def test_issue_17671():
assert limit(Ei(-log(x)) - log(log(x)) / x, x, 1) == EulerGamma
def test_nth_algebraic_noprep2():
eqn = Eq(Derivative(x*Derivative(f(x), x), x)/x, exp(x))
sol = Eq(f(x), C1 + C2*log(x) + exp(x) - Ei(x))
assert checkodesol(eqn, sol, order=2, solve_for_func=False)[0]
assert sol == dsolve(eqn, f(x), prep=False, hint='nth_algebraic')
def test_issue_3583():
assert gruntz(exp(2 * Ei(-x)) / x**2, x, 0) == exp(2 * EulerGamma)
def test_manualintegrate_trivial_substitution():
assert manualintegrate((exp(x) - exp(-x)) / x, x) == -Ei(-x) + Ei(x)
f = Function('f')
assert manualintegrate((f(x) - f(-x))/x, x) == \
-Integral(f(-x)/x, x) + Integral(f(x)/x, x)
def test_ei():
pos = Symbol('p', positive=True)
neg = Symbol('n', negative=True)
assert Ei(-pos) == Ei(polar_lift(-1) * pos) - I * pi
assert Ei(neg) == Ei(polar_lift(neg)) - I * pi
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)
def test_latex_functions():
assert latex(exp(x)) == "e^{x}"
assert latex(exp(1) + exp(2)) == "e + e^{2}"
f = Function('f')
assert latex(f(x)) == '\\operatorname{f}{\\left (x \\right )}'
beta = Function('beta')
assert latex(beta(x)) == r"\beta{\left (x \right )}"
assert latex(sin(x)) == r"\sin{\left (x \right )}"
assert latex(sin(x), fold_func_brackets=True) == r"\sin {x}"
assert latex(sin(2*x**2), fold_func_brackets=True) == \
r"\sin {2 x^{2}}"
assert latex(sin(x**2), fold_func_brackets=True) == \
r"\sin {x^{2}}"
assert latex(asin(x)**2) == r"\operatorname{asin}^{2}{\left (x \right )}"
assert latex(asin(x)**2, inv_trig_style="full") == \
r"\arcsin^{2}{\left (x \right )}"
assert latex(asin(x)**2, inv_trig_style="power") == \
r"\sin^{-1}{\left (x \right )}^{2}"
assert latex(asin(x**2), inv_trig_style="power",
fold_func_brackets=True) == \
r"\sin^{-1} {x^{2}}"
assert latex(factorial(k)) == r"k!"
assert latex(factorial(-k)) == r"\left(- k\right)!"
assert latex(factorial2(k)) == r"k!!"
assert latex(factorial2(-k)) == r"\left(- k\right)!!"
assert latex(binomial(2, k)) == r"{\binom{2}{k}}"
assert latex(FallingFactorial(3,
k)) == r"{\left(3\right)}_{\left(k\right)}"
assert latex(RisingFactorial(3, k)) == r"{\left(3\right)}^{\left(k\right)}"
assert latex(floor(x)) == r"\lfloor{x}\rfloor"
assert latex(ceiling(x)) == r"\lceil{x}\rceil"
assert latex(Min(x, 2, x**3)) == r"\min\left(2, x, x^{3}\right)"
assert latex(Max(x, 2, x**3)) == r"\max\left(2, x, x^{3}\right)"
assert latex(Abs(x)) == r"\lvert{x}\rvert"
assert latex(re(x)) == r"\Re{x}"
assert latex(re(x + y)) == r"\Re{x} + \Re{y}"
assert latex(im(x)) == r"\Im{x}"
assert latex(conjugate(x)) == r"\overline{x}"
assert latex(gamma(x)) == r"\Gamma\left(x\right)"
assert latex(Order(x)) == r"\mathcal{O}\left(x\right)"
assert latex(lowergamma(x, y)) == r'\gamma\left(x, y\right)'
assert latex(uppergamma(x, y)) == r'\Gamma\left(x, y\right)'
assert latex(cot(x)) == r'\cot{\left (x \right )}'
assert latex(coth(x)) == r'\coth{\left (x \right )}'
assert latex(re(x)) == r'\Re{x}'
assert latex(im(x)) == r'\Im{x}'
assert latex(root(x, y)) == r'x^{\frac{1}{y}}'
assert latex(arg(x)) == r'\arg{\left (x \right )}'
assert latex(zeta(x)) == r'\zeta\left(x\right)'
assert latex(zeta(x)) == r"\zeta\left(x\right)"
assert latex(zeta(x)**2) == r"\zeta^{2}\left(x\right)"
assert latex(zeta(x, y)) == r"\zeta\left(x, y\right)"
assert latex(zeta(x, y)**2) == r"\zeta^{2}\left(x, y\right)"
assert latex(dirichlet_eta(x)) == r"\eta\left(x\right)"
assert latex(dirichlet_eta(x)**2) == r"\eta^{2}\left(x\right)"
assert latex(polylog(x, y)) == r"\operatorname{Li}_{x}\left(y\right)"
assert latex(polylog(x,
y)**2) == r"\operatorname{Li}_{x}^{2}\left(y\right)"
assert latex(lerchphi(x, y, n)) == r"\Phi\left(x, y, n\right)"
assert latex(lerchphi(x, y, n)**2) == r"\Phi^{2}\left(x, y, n\right)"
assert latex(Ei(x)) == r'\operatorname{Ei}{\left (x \right )}'
assert latex(Ei(x)**2) == r'\operatorname{Ei}^{2}{\left (x \right )}'
assert latex(expint(x, y)**2) == r'\operatorname{E}_{x}^{2}\left(y\right)'
assert latex(Shi(x)**2) == r'\operatorname{Shi}^{2}{\left (x \right )}'
assert latex(Si(x)**2) == r'\operatorname{Si}^{2}{\left (x \right )}'
assert latex(Ci(x)**2) == r'\operatorname{Ci}^{2}{\left (x \right )}'
assert latex(Chi(x)**2) == r'\operatorname{Chi}^{2}{\left (x \right )}'
# Test latex printing of function names with "_"
assert latex(
polar_lift(0)) == r"\operatorname{polar\_lift}{\left (0 \right )}"
assert latex(polar_lift(0)**
3) == r"\operatorname{polar\_lift}^{3}{\left (0 \right )}"
def _get_examples_ode_sol_nth_algebraic():
M, m, r, t = symbols('M m r t')
phi = Function('phi')
# This one needs a substitution f' = g.
# 'algeb_12': {
# 'eq': -exp(x) + (x*Derivative(f(x), (x, 2)) + Derivative(f(x), x))/x,
# 'sol': [Eq(f(x), C1 + C2*log(x) + exp(x) - Ei(x))],
# },
return {
'hint': "nth_algebraic",
'func': f(x),
'examples': {
'algeb_01': {
'eq':
f(x) * f(x).diff(x) * f(x).diff(x, x) * (f(x) - 1) *
(f(x).diff(x) - x),
'sol': [Eq(f(x), C1 + x**2 / 2),
Eq(f(x), C1 + C2 * x)]
},
'algeb_02': {
'eq': f(x) * f(x).diff(x) * f(x).diff(x, x) * (f(x) - 1),
'sol': [Eq(f(x), C1 + C2 * x)]
},
'algeb_03': {
'eq': f(x) * f(x).diff(x) * f(x).diff(x, x),
'sol': [Eq(f(x), C1 + C2 * x)]
},
'algeb_04': {
'eq':
Eq(
-M * phi(t).diff(t),
Rational(3, 2) * m * r**2 * phi(t).diff(t) *
phi(t).diff(t, t)),
'sol': [
Eq(phi(t), C1),
Eq(phi(t), C1 + C2 * t - M * t**2 / (3 * m * r**2))
],
'func':
phi(t)
},
'algeb_05': {
'eq': (1 - sin(f(x))) * f(x).diff(x),
'sol': [Eq(f(x), C1)],
'XFAIL': ['separable'] #It raised exception.
},
'algeb_06': {
'eq': (diff(f(x)) - x) * (diff(f(x)) + x),
'sol': [Eq(f(x), C1 - x**2 / 2),
Eq(f(x), C1 + x**2 / 2)]
},
'algeb_07': {
'eq': Eq(Derivative(f(x), x), Derivative(g(x), x)),
'sol': [Eq(f(x), C1 + g(x))],
},
'algeb_08': {
'eq': f(x).diff(x) - C1, #this example is from issue 15999
'sol': [Eq(f(x), C1 * x + C2)],
},
'algeb_09': {
'eq': f(x) * f(x).diff(x),
'sol': [Eq(f(x), C1)],
},
'algeb_10': {
'eq': (diff(f(x)) - x) * (diff(f(x)) + x),
'sol': [Eq(f(x), C1 - x**2 / 2),
Eq(f(x), C1 + x**2 / 2)],
},
'algeb_11': {
'eq':
f(x) + f(x) * f(x).diff(x),
'sol': [Eq(f(x), 0), Eq(f(x), C1 - x)],
'XFAIL': [
'separable', '1st_exact', '1st_linear', 'Bernoulli',
'1st_homogeneous_coeff_best',
'1st_homogeneous_coeff_subs_indep_div_dep',
'1st_homogeneous_coeff_subs_dep_div_indep', 'lie_group',
'nth_linear_constant_coeff_undetermined_coefficients',
'nth_linear_euler_eq_nonhomogeneous_undetermined_coefficients',
'nth_linear_constant_coeff_variation_of_parameters',
'nth_linear_euler_eq_nonhomogeneous_variation_of_parameters'
]
#nth_linear_constant_coeff_undetermined_coefficients raises exception rest all of them misses a solution.
},
'algeb_12': {
'eq': Derivative(x * f(x), x, x, x),
'sol': [Eq(f(x), (C1 + C2 * x + C3 * x**2) / x)],
'XFAIL': ['nth_algebraic'
] # It passes only when prep=False is set in dsolve.
},
'algeb_13': {
'eq': Eq(Derivative(x * Derivative(f(x), x), x) / x, exp(x)),
'sol': [Eq(f(x), C1 + C2 * log(x) + exp(x) - Ei(x))],
'XFAIL': ['nth_algebraic'
] # It passes only when prep=False is set in dsolve.
},
}
}
def test_checkodesol():
# For the most part, checkodesol is well tested in the tests below.
# These tests only handle cases not checked below.
raises(ValueError, lambda: checkodesol(f(x, y).diff(x), Eq(f(x, y), x)))
raises(ValueError,
lambda: checkodesol(f(x).diff(x), Eq(f(x, y), x), f(x, y)))
assert checkodesol(f(x).diff(x), Eq(f(x, y), x)) == (
False,
-f(x).diff(x) + f(x, y).diff(x) - 1,
)
assert checkodesol(f(x).diff(x), Eq(f(x), x)) is not True
assert checkodesol(f(x).diff(x), Eq(f(x), x)) == (False, 1)
sol1 = Eq(f(x)**5 + 11 * f(x) - 2 * f(x) + x, 0)
assert checkodesol(diff(sol1.lhs, x), sol1) == (True, 0)
assert checkodesol(diff(sol1.lhs, x) * exp(f(x)), sol1) == (True, 0)
assert checkodesol(diff(sol1.lhs, x, 2), sol1) == (True, 0)
assert checkodesol(diff(sol1.lhs, x, 2) * exp(f(x)), sol1) == (True, 0)
assert checkodesol(diff(sol1.lhs, x, 3), sol1) == (True, 0)
assert checkodesol(diff(sol1.lhs, x, 3) * exp(f(x)), sol1) == (True, 0)
assert checkodesol(diff(sol1.lhs, x, 3), Eq(f(x), x * log(x))) == (
False,
60 * x**4 * ((log(x) + 1)**2 + log(x)) * (log(x) + 1) * log(x)**2 -
5 * x**4 * log(x)**4 - 9,
)
assert checkodesol(diff(exp(f(x)) + x, x) * x, Eq(exp(f(x)) + x,
0)) == (True, 0)
assert checkodesol(diff(exp(f(x)) + x, x) * x,
Eq(exp(f(x)) + x, 0),
solve_for_func=False) == (True, 0)
assert checkodesol(
f(x).diff(x, 2),
[
Eq(f(x), C1 + C2 * x),
Eq(f(x), C2 + C1 * x),
Eq(f(x), C1 * x + C2 * x**2)
],
) == [(True, 0), (True, 0), (False, C2)]
assert checkodesol(
f(x).diff(x, 2),
set([
Eq(f(x), C1 + C2 * x),
Eq(f(x), C2 + C1 * x),
Eq(f(x), C1 * x + C2 * x**2),
]),
) == set([(True, 0), (True, 0), (False, C2)])
assert checkodesol(f(x).diff(x) - 1 / f(x) / 2, Eq(f(x)**2, x)) == [
(True, 0),
(True, 0),
]
assert checkodesol(f(x).diff(x) - f(x), Eq(C1 * exp(x), f(x))) == (True, 0)
# Based on test_1st_homogeneous_coeff_ode2_eq3sol. Make sure that
# checkodesol tries back substituting f(x) when it can.
eq3 = x * exp(f(x) / x) + f(x) - x * f(x).diff(x)
sol3 = Eq(f(x), log(log(C1 / x)**(-x)))
assert not checkodesol(eq3, sol3)[1].has(f(x))
# This case was failing intermittently depending on hash-seed:
eqn = Eq(Derivative(x * Derivative(f(x), x), x) / x, exp(x))
sol = Eq(f(x), C1 + C2 * log(x) + exp(x) - Ei(x))
assert checkodesol(eqn, sol, order=2, solve_for_func=False)[0]
eq = x**2 * (f(x).diff(x, 2)) + x * (f(x).diff(x)) + (2 * x**2 + 25) * f(x)
sol = Eq(
f(x),
C1 * besselj(5 * I,
sqrt(2) * x) + C2 * bessely(5 * I,
sqrt(2) * x))
assert checkodesol(eq, sol) == (True, 0)
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))
t = Symbol("t", Dummy=True)
assert Si(x).rewrite(sinc) == Integral(sinc(t), (t, 0, x))
def _get_examples_ode_sol_nth_order_reducible():
return {
'hint': "nth_order_reducible",
'func': f(x),
'examples':{
'reducible_01': {
'eq': Eq(x*Derivative(f(x), x)**2 + Derivative(f(x), x, 2), 0),
'sol': [Eq(f(x),C1 - sqrt(-1/C2)*log(-C2*sqrt(-1/C2) + x) +
sqrt(-1/C2)*log(C2*sqrt(-1/C2) + x))],
'slow': True,
},
'reducible_02': {
'eq': -exp(x) + (x*Derivative(f(x), (x, 2)) + Derivative(f(x), x))/x,
'sol': [Eq(f(x), C1 + C2*log(x) + exp(x) - Ei(x))],
'slow': True,
},
'reducible_03': {
'eq': Eq(sqrt(2) * f(x).diff(x,x,x) + f(x).diff(x), 0),
'sol': [Eq(f(x), C1 + C2*sin(2**Rational(3, 4)*x/2) + C3*cos(2**Rational(3, 4)*x/2))],
'slow': True,
},
'reducible_04': {
'eq': f(x).diff(x, 2) + 2*f(x).diff(x),
'sol': [Eq(f(x), C1 + C2*exp(-2*x))],
},
'reducible_05': {
'eq': f(x).diff(x, 3) + f(x).diff(x, 2) - 6*f(x).diff(x),
'sol': [Eq(f(x), C1 + C2*exp(-3*x) + C3*exp(2*x))],
'slow': True,
},
'reducible_06': {
'eq': f(x).diff(x, 4) - f(x).diff(x, 3) - 4*f(x).diff(x, 2) + \
4*f(x).diff(x),
'sol': [Eq(f(x), C1 + C2*exp(-2*x) + C3*exp(x) + C4*exp(2*x))],
'slow': True,
},
'reducible_07': {
'eq': f(x).diff(x, 4) + 3*f(x).diff(x, 3),
'sol': [Eq(f(x), C1 + C2*x + C3*x**2 + C4*exp(-3*x))],
'slow': True,
},
'reducible_08': {
'eq': f(x).diff(x, 4) - 2*f(x).diff(x, 2),
'sol': [Eq(f(x), C1 + C2*x + C3*exp(-sqrt(2)*x) + C4*exp(sqrt(2)*x))],
'slow': True,
},
'reducible_09': {
'eq': f(x).diff(x, 4) + 4*f(x).diff(x, 2),
'sol': [Eq(f(x), C1 + C2*x + C3*sin(2*x) + C4*cos(2*x))],
'slow': True,
},
'reducible_10': {
'eq': f(x).diff(x, 5) + 2*f(x).diff(x, 3) + f(x).diff(x),
'sol': [Eq(f(x), C1 + C2*(x*sin(x) + cos(x)) + C3*(-x*cos(x) + sin(x)) + C4*sin(x) + C5*cos(x))],
'slow': True,
},
'reducible_11': {
'eq': f(x).diff(x, 2) - f(x).diff(x)**3,
'sol': [Eq(f(x), C1 - sqrt(2)*I*(C2 + x)*sqrt(1/(C2 + x))),
Eq(f(x), C1 + sqrt(2)*I*(C2 + x)*sqrt(1/(C2 + x)))],
'slow': True,
},
}
}
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(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_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 str(Ei(cos(2)).evalf(n=10)) == "-0.6760647401"
raises(ArgumentIndexError, lambda: Ei(x).fdiff(2))
def test_ei():
pos = Symbol('p', positive=True)
neg = Symbol('n', negative=True)
assert Ei(-pos) == Ei(polar_lift(-1) * pos) - I * pi
assert Ei(neg) == Ei(polar_lift(neg)) - I * pi
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)
def test_latex_functions():
assert latex(exp(x)) == "e^{x}"
assert latex(exp(1) + exp(2)) == "e + e^{2}"
f = Function('f')
assert latex(f(x)) == '\\operatorname{f}{\\left (x \\right )}'
beta = Function('beta')
assert latex(beta(x)) == r"\beta{\left (x \right )}"
assert latex(sin(x)) == r"\sin{\left (x \right )}"
assert latex(sin(x), fold_func_brackets=True) == r"\sin {x}"
assert latex(sin(2*x**2), fold_func_brackets=True) == \
r"\sin {2 x^{2}}"
assert latex(sin(x**2), fold_func_brackets=True) == \
r"\sin {x^{2}}"
assert latex(asin(x)**2) == r"\operatorname{asin}^{2}{\left (x \right )}"
assert latex(asin(x)**2, inv_trig_style="full") == \
r"\arcsin^{2}{\left (x \right )}"
assert latex(asin(x)**2, inv_trig_style="power") == \
r"\sin^{-1}{\left (x \right )}^{2}"
assert latex(asin(x**2), inv_trig_style="power",
fold_func_brackets=True) == \
r"\sin^{-1} {x^{2}}"
assert latex(factorial(k)) == r"k!"
assert latex(factorial(-k)) == r"\left(- k\right)!"
assert latex(subfactorial(k)) == r"!k"
assert latex(subfactorial(-k)) == r"!\left(- k\right)"
assert latex(factorial2(k)) == r"k!!"
assert latex(factorial2(-k)) == r"\left(- k\right)!!"
assert latex(binomial(2, k)) == r"{\binom{2}{k}}"
assert latex(FallingFactorial(3,
k)) == r"{\left(3\right)}_{\left(k\right)}"
assert latex(RisingFactorial(3, k)) == r"{\left(3\right)}^{\left(k\right)}"
assert latex(floor(x)) == r"\lfloor{x}\rfloor"
assert latex(ceiling(x)) == r"\lceil{x}\rceil"
assert latex(Min(x, 2, x**3)) == r"\min\left(2, x, x^{3}\right)"
assert latex(Min(x, y)**2) == r"\min\left(x, y\right)^{2}"
assert latex(Max(x, 2, x**3)) == r"\max\left(2, x, x^{3}\right)"
assert latex(Max(x, y)**2) == r"\max\left(x, y\right)^{2}"
assert latex(Abs(x)) == r"\left\lvert{x}\right\rvert"
assert latex(re(x)) == r"\Re{x}"
assert latex(re(x + y)) == r"\Re{x} + \Re{y}"
assert latex(im(x)) == r"\Im{x}"
assert latex(conjugate(x)) == r"\overline{x}"
assert latex(gamma(x)) == r"\Gamma\left(x\right)"
assert latex(Order(x)) == r"\mathcal{O}\left(x\right)"
assert latex(lowergamma(x, y)) == r'\gamma\left(x, y\right)'
assert latex(uppergamma(x, y)) == r'\Gamma\left(x, y\right)'
assert latex(cot(x)) == r'\cot{\left (x \right )}'
assert latex(coth(x)) == r'\coth{\left (x \right )}'
assert latex(re(x)) == r'\Re{x}'
assert latex(im(x)) == r'\Im{x}'
assert latex(root(x, y)) == r'x^{\frac{1}{y}}'
assert latex(arg(x)) == r'\arg{\left (x \right )}'
assert latex(zeta(x)) == r'\zeta\left(x\right)'
assert latex(zeta(x)) == r"\zeta\left(x\right)"
assert latex(zeta(x)**2) == r"\zeta^{2}\left(x\right)"
assert latex(zeta(x, y)) == r"\zeta\left(x, y\right)"
assert latex(zeta(x, y)**2) == r"\zeta^{2}\left(x, y\right)"
assert latex(dirichlet_eta(x)) == r"\eta\left(x\right)"
assert latex(dirichlet_eta(x)**2) == r"\eta^{2}\left(x\right)"
assert latex(polylog(x, y)) == r"\operatorname{Li}_{x}\left(y\right)"
assert latex(polylog(x,
y)**2) == r"\operatorname{Li}_{x}^{2}\left(y\right)"
assert latex(lerchphi(x, y, n)) == r"\Phi\left(x, y, n\right)"
assert latex(lerchphi(x, y, n)**2) == r"\Phi^{2}\left(x, y, n\right)"
assert latex(elliptic_k(z)) == r"K\left(z\right)"
assert latex(elliptic_k(z)**2) == r"K^{2}\left(z\right)"
assert latex(elliptic_f(x, y)) == r"F\left(x\middle| y\right)"
assert latex(elliptic_f(x, y)**2) == r"F^{2}\left(x\middle| y\right)"
assert latex(elliptic_e(x, y)) == r"E\left(x\middle| y\right)"
assert latex(elliptic_e(x, y)**2) == r"E^{2}\left(x\middle| y\right)"
assert latex(elliptic_e(z)) == r"E\left(z\right)"
assert latex(elliptic_e(z)**2) == r"E^{2}\left(z\right)"
assert latex(elliptic_pi(x, y, z)) == r"\Pi\left(x; y\middle| z\right)"
assert latex(elliptic_pi(x, y, z)**2) == \
r"\Pi^{2}\left(x; y\middle| z\right)"
assert latex(elliptic_pi(x, y)) == r"\Pi\left(x\middle| y\right)"
assert latex(elliptic_pi(x, y)**2) == r"\Pi^{2}\left(x\middle| y\right)"
assert latex(Ei(x)) == r'\operatorname{Ei}{\left (x \right )}'
assert latex(Ei(x)**2) == r'\operatorname{Ei}^{2}{\left (x \right )}'
assert latex(expint(x, y)**2) == r'\operatorname{E}_{x}^{2}\left(y\right)'
assert latex(Shi(x)**2) == r'\operatorname{Shi}^{2}{\left (x \right )}'
assert latex(Si(x)**2) == r'\operatorname{Si}^{2}{\left (x \right )}'
assert latex(Ci(x)**2) == r'\operatorname{Ci}^{2}{\left (x \right )}'
assert latex(Chi(x)**2) == r'\operatorname{Chi}^{2}{\left (x \right )}'
assert latex(jacobi(n, a, b,
x)) == r'P_{n}^{\left(a,b\right)}\left(x\right)'
assert latex(jacobi(
n, a, b,
x)**2) == r'\left(P_{n}^{\left(a,b\right)}\left(x\right)\right)^{2}'
assert latex(gegenbauer(n, a,
x)) == r'C_{n}^{\left(a\right)}\left(x\right)'
assert latex(gegenbauer(
n, a,
x)**2) == r'\left(C_{n}^{\left(a\right)}\left(x\right)\right)^{2}'
assert latex(chebyshevt(n, x)) == r'T_{n}\left(x\right)'
assert latex(chebyshevt(n,
x)**2) == r'\left(T_{n}\left(x\right)\right)^{2}'
assert latex(chebyshevu(n, x)) == r'U_{n}\left(x\right)'
assert latex(chebyshevu(n,
x)**2) == r'\left(U_{n}\left(x\right)\right)^{2}'
assert latex(legendre(n, x)) == r'P_{n}\left(x\right)'
assert latex(legendre(n, x)**2) == r'\left(P_{n}\left(x\right)\right)^{2}'
assert latex(assoc_legendre(n, a,
x)) == r'P_{n}^{\left(a\right)}\left(x\right)'
assert latex(assoc_legendre(
n, a,
x)**2) == r'\left(P_{n}^{\left(a\right)}\left(x\right)\right)^{2}'
assert latex(laguerre(n, x)) == r'L_{n}\left(x\right)'
assert latex(laguerre(n, x)**2) == r'\left(L_{n}\left(x\right)\right)^{2}'
assert latex(assoc_laguerre(n, a,
x)) == r'L_{n}^{\left(a\right)}\left(x\right)'
assert latex(assoc_laguerre(
n, a,
x)**2) == r'\left(L_{n}^{\left(a\right)}\left(x\right)\right)^{2}'
assert latex(hermite(n, x)) == r'H_{n}\left(x\right)'
assert latex(hermite(n, x)**2) == r'\left(H_{n}\left(x\right)\right)^{2}'
theta = Symbol("theta", real=True)
phi = Symbol("phi", real=True)
assert latex(Ynm(n, m, theta, phi)) == r'Y_{n}^{m}\left(\theta,\phi\right)'
assert latex(
Ynm(n, m, theta,
phi)**3) == r'\left(Y_{n}^{m}\left(\theta,\phi\right)\right)^{3}'
assert latex(Znm(n, m, theta, phi)) == r'Z_{n}^{m}\left(\theta,\phi\right)'
assert latex(
Znm(n, m, theta,
phi)**3) == r'\left(Z_{n}^{m}\left(\theta,\phi\right)\right)^{3}'
# Test latex printing of function names with "_"
assert latex(
polar_lift(0)) == r"\operatorname{polar\_lift}{\left (0 \right )}"
assert latex(polar_lift(0)**
3) == r"\operatorname{polar\_lift}^{3}{\left (0 \right )}"
assert latex(totient(n)) == r'\phi\left( n \right)'
def test_ei():
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 str(Ei(cos(2)).evalf(n=10)) == '-0.6760647401'
