def test_gosper_sum():
assert gosper_sum(1, (k, 0, n)) == 1 + n
assert gosper_sum(k, (k, 0, n)) == n*(1 + n)/2
assert gosper_sum(k**2, (k, 0, n)) == n*(1 + n)*(1 + 2*n)/6
assert gosper_sum(k**3, (k, 0, n)) == n**2*(1 + n)**2/4
assert gosper_sum(2**k, (k, 0, n)) == 2*2**n - 1
assert gosper_sum(factorial(k), (k, 0, n)) is None
assert gosper_sum(binomial(n, k), (k, 0, n)) is None
assert gosper_sum(factorial(k)/k**2, (k, 0, n)) is None
assert gosper_sum((k - 3)*factorial(k), (k, 0, n)) is None
assert gosper_sum(k*factorial(k), k) == factorial(k)
assert gosper_sum(
k*factorial(k), (k, 0, n)) == n*factorial(n) + factorial(n) - 1
assert gosper_sum((-1)**k*binomial(n, k), (k, 0, n)) == 0
assert gosper_sum((
-1)**k*binomial(n, k), (k, 0, m)) == -(-1)**m*(m - n)*binomial(n, m)/n
assert gosper_sum((4*k + 1)*factorial(k)/factorial(2*k + 1), (k, 0, n)) == \
(2*factorial(2*n + 1) - factorial(n))/factorial(2*n + 1)
# issue 6033:
assert gosper_sum(
n*(n + a + b)*a**n*b**n/(factorial(n + a)*factorial(n + b)), \
(n, 0, m)) == -a*b*(exp(m*log(a))*exp(m*log(b))*factorial(a)* \
factorial(b) - factorial(a + m)*factorial(b + m))/(factorial(a)* \
factorial(b)*factorial(a + m)*factorial(b + m))
def test_gosper_sum_AeqB_part1():
f1a = n**4
f1b = n**3*2**n
f1c = 1/(n**2 + sqrt(5)*n - 1)
f1d = n**4*4**n/binomial(2*n, n)
f1e = factorial(3*n)/(factorial(n)*factorial(n + 1)*factorial(n + 2)*27**n)
f1f = binomial(2*n, n)**2/((n + 1)*4**(2*n))
f1g = (4*n - 1)*binomial(2*n, n)**2/((2*n - 1)**2*4**(2*n))
f1h = n*factorial(n - S(1)/2)**2/factorial(n + 1)**2
g1a = m*(m + 1)*(2*m + 1)*(3*m**2 + 3*m - 1)/30
g1b = 26 + 2**(m + 1)*(m**3 - 3*m**2 + 9*m - 13)
g = gosper_sum(f1a, (n, 0, m))
assert g is not None and simplify(g - g1a) == 0
g = gosper_sum(f1b, (n, 0, m))
assert g is not None and simplify(g - g1b) == 0
g = gosper_sum(f1c, (n, 0, m))
assert g is not None # and simplify(g - g1c) == 0
g = gosper_sum(f1d, (n, 0, m))
assert g is not None # and simplify(g - g1d) == 0
g = gosper_sum(f1e, (n, 0, m))
assert g is not None # and simplify(g - g1e) == 0
g = gosper_sum(f1f, (n, 0, m))
assert g is not None # and simplify(g - g1f) == 0
g = gosper_sum(f1g, (n, 0, m))
assert g is not None # and simplify(g - g1g) == 0
g = gosper_sum(f1h, (n, 0, m))
assert g is not None # and simplify(g - g1h) == 0
def test_gosper_sum_AeqB_part2():
f2a = n**2*a**n
f2b = (n - r/2)*binomial(r, n)
f2c = factorial(n - 1)**2/(factorial(n - x)*factorial(n + x))
g2a = -a*(a + 1)/(a - 1)**3 + a**(
m + 1)*(a**2*m**2 - 2*a*m**2 + m**2 - 2*a*m + 2*m + a + 1)/(a - 1)**3
g2b = (m - r)*binomial(r, m)/2
ff = factorial(1 - x)*factorial(1 + x)
g2c = 1/ff*(
1 - 1/x**2) + factorial(m)**2/(x**2*factorial(m - x)*factorial(m + x))
g = gosper_sum(f2a, (n, 0, m))
assert g is not None and simplify(g - g2a) == 0
g = gosper_sum(f2b, (n, 0, m))
assert g is not None and simplify(g - g2b) == 0
g = gosper_sum(f2c, (n, 1, m))
assert g is not None and simplify(g - g2c) == 0
# delete these lines and unXFAIL the nan test below when it passes
f2d = n*(n + a + b)*a**n*b**n/(factorial(n + a)*factorial(n + b))
g2d = 1/(factorial(a - 1)*factorial(
b - 1)) - a**(m + 1)*b**(m + 1)/(factorial(a + m)*factorial(b + m))
assert simplify(
sum(f2d.subs(n, i) for i in range(3)) - g2d.subs(m, 2)) == 0
def test_binomial_rewrite():
n = Symbol("n", integer=True)
k = Symbol("k", integer=True)
assert binomial(n, k).rewrite(factorial) == factorial(n) / (factorial(k) * factorial(n - k))
assert binomial(n, k).rewrite(gamma) == gamma(n + 1) / (gamma(k + 1) * gamma(n - k + 1))
assert binomial(n, k).rewrite(ff) == ff(n, k) / factorial(k)
def test_limit_seq():
assert limit(Sum(1/x, (x, 1, y)) - log(y), y, oo) == EulerGamma
assert limit(Sum(1/x, (x, 1, y)) - 1/y, y, oo) == S.Infinity
assert (limit(binomial(2*x, x) / Sum(binomial(2*y, y), (y, 1, x)), x, oo) ==
S(3) / 4)
assert (limit(Sum(y**2 * Sum(2**z/z, (z, 1, y)), (y, 1, x)) /
(2**x*x), x, oo) == 4)
def test_issue_9699():
n, k = symbols('n k', real=True)
x, y = symbols('x, y')
assert combsimp((n + 1)*factorial(n)) == factorial(n + 1)
assert combsimp((x + 1)*factorial(x)/gamma(y)) == gamma(x + 2)/gamma(y)
assert combsimp(factorial(n)/n) == factorial(n - 1)
assert combsimp(rf(x + n, k)*binomial(n, k)) == binomial(n, k)*gamma(k + n + x)/gamma(n + x)
def test_limitseq_sum():
from sympy.abc import x, y, z
assert limit_seq(Sum(1/x, (x, 1, y)) - log(y), y) == S.EulerGamma
assert limit_seq(Sum(1/x, (x, 1, y)) - 1/y, y) == S.Infinity
assert (limit_seq(binomial(2*x, x) / Sum(binomial(2*y, y), (y, 1, x)), x) ==
S(3) / 4)
assert (limit_seq(Sum(y**2 * Sum(2**z/z, (z, 1, y)), (y, 1, x)) /
(2**x*x), x) == 4)
def dict(self):
N, m, n = self.N, self.m, self.n
N, m, n = list(map(sympify, (N, m, n)))
density = dict((sympify(k),
Rational(binomial(m, k) * binomial(N - m, n - k),
binomial(N, n)))
for k in range(max(0, n + m - N), min(m, n) + 1))
return density
def pxbar2( i, nup, bp ):
bp2 = float(nup)/float(numX)
if (nup==0):
if (i==0):
return 1
else:
return 0
return sp.binomial(Ns,i) * bp2**i* (1-bp2)**(Ns-i)* tdown(i/float(Ns)) / sum(sp.binomial(Ns,j) * bp2**j* (1-bp2)**(Ns-j)* tdown(j/float(Ns)) for j in xrange(0,Ns+1) )
def test_issue_2787():
n, k = symbols('n k', positive=True, integer=True)
p = symbols('p', positive=True)
binomial_dist = binomial(n, k)*p**k*(1 - p)**(n - k)
s = Sum(binomial_dist*k, (k, 0, n))
res = s.doit().simplify()
assert res == Piecewise((n*p, And(Or(-n + 1 < 0, -n + 1 >= 0),
Or(-n + 1 < 0, Ne(p/(p - 1), 1)), p*Abs(1/(p - 1)) <= 1)),
(Sum(k*p**k*(-p + 1)**(-k)*(-p + 1)**n*binomial(n, k), (k, 0, n)), True))
def test_issue_2787():
n, k = symbols('n k', positive=True, integer=True)
p = symbols('p', positive=True)
binomial_dist = binomial(n, k)*p**k*(1 - p)**(n - k)
s = Sum(binomial_dist*k, (k, 0, n))
res = s.doit().simplify()
assert res == Piecewise(
(n*p, p/Abs(p - 1) <= 1),
((-p + 1)**n*Sum(k*p**k*(-p + 1)**(-k)*binomial(n, k), (k, 0, n)),
True))
def test_gosper_sum_iterated():
f1 = binomial(2*k, k)/4**k
f2 = (1 + 2*n)*binomial(2*n, n)/4**n
f3 = (1 + 2*n)*(3 + 2*n)*binomial(2*n, n)/(3*4**n)
f4 = (1 + 2*n)*(3 + 2*n)*(5 + 2*n)*binomial(2*n, n)/(15*4**n)
f5 = (1 + 2*n)*(3 + 2*n)*(5 + 2*n)*(7 + 2*n)*binomial(2*n, n)/(105*4**n)
assert gosper_sum(f1, (k, 0, n)) == f2
assert gosper_sum(f2, (n, 0, n)) == f3
assert gosper_sum(f3, (n, 0, n)) == f4
assert gosper_sum(f4, (n, 0, n)) == f5
def test_evalf_fast_series():
# Euler transformed series for sqrt(1+x)
assert NS(Sum(
fac(2*n + 1)/fac(n)**2/2**(3*n + 1), (n, 0, oo)), 100) == NS(sqrt(2), 100)
# Some series for exp(1)
estr = NS(E, 100)
assert NS(Sum(1/fac(n), (n, 0, oo)), 100) == estr
assert NS(1/Sum((1 - 2*n)/fac(2*n), (n, 0, oo)), 100) == estr
assert NS(Sum((2*n + 1)/fac(2*n), (n, 0, oo)), 100) == estr
assert NS(Sum((4*n + 3)/2**(2*n + 1)/fac(2*n + 1), (n, 0, oo))**2, 100) == estr
pistr = NS(pi, 100)
# Ramanujan series for pi
assert NS(9801/sqrt(8)/Sum(fac(
4*n)*(1103 + 26390*n)/fac(n)**4/396**(4*n), (n, 0, oo)), 100) == pistr
assert NS(1/Sum(
binomial(2*n, n)**3 * (42*n + 5)/2**(12*n + 4), (n, 0, oo)), 100) == pistr
# Machin's formula for pi
assert NS(16*Sum((-1)**n/(2*n + 1)/5**(2*n + 1), (n, 0, oo)) -
4*Sum((-1)**n/(2*n + 1)/239**(2*n + 1), (n, 0, oo)), 100) == pistr
# Apery's constant
astr = NS(zeta(3), 100)
P = 126392*n**5 + 412708*n**4 + 531578*n**3 + 336367*n**2 + 104000* \
n + 12463
assert NS(Sum((-1)**n * P / 24 * (fac(2*n + 1)*fac(2*n)*fac(
n))**3 / fac(3*n + 2) / fac(4*n + 3)**3, (n, 0, oo)), 100) == astr
assert NS(Sum((-1)**n * (205*n**2 + 250*n + 77)/64 * fac(n)**10 /
fac(2*n + 1)**5, (n, 0, oo)), 100) == astr
def _estimate_gradients_2d_global():
#
# Compute
#
#
f1, f2, df1, df2, x = symbols(['f1', 'f2', 'df1', 'df2', 'x'])
c = [f1, (df1 + 3*f1)/3, (df2 + 3*f2)/3, f2]
w = 0
for k in range(4):
w += binomial(3, k) * c[k] * x**k*(1-x)**(3-k)
wpp = w.diff(x, 2).expand()
intwpp2 = (wpp**2).integrate((x, 0, 1)).expand()
A = Matrix([[intwpp2.coeff(df1**2), intwpp2.coeff(df1*df2)/2],
[intwpp2.coeff(df1*df2)/2, intwpp2.coeff(df2**2)]])
B = Matrix([[intwpp2.coeff(df1).subs(df2, 0)],
[intwpp2.coeff(df2).subs(df1, 0)]]) / 2
print("A")
print(A)
print("B")
print(B)
print("solution")
print(A.inv() * B)
def map_substitution(self, expr):
assert isinstance(expr.child, prim.Derivative)
call = expr.child.child
if (isinstance(call.function, prim.Variable)
and call.function.name in ["hankel_1", "bessel_j"]):
function = call.function
order, _ = call.parameters
arg, = expr.values
n_derivs = len(expr.child.variables)
import sympy as sp
# AS (9.1.31)
# http://dlmf.nist.gov/10.6.7
if order >= 0:
order_str = str(order)
else:
order_str = "m"+str(-order)
k = n_derivs
return prim.CommonSubexpression(
2**(-k)*sum(
(-1)**idx*int(sp.binomial(k, idx)) * function(i, arg)
for idx, i in enumerate(range(order-k, order+k+1, 2))),
"d%d_%s_%s" % (n_derivs, function.name, order_str))
else:
return IdentityMapper.map_substitution(self, expr)
def vasicek_base(N, k, p, rho):
"""
:param N:
:param k:
:param p:
:param rho:
:return:
"""
zmin = - settings.SCALE
zmax = settings.SCALE
grid = settings.GRID_POINTS
dz = float(zmax - zmin) / float(grid - 1)
a = stats.norm.ppf(p, loc=0.0, scale=1.0)
integral = 0
for i in range(1, grid):
z = zmin + dz * i
arg = (a - rho * z) / math.sqrt(1 - rho * rho)
phi_den = stats.norm.pdf(z, loc=0.0, scale=1.0)
phi_cum = stats.norm.cdf(arg, loc=0.0, scale=1.0)
integrant = phi_den * math.pow(phi_cum, k) * math.pow(1 - phi_cum, N - k) * binomial(N, k)
integral = integral + integrant
return dz * integral
def test_assoc_laguerre():
n = Symbol("n")
m = Symbol("m")
alpha = Symbol("alpha")
# generalized Laguerre polynomials:
assert assoc_laguerre(0, alpha, x) == 1
assert assoc_laguerre(1, alpha, x) == -x + alpha + 1
assert assoc_laguerre(2, alpha, x).expand() == \
(x**2/2 - (alpha + 2)*x + (alpha + 2)*(alpha + 1)/2).expand()
assert assoc_laguerre(3, alpha, x).expand() == \
(-x**3/6 + (alpha + 3)*x**2/2 - (alpha + 2)*(alpha + 3)*x/2 +
(alpha + 1)*(alpha + 2)*(alpha + 3)/6).expand()
# Test the lowest 10 polynomials with laguerre_poly, to make sure it works:
for i in range(10):
assert assoc_laguerre(i, 0, x).expand() == laguerre_poly(i, x)
X = assoc_laguerre(n, m, x)
assert isinstance(X, assoc_laguerre)
assert assoc_laguerre(n, 0, x) == laguerre(n, x)
assert assoc_laguerre(n, alpha, 0) == binomial(alpha + n, alpha)
assert diff(assoc_laguerre(n, alpha, x), x) == \
-assoc_laguerre(n - 1, alpha + 1, x)
assert conjugate(assoc_laguerre(n, alpha, x)) == \
assoc_laguerre(n, conjugate(alpha), conjugate(x))
raises(ValueError, lambda: assoc_laguerre(-2.1, alpha, x))
def test_uniformsum():
n = Symbol("n", integer=True)
_k = Symbol("k")
X = UniformSum('x', n)
assert density(X)(x) == (Sum((-1)**_k*(-_k + x)**(n - 1)
*binomial(n, _k), (_k, 0, floor(x)))/factorial(n - 1))
def translate_from(self, src_expansion, src_coeff_exprs, src_rscale,
dvec, tgt_rscale):
if not isinstance(src_expansion, type(self)):
raise RuntimeError("do not know how to translate %s to "
"Taylor multipole expansion"
% type(src_expansion).__name__)
if not self.use_rscale:
src_rscale = 1
tgt_rscale = 1
logger.info("building translation operator: %s(%d) -> %s(%d): start"
% (type(src_expansion).__name__,
src_expansion.order,
type(self).__name__,
self.order))
from sumpy.tools import mi_factorial
src_mi_to_index = dict((mi, i) for i, mi in enumerate(
src_expansion.get_coefficient_identifiers()))
for i, mi in enumerate(src_expansion.get_coefficient_identifiers()):
src_coeff_exprs[i] *= mi_factorial(mi)
result = [0] * len(self.get_full_coefficient_identifiers())
from pytools import generate_nonnegative_integer_tuples_below as gnitb
for i, tgt_mi in enumerate(
self.get_full_coefficient_identifiers()):
tgt_mi_plus_one = tuple(mi_i + 1 for mi_i in tgt_mi)
for src_mi in gnitb(tgt_mi_plus_one):
try:
src_index = src_mi_to_index[src_mi]
except KeyError:
# Omitted coefficients: not life-threatening
continue
contrib = src_coeff_exprs[src_index]
for idim in range(self.dim):
n = tgt_mi[idim]
k = src_mi[idim]
assert n >= k
from sympy import binomial
contrib *= (binomial(n, k)
* sym.UnevaluatedExpr(dvec[idim]/tgt_rscale)**(n-k))
result[i] += (
contrib
* sym.UnevaluatedExpr(src_rscale/tgt_rscale)**sum(src_mi))
result[i] /= mi_factorial(tgt_mi)
logger.info("building translation operator: done")
return (
self.derivative_wrangler.get_stored_mpole_coefficients_from_full(
result, tgt_rscale))
def __init__(self, states, interval, differential_order):
"""
:param states: tuple of states in beginning and end of interval
:param interval: time interval (tuple)
:param differential_order: grade of differential flatness :math:`\\gamma`
"""
self.yd = states
self.t0 = interval[0]
self.t1 = interval[1]
self.dt = interval[1] - interval[0]
gamma = differential_order # + 1 # TODO check this against notes
# setup symbolic expressions
tau, k = sp.symbols('tau, k')
alpha = sp.factorial(2 * gamma + 1)
f = sp.binomial(gamma, k) * (-1) ** k * tau ** (gamma + k + 1) / (gamma + k + 1)
phi = alpha / sp.factorial(gamma) ** 2 * sp.summation(f, (k, 0, gamma))
# differentiate phi(tau), index in list corresponds to order
dphi_sym = [phi] # init with phi(tau)
for order in range(differential_order):
dphi_sym.append(dphi_sym[-1].diff(tau))
# lambdify
self.dphi_num = []
for der in dphi_sym:
self.dphi_num.append(sp.lambdify(tau, der, 'numpy'))
def test_rf_eval_apply():
x, y = symbols('x,y')
n, k = symbols('n k', integer=True)
m = Symbol('m', integer=True, nonnegative=True)
assert rf(nan, y) == nan
assert rf(x, nan) == nan
assert rf(x, y) == rf(x, y)
assert rf(oo, 0) == 1
assert rf(-oo, 0) == 1
assert rf(oo, 6) == oo
assert rf(-oo, 7) == -oo
assert rf(oo, -6) == oo
assert rf(-oo, -7) == oo
assert rf(x, 0) == 1
assert rf(x, 1) == x
assert rf(x, 2) == x*(x + 1)
assert rf(x, 3) == x*(x + 1)*(x + 2)
assert rf(x, 5) == x*(x + 1)*(x + 2)*(x + 3)*(x + 4)
assert rf(x, -1) == 1/(x - 1)
assert rf(x, -2) == 1/((x - 1)*(x - 2))
assert rf(x, -3) == 1/((x - 1)*(x - 2)*(x - 3))
assert rf(1, 100) == factorial(100)
assert rf(x**2 + 3*x, 2) == (x**2 + 3*x)*(x**2 + 3*x + 1)
assert isinstance(rf(x**2 + 3*x, 2), Mul)
assert rf(x**3 + x, -2) == 1/((x**3 + x - 1)*(x**3 + x - 2))
assert rf(Poly(x**2 + 3*x, x), 2) == Poly(x**4 + 8*x**3 + 19*x**2 + 12*x, x)
assert isinstance(rf(Poly(x**2 + 3*x, x), 2), Poly)
raises(ValueError, lambda: rf(Poly(x**2 + 3*x, x, y), 2))
assert rf(Poly(x**3 + x, x), -2) == 1/(x**6 - 9*x**5 + 35*x**4 - 75*x**3 + 94*x**2 - 66*x + 20)
raises(ValueError, lambda: rf(Poly(x**3 + x, x, y), -2))
assert rf(x, m).is_integer is None
assert rf(n, k).is_integer is None
assert rf(n, m).is_integer is True
assert rf(n, k + pi).is_integer is False
assert rf(n, m + pi).is_integer is False
assert rf(pi, m).is_integer is False
assert rf(x, k).rewrite(ff) == ff(x + k - 1, k)
assert rf(x, k).rewrite(binomial) == factorial(k)*binomial(x + k - 1, k)
assert rf(n, k).rewrite(factorial) == \
factorial(n + k - 1) / factorial(n - 1)
import random
from mpmath import rf as mpmath_rf
for i in range(100):
x = -500 + 500 * random.random()
k = -500 + 500 * random.random()
assert (abs(mpmath_rf(x, k) - rf(x, k)) < 10**(-15))
def Bernstein_series(N):
# FIXME: check if a normalization constant is common in the definition
# advantage is that the basis is always positive
psi = []
for k in range(0,N+1):
psi_k = sym.binomial(N, k)*x**k*(1-x)**(N-k)
psi.append(psi_k)
return psi
def test_uniformsum():
n = Symbol("n", integer=True)
x = Symbol("x")
_k = Symbol("k")
X = UniformSum(n, symbol=x)
assert Density(X) == (Lambda(_x, Sum((-1)**_k*(-_k + _x)**(n - 1)
*binomial(n, _k), (_k, 0, floor(_x)))/factorial(n - 1)))
def sumFibPower(n, p, viaPowers = True):
"""Sum Fib(i)^p, i = 0..n"""
#Expand power, sum each element, then convert to fibonacci numbers
s = 0
for i in range(0, p+1):
si = sumGeomAB( p-i, i, 0, n, viaPowers=viaPowers )
s = s + binomial(p,i) * (-1)**(i) * si
return s / (sqrts(5))**p
def _eval_wignerd(self):
j = sympify(self.j)
m = sympify(self.m)
mp = sympify(self.mp)
alpha = sympify(self.alpha)
beta = sympify(self.beta)
gamma = sympify(self.gamma)
if not j.is_number:
raise ValueError("j parameter must be numerical to evaluate, got %s", j)
r = 0
if beta == pi / 2:
# Varshalovich Equation (5), Section 4.16, page 113, setting
# alpha=gamma=0.
for k in range(2 * j + 1):
if k > j + mp or k > j - m or k < mp - m:
continue
r += (-S(1)) ** k * binomial(j + mp, k) * binomial(j - mp, k + m - mp)
r *= (
(-S(1)) ** (m - mp)
/ 2 ** j
* sqrt(factorial(j + m) * factorial(j - m) / (factorial(j + mp) * factorial(j - mp)))
)
else:
# Varshalovich Equation(5), Section 4.7.2, page 87, where we set
# beta1=beta2=pi/2, and we get alpha=gamma=pi/2 and beta=phi+pi,
# then we use the Eq. (1), Section 4.4. page 79, to simplify:
# d(j, m, mp, beta+pi) = (-1)**(j-mp) * d(j, m, -mp, beta)
# This happens to be almost the same as in Eq.(10), Section 4.16,
# except that we need to substitute -mp for mp.
size, mvals = m_values(j)
for mpp in mvals:
r += (
Rotation.d(j, m, mpp, pi / 2).doit()
* (cos(-mpp * beta) + I * sin(-mpp * beta))
* Rotation.d(j, mpp, -mp, pi / 2).doit()
)
# Empirical normalization factor so results match Varshalovich
# Tables 4.3-4.12
# Note that this exact normalization does not follow from the
# above equations
r = r * I ** (2 * j - m - mp) * (-1) ** (2 * m)
# Finally, simplify the whole expression
r = simplify(r)
r *= exp(-I * m * alpha) * exp(-I * mp * gamma)
return r
def __new__(cls, n, symbol=None):
n = sympify(n)
x = symbol or SingleContinuousPSpace.create_symbol()
k = Dummy("k")
pdf =1/factorial(n-1)*Sum((-1)**k*binomial(n,k)*(x-k)**(n-1), (k,0,floor(x)))
obj = SingleContinuousPSpace.__new__(cls, x, pdf, set=Interval(0,n))
return obj
def test_gosper_sum_AeqB_part2():
f2a = n**2*a**n
f2b = (n - r/2)*binomial(r, n)
f2c = factorial(n - 1)**2/(factorial(n - x)*factorial(n + x))
g2a = -a*(a + 1)/(a - 1)**3 + a**(
m + 1)*(a**2*m**2 - 2*a*m**2 + m**2 - 2*a*m + 2*m + a + 1)/(a - 1)**3
g2b = (m - r)*binomial(r, m)/2
ff = factorial(1 - x)*factorial(1 + x)
g2c = 1/ff*(
1 - 1/x**2) + factorial(m)**2/(x**2*factorial(m - x)*factorial(m + x))
g = gosper_sum(f2a, (n, 0, m))
assert g is not None and simplify(g - g2a) == 0
g = gosper_sum(f2b, (n, 0, m))
assert g is not None and simplify(g - g2b) == 0
g = gosper_sum(f2c, (n, 1, m))
assert g is not None and simplify(g - g2c) == 0
def tdown( x ):
alpha1 = alpha*1.0/(1.0+exp(-(x-xthresh)/thresh))
if x > 0.0625:
alpha1=alpha
else:
alpha1 = 0
alpha1 = alpha*(1.0-exp(-x/0.1))
xx = 1.0-(1.0-alpha1)*(1.0-x)
return (x) * (1 - sum(sp.binomial(K,j) * xx**j * (1-xx)**(K-j) * psw(j) for j in xrange(0,K+1)))
def S(n, k):
if k == 0:
return n
elif k == 1:
return n * (n + 1) // 2
elif k == 2:
return (n) * (n + 1) * (2 * n + 1) // 6
elif k >= 3:
return ((1 + n) ** (k + 1) - 1 - sum(binomial(k + 1, i) * S(n, i) for i in range(0, k))) // (k + 1)
def ncr(n, r):
"""Number of ways to choose r elements from n
This is in as a reminder of how the sympy api works
>>> ncr(10, 5)
252
"""
return sympy.binomial(n, r)
def test_rsolve():
f = y(n + 2) - y(n + 1) - y(n)
h = sqrt(5)*(S.Half + S.Half*sqrt(5))**n \
- sqrt(5)*(S.Half - S.Half*sqrt(5))**n
assert rsolve(f, y(n)) in [
C0 * (S.Half - S.Half * sqrt(5))**n + C1 *
(S.Half + S.Half * sqrt(5))**n,
C1 * (S.Half - S.Half * sqrt(5))**n + C0 *
(S.Half + S.Half * sqrt(5))**n,
]
assert rsolve(f, y(n), [0, 5]) == h
assert rsolve(f, y(n), {0: 0, 1: 5}) == h
assert rsolve(f, y(n), {y(0): 0, y(1): 5}) == h
assert rsolve(y(n) - y(n - 1) - y(n - 2), y(n), [0, 5]) == h
assert rsolve(Eq(y(n), y(n - 1) + y(n - 2)), y(n), [0, 5]) == h
assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
f = (n - 1) * y(n + 2) - (n**2 + 3 * n - 2) * y(n + 1) + 2 * n * (n +
1) * y(n)
g = C1 * factorial(n) + C0 * 2**n
h = -3 * factorial(n) + 3 * 2**n
assert rsolve(f, y(n)) == g
assert rsolve(f, y(n), []) == g
assert rsolve(f, y(n), {}) == g
assert rsolve(f, y(n), [0, 3]) == h
assert rsolve(f, y(n), {0: 0, 1: 3}) == h
assert rsolve(f, y(n), {y(0): 0, y(1): 3}) == h
assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
f = y(n) - y(n - 1) - 2
assert rsolve(f, y(n), {y(0): 0}) == 2 * n
assert rsolve(f, y(n), {y(0): 1}) == 2 * n + 1
assert rsolve(f, y(n), {y(0): 0, y(1): 1}) is None
assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
f = 3 * y(n - 1) - y(n) - 1
assert rsolve(f, y(n), {y(0): 0}) == -3**n / 2 + S.Half
assert rsolve(f, y(n), {y(0): 1}) == 3**n / 2 + S.Half
assert rsolve(f, y(n), {y(0): 2}) == 3 * 3**n / 2 + S.Half
assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
f = y(n) - 1 / n * y(n - 1)
assert rsolve(f, y(n)) == C0 / factorial(n)
assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
f = y(n) - 1 / n * y(n - 1) - 1
assert rsolve(f, y(n)) is None
f = 2 * y(n - 1) + (1 - n) * y(n) / n
assert rsolve(f, y(n), {y(1): 1}) == 2**(n - 1) * n
assert rsolve(f, y(n), {y(1): 2}) == 2**(n - 1) * n * 2
assert rsolve(f, y(n), {y(1): 3}) == 2**(n - 1) * n * 3
assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
f = (n - 1) * (n - 2) * y(n + 2) - (n + 1) * (n + 2) * y(n)
assert rsolve(f, y(n), {y(3): 6, y(4): 24}) == n * (n - 1) * (n - 2)
assert rsolve(f, y(n), {
y(3): 6,
y(4): -24
}) == -n * (n - 1) * (n - 2) * (-1)**(n)
assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
assert rsolve(Eq(y(n + 1), a * y(n)), y(n), {y(1): a}).simplify() == a**n
assert rsolve(y(n) - a*y(n-2),y(n), \
{y(1): sqrt(a)*(a + b), y(2): a*(a - b)}).simplify() == \
a**(n/2)*(-(-1)**n*b + a)
f = (-16 * n**2 + 32 * n - 12) * y(n - 1) + (4 * n**2 - 12 * n + 9) * y(n)
assert expand_func(rsolve(f, y(n), \
{y(1): binomial(2*n + 1, 3)}).rewrite(gamma)).simplify() == \
2**(2*n)*n*(2*n - 1)*(4*n**2 - 1)/12
assert (rsolve(y(n) + a * (y(n + 1) + y(n - 1)) / 2, y(n)) -
(C0 * ((sqrt(-a**2 + 1) - 1) / a)**n + C1 *
((-sqrt(-a**2 + 1) - 1) / a)**n)).simplify() == 0
assert rsolve((k + 1) * y(k), y(k)) is None
assert (rsolve((k + 1) * y(k) + (k + 3) * y(k + 1) +
(k + 5) * y(k + 2), y(k)) is None)
def convert_binom(binom):
expr_n = convert_expr(binom.n)
expr_k = convert_expr(binom.k)
return sympy.binomial(expr_n, expr_k, evaluate=False)
def test_hypergeometric_sums():
assert summation(binomial(2 * k, k) / 4**k,
(k, 0, n)) == (1 + 2 * n) * binomial(2 * n, n) / 4**n
def test_euler_failing():
# depends on dummy variables being implemented https://github.com/sympy/sympy/issues/5665
assert euler(2 * n).rewrite(Sum) == I * Sum(
Sum((-1)**_j * 2**(-_k) * I**(-_k) *
(-2 * _j + _k)**(2 * n + 1) * binomial(_k, _j) / _k, (_j, 0, _k)),
(_k, 1, 2 * n + 1))
def pmf(self, k):
n, a, b = self.n, self.alpha, self.beta
return binomial(n, k) * beta_fn(k + a, n - k + b) / beta_fn(a, b)
def dict(self):
n, p, succ, fail = self.n, self.p, self.succ, self.fail
n = as_int(n)
return dict((k * succ + (n - k) * fail,
binomial(n, k) * p**k * (1 - p)**(n - k))
for k in range(0, n + 1))
def count_cnr_bigger(n, min_n):
bin_gen = (binomial(i, j) for i in range(1, n + 1)
for j in range(1, i + 1))
return sum(1 for x in bin_gen if x > min_n)
def test_issue_10801():
# make sure limits work with binomial
assert limit(16**k / (k * binomial(2*k, k)**2), k, oo) == pi
def med_hamm1(n, k):
res = 0
for i in range(1, k + 1):
res += 2*i*binomial(k, i)*binomial(n-k,i)
return (res / binomial(n, k))
def test_binomial_Mod_slow():
p, q = 10**5 + 3, 10**9 + 33 # prime modulo
r, s = 10**7 + 5, 33333333 # composite modulo
n, k, m = symbols('n k m')
assert (binomial(n, k) % q).subs({n: s, k: p}) == Mod(binomial(s, p), q)
assert (binomial(n, k) % m).subs({n: 8, k: 5, m: 13}) == 4
assert (binomial(9, k) % 7).subs(k, 2) == 1
# Lucas Theorem
assert Mod(binomial(123456, 43253, evaluate=False), p) == Mod(binomial(123456, 43253), p)
assert Mod(binomial(-178911, 237, evaluate=False), p) == Mod(-binomial(178911 + 237 - 1, 237), p)
assert Mod(binomial(-178911, 238, evaluate=False), p) == Mod(binomial(178911 + 238 - 1, 238), p)
# factorial Mod
assert Mod(binomial(9734, 451, evaluate=False), q) == Mod(binomial(9734, 451), q)
assert Mod(binomial(-10733, 4459, evaluate=False), q) == Mod(binomial(-10733, 4459), q)
assert Mod(binomial(-15733, 4458, evaluate=False), q) == Mod(binomial(-15733, 4458), q)
# binomial factorize
assert Mod(binomial(753, 119, evaluate=False), r) == Mod(binomial(753, 119), r)
assert Mod(binomial(3781, 948, evaluate=False), s) == Mod(binomial(3781, 948), s)
assert Mod(binomial(25773, 1793, evaluate=False), s) == Mod(binomial(25773, 1793), s)
assert Mod(binomial(-753, 118, evaluate=False), r) == Mod(binomial(-753, 118), r)
assert Mod(binomial(-25773, 1793, evaluate=False), s) == Mod(binomial(-25773, 1793), s)
def wigner_d_small(J, beta):
"""Return the small Wigner d matrix for angular momentum J.
Explanation
===========
J : An integer, half-integer, or sympy symbol for the total angular
momentum of the angular momentum space being rotated.
beta : A real number representing the Euler angle of rotation about
the so-called line of nodes. See [Edmonds74]_.
Returns
=======
A matrix representing the corresponding Euler angle rotation( in the basis
of eigenvectors of `J_z`).
.. math ::
\\mathcal{d}_{\\beta} = \\exp\\big( \\frac{i\\beta}{\\hbar} J_y\\big)
The components are calculated using the general form [Edmonds74]_,
equation 4.1.15.
Examples
========
>>> from sympy import Integer, symbols, pi, pprint
>>> from sympy.physics.wigner import wigner_d_small
>>> half = 1/Integer(2)
>>> beta = symbols("beta", real=True)
>>> pprint(wigner_d_small(half, beta), use_unicode=True)
⎡ ⎛β⎞ ⎛β⎞⎤
⎢cos⎜─⎟ sin⎜─⎟⎥
⎢ ⎝2⎠ ⎝2⎠⎥
⎢ ⎥
⎢ ⎛β⎞ ⎛β⎞⎥
⎢-sin⎜─⎟ cos⎜─⎟⎥
⎣ ⎝2⎠ ⎝2⎠⎦
>>> pprint(wigner_d_small(2*half, beta), use_unicode=True)
⎡ 2⎛β⎞ ⎛β⎞ ⎛β⎞ 2⎛β⎞ ⎤
⎢ cos ⎜─⎟ √2⋅sin⎜─⎟⋅cos⎜─⎟ sin ⎜─⎟ ⎥
⎢ ⎝2⎠ ⎝2⎠ ⎝2⎠ ⎝2⎠ ⎥
⎢ ⎥
⎢ ⎛β⎞ ⎛β⎞ 2⎛β⎞ 2⎛β⎞ ⎛β⎞ ⎛β⎞⎥
⎢-√2⋅sin⎜─⎟⋅cos⎜─⎟ - sin ⎜─⎟ + cos ⎜─⎟ √2⋅sin⎜─⎟⋅cos⎜─⎟⎥
⎢ ⎝2⎠ ⎝2⎠ ⎝2⎠ ⎝2⎠ ⎝2⎠ ⎝2⎠⎥
⎢ ⎥
⎢ 2⎛β⎞ ⎛β⎞ ⎛β⎞ 2⎛β⎞ ⎥
⎢ sin ⎜─⎟ -√2⋅sin⎜─⎟⋅cos⎜─⎟ cos ⎜─⎟ ⎥
⎣ ⎝2⎠ ⎝2⎠ ⎝2⎠ ⎝2⎠ ⎦
From table 4 in [Edmonds74]_
>>> pprint(wigner_d_small(half, beta).subs({beta:pi/2}), use_unicode=True)
⎡ √2 √2⎤
⎢ ── ──⎥
⎢ 2 2 ⎥
⎢ ⎥
⎢-√2 √2⎥
⎢──── ──⎥
⎣ 2 2 ⎦
>>> pprint(wigner_d_small(2*half, beta).subs({beta:pi/2}),
... use_unicode=True)
⎡ √2 ⎤
⎢1/2 ── 1/2⎥
⎢ 2 ⎥
⎢ ⎥
⎢-√2 √2 ⎥
⎢──── 0 ── ⎥
⎢ 2 2 ⎥
⎢ ⎥
⎢ -√2 ⎥
⎢1/2 ──── 1/2⎥
⎣ 2 ⎦
>>> pprint(wigner_d_small(3*half, beta).subs({beta:pi/2}),
... use_unicode=True)
⎡ √2 √6 √6 √2⎤
⎢ ── ── ── ──⎥
⎢ 4 4 4 4 ⎥
⎢ ⎥
⎢-√6 -√2 √2 √6⎥
⎢──── ──── ── ──⎥
⎢ 4 4 4 4 ⎥
⎢ ⎥
⎢ √6 -√2 -√2 √6⎥
⎢ ── ──── ──── ──⎥
⎢ 4 4 4 4 ⎥
⎢ ⎥
⎢-√2 √6 -√6 √2⎥
⎢──── ── ──── ──⎥
⎣ 4 4 4 4 ⎦
>>> pprint(wigner_d_small(4*half, beta).subs({beta:pi/2}),
... use_unicode=True)
⎡ √6 ⎤
⎢1/4 1/2 ── 1/2 1/4⎥
⎢ 4 ⎥
⎢ ⎥
⎢-1/2 -1/2 0 1/2 1/2⎥
⎢ ⎥
⎢ √6 √6 ⎥
⎢ ── 0 -1/2 0 ── ⎥
⎢ 4 4 ⎥
⎢ ⎥
⎢-1/2 1/2 0 -1/2 1/2⎥
⎢ ⎥
⎢ √6 ⎥
⎢1/4 -1/2 ── -1/2 1/4⎥
⎣ 4 ⎦
"""
M = [J-i for i in range(2*J+1)]
d = zeros(2*J+1)
for i, Mi in enumerate(M):
for j, Mj in enumerate(M):
# We get the maximum and minimum value of sigma.
sigmamax = max([-Mi-Mj, J-Mj])
sigmamin = min([0, J-Mi])
dij = sqrt(factorial(J+Mi)*factorial(J-Mi) /
factorial(J+Mj)/factorial(J-Mj))
terms = [(-1)**(J-Mi-s) *
binomial(J+Mj, J-Mi-s) *
binomial(J-Mj, s) *
cos(beta/2)**(2*s+Mi+Mj) *
sin(beta/2)**(2*J-2*s-Mj-Mi)
for s in range(sigmamin, sigmamax+1)]
d[i, j] = dij*Add(*terms)
return ImmutableMatrix(d)
def _binomial(n, k):
return binomial(n, k, evaluate=False)
def test_binomial():
n = Symbol('n', integer=True)
k = Symbol('k', integer=True)
u = Symbol('v', negative=True)
v = Symbol('m', positive=True)
assert binomial(0, 0) == 1
assert binomial(1, 1) == 1
assert binomial(10, 10) == 1
assert binomial(1, 2) == 0
assert binomial(1, -1) == 0
assert binomial(-1, 1) == -1
assert binomial(-10, 1) == -10
assert binomial(-10, 7) == -11440
assert binomial(n, -1) == 0
assert binomial(n, 0) == 1
assert expand_func(binomial(n, 1)) == n
assert expand_func(binomial(n, 2)) == n * (n - 1) / 2
assert expand_func(binomial(n, n - 2)) == n * (n - 1) / 2
assert expand_func(binomial(n, n - 1)) == n
assert binomial(n, 3).func == binomial
assert binomial(n, 3).expand(func=True) == n**3 / 6 - n**2 / 2 + n / 3
assert expand_func(binomial(n, 3)) == n * (n - 2) * (n - 1) / 6
assert binomial(n, n) == 1
assert binomial(n, n + 1) == 0
assert binomial(n, u) == 0
assert binomial(n, v).func == binomial
assert binomial(n, k).func == binomial
assert binomial(n, n + v) == 0
assert expand_func(binomial(n, n - 3)) == n * (n - 2) * (n - 1) / 6
assert binomial(n, k).is_integer
def test_issue_14528():
p = symbols("p", integer=True, positive=True)
assert combsimp(binomial(1, p)) == 1 / (factorial(p) * factorial(1 - p))
assert combsimp(factorial(2 - p)) == factorial(2 - p)
def test_ff_eval_apply():
x, y = symbols('x,y')
n, k = symbols('n k', integer=True)
m = Symbol('m', integer=True, nonnegative=True)
assert ff(nan, y) == nan
assert ff(x, nan) == nan
assert ff(x, y) == ff(x, y)
assert ff(oo, 0) == 1
assert ff(-oo, 0) == 1
assert ff(oo, 6) == oo
assert ff(-oo, 7) == -oo
assert ff(-oo, 6) == oo
assert ff(oo, -6) == oo
assert ff(-oo, -7) == oo
assert ff(x, 0) == 1
assert ff(x, 1) == x
assert ff(x, 2) == x*(x - 1)
assert ff(x, 3) == x*(x - 1)*(x - 2)
assert ff(x, 5) == x*(x - 1)*(x - 2)*(x - 3)*(x - 4)
assert ff(x, -1) == 1/(x + 1)
assert ff(x, -2) == 1/((x + 1)*(x + 2))
assert ff(x, -3) == 1/((x + 1)*(x + 2)*(x + 3))
assert ff(100, 100) == factorial(100)
assert ff(2*x**2 - 5*x, 2) == (2*x**2 - 5*x)*(2*x**2 - 5*x - 1)
assert isinstance(ff(2*x**2 - 5*x, 2), Mul)
assert ff(x**2 + 3*x, -2) == 1/((x**2 + 3*x + 1)*(x**2 + 3*x + 2))
assert ff(Poly(2*x**2 - 5*x, x), 2) == Poly(4*x**4 - 28*x**3 + 59*x**2 - 35*x, x)
assert isinstance(ff(Poly(2*x**2 - 5*x, x), 2), Poly)
raises(ValueError, lambda: ff(Poly(2*x**2 - 5*x, x, y), 2))
assert ff(Poly(x**2 + 3*x, x), -2) == 1/(x**4 + 12*x**3 + 49*x**2 + 78*x + 40)
raises(ValueError, lambda: ff(Poly(x**2 + 3*x, x, y), -2))
assert ff(x, m).is_integer is None
assert ff(n, k).is_integer is None
assert ff(n, m).is_integer is True
assert ff(n, k + pi).is_integer is False
assert ff(n, m + pi).is_integer is False
assert ff(pi, m).is_integer is False
assert isinstance(ff(x, x), ff)
assert ff(n, n) == factorial(n)
assert ff(x, k).rewrite(rf) == rf(x - k + 1, k)
assert ff(x, k).rewrite(gamma) == (-1)**k*gamma(k - x) / gamma(-x)
assert ff(n, k).rewrite(factorial) == factorial(n) / factorial(n - k)
assert ff(x, k).rewrite(binomial) == factorial(k) * binomial(x, k)
assert ff(x, y).rewrite(factorial) == ff(x, y)
assert ff(x, y).rewrite(binomial) == ff(x, y)
import random
from mpmath import ff as mpmath_ff
for i in range(100):
x = -500 + 500 * random.random()
k = -500 + 500 * random.random()
assert (abs(mpmath_ff(x, k) - ff(x, k)) < 10**(-15))
def lattice_path(n):
return binomial(2 * n, n)
def pmf(self, k):
N, m, n = self.N, self.m, self.n
return S(binomial(m, k) * binomial(N - m, n - k))/binomial(N, n)
def test_gammasimp():
R = Rational
# was part of test_combsimp_gamma() in test_combsimp.py
assert gammasimp(gamma(x)) == gamma(x)
assert gammasimp(gamma(x + 1) / x) == gamma(x)
assert gammasimp(gamma(x) / (x - 1)) == gamma(x - 1)
assert gammasimp(x * gamma(x)) == gamma(x + 1)
assert gammasimp((x + 1) * gamma(x + 1)) == gamma(x + 2)
assert gammasimp(gamma(x + y) * (x + y)) == gamma(x + y + 1)
assert gammasimp(x / gamma(x + 1)) == 1 / gamma(x)
assert gammasimp((x + 1)**2 / gamma(x + 2)) == (x + 1) / gamma(x + 1)
assert gammasimp(x*gamma(x) + gamma(x + 3)/(x + 2)) == \
(x + 2)*gamma(x + 1)
assert gammasimp(gamma(2 * x) * x) == gamma(2 * x + 1) / 2
assert gammasimp(gamma(2 * x) / (x - S(1) / 2)) == 2 * gamma(2 * x - 1)
assert gammasimp(gamma(x) * gamma(1 - x)) == pi / sin(pi * x)
assert gammasimp(gamma(x) * gamma(-x)) == -pi / (x * sin(pi * x))
assert gammasimp(1/gamma(x + 3)/gamma(1 - x)) == \
sin(pi*x)/(pi*x*(x + 1)*(x + 2))
assert gammasimp(factorial(n + 2)) == gamma(n + 3)
assert gammasimp(binomial(n, k)) == \
gamma(n + 1)/(gamma(k + 1)*gamma(-k + n + 1))
assert powsimp(gammasimp(
gamma(x)*gamma(x + S(1)/2)*gamma(y)/gamma(x + y))) == \
2**(-2*x + 1)*sqrt(pi)*gamma(2*x)*gamma(y)/gamma(x + y)
assert gammasimp(1/gamma(x)/gamma(x - S(1)/3)/gamma(x + S(1)/3)) == \
3**(3*x - S(3)/2)/(2*pi*gamma(3*x - 1))
assert simplify(
gamma(S(1) / 2 + x / 2) * gamma(1 + x / 2) / gamma(1 + x) / sqrt(pi) *
2**x) == 1
assert gammasimp(gamma(S(-1) / 4) *
gamma(S(-3) / 4)) == 16 * sqrt(2) * pi / 3
assert powsimp(gammasimp(gamma(2*x)/gamma(x))) == \
2**(2*x - 1)*gamma(x + S(1)/2)/sqrt(pi)
# issue 6792
e = (-gamma(k) * gamma(k + 2) + gamma(k + 1)**2) / gamma(k)**2
assert gammasimp(e) == -k
assert gammasimp(1 / e) == -1 / k
e = (gamma(x) + gamma(x + 1)) / gamma(x)
assert gammasimp(e) == x + 1
assert gammasimp(1 / e) == 1 / (x + 1)
e = (gamma(x) + gamma(x + 2)) * (gamma(x - 1) + gamma(x)) / gamma(x)
assert gammasimp(e) == (x**2 + x + 1) * gamma(x + 1) / (x - 1)
e = (-gamma(k) * gamma(k + 2) + gamma(k + 1)**2) / gamma(k)**2
assert gammasimp(e**2) == k**2
assert gammasimp(e**2 / gamma(k + 1)) == k / gamma(k)
a = R(1, 2) + R(1, 3)
b = a + R(1, 3)
assert gammasimp(gamma(2 * k) / gamma(k) * gamma(k + a) * gamma(k + b))
3 * 2**(2 * k + 1) * 3**(-3 * k - 2) * sqrt(pi) * gamma(3 * k +
R(3, 2)) / 2
# issue 9699
assert gammasimp(
(x + 1) * factorial(x) / gamma(y)) == gamma(x + 2) / gamma(y)
assert gammasimp(rf(x + n, k) *
binomial(n, k)) == gamma(n + 1) * gamma(k + n + x) / (
gamma(k + 1) * gamma(n + x) * gamma(-k + n + 1))
A, B = symbols('A B', commutative=False)
assert gammasimp(e * B * A) == gammasimp(e) * B * A
# check iteration
assert gammasimp(gamma(2 * k) / gamma(k) *
gamma(-k - R(1, 2))) == (-2**(2 * k + 1) * sqrt(pi) /
(2 *
((2 * k + 1) * cos(pi * k))))
assert gammasimp(
gamma(k) * gamma(k + R(1, 3)) * gamma(k + R(2, 3)) /
gamma(3 * k / 2)) == (3 * 2**(3 * k + 1) * 3**(-3 * k - S.Half) *
sqrt(pi) * gamma(3 * k / 2 + S.Half) / 2)
# issue 6153
assert gammasimp(gamma(S(1) / 4) / gamma(S(5) / 4)) == 4
# was part of test_combsimp() in test_combsimp.py
assert gammasimp(binomial(n + 2, k + S(1)/2)) == gamma(n + 3)/ \
(gamma(k + 3/2)*gamma(-k + n + 5/2))
assert gammasimp(binomial(n + 2, k + 2.0)) == \
gamma(n + 3)/(gamma(k + 3.0)*gamma(-k + n + 1))
# issue 11548
assert gammasimp(binomial(0, x)) == sin(pi * x) / (pi * x)
e = gamma(n + S(1) / 3) * gamma(n + S(2) / 3)
assert gammasimp(e) == e
assert gammasimp(gamma(4*n + S(1)/2)/gamma(2*n - S(3)/4)) == \
2**(4*n - S(5)/2)*(8*n - 3)*gamma(2*n + S(3)/4)/sqrt(pi)
i, m = symbols('i m', integer=True)
e = gamma(exp(i))
assert gammasimp(e) == e
e = gamma(m + 3)
assert gammasimp(e) == e
e = gamma(m + 1) / (gamma(i + 1) * gamma(-i + m + 1))
assert gammasimp(e) == e
def test_F2():
assert expand_func(binomial(n, 3)) == n * (n - 1) * (n - 2) / 6
def test_issue_15943():
s = Sum(binomial(n, k) * factorial(n - k), (k, 0, n)).doit().rewrite(gamma)
assert s == -E * (n + 1) * gamma(n + 1) * lowergamma(
n + 1, 1) / gamma(n + 2) + E * gamma(n + 1)
assert s.simplify() == E * (factorial(n) - lowergamma(n + 1, 1))
def test_binomial():
n = Symbol('n', integer=True)
nz = Symbol('nz', integer=True, nonzero=True)
k = Symbol('k', integer=True)
kp = Symbol('kp', integer=True, positive=True)
u = Symbol('v', negative=True)
p = Symbol('p', positive=True)
assert binomial(0, 0) == 1
assert binomial(1, 1) == 1
assert binomial(10, 10) == 1
assert binomial(1, 2) == 0
assert binomial(1, -1) == 0
assert binomial(-1, 1) == -1
assert binomial(-1, -1) == 1
assert binomial(S.Half, S.Half) == 1
assert binomial(-10, 1) == -10
assert binomial(-10, 7) == -11440
assert binomial(n, -1).func == binomial
assert binomial(kp, -1) == 0
assert binomial(nz, 0) == 1
assert binomial(n, 0).func == binomial
assert expand_func(binomial(n, 1)) == n
assert expand_func(binomial(n, 2)) == n * (n - 1) / 2
assert expand_func(binomial(n, n - 2)) == n * (n - 1) / 2
assert expand_func(binomial(n, n - 1)) == n
assert binomial(n, 3).func == binomial
assert binomial(n, 3).expand(func=True) == n**3 / 6 - n**2 / 2 + n / 3
assert expand_func(binomial(n, 3)) == n * (n - 2) * (n - 1) / 6
assert binomial(n, n) == 1
assert binomial(n, n + 1).func == binomial # e.g. (-1, 0) == 1
assert binomial(kp, kp + 1) == 0
assert binomial(n, u).func == binomial
assert binomial(kp, u) == 0
assert binomial(n, p).func == binomial
assert binomial(n, k).func == binomial
assert binomial(n, n + p).func == binomial
assert binomial(kp, kp + p) == 0
assert expand_func(binomial(n, n - 3)) == n * (n - 2) * (n - 1) / 6
assert binomial(n, k).is_integer
def create_mgf_expr(self, coal_rates, migration_rates, initial_config):
""" Generates the mgf, only should be called by __init__
Arguments:
coal_rates -- a list giving the coalescent rate in each deme
ex: [1, 1]
migration_rates -- a matrix giving the migration rates from each deme to each other deme
ex: sympy.Matrix([[0, 1], [1, 0]])
initial_config -- a list giving the starting configuration of the lineages
ex: [ [[1], [2]], [[3]] ]
"""
Eqns = []
num_demes = len(coal_rates)
# Get all partitions of starting lineages aka all coalescent states
indv_partitions = list(partition(self.lineages))
indv_partitions.remove([[
individual for lineage in self.lineages for individual in lineage
]])
deme_partitions = [
deme_part for indv_partition in indv_partitions
for deme_part in deme_partition(indv_partition, num_demes)
]
print("There are " + str(len(deme_partitions)) + " possible states.")
print("Setting up a system of " + str(len(deme_partitions)) +
" equations...")
deme_part_symbols = []
all_symbols = []
for deme_part in deme_partitions:
print("Working with partition: " + str(deme_part))
deme_part_symbol = deme_part_to_symbol(deme_part)
deme_part_symbols.append(deme_part_symbol)
all_symbols.append(deme_part_symbol)
# Make the factor for this partition
print("Creating the factor for this partition")
deme_part_factor = sympy.Integer(0)
for deme_idx, deme in enumerate(deme_part):
n_deme_lineages = len(deme)
deme_part_factor += sympy.binomial(n_deme_lineages,
2) * coal_rates[deme_idx]
for other_deme_idx in range(num_demes):
if deme_idx != other_deme_idx:
deme_part_factor += n_deme_lineages * migration_rates[
deme_idx, other_deme_idx]
for lineage in deme:
deme_part_factor -= sympy.symbols(
's_' + '.'.join([str(tip) for tip in sorted(lineage)]))
# Add the left side in (sign is negative, see eq 8 Lohse et al.)
deme_part_eqn = -deme_part_factor * deme_part_symbol
# sympy.pprint(deme_part_eqn)
# Add the transfer rates to coalescent states
print("Adding rates to other coal states")
for deme_idx, deme in enumerate(deme_part):
for pair in itertools.combinations(deme, 2):
# If only two lineages left, the next coal event reduces us to one
if sum([len(deme_lins) for deme_lins in deme_part]) == 2:
symbol_after_coal = sympy.Integer(1)
else:
symbol_after_coal = deme_part_symbol_after_coal(
deme_part, pair)
all_symbols.append(symbol_after_coal)
deme_part_eqn += coal_rates[deme_idx] * symbol_after_coal
# Add the transfer rates for migration events
print("Adding rates to other migration states")
for deme_idx, deme in enumerate(deme_part):
# For each lineage in the deme add a term for the probability of that lineage
# immigrating to each other deme
for lin in deme:
for deme_to_idx in range(num_demes):
deme_part_eqn += (
migration_rates[deme_idx, deme_to_idx] *
deme_part_symbol_after_migr(
deme_part, lin, deme_idx, deme_to_idx))
all_symbols.append(
deme_part_symbol_after_migr(
deme_part, lin, deme_idx, deme_to_idx))
print("Done! Adding this to the list of equations")
Eqns.append(deme_part_eqn)
print("The terms being solved for are:")
for deme_part_symbol in deme_part_symbols:
sympy.pprint(deme_part_symbol)
all_symbols = set(all_symbols)
print("There are " + str(len(all_symbols)) +
" terms in the system of equation")
for symbol in all_symbols:
sympy.pprint(symbol)
starting_part = deme_part_to_symbol(initial_config)
starting_idx = deme_part_symbols.index(starting_part)
print('Solving system of equations...')
mgf_solution = sympy.linsolve(Eqns, *deme_part_symbols)
return list(mgf_solution)[0][starting_idx]
def solve():
return sum(
int(binomial(n, r)) > 1_000_000 for n in range(1, LIMIT + 1)
for r in range(1, n))
def test_combsimp():
k, m, n = symbols('k m n', integer=True)
assert combsimp(factorial(n)) == factorial(n)
assert combsimp(binomial(n, k)) == binomial(n, k)
assert combsimp(factorial(n) / factorial(n - 3)) == n * (-1 + n) * (-2 + n)
assert combsimp(binomial(n + 1, k + 1) /
binomial(n, k)) == (1 + n) / (1 + k)
assert combsimp(binomial(3*n + 4, n + 1)/binomial(3*n + 1, n)) == \
Rational(3, 2)*((3*n + 2)*(3*n + 4)/((n + 1)*(2*n + 3)))
assert combsimp(factorial(n)**2/factorial(n - 3)) == \
factorial(n)*n*(-1 + n)*(-2 + n)
assert combsimp(factorial(n)*binomial(n + 1, k + 1)/binomial(n, k)) == \
factorial(n + 1)/(1 + k)
assert combsimp(gamma(n + 3)) == factorial(n + 2)
assert combsimp(factorial(x)) == gamma(x + 1)
# issue 9699
assert combsimp((n + 1) * factorial(n)) == factorial(n + 1)
assert combsimp(factorial(n) / n) == factorial(n - 1)
# issue 6658
assert combsimp(binomial(n, n - k)) == binomial(n, k)
# issue 6341, 7135
assert combsimp(factorial(n)/(factorial(k)*factorial(n - k))) == \
binomial(n, k)
assert combsimp(factorial(k)*factorial(n - k)/factorial(n)) == \
1/binomial(n, k)
assert combsimp(factorial(2 * n) / factorial(n)**2) == binomial(2 * n, n)
assert combsimp(
factorial(2 * n) * factorial(k) * factorial(n - k) /
factorial(n)**3) == binomial(2 * n, n) / binomial(n, k)
assert combsimp(factorial(n * (1 + n) - n**2 - n)) == 1
assert combsimp(6*FallingFactorial(-4, n)/factorial(n)) == \
(-1)**n*(n + 1)*(n + 2)*(n + 3)
assert combsimp(6*FallingFactorial(-4, n - 1)/factorial(n - 1)) == \
(-1)**(n - 1)*n*(n + 1)*(n + 2)
assert combsimp(6*FallingFactorial(-4, n - 3)/factorial(n - 3)) == \
(-1)**(n - 3)*n*(n - 1)*(n - 2)
assert combsimp(6*FallingFactorial(-4, -n - 1)/factorial(-n - 1)) == \
-(-1)**(-n - 1)*n*(n - 1)*(n - 2)
assert combsimp(6*RisingFactorial(4, n)/factorial(n)) == \
(n + 1)*(n + 2)*(n + 3)
assert combsimp(6*RisingFactorial(4, n - 1)/factorial(n - 1)) == \
n*(n + 1)*(n + 2)
assert combsimp(6*RisingFactorial(4, n - 3)/factorial(n - 3)) == \
n*(n - 1)*(n - 2)
assert combsimp(6*RisingFactorial(4, -n - 1)/factorial(-n - 1)) == \
-n*(n - 1)*(n - 2)
def convert_binom(binom):
expr_top = convert_expr(binom.upper)
expr_bot = convert_expr(binom.lower)
return sympy.binomial(expr_top, expr_bot)
def test_issue_16722():
z = symbols('z', positive=True)
assert limit(binomial(n + z, n)*n**-z, n, oo) == 1/gamma(z + 1)
z = symbols('z', positive=True, integer=True)
assert limit(binomial(n + z, n)*n**-z, n, oo) == 1/gamma(z + 1)
def main():
tokens = [
Expression(1),
Expression(2),
Expression(3),
Expression(5),
Expression(-1),
Expression(I),
Expression(E),
Expression(PI),
Operation('Add', lambda x, y: sympy.Add(x, y)),
Operation('Sub',
lambda x, y: sympy.Add(x, sympy.Mul(sympy.Integer(-1), y))),
Operation('Mul', lambda x, y: sympy.Mul(x, y)),
Operation('Div',
lambda x, y: sympy.Mul(x, sympy.Pow(y, sympy.Integer(-1)))),
Operation('Pow', lambda x, y: sympy.Pow(x, y)),
]
# increment this to expand the search...
# small increases in this explode the search space
stack_size = 3
# the number we're looking for
target = 14.134725141734693790457251983562470270784257115699243175685567460149963429809256764949010393171561012779202971548797436766142691469882254582505363239447137780413381237205970549621955865860200555566725836010773700205410982661507542780517442591306254481978651072304938725629738321577420395215725674809332140034990468034346267314420920377385487141378317356396995365428113079680531491688529067820822980492643386667346233200787587617920056048680543568014444246510655975686659032286865105448594443206240727270320942745222130487487209241238514183514605427901524478338354254533440044879368067616973008190007313938549837362150130451672696838920039176285123212854220523969133425832275335164060169763527563758969537674920336127209259991730427075683087951184453489180086300826483125169112710682910523759617977431815170713545316775495153828937849036474709727019948485532209253574357909226125247736595518016975233461213977316005354125926747455725877801472609830808978600712532087509395997966660675378381214891908864977277554420656532052405
# cant forget to optimize -- keep a hash table of already-computed answers
memoize_dict = {}
# keep a list of the best guesses
best_guesses = []
max_best_guesses = 10
# test to make sure phi works
phi = 1.6180339887498948482
test_args = [
Expression(2),
Expression(1),
Expression(2),
Expression(1),
Operation('Div',
lambda x, y: sympy.Mul(x, sympy.Pow(y, sympy.Integer(-1)))),
Expression(5),
Operation('Pow', lambda x, y: sympy.Pow(x, y)),
Operation('Add', lambda x, y: sympy.Add(x, y)),
Operation('Div',
lambda x, y: sympy.Mul(x, sympy.Pow(y, sympy.Integer(-1)))),
]
test = reduce(test_args[::-1])
test_tolerance = 0.000000001
assert (test - phi < test_tolerance)
# brute force the maths
# ... forever
while True:
# we want updates to know how far along we are
total_iters = binomial(len(tokens) + stack_size - 1,
stack_size) * sympy.factorial(stack_size)
i = 0
last_percent = 0.0
for args in itertools.combinations_with_replacement(
tokens, stack_size):
for perms in itertools.permutations(args):
# update our progress, if we've made enough progress
percent_done = float(i) / float(total_iters)
if (percent_done) - last_percent > 0.01:
print('[{} / %{:02}] {}'.format(
stack_size, int(percent_done * 100),
best_guesses[0] if best_guesses else 'No Guesses'))
last_percent = percent_done
i += 1
if str(perms) in memoize_dict:
continue
if not is_valid_rpn(perms):
memoize_dict[str(perms)] = 'INVALID'
continue
try:
expression = reduce(list(perms))
except:
continue
if str(expression) in memoize_dict:
# check to see if we've already done the work
guess = memoize_dict[str(perms)]
else:
# otherwise, calculate the result and record the answer
guess = expression.evalf()
memoize_dict[str(perms)] = guess
# how good of a guess was this?
delta = sympy.Abs(guess - target)
try:
best_guesses = sorted(
best_guesses + [(delta, guess, perms)],
key=lambda x: x[0])[:max_best_guesses]
except:
continue
print('done after: {}'.format(i))
print('stack size: {}'.format(stack_size))
pprint.pprint(best_guesses)
stack_size += 1
return
def pdf(self, k):
r = self.r
p = self.p
return binomial(k + r - 1, k) * (1 - p)**r * p**k
def test_combsimp():
from sympy.abc import n, k
assert combsimp(factorial(n)) == factorial(n)
assert combsimp(binomial(n, k)) == binomial(n, k)
assert combsimp(factorial(n) / factorial(n - 3)) == n * (-1 + n) * (-2 + n)
assert combsimp(binomial(n + 1, k + 1) /
binomial(n, k)) == (1 + n) / (1 + k)
assert combsimp(binomial(3*n + 4, n + 1)/binomial(3*n + 1, n)) == \
S(3)/2*((3*n + 2)*(3*n + 4)/((n + 1)*(2*n + 3)))
assert combsimp(factorial(n)**2 /
factorial(n - 3)) == factorial(n) * n * (-1 + n) * (-2 + n)
assert combsimp(factorial(n) * binomial(n + 1, k + 1) /
binomial(n, k)) == factorial(n) * (1 + n) / (1 + k)
assert combsimp(binomial(n - 1, k)) == -((-n + k) * binomial(n, k)) / n
assert combsimp(binomial(n + 2, k + S(1)/2)) == \
4*((n + 1)*(n + 2)*binomial(n, k + S(1)/2))/((2*k - 2*n - 1)*(2*k - 2*n - 3))
assert combsimp(binomial(n + 2, k + 2.0)) == \
-((1.0*n + 2.0)*binomial(n + 1.0, k + 2.0))/(k - n)
#!/usr/bin/env python3.6
"""
PROBLEM: 015
AUTHOR: Dirk Meijer
STATUS: done
EXPLANATION:
library solution
"""
from Euler.tictoc import *
from sympy import binomial
if __name__ == "__main__":
tic()
print(binomial(40, 20))
toc()
exit()
