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_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_expint(): from sympy.functions.elementary.miscellaneous import Max from sympy.functions.special.error_functions import (Ci, E1, Ei, Si) from sympy.functions.special.zeta_functions import lerchphi from sympy.simplify.simplify import simplify aneg = Symbol('a', negative=True) u = Symbol('u', polar=True) assert mellin_transform(E1(x), x, s) == (gamma(s)/s, (0, oo), True) assert inverse_mellin_transform(gamma(s)/s, s, x, (0, oo)).rewrite(expint).expand() == E1(x) assert mellin_transform(expint(a, x), x, s) == \ (gamma(s)/(a + s - 1), (Max(1 - re(a), 0), oo), True) # XXX IMT has hickups with complicated strips ... assert simplify(unpolarify( inverse_mellin_transform(gamma(s)/(aneg + s - 1), s, x, (1 - aneg, oo)).rewrite(expint).expand(func=True))) == \ expint(aneg, x) assert mellin_transform(Si(x), x, s) == \ (-2**s*sqrt(pi)*gamma(s/2 + S.Half)/( 2*s*gamma(-s/2 + 1)), (-1, 0), True) assert inverse_mellin_transform(-2**s*sqrt(pi)*gamma((s + 1)/2) /(2*s*gamma(-s/2 + 1)), s, x, (-1, 0)) \ == Si(x) assert mellin_transform(Ci(sqrt(x)), x, s) == \ (-2**(2*s - 1)*sqrt(pi)*gamma(s)/(s*gamma(-s + S.Half)), (0, 1), True) assert inverse_mellin_transform( -4**s*sqrt(pi)*gamma(s)/(2*s*gamma(-s + S.Half)), s, u, (0, 1)).expand() == Ci(sqrt(u)) # TODO LT of Si, Shi, Chi is a mess ... assert laplace_transform(Ci(x), x, s) == (-log(1 + s**2)/2/s, 0, True) assert laplace_transform(expint(a, x), x, s) == \ (lerchphi(s*exp_polar(I*pi), 1, a), 0, re(a) > S.Zero) assert laplace_transform(expint(1, x), x, s) == (log(s + 1)/s, 0, True) assert laplace_transform(expint(2, x), x, s) == \ ((s - log(s + 1))/s**2, 0, True) assert inverse_laplace_transform(-log(1 + s**2)/2/s, s, u).expand() == \ Heaviside(u)*Ci(u) assert inverse_laplace_transform(log(s + 1)/s, s, x).rewrite(expint) == \ Heaviside(x)*E1(x) assert inverse_laplace_transform((s - log(s + 1))/s**2, s, x).rewrite(expint).expand() == \ (expint(2, x)*Heaviside(x)).rewrite(Ei).rewrite(expint).expand()
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_integrate(): x = symbols('x') R, Dx = DifferentialOperators(ZZ.old_poly_ring(x), 'Dx') p = expr_to_holonomic(sin(x)**2 / x, x0=1).integrate((x, 2, 3)) q = '0.166270406994788' assert sstr(p) == q p = expr_to_holonomic(sin(x)).integrate((x, 0, x)).to_expr() q = 1 - cos(x) assert p == q p = expr_to_holonomic(sin(x)).integrate((x, 0, 3)) q = 1 - cos(3) assert p == q p = expr_to_holonomic(sin(x) / x, x0=1).integrate((x, 1, 2)) q = '0.659329913368450' assert sstr(p) == q p = expr_to_holonomic(sin(x)**2 / x, x0=1).integrate((x, 1, 0)) q = '-0.423690480850035' assert sstr(p) == q p = expr_to_holonomic(sin(x) / x) assert p.integrate(x).to_expr() == Si(x) assert p.integrate((x, 0, 2)) == Si(2) p = expr_to_holonomic(sin(x)**2 / x) q = p.to_expr() assert p.integrate(x).to_expr() == q.integrate((x, 0, x)) assert p.integrate((x, 0, 1)) == q.integrate((x, 0, 1)) assert expr_to_holonomic(1 / x, x0=1).integrate(x).to_expr() == log(x) p = expr_to_holonomic((x + 1)**3 * exp(-x), x0=-1).integrate(x).to_expr() q = (-x**3 - 6 * x**2 - 15 * x + 6 * exp(x + 1) - 16) * exp(-x) assert p == q p = expr_to_holonomic(cos(x)**2 / x**2, y0={ -2: [1, 0, -1] }).integrate(x).to_expr() q = -Si(2 * x) - cos(x)**2 / x assert p == q p = expr_to_holonomic(sqrt(x**2 + x)).integrate(x).to_expr() q = (x**Rational(3, 2) * (2 * x**2 + 3 * x + 1) - x * sqrt(x + 1) * asinh(sqrt(x))) / (4 * x * sqrt(x + 1)) assert p == q p = expr_to_holonomic(sqrt(x**2 + 1)).integrate(x).to_expr() q = (sqrt(x**2 + 1)).integrate(x) assert (p - q).simplify() == 0 p = expr_to_holonomic(1 / x**2, y0={-2: [1, 0, 0]}) r = expr_to_holonomic(1 / x**2, lenics=3) assert p == r q = expr_to_holonomic(cos(x)**2) assert (r * q).integrate(x).to_expr() == -Si(2 * x) - cos(x)**2 / x
def test_meijerg_lookup(): from sympy.functions.special.error_functions import (Ci, Si) from sympy.functions.special.gamma_functions import uppergamma assert hyperexpand(meijerg([a], [], [b, a], [], z)) == \ z**b*exp(z)*gamma(-a + b + 1)*uppergamma(a - b, z) assert hyperexpand(meijerg([0], [], [0, 0], [], z)) == \ exp(z)*uppergamma(0, z) assert can_do_meijer([a], [], [b, a + 1], []) assert can_do_meijer([a], [], [b + 2, a], []) assert can_do_meijer([a], [], [b - 2, a], []) assert hyperexpand(meijerg([a], [], [a, a, a - S.Half], [], z)) == \ -sqrt(pi)*z**(a - S.Half)*(2*cos(2*sqrt(z))*(Si(2*sqrt(z)) - pi/2) - 2*sin(2*sqrt(z))*Ci(2*sqrt(z))) == \ hyperexpand(meijerg([a], [], [a, a - S.Half, a], [], z)) == \ hyperexpand(meijerg([a], [], [a - S.Half, a, a], [], z)) assert can_do_meijer([a - 1], [], [a + 2, a - Rational(3, 2), a + 1], [])
def test_cosine_transform(): from sympy.functions.special.error_functions import (Ci, Si) t = symbols("t") w = symbols("w") a = symbols("a") f = Function("f") # Test unevaluated form assert cosine_transform(f(t), t, w) == CosineTransform(f(t), t, w) assert inverse_cosine_transform( f(w), w, t) == InverseCosineTransform(f(w), w, t) assert cosine_transform(1/sqrt(t), t, w) == 1/sqrt(w) assert inverse_cosine_transform(1/sqrt(w), w, t) == 1/sqrt(t) assert cosine_transform(1/( a**2 + t**2), t, w) == sqrt(2)*sqrt(pi)*exp(-a*w)/(2*a) assert cosine_transform(t**( -a), t, w) == 2**(-a + S.Half)*w**(a - 1)*gamma((-a + 1)/2)/gamma(a/2) assert inverse_cosine_transform(2**(-a + S( 1)/2)*w**(a - 1)*gamma(-a/2 + S.Half)/gamma(a/2), w, t) == t**(-a) assert cosine_transform( exp(-a*t), t, w) == sqrt(2)*a/(sqrt(pi)*(a**2 + w**2)) assert inverse_cosine_transform( sqrt(2)*a/(sqrt(pi)*(a**2 + w**2)), w, t) == exp(-a*t) assert cosine_transform(exp(-a*sqrt(t))*cos(a*sqrt( t)), t, w) == a*exp(-a**2/(2*w))/(2*w**Rational(3, 2)) assert cosine_transform(1/(a + t), t, w) == sqrt(2)*( (-2*Si(a*w) + pi)*sin(a*w)/2 - cos(a*w)*Ci(a*w))/sqrt(pi) assert inverse_cosine_transform(sqrt(2)*meijerg(((S.Half, 0), ()), ( (S.Half, 0, 0), (S.Half,)), a**2*w**2/4)/(2*pi), w, t) == 1/(a + t) assert cosine_transform(1/sqrt(a**2 + t**2), t, w) == sqrt(2)*meijerg( ((S.Half,), ()), ((0, 0), (S.Half,)), a**2*w**2/4)/(2*sqrt(pi)) assert inverse_cosine_transform(sqrt(2)*meijerg(((S.Half,), ()), ((0, 0), (S.Half,)), a**2*w**2/4)/(2*sqrt(pi)), w, t) == 1/(t*sqrt(a**2/t**2 + 1))
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_diff(): x, y = symbols('x, y') R, Dx = DifferentialOperators(ZZ.old_poly_ring(x), 'Dx') p = HolonomicFunction(x * Dx**2 + 1, x, 0, [0, 1]) assert p.diff().to_expr() == p.to_expr().diff().simplify() p = HolonomicFunction(Dx**2 - 1, x, 0, [1, 0]) assert p.diff(x, 2).to_expr() == p.to_expr() p = expr_to_holonomic(Si(x)) assert p.diff().to_expr() == sin(x) / x assert p.diff(y) == 0 C_0, C_1, C_2, C_3 = symbols('C_0, C_1, C_2, C_3') q = Si(x) assert p.diff(x).to_expr() == q.diff() assert p.diff(x, 2).to_expr().subs(C_0, Rational(-1, 3)).cancel() == q.diff( x, 2).cancel() assert p.diff(x, 3).series().subs({ C_3: Rational(-1, 3), C_0: 0 }) == q.diff(x, 3).series()
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