def _eval_rewrite_as_besseli(self, z):
ot = Rational(1, 3)
tt = Rational(2, 3)
a = C.Pow(z, Rational(3, 2))
if re(z).is_positive:
return ot*sqrt(z) * (besseli(-ot, tt*a) - besseli(ot, tt*a))
else:
return ot*(C.Pow(a, ot)*besseli(-ot, tt*a) - z*C.Pow(a, -ot)*besseli(ot, tt*a))
def _eval_rewrite_as_Sum(self, arg):
if arg.is_even:
k = C.Dummy("k", integer=True)
j = C.Dummy("j", integer=True)
n = self.args[0] / 2
Em = (S.ImaginaryUnit * C.Sum( C.Sum( C.binomial(k, j) * ((-1)**j * (k - 2*j)**(2*n + 1)) /
(2**k*S.ImaginaryUnit**k * k), (j, 0, k)), (k, 1, 2*n + 1)))
return Em
def _show_NT_np_p2(max_p):
'''[n>=p**2]: NT(n,p**2) = C(n,p**2) - [p\n]C(n/p,p)
[n>=p]: NT(n*p,p**2) = C(n*p,p**2) - C(n,p)
'''
for p in primes(max_p):
f = C(n * p, p**2) - C(n, p)
g = f.factor()
print('NT(n*p, {p}**2) = {f}'.format(p=p, f=g))
def _eval_rewrite_as_besseli(self, z):
ot = Rational(1, 3)
tt = Rational(2, 3)
a = C.Pow(z, Rational(3, 2))
if re(z).is_positive:
return sqrt(z)/sqrt(3) * (besseli(-ot, tt*a) + besseli(ot, tt*a))
else:
b = C.Pow(a, ot)
c = C.Pow(a, -ot)
return sqrt(ot)*(b*besseli(-ot, tt*a) + z*c*besseli(ot, tt*a))
def ufuncify(args, expr, **kwargs):
"""
Generates a binary ufunc-like lambda function for numpy arrays
``args``
Either a Symbol or a tuple of symbols. Specifies the argument sequence
for the ufunc-like function.
``expr``
A SymPy expression that defines the element wise operation
``kwargs``
Optional keyword arguments are forwarded to autowrap().
The returned function can only act on one array at a time, as only the
first argument accept arrays as input.
.. Note:: a *proper* numpy ufunc is required to support broadcasting, type
casting and more. The function returned here, may not qualify for
numpy's definition of a ufunc. That why we use the term ufunc-like.
References
==========
[1] http://docs.scipy.org/doc/numpy/reference/ufuncs.html
Examples
========
>>> from sympy.utilities.autowrap import ufuncify
>>> from sympy.abc import x, y
>>> import numpy as np
>>> f = ufuncify([x, y], y + x**2)
>>> f([1, 2, 3], 2)
[ 3. 6. 11.]
>>> a = f(np.arange(5), 3)
>>> isinstance(a, np.ndarray)
True
>>> print a
[ 3. 4. 7. 12. 19.]
"""
y = C.IndexedBase(C.Dummy('y'))
x = C.IndexedBase(C.Dummy('x'))
m = C.Dummy('m', integer=True)
i = C.Dummy('i', integer=True)
i = C.Idx(i, m)
l = C.Lambda(args, expr)
f = implemented_function('f', l)
if isinstance(args, C.Symbol):
args = [args]
else:
args = list(args)
# ensure correct order of arguments
kwargs['args'] = [y, x] + args[1:] + [m]
# first argument accepts an array
args[0] = x[i]
return autowrap(C.Equality(y[i], f(*args)), **kwargs)
def _eval_rewrite_as_besseli(self, z):
ot = Rational(1, 3)
tt = Rational(2, 3)
a = tt * C.Pow(z, Rational(3, 2))
if re(z).is_positive:
return z/sqrt(3) * (besseli(-tt, a) + besseli(tt, a))
else:
a = C.Pow(z, Rational(3, 2))
b = C.Pow(a, tt)
c = C.Pow(a, -tt)
return sqrt(ot) * (b*besseli(-tt, tt*a) + z**2*c*besseli(tt, tt*a))
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 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))*C.factorial(n) *
gamma(n/3 + S(2)/3)/(sin(pi*(2*n/3 + S(2)/3))*C.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)) /
C.factorial(n) * (root(3, 3)*x)**n)
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))*C.factorial(n) *
gamma(n/3 + S(2)/3)/(sin(pi*(2*n/3 + S(2)/3))*C.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)) /
C.factorial(n) * (root(3, 3)*x)**n)
def Zlm(l, m, th, ph):
from sympy import simplify
if m > 0:
zz = C.NegativeOne()**m*(Ylm(l, m, th, ph) + Ylm_c(l, m, th, ph))/sqrt(2)
elif m == 0:
return Ylm(l, m, th, ph)
else:
zz = C.NegativeOne()**m*(Ylm(l, -m, th, ph) - Ylm_c(l, -m, th, ph))/(I*sqrt(2))
zz = zz.expand(complex=True)
zz = simplify(zz)
return zz
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 _calc_bernoulli(n):
s = 0
a = int(C.binomial(n+3, n-6))
for j in xrange(1, n//6+1):
s += a * bernoulli(n - 6*j)
# Avoid computing each binomial coefficient from scratch
a *= _product(n-6 - 6*j + 1, n-6*j)
a //= _product(6*j+4, 6*j+9)
if n % 6 == 4:
s = -Rational(n+3, 6) - s
else:
s = Rational(n+3, 3) - s
return s / C.binomial(n+3, n)
def _calc_bernoulli(n):
s = 0
a = int(C.Binomial(n + 3, n - 6))
for j in xrange(1, n // 6 + 1):
s += a * bernoulli(n - 6 * j)
# Avoid computing each binomial coefficient from scratch
a *= _product(n - 6 - 6 * j + 1, n - 6 * j)
a //= _product(6 * j + 4, 6 * j + 9)
if n % 6 == 4:
s = -Rational(n + 3, 6) - s
else:
s = Rational(n + 3, 3) - s
return s / C.Binomial(n + 3, n)
def calc_B(m, base):
assert m >= 0
L = m + 1
Cs = [C(m, j) for j in range(L)]
B = [[c * (i + base)**(m - j) for j, c in zip(range(L), Cs)]
for i in range(L)]
return Matrix(B)
def test_subfactorial():
assert all(subfactorial(i) == ans for i, ans in enumerate(
[1, 0, 1, 2, 9, 44, 265, 1854, 14833, 133496]))
assert subfactorial(oo) == oo
x = Symbol('x')
assert subfactorial(x).rewrite(C.uppergamma) == \
C.uppergamma(x + 1, -1)/S.Exp1
tt = Symbol('tt', integer=True, nonnegative=True)
tf = Symbol('tf', integer=True, nonnegative=False)
tn = Symbol('tf', integer=True)
ft = Symbol('ft', integer=False, nonnegative=True)
ff = Symbol('ff', integer=False, nonnegative=False)
fn = Symbol('ff', integer=False)
nt = Symbol('nt', nonnegative=True)
nf = Symbol('nf', nonnegative=False)
nn = Symbol('nf')
assert subfactorial(tt).is_integer
assert subfactorial(tf).is_integer is None
assert subfactorial(tn).is_integer is None
assert subfactorial(ft).is_integer is None
assert subfactorial(ff).is_integer is None
assert subfactorial(fn).is_integer is None
assert subfactorial(nt).is_integer is None
assert subfactorial(nf).is_integer is None
assert subfactorial(nn).is_integer is None
def _print_Pow(self, expr):
base = self._print(expr.base)
if ('_' in base or '^' in base) and 'cdot' not in base:
mode = True
else:
mode = False
# Treat x**Rational(1,n) as special case
if expr.exp.is_Rational and abs(expr.exp.p) == 1 and expr.exp.q != 1:
expq = expr.exp.q
if expq == 2:
tex = r"\sqrt{%s}" % base
elif self._settings['itex']:
tex = r"\root{%d}{%s}" % (expq, base)
else:
tex = r"\sqrt[%d]{%s}" % (expq, base)
if expr.exp.is_negative:
return r"\frac{1}{%s}" % tex
else:
return tex
elif self._settings['fold_frac_powers'] \
and expr.exp.is_Rational \
and expr.exp.q != 1:
base, p, q = self._print(expr.base), expr.exp.p, expr.exp.q
if mode:
return r"{\lp %s \rp}^{%s/%s}" % (base, p, q)
else:
return r"%s^{%s/%s}" % (base, p, q)
elif expr.exp.is_Rational and expr.exp.is_negative and expr.base.is_Function:
# Things like 1/x
return r"\frac{%s}{%s}" % \
(1, self._print(C.Pow(expr.base, -expr.exp)))
else:
if expr.base.is_Function:
return self._print(expr.base, self._print(expr.exp))
else:
if expr.is_commutative and expr.exp == -1:
"""
solves issue 4129
As Mul always simplify 1/x to x**-1
The objective is achieved with this hack
first we get the latex for -1 * expr,
which is a Mul expression
"""
tex = self._print(S.NegativeOne * expr).strip()
# the result comes with a minus and a space, so we remove
if tex[:1] == "-":
return tex[1:].strip()
if self._needs_brackets(expr.base):
tex = r"\left(%s\right)^{%s}"
else:
if mode:
tex = r"{\lp %s \rp}^{%s}"
else:
tex = r"%s^{%s}"
return tex % (self._print(expr.base), self._print(expr.exp))
def choose_without_period(n, k):
r'''NT n k = sum Mu d * C(n/d, k/d) {d\gcd(n,k)} for [(n,k)!=(0,0)]
NT 0 0 = 1
'''
if (n, k) == (0, 0):
return 1
return sum(Mu_d * C(n // d, k // d) for Mu_d, d in iter_Mu(gcd(n, k)))
def _eval_rewrite_as_Sum(self, arg):
if arg.is_even:
k = C.Dummy("k", integer=True)
j = C.Dummy("j", integer=True)
n = self.args[0] / 2
Em = (S.ImaginaryUnit * C.Sum( C.Sum( C.binomial(k,j) * ((-1)**j * (k-2*j)**(2*n+1)) /
(2**k*S.ImaginaryUnit**k * k), (j,0,k)), (k, 1, 2*n+1)))
return Em
def ufuncify(args, expr, **kwargs):
"""Generates a binary ufunc-like lambda function for numpy arrays
``args``
Either a Symbol or a tuple of symbols. Specifies the argument sequence
for the ufunc-like function.
``expr``
A Sympy expression that defines the element wise operation
``kwargs``
Optional keyword arguments are forwarded to autowrap().
The returned function can only act on one array at a time, as only the
first argument accept arrays as input.
.. Note:: a *proper* numpy ufunc is required to support broadcasting, type
casting and more. The function returned here, may not qualify for
numpy's definition of a ufunc. That why we use the term ufunc-like.
See http://docs.scipy.org/doc/numpy/reference/ufuncs.html
:Examples:
>>> from sympy.utilities.autowrap import ufuncify
>>> from sympy.abc import x, y, z
>>> f = ufuncify([x, y], y + x**2) # doctest: +SKIP
>>> f([1, 2, 3], 2) # doctest: +SKIP
[2. 5. 10.]
"""
y = C.IndexedBase(C.Dummy('y'))
x = C.IndexedBase(C.Dummy('x'))
m = C.Dummy('m', integer=True)
i = C.Dummy('i', integer=True)
i = C.Idx(i, m)
l = C.Lambda(args, expr)
f = implemented_function('f', l)
if isinstance(args, C.Symbol):
args = [args]
else:
args = list(args)
# first argument accepts an array
args[0] = x[i]
return autowrap(C.Equality(y[i], f(*args)), **kwargs)
def full(self):
# remove unused commands
self.clean()
# evalf
for command in self.commands:
command.expr = mypowsimp(mycollectsimp(command.expr.evalf()))
command.expr = command.expr.subs(C.Real(-1.0), -1)
command.expr = command.expr.subs(C.Real(-2.0), -2)
# substitute as much as possible
while self.autosub(level=0):
pass
while self.autosub(level=1):
pass
# substitute back temporary variables that are used only once
self.singles()
# mypowsimp
for command in self.commands:
command.expr = mypowsimp(command.expr)
command.expr = command.expr.subs(C.Real(-1.0), -1)
command.expr = command.expr.subs(C.Real(-2.0), -2)
def mypowsimp(expr):
def find_double_pow(expr):
for sub in preorder_traversal(expr):
if isinstance(sub, C.Pow) and isinstance(sub.base, C.Pow):
return sub
while True:
sub = find_double_pow(expr)
if sub is None:
break
expr = expr.subs(sub, C.Pow(sub.base.base, sub.exp*sub.base.exp))
return expr
def Pow(expr, assumptions):
"""
Real**Integer -> Real
Positive**Real -> Real
Real**(Integer/Even) -> Real if base is nonnegative
Real**(Integer/Odd) -> Real
Imaginary**(Integer/Even) -> Real
Imaginary**(Integer/Odd) -> not Real
Imaginary**Real -> ? since Real could be 0 (giving real) or 1 (giving imaginary)
b**Imaginary -> Real if log(b) is imaginary and b != 0 and exponent != integer multiple of I*pi/log(b)
Real**Real -> ? e.g. sqrt(-1) is imaginary and sqrt(2) is not
"""
if expr.is_number:
return AskRealHandler._number(expr, assumptions)
if expr.base.func == C.exp:
if ask(Q.imaginary(expr.base.args[0]), assumptions):
if ask(Q.imaginary(expr.exp), assumptions):
return True
# If the i = (exp's arg)/(I*pi) is an integer or half-integer
# multiple of I*pi then 2*i will be an integer. In addition,
# exp(i*I*pi) = (-1)**i so the overall realness of the expr
# can be determined by replacing exp(i*I*pi) with (-1)**i.
i = expr.base.args[0] / I / pi
if ask(Q.integer(2 * i), assumptions):
return ask(Q.real(((-1)**i)**expr.exp), assumptions)
return
if ask(Q.imaginary(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
odd = ask(Q.odd(expr.exp), assumptions)
if odd is not None:
return not odd
return
if ask(Q.imaginary(expr.exp), assumptions):
imlog = ask(Q.imaginary(C.log(expr.base)), assumptions)
if imlog is not None:
# I**i -> real, log(I) is imag;
# (2*I)**i -> complex, log(2*I) is not imag
return imlog
if ask(Q.real(expr.base), assumptions):
if ask(Q.real(expr.exp), assumptions):
if expr.exp.is_Rational and \
ask(Q.even(expr.exp.q), assumptions):
return ask(Q.positive(expr.base), assumptions)
elif ask(Q.integer(expr.exp), assumptions):
return True
elif ask(Q.positive(expr.base), assumptions):
return True
elif ask(Q.negative(expr.base), assumptions):
return False
def Pow(expr, assumptions):
"""
Real**Integer -> Real
Positive**Real -> Real
Real**(Integer/Even) -> Real if base is nonnegative
Real**(Integer/Odd) -> Real
Imaginary**(Integer/Even) -> Real
Imaginary**(Integer/Odd) -> not Real
Imaginary**Real -> ? since Real could be 0 (giving real) or 1 (giving imaginary)
b**Imaginary -> Real if log(b) is imaginary and b != 0 and exponent != integer multiple of I*pi/log(b)
Real**Real -> ? e.g. sqrt(-1) is imaginary and sqrt(2) is not
"""
if expr.is_number:
return AskRealHandler._number(expr, assumptions)
if expr.base.func == C.exp:
if ask(Q.imaginary(expr.base.args[0]), assumptions):
if ask(Q.imaginary(expr.exp), assumptions):
return True
# If the i = (exp's arg)/(I*pi) is an integer or half-integer
# multiple of I*pi then 2*i will be an integer. In addition,
# exp(i*I*pi) = (-1)**i so the overall realness of the expr
# can be determined by replacing exp(i*I*pi) with (-1)**i.
i = expr.base.args[0]/I/pi
if ask(Q.integer(2*i), assumptions):
return ask(Q.real(((-1)**i)**expr.exp), assumptions)
return
if ask(Q.imaginary(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
odd = ask(Q.odd(expr.exp), assumptions)
if odd is not None:
return not odd
return
if ask(Q.imaginary(expr.exp), assumptions):
imlog = ask(Q.imaginary(C.log(expr.base)), assumptions)
if imlog is not None:
# I**i -> real, log(I) is imag;
# (2*I)**i -> complex, log(2*I) is not imag
return imlog
if ask(Q.real(expr.base), assumptions):
if ask(Q.real(expr.exp), assumptions):
if expr.exp.is_Rational and \
ask(Q.even(expr.exp.q), assumptions):
return ask(Q.positive(expr.base), assumptions)
elif ask(Q.integer(expr.exp), assumptions):
return True
elif ask(Q.positive(expr.base), assumptions):
return True
elif ask(Q.negative(expr.base), assumptions):
return False
def test_curve():
s = Symbol('s')
z = Symbol('z')
# this curve is independent of the indicated parameter
C = Curve([2*s, s**2], (z, 0, 2))
assert C.parameter == z
assert C.functions == (2*s, s**2)
assert C.arbitrary_point() == Point(2*s, s**2)
assert C.arbitrary_point(z) == Point(2*s, s**2)
# this is how it is normally used
C = Curve([2*s, s**2], (s, 0, 2))
assert C.parameter == s
assert C.functions == (2*s, s**2)
t = Symbol('t')
assert C.arbitrary_point() != Point(2*t, t**2) # the t returned as assumptions
t = Symbol('t', real=True) # now t has the same assumptions so the test passes
assert C.arbitrary_point() == Point(2*t, t**2)
assert C.arbitrary_point(z) == Point(2*z, z**2)
assert C.arbitrary_point(C.parameter) == Point(2*s, s**2)
raises(ValueError, 'Curve((s, s + t), (s, 1, 2)).arbitrary_point()')
raises(ValueError, 'Curve((s, s + t), (t, 1, 2)).arbitrary_point(s)')
def test_curve():
s = Symbol("s")
z = Symbol("z")
# this curve is independent of the indicated parameter
C = Curve([2 * s, s ** 2], (z, 0, 2))
assert C.parameter == z
assert C.functions == (2 * s, s ** 2)
assert C.arbitrary_point() == Point(2 * s, s ** 2)
assert C.arbitrary_point(z) == Point(2 * s, s ** 2)
# this is how it is normally used
C = Curve([2 * s, s ** 2], (s, 0, 2))
assert C.parameter == s
assert C.functions == (2 * s, s ** 2)
t = Symbol("t")
assert C.arbitrary_point() != Point(2 * t, t ** 2) # the t returned as assumptions
t = Symbol("t", real=True) # now t has the same assumptions so the test passes
assert C.arbitrary_point() == Point(2 * t, t ** 2)
assert C.arbitrary_point(z) == Point(2 * z, z ** 2)
assert C.arbitrary_point(C.parameter) == Point(2 * s, s ** 2)
raises(ValueError, "Curve((s, s + t), (s, 1, 2)).arbitrary_point()")
raises(ValueError, "Curve((s, s + t), (t, 1, 2)).arbitrary_point(s)")
def canonize(cls, n, sym=None):
if n.is_Number:
if n.is_Integer and n.is_nonnegative:
if n is S.Zero:
return S.One
elif n is S.One:
if sym is None: return -S.Half
else: return sym - S.Half
# Bernoulli numbers
elif sym is None:
if n.is_odd:
return S.Zero
n = int(n)
# Use mpmath for enormous Bernoulli numbers
if n > 500:
p, q = bernfrac(n)
return Rational(int(p), q)
case = n % 6
highest_cached = cls._highest[case]
if n <= highest_cached:
return cls._cache[n]
# To avoid excessive recursion when, say, bernoulli(1000) is
# requested, calculate and cache the entire sequence ... B_988,
# B_994, B_1000 in increasing order
for i in xrange(highest_cached + 6, n + 6, 6):
b = cls._calc_bernoulli(i)
cls._cache[i] = b
cls._highest[case] = i
return b
# Bernoulli polynomials
else:
n, result = int(n), []
for k in xrange(n + 1):
result.append(C.Binomial(n, k) * cls(k) * sym**(n - k))
return C.Add(*result)
else:
raise ValueError("Bernoulli numbers are defined only"
" for nonnegative integer indices.")
def eval(cls, n, m=None):
if m is None:
m = S.One
if n == oo:
return C.zeta(m)
if n.is_Integer and n.is_nonnegative and m.is_Integer:
if n == 0:
return S.Zero
if not m in cls._functions:
@recurrence_memo([0])
def f(n, prev):
return prev[-1] + S.One / n**m
cls._functions[m] = f
return cls._functions[m](int(n))
def eval(cls, n, m=None):
if m is None:
m = S.One
if n == oo:
return C.zeta(m)
if n.is_Integer and n.is_nonnegative and m.is_Integer:
if n == 0:
return S.Zero
if not m in cls._functions:
@recurrence_memo([0])
def f(n, prev):
return prev[-1] + S.One / n**m
cls._functions[m] = f
return cls._functions[m](int(n))
def Pow(expr, assumptions):
"""
Imaginary**Odd -> Imaginary
Imaginary**Even -> Real
b**Imaginary -> !Imaginary if exponent is an integer multiple of I*pi/log(b)
Imaginary**Real -> ?
Positive**Real -> Real
Negative**Integer -> Real
Negative**(Integer/2) -> Imaginary
Negative**Real -> not Imaginary if exponent is not Rational
"""
if expr.is_number:
return AskImaginaryHandler._number(expr, assumptions)
if expr.base.func == C.exp:
if ask(Q.imaginary(expr.base.args[0]), assumptions):
if ask(Q.imaginary(expr.exp), assumptions):
return False
i = expr.base.args[0] / I / pi
if ask(Q.integer(2 * i), assumptions):
return ask(Q.imaginary(((-1)**i)**expr.exp), assumptions)
if ask(Q.imaginary(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
odd = ask(Q.odd(expr.exp), assumptions)
if odd is not None:
return odd
return
if ask(Q.imaginary(expr.exp), assumptions):
imlog = ask(Q.imaginary(C.log(expr.base)), assumptions)
if imlog is not None:
return False # I**i -> real; (2*I)**i -> complex ==> not imaginary
if ask(Q.real(expr.base) & Q.real(expr.exp), assumptions):
if ask(Q.positive(expr.base), assumptions):
return False
else:
rat = ask(Q.rational(expr.exp), assumptions)
if not rat:
return rat
if ask(Q.integer(expr.exp), assumptions):
return False
else:
half = ask(Q.integer(2 * expr.exp), assumptions)
if half:
return ask(Q.negative(expr.base), assumptions)
return half
def Pow(expr, assumptions):
"""
Imaginary**Odd -> Imaginary
Imaginary**Even -> Real
b**Imaginary -> !Imaginary if exponent is an integer multiple of I*pi/log(b)
Imaginary**Real -> ?
Positive**Real -> Real
Negative**Integer -> Real
Negative**(Integer/2) -> Imaginary
Negative**Real -> not Imaginary if exponent is not Rational
"""
if expr.is_number:
return AskImaginaryHandler._number(expr, assumptions)
if expr.base.func == C.exp:
if ask(Q.imaginary(expr.base.args[0]), assumptions):
if ask(Q.imaginary(expr.exp), assumptions):
return False
i = expr.base.args[0]/I/pi
if ask(Q.integer(2*i), assumptions):
return ask(Q.imaginary(((-1)**i)**expr.exp), assumptions)
if ask(Q.imaginary(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
odd = ask(Q.odd(expr.exp), assumptions)
if odd is not None:
return odd
return
if ask(Q.imaginary(expr.exp), assumptions):
imlog = ask(Q.imaginary(C.log(expr.base)), assumptions)
if imlog is not None:
return False # I**i -> real; (2*I)**i -> complex ==> not imaginary
if ask(Q.real(expr.base) & Q.real(expr.exp), assumptions):
if ask(Q.positive(expr.base), assumptions):
return False
else:
rat = ask(Q.rational(expr.exp), assumptions)
if not rat:
return rat
if ask(Q.integer(expr.exp), assumptions):
return False
else:
half = ask(Q.integer(2*expr.exp), assumptions)
if half:
return ask(Q.negative(expr.base), assumptions)
return half
def Pow(expr, assumptions):
"""
Imaginary**integer/odd -> Imaginary
Imaginary**integer/even -> Real if integer % 2 == 0
b**Imaginary -> !Imaginary if exponent is an integer multiple of I*pi/log(b)
Imaginary**Real -> ?
Negative**even root -> Imaginary
Negative**odd root -> Real
Negative**Real -> Imaginary
Real**Integer -> Real
Real**Positive -> Real
"""
if expr.is_number:
return AskImaginaryHandler._number(expr, assumptions)
if expr.base.func == C.exp:
if ask(Q.imaginary(expr.base.args[0]), assumptions):
if ask(Q.imaginary(expr.exp), assumptions):
return False
i = expr.base.args[0] / I / pi
if ask(Q.integer(2 * i), assumptions):
return ask(Q.imaginary(((-1)**i)**expr.exp), assumptions)
if ask(Q.imaginary(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
odd = ask(Q.odd(expr.exp), assumptions)
if odd is not None:
return odd
return
if ask(Q.imaginary(expr.exp), assumptions):
imlog = ask(Q.imaginary(C.log(expr.base)), assumptions)
if imlog is not None:
return False # I**i -> real; (2*I)**i -> complex ==> not imaginary
if ask(Q.real(expr.base), assumptions):
if ask(Q.real(expr.exp), assumptions):
if ask(
Q.rational(expr.exp) & Q.even(denom(expr.exp)),
assumptions):
return ask(Q.negative(expr.base), assumptions)
elif ask(Q.integer(expr.exp), assumptions):
return False
elif ask(Q.positive(expr.base), assumptions):
return False
elif ask(Q.negative(expr.base), assumptions):
return True
def Pow(expr, assumptions):
"""
Imaginary**integer/odd -> Imaginary
Imaginary**integer/even -> Real if integer % 2 == 0
b**Imaginary -> !Imaginary if exponent is an integer multiple of I*pi/log(b)
Imaginary**Real -> ?
Negative**even root -> Imaginary
Negative**odd root -> Real
Negative**Real -> Imaginary
Real**Integer -> Real
Real**Positive -> Real
"""
if expr.is_number:
return AskImaginaryHandler._number(expr, assumptions)
if expr.base.func == C.exp:
if ask(Q.imaginary(expr.base.args[0]), assumptions):
if ask(Q.imaginary(expr.exp), assumptions):
return False
i = expr.base.args[0]/I/pi
if ask(Q.integer(2*i), assumptions):
return ask(Q.imaginary(((-1)**i)**expr.exp), assumptions)
if ask(Q.imaginary(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
odd = ask(Q.odd(expr.exp), assumptions)
if odd is not None:
return odd
return
if ask(Q.imaginary(expr.exp), assumptions):
imlog = ask(Q.imaginary(C.log(expr.base)), assumptions)
if imlog is not None:
return False # I**i -> real; (2*I)**i -> complex ==> not imaginary
if ask(Q.real(expr.base), assumptions):
if ask(Q.real(expr.exp), assumptions):
if ask(Q.rational(expr.exp) & Q.even(denom(expr.exp)), assumptions):
return ask(Q.negative(expr.base), assumptions)
elif ask(Q.integer(expr.exp), assumptions):
return False
elif ask(Q.positive(expr.base), assumptions):
return False
elif ask(Q.negative(expr.base), assumptions):
return True
def test_subfactorial():
assert all(
subfactorial(i) == ans
for i, ans in enumerate([1, 0, 1, 2, 9, 44, 265, 1854, 14833, 133496]))
assert subfactorial(oo) == oo
x = Symbol('x')
assert subfactorial(x).rewrite(C.uppergamma) == \
C.uppergamma(x + 1, -1)/S.Exp1
tt = Symbol('tt', integer=True, nonnegative=True)
tf = Symbol('tf', integer=True, nonnegative=False)
tn = Symbol('tf', integer=True)
ft = Symbol('ft', integer=False, nonnegative=True)
ff = Symbol('ff', integer=False, nonnegative=False)
fn = Symbol('ff', integer=False)
nt = Symbol('nt', nonnegative=True)
nf = Symbol('nf', nonnegative=False)
nn = Symbol('nf')
te = Symbol('te', even=True, nonnegative=True)
to = Symbol('to', odd=True, nonnegative=True)
assert subfactorial(tt).is_integer
assert subfactorial(tf).is_integer is None
assert subfactorial(tn).is_integer is None
assert subfactorial(ft).is_integer is None
assert subfactorial(ff).is_integer is None
assert subfactorial(fn).is_integer is None
assert subfactorial(nt).is_integer is None
assert subfactorial(nf).is_integer is None
assert subfactorial(nn).is_integer is None
assert subfactorial(tt).is_nonnegative
assert subfactorial(tf).is_nonnegative is None
assert subfactorial(tn).is_nonnegative is None
assert subfactorial(ft).is_nonnegative is None
assert subfactorial(ff).is_nonnegative is None
assert subfactorial(fn).is_nonnegative is None
assert subfactorial(nt).is_nonnegative is None
assert subfactorial(nf).is_nonnegative is None
assert subfactorial(nn).is_nonnegative is None
assert subfactorial(tt).is_even is None
assert subfactorial(tt).is_odd is None
assert subfactorial(te).is_odd is True
assert subfactorial(to).is_even is True
def Ylm(l, m, theta, phi):
"""
Spherical harmonics Ylm.
Examples:
>>> from sympy import symbols, Ylm
>>> theta, phi = symbols("theta phi")
>>> Ylm(0, 0, theta, phi)
1/(2*sqrt(pi))
>>> Ylm(1, -1, theta, phi)
sqrt(6)*exp(-I*phi)*sin(theta)/(4*sqrt(pi))
>>> Ylm(1, 0, theta, phi)
sqrt(3)*cos(theta)/(2*sqrt(pi))
"""
l, m, theta, phi = [sympify(x) for x in (l, m, theta, phi)]
factorial = C.factorial
return sqrt((2*l+1)/(4*pi) * factorial(l-m)/factorial(l+m)) * \
Plmcos(l, m, theta) * C.exp(I*m*phi)
def Ylm(l, m, theta, phi):
"""
Spherical harmonics Ylm.
Examples:
>>> from sympy import symbols, Ylm
>>> theta, phi = symbols("theta phi")
>>> Ylm(0, 0, theta, phi)
1/(2*pi**(1/2))
>>> Ylm(1, -1, theta, phi)
6**(1/2)*exp(-I*phi)*sin(theta)/(4*pi**(1/2))
>>> Ylm(1, 0, theta, phi)
3**(1/2)*cos(theta)/(2*pi**(1/2))
"""
l, m, theta, phi = [sympify(x) for x in (l, m, theta, phi)]
factorial = C.Factorial
return sqrt((2*l+1)/(4*pi) * factorial(l-m)/factorial(l+m)) * \
Plmcos(l, m, theta) * C.exp(I*m*phi)
def eval(cls, n, sym=None):
if n.is_Number:
if n.is_Integer and n.is_nonnegative:
if n is S.Zero:
return S.One
elif n is S.One:
if sym is None:
return -S.Half
else:
return sym - S.Half
# Bernoulli numbers
elif sym is None:
if n.is_odd:
return S.Zero
n = int(n)
# Use mpmath for enormous Bernoulli numbers
if n > 500:
p, q = bernfrac(n)
return Rational(int(p), int(q))
case = n % 6
highest_cached = cls._highest[case]
if n <= highest_cached:
return cls._cache[n]
# To avoid excessive recursion when, say, bernoulli(1000) is
# requested, calculate and cache the entire sequence ... B_988,
# B_994, B_1000 in increasing order
for i in xrange(highest_cached + 6, n + 6, 6):
b = cls._calc_bernoulli(i)
cls._cache[i] = b
cls._highest[case] = i
return b
# Bernoulli polynomials
else:
n, result = int(n), []
for k in xrange(n + 1):
result.append(C.binomial(n, k)*cls(k)*sym**(n - k))
return Add(*result)
else:
raise ValueError("Bernoulli numbers are defined only"
" for nonnegative integer indices.")
def _minpoly_sin(ex, x):
"""
Returns the minimal polynomial of ``sin(ex)``
see http://mathworld.wolfram.com/TrigonometryAngles.html
"""
from sympy.functions.combinatorial.factorials import binomial
c, a = ex.args[0].as_coeff_Mul()
if a is pi:
if c.is_rational:
n = c.q
q = sympify(n)
if q.is_prime:
# for a = pi*p/q with q odd prime, using chebyshevt
# write sin(q*a) = mp(sin(a))*sin(a);
# the roots of mp(x) are sin(pi*p/q) for p = 1,..., q - 1
a = dup_chebyshevt(n, ZZ)
return Add(*[x**(n - i - 1) * a[i] for i in range(n)])
if c.p == 1:
if q == 9:
return 64 * x**6 - 96 * x**4 + 36 * x**2 - 3
if n % 2 == 1:
# for a = pi*p/q with q odd, use
# sin(q*a) = 0 to see that the minimal polynomial must be
# a factor of dup_chebyshevt(n, ZZ)
a = dup_chebyshevt(n, ZZ)
a = [x**(n - i) * a[i] for i in range(n + 1)]
r = Add(*a)
_, factors = factor_list(r)
res = _choose_factor(factors, x, ex)
return res
expr = ((1 - C.cos(2 * c * pi)) / 2)**S.Half
res = _minpoly_compose(expr, x, QQ)
return res
raise NotAlgebraic("%s doesn't seem to be an algebraic element" % ex)
def _minpoly_sin(ex, x):
"""
Returns the minimal polynomial of ``sin(ex)``
see http://mathworld.wolfram.com/TrigonometryAngles.html
"""
from sympy.functions.combinatorial.factorials import binomial
c, a = ex.args[0].as_coeff_Mul()
if a is pi:
if c.is_rational:
n = c.q
q = sympify(n)
if q.is_prime:
# for a = pi*p/q with q odd prime, using chebyshevt
# write sin(q*a) = mp(sin(a))*sin(a);
# the roots of mp(x) are sin(pi*p/q) for p = 1,..., q - 1
a = dup_chebyshevt(n, ZZ)
return Add(*[x**(n - i - 1)*a[i] for i in range(n)])
if c.p == 1:
if q == 9:
return 64*x**6 - 96*x**4 + 36*x**2 - 3
if n % 2 == 1:
# for a = pi*p/q with q odd, use
# sin(q*a) = 0 to see that the minimal polynomial must be
# a factor of dup_chebyshevt(n, ZZ)
a = dup_chebyshevt(n, ZZ)
a = [x**(n - i)*a[i] for i in range(n + 1)]
r = Add(*a)
_, factors = factor_list(r)
res = _choose_factor(factors, x, ex)
return res
expr = ((1 - C.cos(2*c*pi))/2)**S.Half
res = _minpoly_compose(expr, x, QQ)
return res
raise NotAlgebraic("%s doesn't seem to be an algebraic element" % ex)
def test_line():
p1 = Point(0, 0)
p2 = Point(1, 1)
p3 = Point(x1, x1)
p4 = Point(y1, y1)
p5 = Point(x1, 1 + x1)
p6 = Point(1, 0)
p7 = Point(0, 1)
p8 = Point(2, 0)
p9 = Point(2, 1)
l1 = Line(p1, p2)
l2 = Line(p3, p4)
l3 = Line(p3, p5)
l4 = Line(p1, p6)
l5 = Line(p1, p7)
l6 = Line(p8, p9)
l7 = Line(p2, p9)
raises(ValueError, lambda: Line(Point(0, 0), Point(0, 0)))
# Basic stuff
assert Line((1, 1), slope=1) == Line((1, 1), (2, 2))
assert Line((1, 1), slope=oo) == Line((1, 1), (1, 2))
assert Line((1, 1), slope=-oo) == Line((1, 1), (1, 2))
raises(ValueError, lambda: Line((1, 1), 1))
assert Line(p1, p2) == Line(p2, p1)
assert l1 == l2
assert l1 != l3
assert l1.slope == 1
assert l1.length == oo
assert l3.slope == oo
assert l4.slope == 0
assert l4.coefficients == (0, 1, 0)
assert l4.equation(x=x, y=y) == y
assert l5.slope == oo
assert l5.coefficients == (1, 0, 0)
assert l5.equation() == x
assert l6.equation() == x - 2
assert l7.equation() == y - 1
assert p1 in l1 # is p1 on the line l1?
assert p1 not in l3
assert Line((-x, x), (-x + 1, x - 1)).coefficients == (1, 1, 0)
assert simplify(l1.equation()) in (x - y, y - x)
assert simplify(l3.equation()) in (x - x1, x1 - x)
assert Line(p1, p2).scale(2, 1) == Line(p1, p9)
assert l2.arbitrary_point() in l2
for ind in xrange(0, 5):
assert l3.random_point() in l3
# Orthogonality
p1_1 = Point(-x1, x1)
l1_1 = Line(p1, p1_1)
assert l1.perpendicular_line(p1) == l1_1
assert Line.is_perpendicular(l1, l1_1)
assert Line.is_perpendicular(l1, l2) == False
p = l1.random_point()
assert l1.perpendicular_segment(p) == p
# Parallelity
p2_1 = Point(-2 * x1, 0)
l2_1 = Line(p3, p5)
assert l2.parallel_line(p1_1) == Line(p2_1, p1_1)
assert l2_1.parallel_line(p1) == Line(p1, Point(0, 2))
assert Line.is_parallel(l1, l2)
assert Line.is_parallel(l2, l3) == False
assert Line.is_parallel(l2, l2.parallel_line(p1_1))
assert Line.is_parallel(l2_1, l2_1.parallel_line(p1))
# Intersection
assert intersection(l1, p1) == [p1]
assert intersection(l1, p5) == []
assert intersection(l1, l2) in [[l1], [l2]]
assert intersection(l1, l1.parallel_line(p5)) == []
# Concurrency
l3_1 = Line(Point(5, x1), Point(-Rational(3, 5), x1))
assert Line.is_concurrent(l1) == False
assert Line.is_concurrent(l1, l3)
assert Line.is_concurrent(l1, l3, l3_1)
assert Line.is_concurrent(l1, l1_1, l3) == False
# Projection
assert l2.projection(p4) == p4
assert l1.projection(p1_1) == p1
assert l3.projection(p2) == Point(x1, 1)
raises(GeometryError, lambda: Line(Point(0, 0), Point(1, 0)).projection(Circle(Point(0, 0), 1)))
# Finding angles
l1_1 = Line(p1, Point(5, 0))
assert feq(Line.angle_between(l1, l1_1).evalf(), pi.evalf() / 4)
# Testing Rays and Segments (very similar to Lines)
assert Ray((1, 1), angle=pi / 4) == Ray((1, 1), (2, 2))
assert Ray((1, 1), angle=pi / 2) == Ray((1, 1), (1, 2))
assert Ray((1, 1), angle=-pi / 2) == Ray((1, 1), (1, 0))
assert Ray((1, 1), angle=-3 * pi / 2) == Ray((1, 1), (1, 2))
assert Ray((1, 1), angle=5 * pi / 2) == Ray((1, 1), (1, 2))
assert Ray((1, 1), angle=5.0 * pi / 2) == Ray((1, 1), (1, 2))
assert Ray((1, 1), angle=pi) == Ray((1, 1), (0, 1))
assert Ray((1, 1), angle=3.0 * pi) == Ray((1, 1), (0, 1))
assert Ray((1, 1), angle=4.0 * pi) == Ray((1, 1), (2, 1))
assert Ray((1, 1), angle=0) == Ray((1, 1), (2, 1))
# XXX don't know why this fails without str
assert str(Ray((1, 1), angle=4.2 * pi)) == str(Ray(Point(1, 1), Point(2, 1 + C.tan(0.2 * pi))))
assert Ray((1, 1), angle=5) == Ray((1, 1), (2, 1 + C.tan(5)))
raises(ValueError, lambda: Ray((1, 1), 1))
r1 = Ray(p1, Point(-1, 5))
r2 = Ray(p1, Point(-1, 1))
r3 = Ray(p3, p5)
r4 = Ray(p1, p2)
r5 = Ray(p2, p1)
r6 = Ray(Point(0, 1), Point(1, 2))
r7 = Ray(Point(0.5, 0.5), Point(1, 1))
assert l1.projection(r1) == Ray(p1, p2)
assert l1.projection(r2) == p1
assert r3 != r1
t = Symbol("t", real=True)
assert Ray((1, 1), angle=pi / 4).arbitrary_point() == Point(1 / (1 - t), 1 / (1 - t))
s1 = Segment(p1, p2)
s2 = Segment(p1, p1_1)
assert s1.midpoint == Point(Rational(1, 2), Rational(1, 2))
assert s2.length == sqrt(2 * (x1 ** 2))
assert s1.perpendicular_bisector() == Line(Point(0, 1), Point(1, 0))
assert Segment((1, 1), (2, 3)).arbitrary_point() == Point(1 + t, 1 + 2 * t)
# intersections
assert s1.intersection(Line(p6, p9)) == []
s3 = Segment(Point(0.25, 0.25), Point(0.5, 0.5))
assert s1.intersection(s3) == [s1]
assert s3.intersection(s1) == [s3]
assert r4.intersection(s3) == [s3]
assert r4.intersection(Segment(Point(2, 3), Point(3, 4))) == []
assert r4.intersection(Segment(Point(-1, -1), Point(0.5, 0.5))) == [Segment(p1, Point(0.5, 0.5))]
s3 = Segment(Point(1, 1), Point(2, 2))
assert s1.intersection(s3) == [Point(1, 1)]
s3 = Segment(Point(0.5, 0.5), Point(1.5, 1.5))
assert s1.intersection(s3) == [Segment(Point(0.5, 0.5), p2)]
assert s1.intersection(Segment(Point(4, 4), Point(5, 5))) == []
assert s1.intersection(Segment(Point(-1, -1), p1)) == [p1]
assert s1.intersection(Segment(Point(-1, -1), Point(0.5, 0.5))) == [Segment(p1, Point(0.5, 0.5))]
assert r4.intersection(r5) == [s1]
assert r5.intersection(r6) == []
assert r4.intersection(r7) == r7.intersection(r4) == [r7]
# Segment contains
a, b = symbols("a,b")
s = Segment((0, a), (0, b))
assert Point(0, (a + b) / 2) in s
s = Segment((a, 0), (b, 0))
assert Point((a + b) / 2, 0) in s
raises(Undecidable, lambda: Point(2 * a, 0) in s)
# Testing distance from a Segment to an object
s1 = Segment(Point(0, 0), Point(1, 1))
s2 = Segment(Point(half, half), Point(1, 0))
pt1 = Point(0, 0)
pt2 = Point(Rational(3) / 2, Rational(3) / 2)
assert s1.distance(pt1) == 0
assert s2.distance(pt1) == 2 ** (half) / 2
assert s2.distance(pt2) == 2 ** (half)
# Special cases of projection and intersection
r1 = Ray(Point(1, 1), Point(2, 2))
r2 = Ray(Point(2, 2), Point(0, 0))
r3 = Ray(Point(1, 1), Point(-1, -1))
r4 = Ray(Point(0, 4), Point(-1, -5))
r5 = Ray(Point(2, 2), Point(3, 3))
assert intersection(r1, r2) == [Segment(Point(1, 1), Point(2, 2))]
assert intersection(r1, r3) == [Point(1, 1)]
assert r1.projection(r3) == Point(1, 1)
assert r1.projection(r4) == Segment(Point(1, 1), Point(2, 2))
r5 = Ray(Point(0, 0), Point(0, 1))
r6 = Ray(Point(0, 0), Point(0, 2))
assert r5 in r6
assert r6 in r5
s1 = Segment(Point(0, 0), Point(2, 2))
s2 = Segment(Point(-1, 5), Point(-5, -10))
s3 = Segment(Point(0, 4), Point(-2, 2))
assert intersection(r1, s1) == [Segment(Point(1, 1), Point(2, 2))]
assert r1.projection(s2) == Segment(Point(1, 1), Point(2, 2))
assert s3.projection(r1) == Segment(Point(0, 4), Point(-1, 3))
l1 = Line(Point(0, 0), Point(3, 4))
r1 = Ray(Point(0, 0), Point(3, 4))
s1 = Segment(Point(0, 0), Point(3, 4))
assert intersection(l1, l1) == [l1]
assert intersection(l1, r1) == [r1]
assert intersection(l1, s1) == [s1]
assert intersection(r1, l1) == [r1]
assert intersection(s1, l1) == [s1]
entity1 = Segment(Point(-10, 10), Point(10, 10))
entity2 = Segment(Point(-5, -5), Point(-5, 5))
assert intersection(entity1, entity2) == []
r1 = Ray(p1, Point(0, 1))
r2 = Ray(Point(0, 1), p1)
r3 = Ray(p1, p2)
r4 = Ray(p2, p1)
s1 = Segment(p1, Point(0, 1))
assert Line(r1.source, r1.random_point()).slope == r1.slope
assert Line(r2.source, r2.random_point()).slope == r2.slope
assert Segment(Point(0, -1), s1.random_point()).slope == s1.slope
p_r3 = r3.random_point()
p_r4 = r4.random_point()
assert p_r3.x >= p1.x and p_r3.y >= p1.y
assert p_r4.x <= p2.x and p_r4.y <= p2.y
p10 = Point(2000, 2000)
s1 = Segment(p1, p10)
p_s1 = s1.random_point()
assert p1.x <= p_s1.x and p_s1.x <= p10.x and p1.y <= p_s1.y and p_s1.y <= p10.y
s2 = Segment(p10, p1)
assert hash(s1) == hash(s2)
p11 = p10.scale(2, 2)
assert s1.is_similar(Segment(p10, p11))
assert s1.is_similar(r1) == False
assert (r1 in s1) == False
assert Segment(p1, p2) in s1
assert s1.plot_interval() == [t, 0, 1]
assert s1 in Line(p1, p10)
assert Line(p1, p10) == Line(p10, p1)
assert Line(p1, p10) != p1
assert Line(p1, p10).plot_interval() == [t, -5, 5]
assert Ray((0, 0), angle=pi / 4).plot_interval() == [t, 0, 5 * sqrt(2) / (1 + 5 * sqrt(2))]
def _eval_rewrite_as_hyper(self,n):
return C.hyper([1-n,-n],[2],1)
def _eval_rewrite_as_gamma(self,n):
# The gamma function allows to generalize Catalan numbers to complex n
return 4**n*C.gamma(n + S.Half)/(C.gamma(S.Half)*C.gamma(n+2))
def _eval_rewrite_as_binomial(self,n):
return C.binomial(2*n,n)/(n + 1)
def fdiff(self, argindex=1):
n = self.args[0]
return catalan(n)*(C.polygamma(0,n+Rational(1,2))-C.polygamma(0,n+2)+C.log(4))
def eval(cls, n, evaluate=True):
if n.is_Integer and n.is_nonnegative:
return 4**n*C.gamma(n + S.Half)/(C.gamma(S.Half)*C.gamma(n+2))
def Ylm(l, m, theta, phi):
l, m, theta, phi = [sympify(x) for x in (l, m, theta, phi)]
factorial = C.Factorial
return sqrt((2 * l + 1) / (4 * pi) * factorial(l - m) / factorial(l + m)) * Plmcos(l, m, theta) * C.exp(I * m * phi)
def test_ellipse():
p1 = Point(0, 0)
p2 = Point(1, 1)
p4 = Point(0, 1)
e1 = Ellipse(p1, 1, 1)
e2 = Ellipse(p2, half, 1)
e3 = Ellipse(p1, y1, y1)
c1 = Circle(p1, 1)
c2 = Circle(p2, 1)
c3 = Circle(Point(sqrt(2), sqrt(2)), 1)
# Test creation with three points
cen, rad = Point(3 * half, 2), 5 * half
assert Circle(Point(0, 0), Point(3, 0), Point(0, 4)) == Circle(cen, rad)
raises(GeometryError, "Circle(Point(0,0), Point(1,1), Point(2,2))")
raises(ValueError, "Ellipse(None, None, None, 1)")
raises(GeometryError, "Circle(Point(0,0))")
# Basic Stuff
assert Ellipse(None, 1, 1).center == Point(0, 0)
assert e1 == c1
assert e1 != e2
assert p4 in e1
assert p2 not in e2
assert e1.area == pi
assert e2.area == pi / 2
assert e3.area == pi * (y1**2)
assert c1.area == e1.area
assert c1.circumference == e1.circumference
assert e3.circumference == 2 * pi * y1
assert e1.plot_interval() == e2.plot_interval() == [t, -pi, pi]
assert e1.plot_interval(x) == e2.plot_interval(x) == [x, -pi, pi]
assert Ellipse(None, 1, None, 1).circumference == 2 * pi
assert c1.minor == 1
# Private Functions
assert hash(c1) == hash(Circle(Point(1, 0), Point(0, 1), Point(0, -1)))
assert c1 in e1
assert (Line(p1, p2) in e1) == False
assert e1.__cmp__(e1) == 0
assert e1.__cmp__(Point(0, 0)) > 0
# Encloses
assert e1.encloses(Segment(Point(-0.5, -0.5), Point(0.5, 0.5))) == True
assert e1.encloses(Line(p1, p2)) == False
assert e1.encloses(Ray(p1, p2)) == False
assert e1.encloses(e1) == False
assert e1.encloses(
Polygon(Point(-0.5, -0.5), Point(-0.5, 0.5), Point(0.5, 0.5))) == True
assert e1.encloses(RegularPolygon(p1, 0.5, 3)) == True
assert e1.encloses(RegularPolygon(p1, 5, 3)) == False
assert e1.encloses(RegularPolygon(p2, 5, 3)) == False
# with generic symbols, the hradius is assumed to contain the major radius
M = Symbol('M')
m = Symbol('m')
c = Ellipse(p1, M, m).circumference
_x = c.atoms(Dummy).pop()
assert c == \
4*M*C.Integral(sqrt((1 - _x**2*(M**2 - m**2)/M**2)/(1 - _x**2)), (_x, 0, 1))
assert e2.arbitrary_point() in e2
# Foci
f1, f2 = Point(sqrt(12), 0), Point(-sqrt(12), 0)
ef = Ellipse(Point(0, 0), 4, 2)
assert ef.foci in [(f1, f2), (f2, f1)]
# Tangents
v = sqrt(2) / 2
p1_1 = Point(v, v)
p1_2 = p2 + Point(half, 0)
p1_3 = p2 + Point(0, 1)
assert e1.tangent_lines(p4) == c1.tangent_lines(p4)
assert e2.tangent_lines(p1_2) == [Line(p1_2, p2 + Point(half, 1))]
assert e2.tangent_lines(p1_3) == [Line(p1_3, p2 + Point(half, 1))]
assert c1.tangent_lines(p1_1) == [Line(p1_1, Point(0, sqrt(2)))]
assert c1.tangent_lines(p1) == []
assert e2.is_tangent(Line(p1_2, p2 + Point(half, 1)))
assert e2.is_tangent(Line(p1_3, p2 + Point(half, 1)))
assert c1.is_tangent(Line(p1_1, Point(0, sqrt(2))))
assert e1.is_tangent(Line(Point(0, 0), Point(1, 1))) == False
assert c1.is_tangent(e1) == False
assert c1.is_tangent(Ellipse(Point(2, 0), 1, 1)) == True
assert c1.is_tangent(Polygon(Point(1, 1), Point(1, -1), Point(2,
0))) == True
assert c1.is_tangent(Polygon(Point(1, 1), Point(1, 0), Point(2,
0))) == False
assert Ellipse(Point(5, 5), 2, 1).tangent_lines(Point(0, 0)) == \
[Line(Point(0, 0), Point(S(77)/25, S(132)/25)),
Line(Point(0, 0), Point(S(33)/5, S(22)/5))]
assert Ellipse(Point(5, 5), 2, 1).tangent_lines(Point(3, 4)) == \
[Line(Point(3, 4), Point(4, 4)), Line(Point(3, 4), Point(3, 5))]
assert Circle(Point(5, 5), 2).tangent_lines(Point(3, 3)) == \
[Line(Point(3, 3), Point(4, 3)), Line(Point(3, 3), Point(3, 4))]
assert Circle(Point(5, 5), 2).tangent_lines(Point(5 - 2*sqrt(2), 5)) == \
[Line(Point(5 - 2*sqrt(2), 5), Point(5 - sqrt(2), 5 - sqrt(2))),
Line(Point(5 - 2*sqrt(2), 5), Point(5 - sqrt(2), 5 + sqrt(2))),]
# Properties
major = 3
minor = 1
e4 = Ellipse(p2, minor, major)
assert e4.focus_distance == sqrt(major**2 - minor**2)
ecc = e4.focus_distance / major
assert e4.eccentricity == ecc
assert e4.periapsis == major * (1 - ecc)
assert e4.apoapsis == major * (1 + ecc)
# independent of orientation
e4 = Ellipse(p2, major, minor)
assert e4.focus_distance == sqrt(major**2 - minor**2)
ecc = e4.focus_distance / major
assert e4.eccentricity == ecc
assert e4.periapsis == major * (1 - ecc)
assert e4.apoapsis == major * (1 + ecc)
# Intersection
l1 = Line(Point(1, -5), Point(1, 5))
l2 = Line(Point(-5, -1), Point(5, -1))
l3 = Line(Point(-1, -1), Point(1, 1))
l4 = Line(Point(-10, 0), Point(0, 10))
pts_c1_l3 = [
Point(sqrt(2) / 2,
sqrt(2) / 2),
Point(-sqrt(2) / 2, -sqrt(2) / 2)
]
assert intersection(e2, l4) == []
assert intersection(c1, Point(1, 0)) == [Point(1, 0)]
assert intersection(c1, l1) == [Point(1, 0)]
assert intersection(c1, l2) == [Point(0, -1)]
assert intersection(c1, l3) in [pts_c1_l3, [pts_c1_l3[1], pts_c1_l3[0]]]
assert intersection(c1, c2) in [[(1, 0), (0, 1)], [(0, 1), (1, 0)]]
assert intersection(c1, c3) == [(sqrt(2) / 2, sqrt(2) / 2)]
assert e1.intersection(l1) == [Point(1, 0)]
assert e2.intersection(l4) == []
assert e1.intersection(Circle(Point(0, 2), 1)) == [Point(0, 1)]
assert e1.intersection(Circle(Point(5, 0), 1)) == []
assert e1.intersection(Ellipse(Point(2, 0), 1, 1)) == [Point(1, 0)]
assert e1.intersection(Ellipse(
Point(5, 0),
1,
1,
)) == []
assert e1.intersection(Point(2, 0)) == []
assert e1.intersection(e1) == e1
# some special case intersections
csmall = Circle(p1, 3)
cbig = Circle(p1, 5)
cout = Circle(Point(5, 5), 1)
# one circle inside of another
assert csmall.intersection(cbig) == []
# separate circles
assert csmall.intersection(cout) == []
# coincident circles
assert csmall.intersection(csmall) == csmall
v = sqrt(2)
t1 = Triangle(Point(0, v), Point(0, -v), Point(v, 0))
points = intersection(t1, c1)
assert len(points) == 4
assert Point(0, 1) in points
assert Point(0, -1) in points
assert Point(v / 2, v / 2) in points
assert Point(v / 2, -v / 2) in points
circ = Circle(Point(0, 0), 5)
elip = Ellipse(Point(0, 0), 5, 20)
assert intersection(circ, elip) in \
[[Point(5, 0), Point(-5, 0)], [Point(-5, 0), Point(5, 0)]]
assert elip.tangent_lines(Point(0, 0)) == []
elip = Ellipse(Point(0, 0), 3, 2)
assert elip.tangent_lines(Point(3,
0)) == [Line(Point(3, 0), Point(3, -12))]
e1 = Ellipse(Point(0, 0), 5, 10)
e2 = Ellipse(Point(2, 1), 4, 8)
a = S(53) / 17
c = 2 * sqrt(3991) / 17
ans = [Point(a - c / 8, a / 2 + c), Point(a + c / 8, a / 2 - c)]
assert e1.intersection(e2) == ans
e2 = Ellipse(Point(x, y), 4, 8)
ans = list(reversed(ans))
assert [p.subs({x: 2, y: 1}) for p in e1.intersection(e2)] == ans
# Combinations of above
assert e3.is_tangent(e3.tangent_lines(p1 + Point(y1, 0))[0])
e = Ellipse((1, 2), 3, 2)
assert e.tangent_lines(Point(10, 0)) == \
[Line(Point(10, 0), Point(1, 0)),
Line(Point(10, 0), Point(S(14)/5, S(18)/5))]
# encloses_point
e = Ellipse((0, 0), 1, 2)
assert e.encloses_point(e.center)
assert e.encloses_point(e.center + Point(0, e.vradius - Rational(1, 10)))
assert e.encloses_point(e.center + Point(e.hradius - Rational(1, 10), 0))
assert e.encloses_point(e.center + Point(e.hradius, 0)) is False
assert e.encloses_point(e.center +
Point(e.hradius + Rational(1, 10), 0)) is False
e = Ellipse((0, 0), 2, 1)
assert e.encloses_point(e.center)
assert e.encloses_point(e.center + Point(0, e.vradius - Rational(1, 10)))
assert e.encloses_point(e.center + Point(e.hradius - Rational(1, 10), 0))
assert e.encloses_point(e.center + Point(e.hradius, 0)) is False
assert e.encloses_point(e.center +
Point(e.hradius + Rational(1, 10), 0)) is False
assert c1.encloses_point(Point(1, 0)) is False
assert c1.encloses_point(Point(0.3, 0.4)) is True
def test_line():
p1 = Point(0, 0)
p2 = Point(1, 1)
p3 = Point(x1, x1)
p4 = Point(y1, y1)
p5 = Point(x1, 1 + x1)
p6 = Point(1, 0)
p7 = Point(0, 1)
p8 = Point(2, 0)
p9 = Point(2, 1)
l1 = Line(p1, p2)
l2 = Line(p3, p4)
l3 = Line(p3, p5)
l4 = Line(p1, p6)
l5 = Line(p1, p7)
l6 = Line(p8, p9)
l7 = Line(p2, p9)
raises(ValueError, 'Line(Point(0, 0), Point(0, 0))')
# Basic stuff
assert Line((1, 1), slope=1) == Line((1, 1), (2, 2))
assert Line((1, 1), slope=oo) == Line((1, 1), (1, 2))
assert Line((1, 1), slope=-oo) == Line((1, 1), (1, 2))
raises(ValueError, 'Line((1, 1), 1)')
assert Line(p1, p2) == Line(p2, p1)
assert l1 == l2
assert l1 != l3
assert l1.slope == 1
assert l1.length == oo
assert l3.slope == oo
assert l4.slope == 0
assert l4.coefficients == (0, 1, 0)
assert l4.equation(x=x, y=y) == y
assert l5.slope == oo
assert l5.coefficients == (1, 0, 0)
assert l5.equation() == x
assert l6.equation() == x - 2
assert l7.equation() == y - 1
assert p1 in l1 # is p1 on the line l1?
assert p1 not in l3
assert simplify(l1.equation()) in (x - y, y - x)
assert simplify(l3.equation()) in (x - x1, x1 - x)
assert Line(p1, p2).scale(2, 1) == Line(p1, p9)
assert l2.arbitrary_point() in l2
for ind in xrange(0, 5):
assert l3.random_point() in l3
# Orthogonality
p1_1 = Point(-x1, x1)
l1_1 = Line(p1, p1_1)
assert l1.perpendicular_line(p1) == l1_1
assert Line.is_perpendicular(l1, l1_1)
assert Line.is_perpendicular(l1, l2) == False
p = l1.random_point()
assert l1.perpendicular_segment(p) == p
# Parallelity
p2_1 = Point(-2 * x1, 0)
l2_1 = Line(p3, p5)
assert l2.parallel_line(p1_1) == Line(p2_1, p1_1)
assert l2_1.parallel_line(p1) == Line(p1, Point(0, 2))
assert Line.is_parallel(l1, l2)
assert Line.is_parallel(l2, l3) == False
assert Line.is_parallel(l2, l2.parallel_line(p1_1))
assert Line.is_parallel(l2_1, l2_1.parallel_line(p1))
# Intersection
assert intersection(l1, p1) == [p1]
assert intersection(l1, p5) == []
assert intersection(l1, l2) in [[l1], [l2]]
assert intersection(l1, l1.parallel_line(p5)) == []
# Concurrency
l3_1 = Line(Point(5, x1), Point(-Rational(3, 5), x1))
assert Line.is_concurrent(l1) == False
assert Line.is_concurrent(l1, l3)
assert Line.is_concurrent(l1, l3, l3_1)
assert Line.is_concurrent(l1, l1_1, l3) == False
# Projection
assert l2.projection(p4) == p4
assert l1.projection(p1_1) == p1
assert l3.projection(p2) == Point(x1, 1)
raises(
GeometryError,
'Line(Point(0, 0), Point(1, 0)).projection(Circle(Point(0, 0), 1))')
# Finding angles
l1_1 = Line(p1, Point(5, 0))
assert feq(Line.angle_between(l1, l1_1).evalf(), pi.evalf() / 4)
# Testing Rays and Segments (very similar to Lines)
assert Ray((1, 1), angle=pi / 4) == Ray((1, 1), (2, 2))
assert Ray((1, 1), angle=pi / 2) == Ray((1, 1), (1, 2))
assert Ray((1, 1), angle=-pi / 2) == Ray((1, 1), (1, 0))
assert Ray((1, 1), angle=-3 * pi / 2) == Ray((1, 1), (1, 2))
assert Ray((1, 1), angle=5 * pi / 2) == Ray((1, 1), (1, 2))
assert Ray((1, 1), angle=5.0 * pi / 2) == Ray((1, 1), (1, 2))
assert Ray((1, 1), angle=pi) == Ray((1, 1), (0, 1))
assert Ray((1, 1), angle=3.0 * pi) == Ray((1, 1), (0, 1))
assert Ray((1, 1), angle=4.0 * pi) == Ray((1, 1), (2, 1))
assert Ray((1, 1), angle=0) == Ray((1, 1), (2, 1))
# XXX don't know why this fails without str
assert str(Ray(
(1, 1),
angle=4.2 * pi)) == str(Ray(Point(1, 1), Point(2,
1 + C.tan(0.2 * pi))))
assert Ray((1, 1), angle=5) == Ray((1, 1), (2, 1 + C.tan(5)))
raises(ValueError, 'Ray((1, 1), 1)')
r1 = Ray(p1, Point(-1, 5))
r2 = Ray(p1, Point(-1, 1))
r3 = Ray(p3, p5)
r4 = Ray(p1, p2)
r5 = Ray(p2, p1)
r6 = Ray(Point(0, 1), Point(1, 2))
r7 = Ray(Point(0.5, 0.5), Point(1, 1))
assert l1.projection(r1) == Ray(p1, p2)
assert l1.projection(r2) == p1
assert r3 != r1
t = Symbol('t', real=True)
assert Ray(
(1, 1),
angle=pi / 4).arbitrary_point() == Point(1 / (1 - t), 1 / (1 - t))
s1 = Segment(p1, p2)
s2 = Segment(p1, p1_1)
assert s1.midpoint == Point(Rational(1, 2), Rational(1, 2))
assert s2.length == sqrt(2 * (x1**2))
assert s1.perpendicular_bisector() == Line(Point(0, 1), Point(1, 0))
assert Segment((1, 1), (2, 3)).arbitrary_point() == Point(1 + t, 1 + 2 * t)
# intersections
assert s1.intersection(Line(p6, p9)) == []
s3 = Segment(Point(0.25, 0.25), Point(0.5, 0.5))
assert s1.intersection(s3) == [s1]
assert s3.intersection(s1) == [s3]
assert r4.intersection(s3) == [s3]
assert r4.intersection(Segment(Point(2, 3), Point(3, 4))) == []
assert r4.intersection(Segment(Point(-1, -1), Point(
0.5, 0.5))) == [Segment(p1, Point(0.5, 0.5))]
s3 = Segment(Point(1, 1), Point(2, 2))
assert s1.intersection(s3) == [Point(1, 1)]
s3 = Segment(Point(0.5, 0.5), Point(1.5, 1.5))
assert s1.intersection(s3) == [Segment(Point(0.5, 0.5), p2)]
assert s1.intersection(Segment(Point(4, 4), Point(5, 5))) == []
assert s1.intersection(Segment(Point(-1, -1), p1)) == [p1]
assert s1.intersection(Segment(Point(-1, -1), Point(
0.5, 0.5))) == [Segment(p1, Point(0.5, 0.5))]
assert r4.intersection(r5) == [s1]
assert r5.intersection(r6) == []
assert r4.intersection(r7) == r7.intersection(r4) == [r7]
# Segment contains
a, b = symbols('a,b')
s = Segment((0, a), (0, b))
assert Point(0, (a + b) / 2) in s
s = Segment((a, 0), (b, 0))
assert Point((a + b) / 2, 0) in s
raises(Undecidable, "Point(2*a, 0) in s")
# Testing distance from a Segment to an object
s1 = Segment(Point(0, 0), Point(1, 1))
s2 = Segment(Point(half, half), Point(1, 0))
pt1 = Point(0, 0)
pt2 = Point(Rational(3) / 2, Rational(3) / 2)
assert s1.distance(pt1) == 0
assert s2.distance(pt1) == 2**(half) / 2
assert s2.distance(pt2) == 2**(half)
# Special cases of projection and intersection
r1 = Ray(Point(1, 1), Point(2, 2))
r2 = Ray(Point(2, 2), Point(0, 0))
r3 = Ray(Point(1, 1), Point(-1, -1))
r4 = Ray(Point(0, 4), Point(-1, -5))
r5 = Ray(Point(2, 2), Point(3, 3))
assert intersection(r1, r2) == [Segment(Point(1, 1), Point(2, 2))]
assert intersection(r1, r3) == [Point(1, 1)]
assert r1.projection(r3) == Point(1, 1)
assert r1.projection(r4) == Segment(Point(1, 1), Point(2, 2))
r5 = Ray(Point(0, 0), Point(0, 1))
r6 = Ray(Point(0, 0), Point(0, 2))
assert r5 in r6
assert r6 in r5
s1 = Segment(Point(0, 0), Point(2, 2))
s2 = Segment(Point(-1, 5), Point(-5, -10))
s3 = Segment(Point(0, 4), Point(-2, 2))
assert intersection(r1, s1) == [Segment(Point(1, 1), Point(2, 2))]
assert r1.projection(s2) == Segment(Point(1, 1), Point(2, 2))
assert s3.projection(r1) == Segment(Point(0, 4), Point(-1, 3))
l1 = Line(Point(0, 0), Point(3, 4))
r1 = Ray(Point(0, 0), Point(3, 4))
s1 = Segment(Point(0, 0), Point(3, 4))
assert intersection(l1, l1) == [l1]
assert intersection(l1, r1) == [r1]
assert intersection(l1, s1) == [s1]
assert intersection(r1, l1) == [r1]
assert intersection(s1, l1) == [s1]
entity1 = Segment(Point(-10, 10), Point(10, 10))
entity2 = Segment(Point(-5, -5), Point(-5, 5))
assert intersection(entity1, entity2) == []
r1 = Ray(p1, Point(0, 1))
r2 = Ray(Point(0, 1), p1)
r3 = Ray(p1, p2)
r4 = Ray(p2, p1)
s1 = Segment(p1, Point(0, 1))
assert Line(r1.source, r1.random_point()).slope == r1.slope
assert Line(r2.source, r2.random_point()).slope == r2.slope
assert Segment(Point(0, -1), s1.random_point()).slope == s1.slope
p_r3 = r3.random_point()
p_r4 = r4.random_point()
assert p_r3.x >= p1.x and p_r3.y >= p1.y
assert p_r4.x <= p2.x and p_r4.y <= p2.y
p10 = Point(2000, 2000)
s1 = Segment(p1, p10)
p_s1 = s1.random_point()
assert p1.x <= p_s1.x and p_s1.x <= p10.x and p1.y <= p_s1.y and p_s1.y <= p10.y
s2 = Segment(p10, p1)
assert hash(s1) == hash(s2)
p11 = p10.scale(2, 2)
assert s1.is_similar(Segment(p10, p11))
assert s1.is_similar(r1) == False
assert (r1 in s1) == False
assert Segment(p1, p2) in s1
assert s1.plot_interval() == [t, 0, 1]
assert s1 in Line(p1, p10)
assert Line(p1, p10) == Line(p10, p1)
assert Line(p1, p10) != p1
assert Line(p1, p10).plot_interval() == [t, -5, 5]
def test_order_oo():
from sympy import C
x = Symbol('x', positive=True, finite=True)
assert C.Order(x)*oo != C.Order(1, x)
assert limit(oo/(x**2 - 4), x, oo) == oo
def Ylm(l, m, theta, phi):
l, m, theta, phi = [sympify(x) for x in (l, m, theta, phi)]
factorial = C.Factorial
return sqrt((2*l+1)/(4*pi) * factorial(l-m)/factorial(l+m)) * \
Plmcos(l, m, theta) * C.exp(I*m*phi)
def test_line():
p1 = Point(0, 0)
p2 = Point(1, 1)
p3 = Point(x1, x1)
p4 = Point(y1, y1)
p5 = Point(x1, 1 + x1)
p6 = Point(1, 0)
p7 = Point(0, 1)
p8 = Point(2, 0)
p9 = Point(2, 1)
l1 = Line(p1, p2)
l2 = Line(p3, p4)
l3 = Line(p3, p5)
l4 = Line(p1, p6)
l5 = Line(p1, p7)
l6 = Line(p8, p9)
l7 = Line(p2, p9)
# Basic stuff
assert Line((1, 1), slope=1) == Line((1, 1), (2, 2))
assert Line((1, 1), slope=oo) == Line((1, 1), (1, 2))
assert Line((1, 1), slope=-oo) == Line((1, 1), (1, 2))
raises(ValueError, "Line((1, 1), 1)")
assert Line(p1, p2) == Line(p2, p1)
assert l1 == l2
assert l1 != l3
assert l1.slope == 1
assert l3.slope == oo
assert l4.slope == 0
assert l4.coefficients == (0, 1, 0)
assert l4.equation(x=x, y=y) == y
assert l5.slope == oo
assert l5.coefficients == (1, 0, 0)
assert l5.equation() == x
assert l6.equation() == x - 2
assert l7.equation() == y - 1
assert p1 in l1 # is p1 on the line l1?
assert p1 not in l3
assert simplify(l1.equation()) in (x - y, y - x)
assert simplify(l3.equation()) in (x - x1, x1 - x)
assert l2.arbitrary_point() in l2
for ind in xrange(0, 5):
assert l3.random_point() in l3
# Orthogonality
p1_1 = Point(-x1, x1)
l1_1 = Line(p1, p1_1)
assert l1.perpendicular_line(p1) == l1_1
assert Line.is_perpendicular(l1, l1_1)
assert Line.is_perpendicular(l1, l2) == False
# Parallelity
p2_1 = Point(-2 * x1, 0)
l2_1 = Line(p3, p5)
assert l2.parallel_line(p1_1) == Line(p2_1, p1_1)
assert l2_1.parallel_line(p1) == Line(p1, Point(0, 2))
assert Line.is_parallel(l1, l2)
assert Line.is_parallel(l2, l3) == False
assert Line.is_parallel(l2, l2.parallel_line(p1_1))
assert Line.is_parallel(l2_1, l2_1.parallel_line(p1))
# Intersection
assert intersection(l1, p1) == [p1]
assert intersection(l1, p5) == []
assert intersection(l1, l2) in [[l1], [l2]]
assert intersection(l1, l1.parallel_line(p5)) == []
# Concurrency
l3_1 = Line(Point(5, x1), Point(-Rational(3, 5), x1))
assert Line.is_concurrent(l1, l3)
assert Line.is_concurrent(l1, l3, l3_1)
assert Line.is_concurrent(l1, l1_1, l3) == False
# Projection
assert l2.projection(p4) == p4
assert l1.projection(p1_1) == p1
assert l3.projection(p2) == Point(x1, 1)
# Finding angles
l1_1 = Line(p1, Point(5, 0))
assert feq(Line.angle_between(l1, l1_1).evalf(), pi.evalf() / 4)
# Testing Rays and Segments (very similar to Lines)
assert Ray((1, 1), angle=pi / 4) == Ray((1, 1), (2, 2))
assert Ray((1, 1), angle=pi / 2) == Ray((1, 1), (1, 2))
assert Ray((1, 1), angle=-pi / 2) == Ray((1, 1), (1, 0))
assert Ray((1, 1), angle=-3 * pi / 2) == Ray((1, 1), (1, 2))
assert Ray((1, 1), angle=5 * pi / 2) == Ray((1, 1), (1, 2))
assert Ray((1, 1), angle=5.0 * pi / 2) == Ray((1, 1), (1, 2))
assert Ray((1, 1), angle=pi) == Ray((1, 1), (0, 1))
assert Ray((1, 1), angle=3.0 * pi) == Ray((1, 1), (0, 1))
assert Ray((1, 1), angle=4.0 * pi) == Ray((1, 1), (2, 1))
assert Ray((1, 1), angle=0) == Ray((1, 1), (2, 1))
# XXX don't know why this fails without str
assert str(Ray((1, 1), angle=4.2 * pi)) == str(Ray(Point(1, 1), Point(2, 1 + C.tan(0.2 * pi))))
assert Ray((1, 1), angle=5) == Ray((1, 1), (2, 1 + C.tan(5)))
raises(ValueError, "Ray((1, 1), 1)")
r1 = Ray(p1, Point(-1, 5))
r2 = Ray(p1, Point(-1, 1))
r3 = Ray(p3, p5)
assert l1.projection(r1) == Ray(p1, p2)
assert l1.projection(r2) == p1
assert r3 != r1
t = Symbol("t", real=True)
assert Ray((1, 1), angle=pi / 4).arbitrary_point() == Point(1 / (1 - t), 1 / (1 - t))
s1 = Segment(p1, p2)
s2 = Segment(p1, p1_1)
assert s1.midpoint == Point(Rational(1, 2), Rational(1, 2))
assert s2.length == sqrt(2 * (x1 ** 2))
assert s1.perpendicular_bisector() == Line(Point(0, 1), Point(1, 0))
assert Segment((1, 1), (2, 3)).arbitrary_point() == Point(1 + t, 1 + 2 * t)
# Segment contains
a, b = symbols("a,b")
s = Segment((0, a), (0, b))
assert Point(0, (a + b) / 2) in s
s = Segment((a, 0), (b, 0))
assert Point((a + b) / 2, 0) in s
assert (Point(2 * a, 0) in s) is False # XXX should be None?
# Testing distance from a Segment to an object
s1 = Segment(Point(0, 0), Point(1, 1))
s2 = Segment(Point(half, half), Point(1, 0))
pt1 = Point(0, 0)
pt2 = Point(Rational(3) / 2, Rational(3) / 2)
assert s1.distance(pt1) == 0
assert s2.distance(pt1) == 2 ** (half) / 2
assert s2.distance(pt2) == 2 ** (half)
# Special cases of projection and intersection
r1 = Ray(Point(1, 1), Point(2, 2))
r2 = Ray(Point(2, 2), Point(0, 0))
r3 = Ray(Point(1, 1), Point(-1, -1))
r4 = Ray(Point(0, 4), Point(-1, -5))
assert intersection(r1, r2) == [Segment(Point(1, 1), Point(2, 2))]
assert intersection(r1, r3) == [Point(1, 1)]
assert r1.projection(r3) == Point(1, 1)
assert r1.projection(r4) == Segment(Point(1, 1), Point(2, 2))
r5 = Ray(Point(0, 0), Point(0, 1))
r6 = Ray(Point(0, 0), Point(0, 2))
assert r5 in r6
assert r6 in r5
s1 = Segment(Point(0, 0), Point(2, 2))
s2 = Segment(Point(-1, 5), Point(-5, -10))
s3 = Segment(Point(0, 4), Point(-2, 2))
assert intersection(r1, s1) == [Segment(Point(1, 1), Point(2, 2))]
assert r1.projection(s2) == Segment(Point(1, 1), Point(2, 2))
assert s3.projection(r1) == Segment(Point(0, 4), Point(-1, 3))
l1 = Line(Point(0, 0), Point(3, 4))
r1 = Ray(Point(0, 0), Point(3, 4))
s1 = Segment(Point(0, 0), Point(3, 4))
assert intersection(l1, l1) == [l1]
assert intersection(l1, r1) == [r1]
assert intersection(l1, s1) == [s1]
assert intersection(r1, l1) == [r1]
assert intersection(s1, l1) == [s1]
entity1 = Segment(Point(-10, 10), Point(10, 10))
entity2 = Segment(Point(-5, -5), Point(-5, 5))
assert intersection(entity1, entity2) == []
def test_ellipse():
p1 = Point(0, 0)
p2 = Point(1, 1)
p3 = Point(x1, x2)
p4 = Point(0, 1)
p5 = Point(-1, 0)
e1 = Ellipse(p1, 1, 1)
e2 = Ellipse(p2, half, 1)
e3 = Ellipse(p1, y1, y1)
c1 = Circle(p1, 1)
c2 = Circle(p2, 1)
c3 = Circle(Point(sqrt(2), sqrt(2)), 1)
# Test creation with three points
cen, rad = Point(3 * half, 2), 5 * half
assert Circle(Point(0, 0), Point(3, 0), Point(0, 4)) == Circle(cen, rad)
raises(GeometryError, "Circle(Point(0,0), Point(1,1), Point(2,2))")
# Basic Stuff
assert e1 == c1
assert e1 != e2
assert p4 in e1
assert p2 not in e2
assert e1.area == pi
assert e2.area == pi / 2
assert e3.area == pi * (y1**2)
assert c1.area == e1.area
assert c1.circumference == e1.circumference
assert e3.circumference == 2 * pi * y1
a = Symbol('a')
b = Symbol('b')
e5 = Ellipse(p1, a, b)
assert e5.circumference == 4*a*C.Integral(((1 - x**2*Abs(b**2 - a**2)/a**2)/(1 - x**2))**(S(1)/2),\
(x, 0, 1))
assert e2.arbitrary_point() in e2
# Foci
f1, f2 = Point(sqrt(12), 0), Point(-sqrt(12), 0)
ef = Ellipse(Point(0, 0), 4, 2)
assert ef.foci in [(f1, f2), (f2, f1)]
# Tangents
v = sqrt(2) / 2
p1_1 = Point(v, v)
p1_2 = p2 + Point(half, 0)
p1_3 = p2 + Point(0, 1)
assert e1.tangent_line(p4) == c1.tangent_line(p4)
assert e2.tangent_line(p1_2) == Line(p1_2, p2 + Point(half, 1))
assert e2.tangent_line(p1_3) == Line(p1_3, p2 + Point(half, 1))
assert c1.tangent_line(p1_1) == Line(p1_1, Point(0, sqrt(2)))
assert e2.is_tangent(Line(p1_2, p2 + Point(half, 1)))
assert e2.is_tangent(Line(p1_3, p2 + Point(half, 1)))
assert c1.is_tangent(Line(p1_1, Point(0, sqrt(2))))
assert e1.is_tangent(Line(Point(0, 0), Point(1, 1))) == False
# Intersection
l1 = Line(Point(1, -5), Point(1, 5))
l2 = Line(Point(-5, -1), Point(5, -1))
l3 = Line(Point(-1, -1), Point(1, 1))
l4 = Line(Point(-10, 0), Point(0, 10))
pts_c1_l3 = [
Point(sqrt(2) / 2,
sqrt(2) / 2),
Point(-sqrt(2) / 2, -sqrt(2) / 2)
]
assert intersection(e2, l4) == []
assert intersection(c1, Point(1, 0)) == [Point(1, 0)]
assert intersection(c1, l1) == [Point(1, 0)]
assert intersection(c1, l2) == [Point(0, -1)]
assert intersection(c1, l3) in [pts_c1_l3, [pts_c1_l3[1], pts_c1_l3[0]]]
assert intersection(c1, c2) in [[(1, 0), (0, 1)], [(0, 1), (1, 0)]]
assert intersection(c1, c3) == [(sqrt(2) / 2, sqrt(2) / 2)]
# some special case intersections
csmall = Circle(p1, 3)
cbig = Circle(p1, 5)
cout = Circle(Point(5, 5), 1)
# one circle inside of another
assert csmall.intersection(cbig) == []
# separate circles
assert csmall.intersection(cout) == []
# coincident circles
assert csmall.intersection(csmall) == csmall
v = sqrt(2)
t1 = Triangle(Point(0, v), Point(0, -v), Point(v, 0))
points = intersection(t1, c1)
assert len(points) == 4
assert Point(0, 1) in points
assert Point(0, -1) in points
assert Point(v / 2, v / 2) in points
assert Point(v / 2, -v / 2) in points
e1 = Circle(Point(0, 0), 5)
e2 = Ellipse(Point(0, 0), 5, 20)
assert intersection(e1, e2) in \
[[Point(5, 0), Point(-5, 0)], [Point(-5, 0), Point(5, 0)]]
# FAILING ELLIPSE INTERSECTION GOES HERE
# Combinations of above
assert e3.is_tangent(e3.tangent_line(p1 + Point(y1, 0)))
major = 3
minor = 1
e4 = Ellipse(p2, major, minor)
assert e4.focus_distance == sqrt(abs(major**2 - minor**2))
ecc = e4.focus_distance / major
assert e4.eccentricity == ecc
assert e4.periapsis == major * (1 - ecc)
assert e4.apoapsis == major * (1 + ecc)
