a period or not.
Returns
=======
period
The period of the function is returned.
`None` is returned when the function is aperiodic or has a complex period.
The value of `0` is returned as the period of a constant function.
Raises
======
NotImplementedError
The value of the period computed cannot be verified.
Notes
=====
Currently, we do not support functions with a complex period.
The period of functions having complex periodic values such
as `exp`, `sinh` is evaluated to `None`.
The value returned might not be the "fundamental" period of the given
function i.e. it may not be the smallest periodic value of the function.
The verification of the period through the `check` flag is not reliable
due to internal simplification of the given expression. Hence, it is set
to `False` by default.
Examples
========
>>> from sympy import Symbol, sin, cos, tan, exp
>>> from sympy.calculus.util import periodicity
>>> x = Symbol('x')
>>> f = sin(x) + sin(2*x) + sin(3*x)
>>> periodicity(f, x)
2*pi
>>> periodicity(sin(x)*cos(x), x)
pi
>>> periodicity(exp(tan(2*x) - 1), x)
pi/2
>>> periodicity(sin(4*x)**cos(2*x), x)
pi
>>> periodicity(exp(x), x)
"""
from sympy.core.function import diff
from sympy.core.mod import Mod
from sympy.core.relational import Relational
from sympy.functions.elementary.complexes import Abs
from sympy.functions.elementary.trigonometric import (
TrigonometricFunction, sin, cos, csc, sec)
from sympy.simplify.simplify import simplify
from sympy.solvers.decompogen import decompogen
from sympy.polys.polytools import degree, lcm_list
def _check(orig_f, period):
'''Return the checked period or raise an error.'''
new_f = orig_f.subs(symbol, symbol + period)
if new_f.equals(orig_f):
return period
else:
raise NotImplementedError(filldedent('''
The period of the given function cannot be verified.
When `%s` was replaced with `%s + %s` in `%s`, the result
was `%s` which was not recognized as being the same as
the original function.
So either the period was wrong or the two forms were
not recognized as being equal.
Set check=False to obtain the value.''' %
(symbol, symbol, period, orig_f, new_f)))
orig_f = f
period = None
if isinstance(f, Relational):
f = f.lhs - f.rhs
f = simplify(f)
if symbol not in f.free_symbols:
return S.Zero
if isinstance(f, TrigonometricFunction):
try:
period = f.period(symbol)
except NotImplementedError:
pass
if isinstance(f, Abs):
arg = f.args[0]
if isinstance(arg, (sec, csc, cos)):
# all but tan and cot might have a
# a period that is half as large
# so recast as sin
arg = sin(arg.args[0])
period = periodicity(arg, symbol)
if period is not None and isinstance(arg, sin):
# the argument of Abs was a trigonometric other than
# cot or tan; test to see if the half-period
# is valid. Abs(arg) has behaviour equivalent to
# orig_f, so use that for test:
orig_f = Abs(arg)
try:
return _check(orig_f, period/2)
except NotImplementedError as err:
if check:
raise NotImplementedError(err)
# else let new orig_f and period be
# checked below
if f.is_Pow:
base, expo = f.args
base_has_sym = base.has(symbol)
expo_has_sym = expo.has(symbol)
if base_has_sym and not expo_has_sym:
period = periodicity(base, symbol)
elif expo_has_sym and not base_has_sym:
period = periodicity(expo, symbol)
else:
period = _periodicity(f.args, symbol)
elif f.is_Mul:
coeff, g = f.as_independent(symbol, as_Add=False)
if isinstance(g, TrigonometricFunction) or coeff is not S.One:
period = periodicity(g, symbol)
else:
period = _periodicity(g.args, symbol)
elif f.is_Add:
k, g = f.as_independent(symbol)
if k is not S.Zero:
return periodicity(g, symbol)
period = _periodicity(g.args, symbol)
elif isinstance(f, Mod):
a, n = f.args
if a == symbol:
period = n
elif isinstance(a, TrigonometricFunction):
period = periodicity(a, symbol)
#check if 'f' is linear in 'symbol'
elif degree(a, symbol) == 1 and symbol not in n.free_symbols:
period = Abs(n / a.diff(symbol))
elif period is None:
from sympy.solvers.decompogen import compogen
g_s = decompogen(f, symbol)
num_of_gs = len(g_s)
if num_of_gs > 1:
for index, g in enumerate(reversed(g_s)):
start_index = num_of_gs - 1 - index
g = compogen(g_s[start_index:], symbol)
if g != orig_f and g != f: # Fix for issue 12620
period = periodicity(g, symbol)
if period is not None:
break
if period is not None:
if check:
return _check(orig_f, period)
return period
return None
def test_issue_6653():
x = Symbol('x')
assert (1 / sqrt(1 + sin(x**2))).series(x, 0, 3) == 1 - x**2 / 2 + O(x**3)
def test_periodicity():
x = Symbol('x')
y = Symbol('y')
z = Symbol('z', real=True)
assert periodicity(sin(2*x), x) == pi
assert periodicity((-2)*tan(4*x), x) == pi/4
assert periodicity(sin(x)**2, x) == 2*pi
assert periodicity(3**tan(3*x), x) == pi/3
assert periodicity(tan(x)*cos(x), x) == 2*pi
assert periodicity(sin(x)**(tan(x)), x) == 2*pi
assert periodicity(tan(x)*sec(x), x) == 2*pi
assert periodicity(sin(2*x)*cos(2*x) - y, x) == pi/2
assert periodicity(tan(x) + cot(x), x) == pi
assert periodicity(sin(x) - cos(2*x), x) == 2*pi
assert periodicity(sin(x) - 1, x) == 2*pi
assert periodicity(sin(4*x) + sin(x)*cos(x), x) == pi
assert periodicity(exp(sin(x)), x) == 2*pi
assert periodicity(log(cot(2*x)) - sin(cos(2*x)), x) == pi
assert periodicity(sin(2*x)*exp(tan(x) - csc(2*x)), x) == pi
assert periodicity(cos(sec(x) - csc(2*x)), x) == 2*pi
assert periodicity(tan(sin(2*x)), x) == pi
assert periodicity(2*tan(x)**2, x) == pi
assert periodicity(sin(x%4), x) == 4
assert periodicity(sin(x)%4, x) == 2*pi
assert periodicity(tan((3*x-2)%4), x) == Rational(4, 3)
assert periodicity((sqrt(2)*(x+1)+x) % 3, x) == 3 / (sqrt(2)+1)
assert periodicity((x**2+1) % x, x) is None
assert periodicity(sin(re(x)), x) == 2*pi
assert periodicity(sin(x)**2 + cos(x)**2, x) is S.Zero
assert periodicity(tan(x), y) is S.Zero
assert periodicity(sin(x) + I*cos(x), x) == 2*pi
assert periodicity(x - sin(2*y), y) == pi
assert periodicity(exp(x), x) is None
assert periodicity(exp(I*x), x) == 2*pi
assert periodicity(exp(I*z), z) == 2*pi
assert periodicity(exp(z), z) is None
assert periodicity(exp(log(sin(z) + I*cos(2*z)), evaluate=False), z) == 2*pi
assert periodicity(exp(log(sin(2*z) + I*cos(z)), evaluate=False), z) == 2*pi
assert periodicity(exp(sin(z)), z) == 2*pi
assert periodicity(exp(2*I*z), z) == pi
assert periodicity(exp(z + I*sin(z)), z) is None
assert periodicity(exp(cos(z/2) + sin(z)), z) == 4*pi
assert periodicity(log(x), x) is None
assert periodicity(exp(x)**sin(x), x) is None
assert periodicity(sin(x)**y, y) is None
assert periodicity(Abs(sin(Abs(sin(x)))), x) == pi
assert all(periodicity(Abs(f(x)), x) == pi for f in (
cos, sin, sec, csc, tan, cot))
assert periodicity(Abs(sin(tan(x))), x) == pi
assert periodicity(Abs(sin(sin(x) + tan(x))), x) == 2*pi
assert periodicity(sin(x) > S.Half, x) == 2*pi
assert periodicity(x > 2, x) is None
assert periodicity(x**3 - x**2 + 1, x) is None
assert periodicity(Abs(x), x) is None
assert periodicity(Abs(x**2 - 1), x) is None
assert periodicity((x**2 + 4)%2, x) is None
assert periodicity((E**x)%3, x) is None
assert periodicity(sin(expint(1, x))/expint(1, x), x) is None
# returning `None` for any Piecewise
p = Piecewise((0, x < -1), (x**2, x <= 1), (log(x), True))
assert periodicity(p, x) is None
m = MatrixSymbol('m', 3, 3)
raises(NotImplementedError, lambda: periodicity(sin(m), m))
raises(NotImplementedError, lambda: periodicity(sin(m[0, 0]), m))
raises(NotImplementedError, lambda: periodicity(sin(m), m[0, 0]))
raises(NotImplementedError, lambda: periodicity(sin(m[0, 0]), m[0, 0]))
def eval(cls, a, q, z):
if q.is_Number and q.is_zero:
return sin(sqrt(a) * z)
# Try to pull out factors of -1
if z.could_extract_minus_sign():
return -cls(a, q, -z)
def test_plane():
x, y, z, u, v = symbols('x y z u v', real=True)
p1 = Point3D(0, 0, 0)
p2 = Point3D(1, 1, 1)
p3 = Point3D(1, 2, 3)
pl3 = Plane(p1, p2, p3)
pl4 = Plane(p1, normal_vector=(1, 1, 1))
pl4b = Plane(p1, p2)
pl5 = Plane(p3, normal_vector=(1, 2, 3))
pl6 = Plane(Point3D(2, 3, 7), normal_vector=(2, 2, 2))
pl7 = Plane(Point3D(1, -5, -6), normal_vector=(1, -2, 1))
pl8 = Plane(p1, normal_vector=(0, 0, 1))
pl9 = Plane(p1, normal_vector=(0, 12, 0))
pl10 = Plane(p1, normal_vector=(-2, 0, 0))
pl11 = Plane(p2, normal_vector=(0, 0, 1))
l1 = Line3D(Point3D(5, 0, 0), Point3D(1, -1, 1))
l2 = Line3D(Point3D(0, -2, 0), Point3D(3, 1, 1))
l3 = Line3D(Point3D(0, -1, 0), Point3D(5, -1, 9))
raises(ValueError, lambda: Plane(p1, p1, p1))
assert Plane(p1, p2, p3) != Plane(p1, p3, p2)
assert Plane(p1, p2, p3).is_coplanar(Plane(p1, p3, p2))
assert Plane(p1, p2, p3).is_coplanar(p1)
assert Plane(p1, p2, p3).is_coplanar(Circle(p1, 1)) is False
assert Plane(p1, normal_vector=(0, 0, 1)).is_coplanar(Circle(p1, 1))
assert pl3 == Plane(Point3D(0, 0, 0), normal_vector=(1, -2, 1))
assert pl3 != pl4
assert pl4 == pl4b
assert pl5 == Plane(Point3D(1, 2, 3), normal_vector=(1, 2, 3))
assert pl5.equation(x, y, z) == x + 2*y + 3*z - 14
assert pl3.equation(x, y, z) == x - 2*y + z
assert pl3.p1 == p1
assert pl4.p1 == p1
assert pl5.p1 == p3
assert pl4.normal_vector == (1, 1, 1)
assert pl5.normal_vector == (1, 2, 3)
assert p1 in pl3
assert p1 in pl4
assert p3 in pl5
assert pl3.projection(Point(0, 0)) == p1
p = pl3.projection(Point3D(1, 1, 0))
assert p == Point3D(Rational(7, 6), Rational(2, 3), Rational(1, 6))
assert p in pl3
l = pl3.projection_line(Line(Point(0, 0), Point(1, 1)))
assert l == Line3D(Point3D(0, 0, 0), Point3D(Rational(7, 6), Rational(2, 3), Rational(1, 6)))
assert l in pl3
# get a segment that does not intersect the plane which is also
# parallel to pl3's normal veector
t = Dummy()
r = pl3.random_point()
a = pl3.perpendicular_line(r).arbitrary_point(t)
s = Segment3D(a.subs(t, 1), a.subs(t, 2))
assert s.p1 not in pl3 and s.p2 not in pl3
assert pl3.projection_line(s).equals(r)
assert pl3.projection_line(Segment(Point(1, 0), Point(1, 1))) == \
Segment3D(Point3D(Rational(5, 6), Rational(1, 3), Rational(-1, 6)), Point3D(Rational(7, 6), Rational(2, 3), Rational(1, 6)))
assert pl6.projection_line(Ray(Point(1, 0), Point(1, 1))) == \
Ray3D(Point3D(Rational(14, 3), Rational(11, 3), Rational(11, 3)), Point3D(Rational(13, 3), Rational(13, 3), Rational(10, 3)))
assert pl3.perpendicular_line(r.args) == pl3.perpendicular_line(r)
assert pl3.is_parallel(pl6) is False
assert pl4.is_parallel(pl6)
assert pl3.is_parallel(Line(p1, p2))
assert pl6.is_parallel(l1) is False
assert pl3.is_perpendicular(pl6)
assert pl4.is_perpendicular(pl7)
assert pl6.is_perpendicular(pl7)
assert pl6.is_perpendicular(pl4) is False
assert pl6.is_perpendicular(l1) is False
assert pl6.is_perpendicular(Line((0, 0, 0), (1, 1, 1)))
assert pl6.is_perpendicular((1, 1)) is False
assert pl6.distance(pl6.arbitrary_point(u, v)) == 0
assert pl7.distance(pl7.arbitrary_point(u, v)) == 0
assert pl6.distance(pl6.arbitrary_point(t)) == 0
assert pl7.distance(pl7.arbitrary_point(t)) == 0
assert pl6.p1.distance(pl6.arbitrary_point(t)).simplify() == 1
assert pl7.p1.distance(pl7.arbitrary_point(t)).simplify() == 1
assert pl3.arbitrary_point(t) == Point3D(-sqrt(30)*sin(t)/30 + \
2*sqrt(5)*cos(t)/5, sqrt(30)*sin(t)/15 + sqrt(5)*cos(t)/5, sqrt(30)*sin(t)/6)
assert pl3.arbitrary_point(u, v) == Point3D(2*u - v, u + 2*v, 5*v)
assert pl7.distance(Point3D(1, 3, 5)) == 5*sqrt(6)/6
assert pl6.distance(Point3D(0, 0, 0)) == 4*sqrt(3)
assert pl6.distance(pl6.p1) == 0
assert pl7.distance(pl6) == 0
assert pl7.distance(l1) == 0
assert pl6.distance(Segment3D(Point3D(2, 3, 1), Point3D(1, 3, 4))) == \
pl6.distance(Point3D(1, 3, 4)) == 4*sqrt(3)/3
assert pl6.distance(Segment3D(Point3D(1, 3, 4), Point3D(0, 3, 7))) == \
pl6.distance(Point3D(0, 3, 7)) == 2*sqrt(3)/3
assert pl6.distance(Segment3D(Point3D(0, 3, 7), Point3D(-1, 3, 10))) == 0
assert pl6.distance(Segment3D(Point3D(-1, 3, 10), Point3D(-2, 3, 13))) == 0
assert pl6.distance(Segment3D(Point3D(-2, 3, 13), Point3D(-3, 3, 16))) == \
pl6.distance(Point3D(-2, 3, 13)) == 2*sqrt(3)/3
assert pl6.distance(Plane(Point3D(5, 5, 5), normal_vector=(8, 8, 8))) == sqrt(3)
assert pl6.distance(Ray3D(Point3D(1, 3, 4), direction_ratio=[1, 0, -3])) == 4*sqrt(3)/3
assert pl6.distance(Ray3D(Point3D(2, 3, 1), direction_ratio=[-1, 0, 3])) == 0
assert pl6.angle_between(pl3) == pi/2
assert pl6.angle_between(pl6) == 0
assert pl6.angle_between(pl4) == 0
assert pl7.angle_between(Line3D(Point3D(2, 3, 5), Point3D(2, 4, 6))) == \
-asin(sqrt(3)/6)
assert pl6.angle_between(Ray3D(Point3D(2, 4, 1), Point3D(6, 5, 3))) == \
asin(sqrt(7)/3)
assert pl7.angle_between(Segment3D(Point3D(5, 6, 1), Point3D(1, 2, 4))) == \
asin(7*sqrt(246)/246)
assert are_coplanar(l1, l2, l3) is False
assert are_coplanar(l1) is False
assert are_coplanar(Point3D(2, 7, 2), Point3D(0, 0, 2),
Point3D(1, 1, 2), Point3D(1, 2, 2))
assert are_coplanar(Plane(p1, p2, p3), Plane(p1, p3, p2))
assert Plane.are_concurrent(pl3, pl4, pl5) is False
assert Plane.are_concurrent(pl6) is False
raises(ValueError, lambda: Plane.are_concurrent(Point3D(0, 0, 0)))
raises(ValueError, lambda: Plane((1, 2, 3), normal_vector=(0, 0, 0)))
assert pl3.parallel_plane(Point3D(1, 2, 5)) == Plane(Point3D(1, 2, 5), \
normal_vector=(1, -2, 1))
# perpendicular_plane
p = Plane((0, 0, 0), (1, 0, 0))
# default
assert p.perpendicular_plane() == Plane(Point3D(0, 0, 0), (0, 1, 0))
# 1 pt
assert p.perpendicular_plane(Point3D(1, 0, 1)) == \
Plane(Point3D(1, 0, 1), (0, 1, 0))
# pts as tuples
assert p.perpendicular_plane((1, 0, 1), (1, 1, 1)) == \
Plane(Point3D(1, 0, 1), (0, 0, -1))
# more than two planes
raises(ValueError, lambda: p.perpendicular_plane((1, 0, 1), (1, 1, 1), (1, 1, 0)))
a, b = Point3D(0, 0, 0), Point3D(0, 1, 0)
Z = (0, 0, 1)
p = Plane(a, normal_vector=Z)
# case 4
assert p.perpendicular_plane(a, b) == Plane(a, (1, 0, 0))
n = Point3D(*Z)
# case 1
assert p.perpendicular_plane(a, n) == Plane(a, (-1, 0, 0))
# case 2
assert Plane(a, normal_vector=b.args).perpendicular_plane(a, a + b) == \
Plane(Point3D(0, 0, 0), (1, 0, 0))
# case 1&3
assert Plane(b, normal_vector=Z).perpendicular_plane(b, b + n) == \
Plane(Point3D(0, 1, 0), (-1, 0, 0))
# case 2&3
assert Plane(b, normal_vector=b.args).perpendicular_plane(n, n + b) == \
Plane(Point3D(0, 0, 1), (1, 0, 0))
p = Plane(a, normal_vector=(0, 0, 1))
assert p.perpendicular_plane() == Plane(a, normal_vector=(1, 0, 0))
assert pl6.intersection(pl6) == [pl6]
assert pl4.intersection(pl4.p1) == [pl4.p1]
assert pl3.intersection(pl6) == [
Line3D(Point3D(8, 4, 0), Point3D(2, 4, 6))]
assert pl3.intersection(Line3D(Point3D(1,2,4), Point3D(4,4,2))) == [
Point3D(2, Rational(8, 3), Rational(10, 3))]
assert pl3.intersection(Plane(Point3D(6, 0, 0), normal_vector=(2, -5, 3))
) == [Line3D(Point3D(-24, -12, 0), Point3D(-25, -13, -1))]
assert pl6.intersection(Ray3D(Point3D(2, 3, 1), Point3D(1, 3, 4))) == [
Point3D(-1, 3, 10)]
assert pl6.intersection(Segment3D(Point3D(2, 3, 1), Point3D(1, 3, 4))) == []
assert pl7.intersection(Line(Point(2, 3), Point(4, 2))) == [
Point3D(Rational(13, 2), Rational(3, 4), 0)]
r = Ray(Point(2, 3), Point(4, 2))
assert Plane((1,2,0), normal_vector=(0,0,1)).intersection(r) == [
Ray3D(Point(2, 3), Point(4, 2))]
assert pl9.intersection(pl8) == [Line3D(Point3D(0, 0, 0), Point3D(12, 0, 0))]
assert pl10.intersection(pl11) == [Line3D(Point3D(0, 0, 1), Point3D(0, 2, 1))]
assert pl4.intersection(pl8) == [Line3D(Point3D(0, 0, 0), Point3D(1, -1, 0))]
assert pl11.intersection(pl8) == []
assert pl9.intersection(pl11) == [Line3D(Point3D(0, 0, 1), Point3D(12, 0, 1))]
assert pl9.intersection(pl4) == [Line3D(Point3D(0, 0, 0), Point3D(12, 0, -12))]
assert pl3.random_point() in pl3
assert pl3.random_point(seed=1) in pl3
# test geometrical entity using equals
assert pl4.intersection(pl4.p1)[0].equals(pl4.p1)
assert pl3.intersection(pl6)[0].equals(Line3D(Point3D(8, 4, 0), Point3D(2, 4, 6)))
pl8 = Plane((1, 2, 0), normal_vector=(0, 0, 1))
assert pl8.intersection(Line3D(p1, (1, 12, 0)))[0].equals(Line((0, 0, 0), (0.1, 1.2, 0)))
assert pl8.intersection(Ray3D(p1, (1, 12, 0)))[0].equals(Ray((0, 0, 0), (1, 12, 0)))
assert pl8.intersection(Segment3D(p1, (21, 1, 0)))[0].equals(Segment3D(p1, (21, 1, 0)))
assert pl8.intersection(Plane(p1, normal_vector=(0, 0, 112)))[0].equals(pl8)
assert pl8.intersection(Plane(p1, normal_vector=(0, 12, 0)))[0].equals(
Line3D(p1, direction_ratio=(112 * pi, 0, 0)))
assert pl8.intersection(Plane(p1, normal_vector=(11, 0, 1)))[0].equals(
Line3D(p1, direction_ratio=(0, -11, 0)))
assert pl8.intersection(Plane(p1, normal_vector=(1, 0, 11)))[0].equals(
Line3D(p1, direction_ratio=(0, 11, 0)))
assert pl8.intersection(Plane(p1, normal_vector=(-1, -1, -11)))[0].equals(
Line3D(p1, direction_ratio=(1, -1, 0)))
assert pl3.random_point() in pl3
assert len(pl8.intersection(Ray3D(Point3D(0, 2, 3), Point3D(1, 0, 3)))) == 0
# check if two plane are equals
assert pl6.intersection(pl6)[0].equals(pl6)
assert pl8.equals(Plane(p1, normal_vector=(0, 12, 0))) is False
assert pl8.equals(pl8)
assert pl8.equals(Plane(p1, normal_vector=(0, 0, -12)))
assert pl8.equals(Plane(p1, normal_vector=(0, 0, -12*sqrt(3))))
assert pl8.equals(p1) is False
# issue 8570
l2 = Line3D(Point3D(Rational(50000004459633, 5000000000000),
Rational(-891926590718643, 1000000000000000),
Rational(231800966893633, 100000000000000)),
Point3D(Rational(50000004459633, 50000000000000),
Rational(-222981647679771, 250000000000000),
Rational(231800966893633, 100000000000000)))
p2 = Plane(Point3D(Rational(402775636372767, 100000000000000),
Rational(-97224357654973, 100000000000000),
Rational(216793600814789, 100000000000000)),
(-S('9.00000087501922'), -S('4.81170658872543e-13'),
S('0.0')))
assert str([i.n(2) for i in p2.intersection(l2)]) == \
'[Point3D(4.0, -0.89, 2.3)]'
def random_point(self, seed=None):
"""A random point on the ellipse.
Returns
=======
point : Point
See Also
========
sympy.geometry.point.Point
arbitrary_point : Returns parameterized point on ellipse
Notes
-----
A random point may not appear to be on the ellipse, ie, `p in e` may
return False. This is because the coordinates of the point will be
floating point values, and when these values are substituted into the
equation for the ellipse the result may not be zero because of floating
point rounding error.
Examples
========
>>> from sympy import Point, Ellipse, Segment
>>> e1 = Ellipse(Point(0, 0), 3, 2)
>>> e1.random_point() # gives some random point
Point(...)
>>> p1 = e1.random_point(seed=0); p1.n(2)
Point(2.1, 1.4)
The random_point method assures that the point will test as being
in the ellipse:
>>> p1 in e1
True
Notes
=====
An arbitrary_point with a random value of t substituted into it may
not test as being on the ellipse because the expression tested that
a point is on the ellipse doesn't simplify to zero and doesn't evaluate
exactly to zero:
>>> from sympy.abc import t
>>> e1.arbitrary_point(t)
Point(3*cos(t), 2*sin(t))
>>> p2 = _.subs(t, 0.1)
>>> p2 in e1
False
Note that arbitrary_point routine does not take this approach. A value
for cos(t) and sin(t) (not t) is substituted into the arbitrary point.
There is a small chance that this will give a point that will not
test as being in the ellipse, so the process is repeated (up to 10
times) until a valid point is obtained.
"""
from sympy import sin, cos, Rational
t = _symbol('t')
x, y = self.arbitrary_point(t).args
# get a random value in [-1, 1) corresponding to cos(t)
# and confirm that it will test as being in the ellipse
if seed is not None:
rng = random.Random(seed)
else:
rng = random
for i in range(10): # should be enough?
# simplify this now or else the Float will turn s into a Float
c = 2*Rational(rng.random()) - 1
s = sqrt(1 - c**2)
p1 = Point(x.subs(cos(t), c), y.subs(sin(t), s))
if p1 in self:
return p1
raise GeometryError(
'Having problems generating a point in the ellipse.')
def test_loggamma():
raises(TypeError, lambda: loggamma(2, 3))
raises(ArgumentIndexError, lambda: loggamma(x).fdiff(2))
assert loggamma(-1) is oo
assert loggamma(-2) is oo
assert loggamma(0) is 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) is oo
assert loggamma(n/2) == log(2**(-n + 1)*sqrt(pi)*gamma(n)/gamma(n/2 + S.Half))
assert loggamma(oo) is oo
assert loggamma(-oo) is zoo
assert loggamma(I*oo) is zoo
assert loggamma(-I*oo) is zoo
assert loggamma(zoo) is zoo
assert loggamma(nan) is 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.n() == E.n()
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.n() == E.n()
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.n() == E.n()
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.n() == E.n()
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.n() == E.n()
assert loggamma(x).diff(x) == polygamma(0, x)
s1 = loggamma(1/(x + sin(x)) + cos(x)).nseries(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 - S.Half)*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).cancel()
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).cancel()
assert conjugate(loggamma(x)) == loggamma(conjugate(x))
assert conjugate(loggamma(0)) is oo
assert conjugate(loggamma(1)) == loggamma(conjugate(1))
assert conjugate(loggamma(-oo)) == conjugate(zoo)
assert loggamma(Symbol('v', positive=True)).is_real is True
assert loggamma(Symbol('v', zero=True)).is_real is False
assert loggamma(Symbol('v', negative=True)).is_real is False
assert loggamma(Symbol('v', nonpositive=True)).is_real is False
assert loggamma(Symbol('v', nonnegative=True)).is_real is None
assert loggamma(Symbol('v', imaginary=True)).is_real is None
assert loggamma(Symbol('v', real=True)).is_real is None
assert loggamma(Symbol('v')).is_real is None
assert loggamma(S.Half).is_real is True
assert loggamma(0).is_real is False
assert loggamma(Rational(-1, 2)).is_real is False
assert loggamma(I).is_real is None
assert loggamma(2 + 3*I).is_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, 2)
tN(3, 3)
tN(4, 4)
tN(5, 5)
def _expand(self, **hints):
n = self.order
z = self.argument
return (-1)**(n+1) * \
(fn(-n-1, z) * sin(z) + (-1)**(-n) * fn(n, z) * cos(z))
def test_meijerg_expand():
from sympy.simplify.gammasimp import gammasimp
from sympy.simplify.simplify import simplify
# from mpmath docs
assert hyperexpand(meijerg([[], []], [[0], []], -z)) == exp(z)
assert hyperexpand(meijerg([[1, 1], []], [[1], [0]], z)) == \
log(z + 1)
assert hyperexpand(meijerg([[1, 1], []], [[1], [1]], z)) == \
z/(z + 1)
assert hyperexpand(meijerg([[], []], [[S.Half], [0]], (z/2)**2)) \
== sin(z)/sqrt(pi)
assert hyperexpand(meijerg([[], []], [[0], [S.Half]], (z/2)**2)) \
== cos(z)/sqrt(pi)
assert can_do_meijer([], [a], [a - 1, a - S.Half], [])
assert can_do_meijer([], [], [a/2], [-a/2], False) # branches...
assert can_do_meijer([a], [b], [a], [b, a - 1])
# wikipedia
assert hyperexpand(meijerg([1], [], [], [0], z)) == \
Piecewise((0, abs(z) < 1), (1, abs(1/z) < 1),
(meijerg([1], [], [], [0], z), True))
assert hyperexpand(meijerg([], [1], [0], [], z)) == \
Piecewise((1, abs(z) < 1), (0, abs(1/z) < 1),
(meijerg([], [1], [0], [], z), True))
# The Special Functions and their Approximations
assert can_do_meijer([], [], [a + b/2], [a, a - b/2, a + S.Half])
assert can_do_meijer(
[], [], [a], [b], False) # branches only agree for small z
assert can_do_meijer([], [S.Half], [a], [-a])
assert can_do_meijer([], [], [a, b], [])
assert can_do_meijer([], [], [a, b], [])
assert can_do_meijer([], [], [a, a + S.Half], [b, b + S.Half])
assert can_do_meijer([], [], [a, -a], [0, S.Half], False) # dito
assert can_do_meijer([], [], [a, a + S.Half, b, b + S.Half], [])
assert can_do_meijer([S.Half], [], [0], [a, -a])
assert can_do_meijer([S.Half], [], [a], [0, -a], False) # dito
assert can_do_meijer([], [a - S.Half], [a, b], [a - S.Half], False)
assert can_do_meijer([], [a + S.Half], [a + b, a - b, a], [], False)
assert can_do_meijer([a + S.Half], [], [b, 2*a - b, a], [], False)
# This for example is actually zero.
assert can_do_meijer([], [], [], [a, b])
# Testing a bug:
assert hyperexpand(meijerg([0, 2], [], [], [-1, 1], z)) == \
Piecewise((0, abs(z) < 1),
(z*(1 - 1/z**2)/2, abs(1/z) < 1),
(meijerg([0, 2], [], [], [-1, 1], z), True))
# Test that the simplest possible answer is returned:
assert gammasimp(simplify(hyperexpand(
meijerg([1], [1 - a], [-a/2, -a/2 + S.Half], [], 1/z)))) == \
-2*sqrt(pi)*(sqrt(z + 1) + 1)**a/a
# Test that hyper is returned
assert hyperexpand(meijerg([1], [], [a], [0, 0], z)) == hyper(
(a,), (a + 1, a + 1), z*exp_polar(I*pi))*z**a*gamma(a)/gamma(a + 1)**2
# Test place option
f = meijerg(((0, 1), ()), ((S.Half,), (0,)), z**2)
assert hyperexpand(f) == sqrt(pi)/sqrt(1 + z**(-2))
assert hyperexpand(f, place=0) == sqrt(pi)*z/sqrt(z**2 + 1)
def test_TableForm_latex():
s = latex(TableForm([[0, x**3], ["c", S(1)/4], [sqrt(x), sin(x**2)]],
wipe_zeros=True, headings=("automatic", "automatic")))
assert s == (
'\\begin{tabular}{r l l}\n'
' & 1 & 2 \\\\\n'
'\\hline\n'
'1 & & $x^{3}$ \\\\\n'
'2 & $c$ & $\\frac{1}{4}$ \\\\\n'
'3 & $\\sqrt{x}$ & $\\sin{\\left (x^{2} \\right )}$ \\\\\n'
'\\end{tabular}'
)
s = latex(TableForm([[0, x**3], ["c", S(1)/4], [sqrt(x), sin(x**2)]],
wipe_zeros=True, headings=("automatic", "automatic"), alignments='l'))
assert s == (
'\\begin{tabular}{r l l}\n'
' & 1 & 2 \\\\\n'
'\\hline\n'
'1 & & $x^{3}$ \\\\\n'
'2 & $c$ & $\\frac{1}{4}$ \\\\\n'
'3 & $\\sqrt{x}$ & $\\sin{\\left (x^{2} \\right )}$ \\\\\n'
'\\end{tabular}'
)
s = latex(TableForm([[0, x**3], ["c", S(1)/4], [sqrt(x), sin(x**2)]],
wipe_zeros=True, headings=("automatic", "automatic"), alignments='l'*3))
assert s == (
'\\begin{tabular}{l l l}\n'
' & 1 & 2 \\\\\n'
'\\hline\n'
'1 & & $x^{3}$ \\\\\n'
'2 & $c$ & $\\frac{1}{4}$ \\\\\n'
'3 & $\\sqrt{x}$ & $\\sin{\\left (x^{2} \\right )}$ \\\\\n'
'\\end{tabular}'
)
s = latex(TableForm([["a", x**3], ["c", S(1)/4], [sqrt(x), sin(x**2)]],
headings=("automatic", "automatic")))
assert s == (
'\\begin{tabular}{r l l}\n'
' & 1 & 2 \\\\\n'
'\\hline\n'
'1 & $a$ & $x^{3}$ \\\\\n'
'2 & $c$ & $\\frac{1}{4}$ \\\\\n'
'3 & $\\sqrt{x}$ & $\\sin{\\left (x^{2} \\right )}$ \\\\\n'
'\\end{tabular}'
)
s = latex(TableForm([["a", x**3], ["c", S(1)/4], [sqrt(x), sin(x**2)]],
formats=['(%s)', None], headings=("automatic", "automatic")))
assert s == (
'\\begin{tabular}{r l l}\n'
' & 1 & 2 \\\\\n'
'\\hline\n'
'1 & (a) & $x^{3}$ \\\\\n'
'2 & (c) & $\\frac{1}{4}$ \\\\\n'
'3 & (sqrt(x)) & $\\sin{\\left (x^{2} \\right )}$ \\\\\n'
'\\end{tabular}'
)
def neg_in_paren(x, i, j):
if i % 2:
return ('(%s)' if x < 0 else '%s') % x
else:
pass # use default print
s = latex(TableForm([[-1, 2], [-3, 4]],
formats=[neg_in_paren]*2, headings=("automatic", "automatic")))
assert s == (
'\\begin{tabular}{r l l}\n'
' & 1 & 2 \\\\\n'
'\\hline\n'
'1 & -1 & 2 \\\\\n'
'2 & (-3) & 4 \\\\\n'
'\\end{tabular}'
)
s = latex(TableForm([["a", x**3], ["c", S(1)/4], [sqrt(x), sin(x**2)]]))
assert s == (
'\\begin{tabular}{l l}\n'
'$a$ & $x^{3}$ \\\\\n'
'$c$ & $\\frac{1}{4}$ \\\\\n'
'$\\sqrt{x}$ & $\\sin{\\left (x^{2} \\right )}$ \\\\\n'
'\\end{tabular}'
)
def _jn(n, z):
return fn(n, z) * sin(z) + (-1)**(n + 1) * fn(-n - 1, z) * cos(z)
def _eval_expand_func(self, **hints):
n, m, theta, phi = self.args
rv = (sqrt((2*n + 1)/(4*pi) * factorial(n - m)/factorial(n + m)) *
exp(I*m*phi) * assoc_legendre(n, m, cos(theta)))
# We can do this because of the range of theta
return rv.subs(sqrt(-cos(theta)**2 + 1), sin(theta))
