def test_expint():
assert mytn(expint(x, y), expint(x, y).rewrite(uppergamma),
y**(x - 1)*uppergamma(1 - x, y), x)
assert mytd(
expint(x, y), -y**(x - 1)*meijerg([], [1, 1], [0, 0, 1 - x], [], y), x)
assert mytd(expint(x, y), -expint(x - 1, y), y)
assert mytn(expint(1, x), expint(1, x).rewrite(Ei),
-Ei(x*polar_lift(-1)) + I*pi, x)
assert expint(-4, x) == exp(-x)/x + 4*exp(-x)/x**2 + 12*exp(-x)/x**3 \
+ 24*exp(-x)/x**4 + 24*exp(-x)/x**5
assert expint(Rational(-3, 2), x) == \
exp(-x)/x + 3*exp(-x)/(2*x**2) + 3*sqrt(pi)*erfc(sqrt(x))/(4*x**S('5/2'))
assert tn_branch(expint, 1)
assert tn_branch(expint, 2)
assert tn_branch(expint, 3)
assert tn_branch(expint, 1.7)
assert tn_branch(expint, pi)
assert expint(y, x*exp_polar(2*I*pi)) == \
x**(y - 1)*(exp(2*I*pi*y) - 1)*gamma(-y + 1) + expint(y, x)
assert expint(y, x*exp_polar(-2*I*pi)) == \
x**(y - 1)*(exp(-2*I*pi*y) - 1)*gamma(-y + 1) + expint(y, x)
assert expint(2, x*exp_polar(2*I*pi)) == 2*I*pi*x + expint(2, x)
assert expint(2, x*exp_polar(-2*I*pi)) == -2*I*pi*x + expint(2, x)
assert expint(1, x).rewrite(Ei).rewrite(expint) == expint(1, x)
assert expint(x, y).rewrite(Ei) == expint(x, y)
assert expint(x, y).rewrite(Ci) == expint(x, y)
assert mytn(E1(x), E1(x).rewrite(Shi), Shi(x) - Chi(x), x)
assert mytn(E1(polar_lift(I)*x), E1(polar_lift(I)*x).rewrite(Si),
-Ci(x) + I*Si(x) - I*pi/2, x)
assert mytn(expint(2, x), expint(2, x).rewrite(Ei).rewrite(expint),
-x*E1(x) + exp(-x), x)
assert mytn(expint(3, x), expint(3, x).rewrite(Ei).rewrite(expint),
x**2*E1(x)/2 + (1 - x)*exp(-x)/2, x)
assert expint(Rational(3, 2), z).nseries(z) == \
2 + 2*z - z**2/3 + z**3/15 - z**4/84 + z**5/540 - \
2*sqrt(pi)*sqrt(z) + O(z**6)
assert E1(z).series(z) == -EulerGamma - log(z) + z - \
z**2/4 + z**3/18 - z**4/96 + z**5/600 + O(z**6)
assert expint(4, z).series(z) == Rational(1, 3) - z/2 + z**2/2 + \
z**3*(log(z)/6 - Rational(11, 36) + EulerGamma/6 - I*pi/6) - z**4/24 + \
z**5/240 + O(z**6)
assert expint(n, x).series(x, oo, n=3) == \
(n*(n + 1)/x**2 - n/x + 1 + O(x**(-3), (x, oo)))*exp(-x)/x
assert expint(z, y).series(z, 0, 2) == exp(-y)/y - z*meijerg(((), (1, 1)),
((0, 0, 1), ()), y)/y + O(z**2)
raises(ArgumentIndexError, lambda: expint(x, y).fdiff(3))
neg = Symbol('neg', negative=True)
assert Ei(neg).rewrite(Si) == Shi(neg) + Chi(neg) - I*pi
def test_expint():
""" Test various exponential integrals. """
from sympy.core.symbol import Symbol
from sympy.functions.elementary.complexes import unpolarify
from sympy.functions.elementary.hyperbolic import sinh
from sympy.functions.special.error_functions import (Chi, Ci, Ei, Shi, Si,
expint)
assert simplify(
unpolarify(
integrate(exp(-z * x) / x**y, (x, 1, oo),
meijerg=True,
conds='none').rewrite(expint).expand(
func=True))) == expint(y, z)
assert integrate(exp(-z*x)/x, (x, 1, oo), meijerg=True,
conds='none').rewrite(expint).expand() == \
expint(1, z)
assert integrate(exp(-z*x)/x**2, (x, 1, oo), meijerg=True,
conds='none').rewrite(expint).expand() == \
expint(2, z).rewrite(Ei).rewrite(expint)
assert integrate(exp(-z*x)/x**3, (x, 1, oo), meijerg=True,
conds='none').rewrite(expint).expand() == \
expint(3, z).rewrite(Ei).rewrite(expint).expand()
t = Symbol('t', positive=True)
assert integrate(-cos(x) / x, (x, t, oo), meijerg=True).expand() == Ci(t)
assert integrate(-sin(x)/x, (x, t, oo), meijerg=True).expand() == \
Si(t) - pi/2
assert integrate(sin(x) / x, (x, 0, z), meijerg=True) == Si(z)
assert integrate(sinh(x) / x, (x, 0, z), meijerg=True) == Shi(z)
assert integrate(exp(-x)/x, x, meijerg=True).expand().rewrite(expint) == \
I*pi - expint(1, x)
assert integrate(exp(-x)/x**2, x, meijerg=True).rewrite(expint).expand() \
== expint(1, x) - exp(-x)/x - I*pi
u = Symbol('u', polar=True)
assert integrate(cos(u)/u, u, meijerg=True).expand().as_independent(u)[1] \
== Ci(u)
assert integrate(cosh(u)/u, u, meijerg=True).expand().as_independent(u)[1] \
== Chi(u)
assert integrate(
expint(1, x), x,
meijerg=True).rewrite(expint).expand() == x * expint(1, x) - exp(-x)
assert integrate(expint(2, x), x, meijerg=True
).rewrite(expint).expand() == \
-x**2*expint(1, x)/2 + x*exp(-x)/2 - exp(-x)/2
assert simplify(unpolarify(integrate(expint(y, x), x,
meijerg=True).rewrite(expint).expand(func=True))) == \
-expint(y + 1, x)
assert integrate(Si(x), x, meijerg=True) == x * Si(x) + cos(x)
assert integrate(Ci(u), u, meijerg=True).expand() == u * Ci(u) - sin(u)
assert integrate(Shi(x), x, meijerg=True) == x * Shi(x) - cosh(x)
assert integrate(Chi(u), u, meijerg=True).expand() == u * Chi(u) - sinh(u)
assert integrate(Si(x) * exp(-x), (x, 0, oo), meijerg=True) == pi / 4
assert integrate(expint(1, x) * sin(x), (x, 0, oo),
meijerg=True) == log(2) / 2
def test_ei():
assert Ei(0) is S.NegativeInfinity
assert Ei(oo) is S.Infinity
assert Ei(-oo) is S.Zero
assert tn_branch(Ei)
assert mytd(Ei(x), exp(x)/x, x)
assert mytn(Ei(x), Ei(x).rewrite(uppergamma),
-uppergamma(0, x*polar_lift(-1)) - I*pi, x)
assert mytn(Ei(x), Ei(x).rewrite(expint),
-expint(1, x*polar_lift(-1)) - I*pi, x)
assert Ei(x).rewrite(expint).rewrite(Ei) == Ei(x)
assert Ei(x*exp_polar(2*I*pi)) == Ei(x) + 2*I*pi
assert Ei(x*exp_polar(-2*I*pi)) == Ei(x) - 2*I*pi
assert mytn(Ei(x), Ei(x).rewrite(Shi), Chi(x) + Shi(x), x)
assert mytn(Ei(x*polar_lift(I)), Ei(x*polar_lift(I)).rewrite(Si),
Ci(x) + I*Si(x) + I*pi/2, x)
assert Ei(log(x)).rewrite(li) == li(x)
assert Ei(2*log(x)).rewrite(li) == li(x**2)
assert gruntz(Ei(x+exp(-x))*exp(-x)*x, x, oo) == 1
assert Ei(x).series(x) == EulerGamma + log(x) + x + x**2/4 + \
x**3/18 + x**4/96 + x**5/600 + O(x**6)
assert Ei(x).series(x, 1, 3) == Ei(1) + E*(x - 1) + O((x - 1)**3, (x, 1))
assert Ei(x).series(x, oo) == \
(120/x**5 + 24/x**4 + 6/x**3 + 2/x**2 + 1/x + 1 + O(x**(-6), (x, oo)))*exp(x)/x
assert str(Ei(cos(2)).evalf(n=10)) == '-0.6760647401'
raises(ArgumentIndexError, lambda: Ei(x).fdiff(2))
def test_manualintegrate_special():
f, F = 4*exp(-x**2/3), 2*sqrt(3)*sqrt(pi)*erf(sqrt(3)*x/3)
assert_is_integral_of(f, F)
f, F = 3*exp(4*x**2), 3*sqrt(pi)*erfi(2*x)/4
assert_is_integral_of(f, F)
f, F = x**Rational(1, 3)*exp(-x/8), -16*uppergamma(Rational(4, 3), x/8)
assert_is_integral_of(f, F)
f, F = exp(2*x)/x, Ei(2*x)
assert_is_integral_of(f, F)
f, F = exp(1 + 2*x - x**2), sqrt(pi)*exp(2)*erf(x - 1)/2
assert_is_integral_of(f, F)
f = sin(x**2 + 4*x + 1)
F = (sqrt(2)*sqrt(pi)*(-sin(3)*fresnelc(sqrt(2)*(2*x + 4)/(2*sqrt(pi))) +
cos(3)*fresnels(sqrt(2)*(2*x + 4)/(2*sqrt(pi))))/2)
assert_is_integral_of(f, F)
f, F = cos(4*x**2), sqrt(2)*sqrt(pi)*fresnelc(2*sqrt(2)*x/sqrt(pi))/4
assert_is_integral_of(f, F)
f, F = sin(3*x + 2)/x, sin(2)*Ci(3*x) + cos(2)*Si(3*x)
assert_is_integral_of(f, F)
f, F = sinh(3*x - 2)/x, -sinh(2)*Chi(3*x) + cosh(2)*Shi(3*x)
assert_is_integral_of(f, F)
f, F = 5*cos(2*x - 3)/x, 5*cos(3)*Ci(2*x) + 5*sin(3)*Si(2*x)
assert_is_integral_of(f, F)
f, F = cosh(x/2)/x, Chi(x/2)
assert_is_integral_of(f, F)
f, F = cos(x**2)/x, Ci(x**2)/2
assert_is_integral_of(f, F)
f, F = 1/log(2*x + 1), li(2*x + 1)/2
assert_is_integral_of(f, F)
f, F = polylog(2, 5*x)/x, polylog(3, 5*x)
assert_is_integral_of(f, F)
f, F = 5/sqrt(3 - 2*sin(x)**2), 5*sqrt(3)*elliptic_f(x, Rational(2, 3))/3
assert_is_integral_of(f, F)
f, F = sqrt(4 + 9*sin(x)**2), 2*elliptic_e(x, Rational(-9, 4))
assert_is_integral_of(f, F)
def test_li():
z = Symbol("z")
zr = Symbol("z", real=True)
zp = Symbol("z", positive=True)
zn = Symbol("z", negative=True)
assert li(0) is S.Zero
assert li(1) is -oo
assert li(oo) is oo
assert isinstance(li(z), li)
assert unchanged(li, -zp)
assert unchanged(li, zn)
assert diff(li(z), z) == 1/log(z)
assert conjugate(li(z)) == li(conjugate(z))
assert conjugate(li(-zr)) == li(-zr)
assert unchanged(conjugate, li(-zp))
assert unchanged(conjugate, li(zn))
assert li(z).rewrite(Li) == Li(z) + li(2)
assert li(z).rewrite(Ei) == Ei(log(z))
assert li(z).rewrite(uppergamma) == (-log(1/log(z))/2 - log(-log(z)) +
log(log(z))/2 - expint(1, -log(z)))
assert li(z).rewrite(Si) == (-log(I*log(z)) - log(1/log(z))/2 +
log(log(z))/2 + Ci(I*log(z)) + Shi(log(z)))
assert li(z).rewrite(Ci) == (-log(I*log(z)) - log(1/log(z))/2 +
log(log(z))/2 + Ci(I*log(z)) + Shi(log(z)))
assert li(z).rewrite(Shi) == (-log(1/log(z))/2 + log(log(z))/2 +
Chi(log(z)) - Shi(log(z)))
assert li(z).rewrite(Chi) == (-log(1/log(z))/2 + log(log(z))/2 +
Chi(log(z)) - Shi(log(z)))
assert li(z).rewrite(hyper) ==(log(z)*hyper((1, 1), (2, 2), log(z)) -
log(1/log(z))/2 + log(log(z))/2 + EulerGamma)
assert li(z).rewrite(meijerg) == (-log(1/log(z))/2 - log(-log(z)) + log(log(z))/2 -
meijerg(((), (1,)), ((0, 0), ()), -log(z)))
assert gruntz(1/li(z), z, oo) is S.Zero
assert li(z).series(z) == log(z)**5/600 + log(z)**4/96 + log(z)**3/18 + log(z)**2/4 + \
log(z) + log(log(z)) + EulerGamma
raises(ArgumentIndexError, lambda: li(z).fdiff(2))
def test_Function_change_name():
assert mcode(abs(x)) == "abs(x)"
assert mcode(ceiling(x)) == "ceil(x)"
assert mcode(arg(x)) == "angle(x)"
assert mcode(im(x)) == "imag(x)"
assert mcode(re(x)) == "real(x)"
assert mcode(conjugate(x)) == "conj(x)"
assert mcode(chebyshevt(y, x)) == "chebyshevT(y, x)"
assert mcode(chebyshevu(y, x)) == "chebyshevU(y, x)"
assert mcode(laguerre(x, y)) == "laguerreL(x, y)"
assert mcode(Chi(x)) == "coshint(x)"
assert mcode(Shi(x)) == "sinhint(x)"
assert mcode(Ci(x)) == "cosint(x)"
assert mcode(Si(x)) == "sinint(x)"
assert mcode(li(x)) == "logint(x)"
assert mcode(loggamma(x)) == "gammaln(x)"
assert mcode(polygamma(x, y)) == "psi(x, y)"
assert mcode(RisingFactorial(x, y)) == "pochhammer(x, y)"
assert mcode(DiracDelta(x)) == "dirac(x)"
assert mcode(DiracDelta(x, 3)) == "dirac(3, x)"
assert mcode(Heaviside(x)) == "heaviside(x)"
assert mcode(Heaviside(x, y)) == "heaviside(x, y)"
def test_messy():
from sympy.functions.elementary.complexes import re
from sympy.functions.elementary.hyperbolic import (acosh, acoth)
from sympy.functions.elementary.piecewise import Piecewise
from sympy.functions.elementary.trigonometric import (asin, atan)
from sympy.functions.special.bessel import besselj
from sympy.functions.special.error_functions import (Chi, E1, Shi, Si)
from sympy.integrals.transforms import (fourier_transform,
laplace_transform)
assert laplace_transform(Si(x), x, s) == ((-atan(s) + pi / 2) / s, 0, True)
assert laplace_transform(Shi(x), x, s) == (acoth(s) / s, -oo, s**2 > 1)
# where should the logs be simplified?
assert laplace_transform(Chi(x), x,
s) == ((log(s**(-2)) - log(1 - 1 / s**2)) /
(2 * s), -oo, s**2 > 1)
# TODO maybe simplify the inequalities? when the simplification
# allows for generators instead of symbols this will work
assert laplace_transform(besselj(a, x), x, s)[1:] == \
(0, (re(a) > -2) & (re(a) > -1))
# NOTE s < 0 can be done, but argument reduction is not good enough yet
ans = fourier_transform(besselj(1, x) / x, x, s, noconds=False)
assert tuple([ans[0].factor(deep=True).expand(), ans[1]]) == \
(Piecewise((0, (s > 1/(2*pi)) | (s < -1/(2*pi))),
(2*sqrt(-4*pi**2*s**2 + 1), True)), s > 0)
# TODO FT(besselj(0,x)) - conditions are messy (but for acceptable reasons)
# - folding could be better
assert integrate(E1(x)*besselj(0, x), (x, 0, oo), meijerg=True) == \
log(1 + sqrt(2))
assert integrate(E1(x)*besselj(1, x), (x, 0, oo), meijerg=True) == \
log(S.Half + sqrt(2)/2)
assert integrate(1/x/sqrt(1 - x**2), x, meijerg=True) == \
Piecewise((-acosh(1/x), abs(x**(-2)) > 1), (I*asin(1/x), True))
def test_si():
assert Si(I*x) == I*Shi(x)
assert Shi(I*x) == I*Si(x)
assert Si(-I*x) == -I*Shi(x)
assert Shi(-I*x) == -I*Si(x)
assert Si(-x) == -Si(x)
assert Shi(-x) == -Shi(x)
assert Si(exp_polar(2*pi*I)*x) == Si(x)
assert Si(exp_polar(-2*pi*I)*x) == Si(x)
assert Shi(exp_polar(2*pi*I)*x) == Shi(x)
assert Shi(exp_polar(-2*pi*I)*x) == Shi(x)
assert Si(oo) == pi/2
assert Si(-oo) == -pi/2
assert Shi(oo) is oo
assert Shi(-oo) is -oo
assert mytd(Si(x), sin(x)/x, x)
assert mytd(Shi(x), sinh(x)/x, x)
assert mytn(Si(x), Si(x).rewrite(Ei),
-I*(-Ei(x*exp_polar(-I*pi/2))/2
+ Ei(x*exp_polar(I*pi/2))/2 - I*pi) + pi/2, x)
assert mytn(Si(x), Si(x).rewrite(expint),
-I*(-expint(1, x*exp_polar(-I*pi/2))/2 +
expint(1, x*exp_polar(I*pi/2))/2) + pi/2, x)
assert mytn(Shi(x), Shi(x).rewrite(Ei),
Ei(x)/2 - Ei(x*exp_polar(I*pi))/2 + I*pi/2, x)
assert mytn(Shi(x), Shi(x).rewrite(expint),
expint(1, x)/2 - expint(1, x*exp_polar(I*pi))/2 - I*pi/2, x)
assert tn_arg(Si)
assert tn_arg(Shi)
assert Si(x).nseries(x, n=8) == \
x - x**3/18 + x**5/600 - x**7/35280 + O(x**9)
assert Shi(x).nseries(x, n=8) == \
x + x**3/18 + x**5/600 + x**7/35280 + O(x**9)
assert Si(sin(x)).nseries(x, n=5) == x - 2*x**3/9 + 17*x**5/450 + O(x**6)
assert Si(x).nseries(x, 1, n=3) == \
Si(1) + (x - 1)*sin(1) + (x - 1)**2*(-sin(1)/2 + cos(1)/2) + O((x - 1)**3, (x, 1))
assert Si(x).series(x, oo) == pi/2 - (- 6/x**3 + 1/x \
+ O(x**(-7), (x, oo)))*sin(x)/x - (24/x**4 - 2/x**2 + 1 \
+ O(x**(-7), (x, oo)))*cos(x)/x
t = Symbol('t', Dummy=True)
assert Si(x).rewrite(sinc) == Integral(sinc(t), (t, 0, x))
assert limit(Shi(x), x, S.NegativeInfinity) == -I*pi/2