def test_meijerg_eval(): from sympy.functions.elementary.exponential import exp_polar from sympy.functions.special.bessel import besseli from sympy.abc import l a = randcplx() arg = x*exp_polar(k*pi*I) expr1 = pi*meijerg([[], [(a + 1)/2]], [[a/2], [-a/2, (a + 1)/2]], arg**2/4) expr2 = besseli(a, arg) # Test that the two expressions agree for all arguments. for x_ in [0.5, 1.5]: for k_ in [0.0, 0.1, 0.3, 0.5, 0.8, 1, 5.751, 15.3]: assert abs((expr1 - expr2).n(subs={x: x_, k: k_})) < 1e-10 assert abs((expr1 - expr2).n(subs={x: x_, k: -k_})) < 1e-10 # Test continuity independently eps = 1e-13 expr2 = expr1.subs(k, l) for x_ in [0.5, 1.5]: for k_ in [0.5, Rational(1, 3), 0.25, 0.75, Rational(2, 3), 1.0, 1.5]: assert abs((expr1 - expr2).n( subs={x: x_, k: k_ + eps, l: k_ - eps})) < 1e-10 assert abs((expr1 - expr2).n( subs={x: x_, k: -k_ + eps, l: -k_ - eps})) < 1e-10 expr = (meijerg(((0.5,), ()), ((0.5, 0, 0.5), ()), exp_polar(-I*pi)/4) + meijerg(((0.5,), ()), ((0.5, 0, 0.5), ()), exp_polar(I*pi)/4)) \ /(2*sqrt(pi)) assert (expr - pi/exp(1)).n(chop=True) == 0
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 eval(cls, arg): from sympy.functions.elementary.complexes import arg as argument if arg.is_number: ar = argument(arg) # In general we want to affirm that something is known, # e.g. `not ar.has(argument) and not ar.has(atan)` # but for now we will just be more restrictive and # see that it has evaluated to one of the known values. if ar in (0, pi/2, -pi/2, pi): return exp_polar(I*ar)*abs(arg) if arg.is_Mul: args = arg.args else: args = [arg] included = [] excluded = [] positive = [] for arg in args: if arg.is_polar: included += [arg] elif arg.is_positive: positive += [arg] else: excluded += [arg] if len(excluded) < len(args): if excluded: return Mul(*(included + positive))*polar_lift(Mul(*excluded)) elif included: return Mul(*(included + positive)) else: return Mul(*positive)*exp_polar(0)
def t(func, hyp, z): """ Test that func is a valid representation of hyp. """ # First test that func agrees with hyp for small z if not tn(func.rewrite('nonrepsmall'), hyp, z, a=Rational(-1, 2), b=Rational(-1, 2), c=S.Half, d=S.Half): return False # Next check that the two small representations agree. if not tn( func.rewrite('nonrepsmall').subs( z, exp_polar(I*pi)*z).replace(exp_polar, exp), func.subs(z, exp_polar(I*pi)*z).rewrite('nonrepsmall'), z, a=Rational(-1, 2), b=Rational(-1, 2), c=S.Half, d=S.Half): return False # Next check continuity along exp_polar(I*pi)*t expr = func.subs(z, exp_polar(I*pi)*z).rewrite('nonrep') if abs(expr.subs(z, 1 + 1e-15).n() - expr.subs(z, 1 - 1e-15).n()) > 1e-10: return False # Finally check continuity of the big reps. def dosubs(func, a, b): rv = func.subs(z, exp_polar(a)*z).rewrite('nonrep') return rv.subs(z, exp_polar(b)*z).replace(exp_polar, exp) for n in [0, 1, 2, 3, 4, -1, -2, -3, -4]: expr1 = dosubs(func, 2*I*pi*n, I*pi/2) expr2 = dosubs(func, 2*I*pi*n + I*pi, -I*pi/2) if not tn(expr1, expr2, z): return False expr1 = dosubs(func, 2*I*pi*(n + 1), -I*pi/2) expr2 = dosubs(func, 2*I*pi*n + I*pi, I*pi/2) if not tn(expr1, expr2, z): return False return True
def eval(cls, arg): from sympy.functions.elementary.complexes import arg as argument if arg.is_number: ar = argument(arg) # In general we want to affirm that something is known, # e.g. `not ar.has(argument) and not ar.has(atan)` # but for now we will just be more restrictive and # see that it has evaluated to one of the known values. if ar in (0, pi / 2, -pi / 2, pi): return exp_polar(I * ar) * abs(arg) if arg.is_Mul: args = arg.args else: args = [arg] included = [] excluded = [] positive = [] for arg in args: if arg.is_polar: included += [arg] elif arg.is_positive: positive += [arg] else: excluded += [arg] if len(excluded) < len(args): if excluded: return Mul(*(included + positive)) * polar_lift(Mul(*excluded)) elif included: return Mul(*(included + positive)) else: return Mul(*positive) * exp_polar(0)
def test_plot_and_save_6(): if not matplotlib: skip("Matplotlib not the default backend") x = Symbol('x') with TemporaryDirectory(prefix='sympy_') as tmpdir: filename = 'test.png' ### # Test expressions that can not be translated to np and generate complex # results. ### p = plot(sin(x) + I*cos(x)) p.save(os.path.join(tmpdir, filename)) p = plot(sqrt(sqrt(-x))) p.save(os.path.join(tmpdir, filename)) p = plot(LambertW(x)) p.save(os.path.join(tmpdir, filename)) p = plot(sqrt(LambertW(x))) p.save(os.path.join(tmpdir, filename)) #Characteristic function of a StudentT distribution with nu=10 x1 = 5 * x**2 * exp_polar(-I*pi)/2 m1 = meijerg(((1 / 2,), ()), ((5, 0, 1 / 2), ()), x1) x2 = 5*x**2 * exp_polar(I*pi)/2 m2 = meijerg(((1/2,), ()), ((5, 0, 1/2), ()), x2) expr = (m1 + m2) / (48 * pi) p = plot(expr, (x, 1e-6, 1e-2)) p.save(os.path.join(tmpdir, filename))
def tn(func, s): from sympy.core.random import uniform c = uniform(1, 5) expr = func(s, c*exp_polar(I*pi)) - func(s, c*exp_polar(-I*pi)) eps = 1e-15 expr2 = func(s + eps, -c + eps*I) - func(s + eps, -c - eps*I) return abs(expr.n() - expr2.n()).n() < 1e-10
def test_branching(): assert besselj(polar_lift(k), x) == besselj(k, x) assert besseli(polar_lift(k), x) == besseli(k, x) n = Symbol('n', integer=True) assert besselj(n, exp_polar(2*pi*I)*x) == besselj(n, x) assert besselj(n, polar_lift(x)) == besselj(n, x) assert besseli(n, exp_polar(2*pi*I)*x) == besseli(n, x) assert besseli(n, polar_lift(x)) == besseli(n, x) def tn(func, s): from sympy.core.random import uniform c = uniform(1, 5) expr = func(s, c*exp_polar(I*pi)) - func(s, c*exp_polar(-I*pi)) eps = 1e-15 expr2 = func(s + eps, -c + eps*I) - func(s + eps, -c - eps*I) return abs(expr.n() - expr2.n()).n() < 1e-10 nu = Symbol('nu') assert besselj(nu, exp_polar(2*pi*I)*x) == exp(2*pi*I*nu)*besselj(nu, x) assert besseli(nu, exp_polar(2*pi*I)*x) == exp(2*pi*I*nu)*besseli(nu, x) assert tn(besselj, 2) assert tn(besselj, pi) assert tn(besselj, I) assert tn(besseli, 2) assert tn(besseli, pi) assert tn(besseli, I)
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_arg(): assert arg(0) is nan assert arg(1) == 0 assert arg(-1) == pi assert arg(I) == pi / 2 assert arg(-I) == -pi / 2 assert arg(1 + I) == pi / 4 assert arg(-1 + I) == pi * Rational(3, 4) assert arg(1 - I) == -pi / 4 assert arg(exp_polar(4 * pi * I)) == 4 * pi assert arg(exp_polar(-7 * pi * I)) == -7 * pi assert arg(exp_polar(5 - 3 * pi * I / 4)) == pi * Rational(-3, 4) f = Function('f') assert not arg(f(0) + I * f(1)).atoms(re) # check nesting x = Symbol('x') assert arg(arg(arg(x))) is not S.NaN assert arg(arg(arg(arg(x)))) is S.NaN r = Symbol('r', extended_real=True) assert arg(arg(r)) is not S.NaN assert arg(arg(arg(r))) is S.NaN p = Function('p', extended_positive=True) assert arg(p(x)) == 0 assert arg((3 + I) * p(x)) == arg(3 + I) p = Symbol('p', positive=True) assert arg(p) == 0 assert arg(p * I) == pi / 2 n = Symbol('n', negative=True) assert arg(n) == pi assert arg(n * I) == -pi / 2 x = Symbol('x') assert conjugate(arg(x)) == arg(x) e = p + I * p**2 assert arg(e) == arg(1 + p * I) # make sure sign doesn't swap e = -2 * p + 4 * I * p**2 assert arg(e) == arg(-1 + 2 * p * I) # make sure sign isn't lost x = symbols('x', real=True) # could be zero e = x + I * x assert arg(e) == arg(x * (1 + I)) assert arg(e / p) == arg(x * (1 + I)) e = p * cos(p) + I * log(p) * exp(p) assert arg(e).args[0] == e # keep it simple -- let the user do more advanced cancellation e = (p + 1) + I * (p**2 - 1) assert arg(e).args[0] == e f = Function('f') e = 2 * x * (f(0) - 1) - 2 * x * f(0) assert arg(e) == arg(-2 * x) assert arg(f(0)).func == arg and arg(f(0)).args == (f(0), )
def test_hyper_unpolarify(): from sympy.functions.elementary.exponential import exp_polar a = exp_polar(2*pi*I)*x b = x assert hyper([], [], a).argument == b assert hyper([0], [], a).argument == a assert hyper([0], [0], a).argument == b assert hyper([0, 1], [0], a).argument == a assert hyper([0, 1], [0], exp_polar(2*pi*I)).argument == 1
def test_principal_branch(): from sympy.functions.elementary.complexes import (polar_lift, principal_branch) p = Symbol('p', positive=True) x = Symbol('x') neg = Symbol('x', negative=True) assert principal_branch(polar_lift(x), p) == principal_branch(x, p) assert principal_branch(polar_lift(2 + I), p) == principal_branch(2 + I, p) assert principal_branch(2 * x, p) == 2 * principal_branch(x, p) assert principal_branch(1, pi) == exp_polar(0) assert principal_branch(-1, 2 * pi) == exp_polar(I * pi) assert principal_branch(-1, pi) == exp_polar(0) assert principal_branch(exp_polar(3*pi*I)*x, 2*pi) == \ principal_branch(exp_polar(I*pi)*x, 2*pi) assert principal_branch(neg * exp_polar(pi * I), 2 * pi) == neg * exp_polar(-I * pi) # related to issue #14692 assert principal_branch(exp_polar(-I*pi/2)/polar_lift(neg), 2*pi) == \ exp_polar(-I*pi/2)/neg assert N_equals(principal_branch((1 + I)**2, 2 * pi), 2 * I) assert N_equals(principal_branch((1 + I)**2, 3 * pi), 2 * I) assert N_equals(principal_branch((1 + I)**2, 1 * pi), 2 * I) # test argument sanitization assert principal_branch(x, I).func is principal_branch assert principal_branch(x, -4).func is principal_branch assert principal_branch(x, -oo).func is principal_branch assert principal_branch(x, zoo).func is principal_branch
def eval(self, x, period): from sympy import oo, exp_polar, I, Mul, polar_lift, Symbol if isinstance(x, polar_lift): return principal_branch(x.args[0], period) if period == oo: return x ub = periodic_argument(x, oo) barg = periodic_argument(x, period) if (ub != barg and not ub.has(periodic_argument) and not barg.has(periodic_argument)): pl = polar_lift(x) def mr(expr): if not isinstance(expr, Symbol): return polar_lift(expr) return expr pl = pl.replace(polar_lift, mr) # Recompute unbranched argument ub = periodic_argument(pl, oo) if not pl.has(polar_lift): if ub != barg: res = exp_polar(I * (barg - ub)) * pl else: res = pl if not res.is_polar and not res.has(exp_polar): res *= exp_polar(0) return res if not x.free_symbols: c, m = x, () else: c, m = x.as_coeff_mul(*x.free_symbols) others = [] for y in m: if y.is_positive: c *= y else: others += [y] m = tuple(others) arg = periodic_argument(c, period) if arg.has(periodic_argument): return None if arg.is_number and (unbranched_argument(c) != arg or (arg == 0 and m != () and c != 1)): if arg == 0: return abs(c) * principal_branch(Mul(*m), period) return principal_branch(exp_polar(I * arg) * Mul(*m), period) * abs(c) if (arg.is_number and ((abs(arg) < period / 2) == True or arg == period / 2) and m == ()): return exp_polar(arg * I) * abs(c)
def tn_arg(func): def test(arg, e1, e2): from sympy.core.random import uniform v = uniform(1, 5) v1 = func(arg*x).subs(x, v).n() v2 = func(e1*v + e2*1e-15).n() return abs(v1 - v2).n() < 1e-10 return test(exp_polar(I*pi/2), I, 1) and \ test(exp_polar(-I*pi/2), -I, 1) and \ test(exp_polar(I*pi), -1, I) and \ test(exp_polar(-I*pi), -1, -I)
def test_polylog_expansion(): assert polylog(s, 0) == 0 assert polylog(s, 1) == zeta(s) assert polylog(s, -1) == -dirichlet_eta(s) assert polylog(s, exp_polar(I*pi*Rational(4, 3))) == polylog(s, exp(I*pi*Rational(4, 3))) assert polylog(s, exp_polar(I*pi)/3) == polylog(s, exp(I*pi)/3) assert myexpand(polylog(1, z), -log(1 - z)) assert myexpand(polylog(0, z), z/(1 - z)) assert myexpand(polylog(-1, z), z/(1 - z)**2) assert ((1-z)**3 * expand_func(polylog(-2, z))).simplify() == z*(1 + z) assert myexpand(polylog(-5, z), None)
def tn_branch(func, s=None): from sympy.core.random import uniform def fn(x): if s is None: return func(x) return func(s, x) c = uniform(1, 5) expr = fn(c*exp_polar(I*pi)) - fn(c*exp_polar(-I*pi)) eps = 1e-15 expr2 = fn(-c + eps*I) - fn(-c - eps*I) return abs(expr.n() - expr2.n()).n() < 1e-10
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
def eval(self, x, period): from sympy import oo, exp_polar, I, Mul, polar_lift, Symbol if isinstance(x, polar_lift): return principal_branch(x.args[0], period) if period == oo: return x ub = periodic_argument(x, oo) barg = periodic_argument(x, period) if ub != barg and not ub.has(periodic_argument) \ and not barg.has(periodic_argument): pl = polar_lift(x) def mr(expr): if not isinstance(expr, Symbol): return polar_lift(expr) return expr pl = pl.replace(polar_lift, mr) # Recompute unbranched argument ub = periodic_argument(pl, oo) if not pl.has(polar_lift): if ub != barg: res = exp_polar(I*(barg - ub))*pl else: res = pl if not res.is_polar and not res.has(exp_polar): res *= exp_polar(0) return res if not x.free_symbols: c, m = x, () else: c, m = x.as_coeff_mul(*x.free_symbols) others = [] for y in m: if y.is_positive: c *= y else: others += [y] m = tuple(others) arg = periodic_argument(c, period) if arg.has(periodic_argument): return None if arg.is_number and (unbranched_argument(c) != arg or (arg == 0 and m != () and c != 1)): if arg == 0: return abs(c)*principal_branch(Mul(*m), period) return principal_branch(exp_polar(I*arg)*Mul(*m), period)*abs(c) if arg.is_number and ((abs(arg) < period/2) == True or arg == period/2) \ and m == (): return exp_polar(arg*I)*abs(c)
def test_branch_bug(): assert hyperexpand(hyper((Rational(-1, 3), S.Half), (Rational(2, 3), Rational(3, 2)), -z)) == \ -z**S('1/3')*lowergamma(exp_polar(I*pi)/3, z)/5 \ + sqrt(pi)*erf(sqrt(z))/(5*sqrt(z)) assert hyperexpand(meijerg([Rational(7, 6), 1], [], [Rational(2, 3)], [Rational(1, 6), 0], z)) == \ 2*z**S('2/3')*(2*sqrt(pi)*erf(sqrt(z))/sqrt(z) - 2*lowergamma( Rational(2, 3), z)/z**S('2/3'))*gamma(Rational(2, 3))/gamma(Rational(5, 3))
def test_meijerg_with_Floats(): # see issue #10681 from sympy.polys.domains.realfield import RR f = meijerg(((3.0, 1), ()), ((Rational(3, 2),), (0,)), z) a = -2.3632718012073 g = a*z**Rational(3, 2)*hyper((-0.5, Rational(3, 2)), (Rational(5, 2),), z*exp_polar(I*pi)) assert RR.almosteq((hyperexpand(f)/g).n(), 1.0, 1e-12)
def unpolarify(eq, subs={}, exponents_only=False): """ If p denotes the projection from the Riemann surface of the logarithm to the complex line, return a simplified version eq' of `eq` such that p(eq') == p(eq). Also apply the substitution subs in the end. (This is a convenience, since ``unpolarify``, in a certain sense, undoes polarify.) >>> from sympy import unpolarify, polar_lift, sin, I >>> unpolarify(polar_lift(I + 2)) 2 + I >>> unpolarify(sin(polar_lift(I + 7))) sin(7 + I) """ if isinstance(eq, bool): return eq eq = sympify(eq) if subs != {}: return unpolarify(eq.subs(subs)) changed = True pause = False if exponents_only: pause = True while changed: changed = False res = _unpolarify(eq, exponents_only, pause) if res != eq: changed = True eq = res if isinstance(res, bool): return res # Finally, replacing Exp(0) by 1 is always correct. # So is polar_lift(0) -> 0. return res.subs({exp_polar(0): 1, polar_lift(0): 0})
def _eval_expand_func(self, **hints): from sympy import exp, I, floor, Add, Poly, Dummy, exp_polar, unpolarify z, s, a = self.args if z == 1: return zeta(s, a) if s.is_Integer and s <= 0: t = Dummy('t') p = Poly((t + a)**(-s), t) start = 1/(1 - t) res = S.Zero for c in reversed(p.all_coeffs()): res += c*start start = t*start.diff(t) return res.subs(t, z) if a.is_Rational: # See section 18 of # Kelly B. Roach. Hypergeometric Function Representations. # In: Proceedings of the 1997 International Symposium on Symbolic and # Algebraic Computation, pages 205-211, New York, 1997. ACM. # TODO should something be polarified here? add = S.Zero mul = S.One # First reduce a to the interaval (0, 1] if a > 1: n = floor(a) if n == a: n -= 1 a -= n mul = z**(-n) add = Add(*[-z**(k - n)/(a + k)**s for k in range(n)]) elif a <= 0: n = floor(-a) + 1 a += n mul = z**n add = Add(*[z**(n - 1 - k)/(a - k - 1)**s for k in range(n)]) m, n = S([a.p, a.q]) zet = exp_polar(2*pi*I/n) root = z**(1/n) return add + mul*n**(s - 1)*Add( *[polylog(s, zet**k*root)._eval_expand_func(**hints) / (unpolarify(zet)**k*root)**m for k in range(n)]) # TODO use minpoly instead of ad-hoc methods when issue 5888 is fixed if isinstance(z, exp) and (z.args[0]/(pi*I)).is_Rational or z in [-1, I, -I]: # TODO reference? if z == -1: p, q = S([1, 2]) elif z == I: p, q = S([1, 4]) elif z == -I: p, q = S([-1, 4]) else: arg = z.args[0]/(2*pi*I) p, q = S([arg.p, arg.q]) return Add(*[exp(2*pi*I*k*p/q)/q**s*zeta(s, (k + a)/q) for k in range(q)]) return lerchphi(z, s, a)
def unpolarify(eq, subs={}, exponents_only=False): """ If p denotes the projection from the Riemann surface of the logarithm to the complex line, return a simplified version eq' of `eq` such that p(eq') == p(eq). Also apply the substitution subs in the end. (This is a convenience, since ``unpolarify``, in a certain sense, undoes polarify.) >>> from sympy import unpolarify, polar_lift, sin, I >>> unpolarify(polar_lift(I + 2)) 2 + I >>> unpolarify(sin(polar_lift(I + 7))) sin(7 + I) """ if isinstance(eq, bool): return eq eq = sympify(eq) if subs != {}: return unpolarify(eq.subs(subs)) changed = True pause = False if exponents_only: pause = True while changed: changed = False res = _unpolarify(eq, exponents_only, pause) if res != eq: changed = True eq = res if isinstance(res, bool): return res # Finally, replacing Exp(0) by 1 is always correct. # So is polar_lift(0) -> 0. return res.subs({exp_polar(0): 1, polar_lift(0): 0})
def _eval_expand_func(self, **hints): from sympy import exp, I, floor, Add, Poly, Dummy, exp_polar, unpolarify z, s, a = self.args if z == 1: return zeta(s, a) if s.is_Integer and s <= 0: t = Dummy('t') p = Poly((t + a)**(-s), t) start = 1/(1 - t) res = S(0) for c in reversed(p.all_coeffs()): res += c*start start = t*start.diff(t) return res.subs(t, z) if a.is_Rational: # See section 18 of # Kelly B. Roach. Hypergeometric Function Representations. # In: Proceedings of the 1997 International Symposium on Symbolic and # Algebraic Computation, pages 205-211, New York, 1997. ACM. # TODO should something be polarified here? add = S(0) mul = S(1) # First reduce a to the interaval (0, 1] if a > 1: n = floor(a) if n == a: n -= 1 a -= n mul = z**(-n) add = Add(*[-z**(k - n)/(a + k)**s for k in range(n)]) elif a <= 0: n = floor(-a) + 1 a += n mul = z**n add = Add(*[z**(n - 1 - k)/(a - k - 1)**s for k in range(n)]) m, n = S([a.p, a.q]) zet = exp_polar(2*pi*I/n) root = z**(1/n) return add + mul*n**(s - 1)*Add( *[polylog(s, zet**k*root)._eval_expand_func(**hints) / (unpolarify(zet)**k*root)**m for k in range(n)]) # TODO use minpoly instead of ad-hoc methods when issue 5888 is fixed if isinstance(z, exp) and (z.args[0]/(pi*I)).is_Rational or z in [-1, I, -I]: # TODO reference? if z == -1: p, q = S([1, 2]) elif z == I: p, q = S([1, 4]) elif z == -I: p, q = S([-1, 4]) else: arg = z.args[0]/(2*pi*I) p, q = S([arg.p, arg.q]) return Add(*[exp(2*pi*I*k*p/q)/q**s*zeta(s, (k + a)/q) for k in range(q)]) return lerchphi(z, s, a)
def test_unpolarify(): from sympy.functions.elementary.complexes import (polar_lift, principal_branch, unpolarify) from sympy.core.relational import Ne from sympy.functions.elementary.hyperbolic import tanh from sympy.functions.special.error_functions import erf from sympy.functions.special.gamma_functions import (gamma, uppergamma) from sympy.abc import x p = exp_polar(7 * I) + 1 u = exp(7 * I) + 1 assert unpolarify(1) == 1 assert unpolarify(p) == u assert unpolarify(p**2) == u**2 assert unpolarify(p**x) == p**x assert unpolarify(p * x) == u * x assert unpolarify(p + x) == u + x assert unpolarify(sqrt(sin(p))) == sqrt(sin(u)) # Test reduction to principal branch 2*pi. t = principal_branch(x, 2 * pi) assert unpolarify(t) == x assert unpolarify(sqrt(t)) == sqrt(t) # Test exponents_only. assert unpolarify(p**p, exponents_only=True) == p**u assert unpolarify(uppergamma(x, p**p)) == uppergamma(x, p**u) # Test functions. assert unpolarify(sin(p)) == sin(u) assert unpolarify(tanh(p)) == tanh(u) assert unpolarify(gamma(p)) == gamma(u) assert unpolarify(erf(p)) == erf(u) assert unpolarify(uppergamma(x, p)) == uppergamma(x, p) assert unpolarify(uppergamma(sin(p), sin(p + exp_polar(0)))) == \ uppergamma(sin(u), sin(u + 1)) assert unpolarify(uppergamma(polar_lift(0), 2*exp_polar(0))) == \ uppergamma(0, 2) assert unpolarify(Eq(p, 0)) == Eq(u, 0) assert unpolarify(Ne(p, 0)) == Ne(u, 0) assert unpolarify(polar_lift(x) > 0) == (x > 0) # Test bools assert unpolarify(True) is True
def test_uppergamma(): from sympy.functions.special.error_functions import expint from sympy.functions.special.hyper import meijerg assert uppergamma(4, 0) == 6 assert uppergamma(x, y).diff(y) == -y**(x - 1)*exp(-y) assert td(uppergamma(randcplx(), y), y) assert uppergamma(x, y).diff(x) == \ uppergamma(x, y)*log(y) + meijerg([], [1, 1], [0, 0, x], [], y) assert td(uppergamma(x, randcplx()), x) p = Symbol('p', positive=True) assert uppergamma(0, p) == -Ei(-p) assert uppergamma(p, 0) == gamma(p) assert uppergamma(S.Half, x) == sqrt(pi)*erfc(sqrt(x)) assert not uppergamma(S.Half - 3, x).has(uppergamma) assert not uppergamma(S.Half + 3, x).has(uppergamma) assert uppergamma(S.Half, x, evaluate=False).has(uppergamma) assert tn(uppergamma(S.Half + 3, x, evaluate=False), uppergamma(S.Half + 3, x), x) assert tn(uppergamma(S.Half - 3, x, evaluate=False), uppergamma(S.Half - 3, x), x) assert unchanged(uppergamma, x, -oo) assert unchanged(uppergamma, x, 0) assert tn_branch(-3, uppergamma) assert tn_branch(-4, uppergamma) assert tn_branch(Rational(1, 3), uppergamma) assert tn_branch(pi, uppergamma) assert uppergamma(3, exp_polar(4*pi*I)*x) == uppergamma(3, x) assert uppergamma(y, exp_polar(5*pi*I)*x) == \ exp(4*I*pi*y)*uppergamma(y, x*exp_polar(pi*I)) + \ gamma(y)*(1 - exp(4*pi*I*y)) assert uppergamma(-2, exp_polar(5*pi*I)*x) == \ uppergamma(-2, x*exp_polar(I*pi)) - 2*pi*I assert uppergamma(-2, x) == expint(3, x)/x**2 assert conjugate(uppergamma(x, y)) == uppergamma(conjugate(x), conjugate(y)) assert unchanged(conjugate, uppergamma(x, -oo)) assert uppergamma(x, y).rewrite(expint) == y**x*expint(-x + 1, y) assert uppergamma(x, y).rewrite(lowergamma) == gamma(x) - lowergamma(x, y) assert uppergamma(70, 6) == 69035724522603011058660187038367026272747334489677105069435923032634389419656200387949342530805432320*exp(-6) assert (uppergamma(S(77) / 2, 6) - uppergamma(S(77) / 2, 6, evaluate=False)).evalf() < 1e-16 assert (uppergamma(-S(77) / 2, 6) - uppergamma(-S(77) / 2, 6, evaluate=False)).evalf() < 1e-16
def test_issue_10681(): from sympy.polys.domains.realfield import RR from sympy.abc import R, r f = integrate(r**2 * (R**2 - r**2)**0.5, r, meijerg=True) g = (1.0 / 3) * R**1.0 * r**3 * hyper( (-0.5, Rational(3, 2)), (Rational(5, 2), ), r**2 * exp_polar(2 * I * pi) / R**2) assert RR.almosteq((f / g).n(), 1.0, 1e-12)
def test_lerchphi(): from sympy.functions.special.zeta_functions import (lerchphi, polylog) from sympy.simplify.gammasimp import gammasimp assert hyperexpand(hyper([1, a], [a + 1], z)/a) == lerchphi(z, 1, a) assert hyperexpand( hyper([1, a, a], [a + 1, a + 1], z)/a**2) == lerchphi(z, 2, a) assert hyperexpand(hyper([1, a, a, a], [a + 1, a + 1, a + 1], z)/a**3) == \ lerchphi(z, 3, a) assert hyperexpand(hyper([1] + [a]*10, [a + 1]*10, z)/a**10) == \ lerchphi(z, 10, a) assert gammasimp(hyperexpand(meijerg([0, 1 - a], [], [0], [-a], exp_polar(-I*pi)*z))) == lerchphi(z, 1, a) assert gammasimp(hyperexpand(meijerg([0, 1 - a, 1 - a], [], [0], [-a, -a], exp_polar(-I*pi)*z))) == lerchphi(z, 2, a) assert gammasimp(hyperexpand(meijerg([0, 1 - a, 1 - a, 1 - a], [], [0], [-a, -a, -a], exp_polar(-I*pi)*z))) == lerchphi(z, 3, a) assert hyperexpand(z*hyper([1, 1], [2], z)) == -log(1 + -z) assert hyperexpand(z*hyper([1, 1, 1], [2, 2], z)) == polylog(2, z) assert hyperexpand(z*hyper([1, 1, 1, 1], [2, 2, 2], z)) == polylog(3, z) assert hyperexpand(hyper([1, a, 1 + S.Half], [a + 1, S.Half], z)) == \ -2*a/(z - 1) + (-2*a**2 + a)*lerchphi(z, 1, a) # Now numerical tests. These make sure reductions etc are carried out # correctly # a rational function (polylog at negative integer order) assert can_do([2, 2, 2], [1, 1]) # NOTE these contain log(1-x) etc ... better make sure we have |z| < 1 # reduction of order for polylog assert can_do([1, 1, 1, b + 5], [2, 2, b], div=10) # reduction of order for lerchphi # XXX lerchphi in mpmath is flaky assert can_do( [1, a, a, a, b + 5], [a + 1, a + 1, a + 1, b], numerical=False) # test a bug from sympy.functions.elementary.complexes import Abs assert hyperexpand(hyper([S.Half, S.Half, S.Half, 1], [Rational(3, 2), Rational(3, 2), Rational(3, 2)], Rational(1, 4))) == \ Abs(-polylog(3, exp_polar(I*pi)/2) + polylog(3, S.Half))
def test_exp_log(): x = Symbol("x", real=True) assert log(exp(x)) == x assert exp(log(x)) == x if not global_parameters.exp_is_pow: assert log(x).inverse() == exp assert exp(x).inverse() == log y = Symbol("y", polar=True) assert log(exp_polar(z)) == z assert exp(log(y)) == y
def test_polar(): x, y = symbols('x y', polar=True) assert abs(exp_polar(I * 4)) == 1 assert abs(exp_polar(0)) == 1 assert abs(exp_polar(2 + 3 * I)) == exp(2) assert exp_polar(I * 10).n() == exp_polar(I * 10) assert log(exp_polar(z)) == z assert log(x * y).expand() == log(x) + log(y) assert log(x**z).expand() == z * log(x) assert exp_polar(3).exp == 3 # Compare exp(1.0*pi*I). assert (exp_polar(1.0 * pi * I).n(n=5)).as_real_imag()[1] >= 0 assert exp_polar(0).is_rational is True # issue 8008
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_rewrite_single(): def t(expr, c, m): e = _rewrite_single(meijerg([a], [b], [c], [d], expr), x) assert e is not None assert isinstance(e[0][0][2], meijerg) assert e[0][0][2].argument.as_coeff_mul(x) == (c, (m, )) def tn(expr): assert _rewrite_single(meijerg([a], [b], [c], [d], expr), x) is None t(x, 1, x) t(x**2, 1, x**2) t(x**2 + y * x**2, y + 1, x**2) tn(x**2 + x) tn(x**y) def u(expr, x): from sympy.core.add import Add r = _rewrite_single(expr, x) e = Add(*[res[0] * res[2] for res in r[0]]).replace(exp_polar, exp) # XXX Hack? assert verify_numerically(e, expr, x) u(exp(-x) * sin(x), x) # The following has stopped working because hyperexpand changed slightly. # It is probably not worth fixing #u(exp(-x)*sin(x)*cos(x), x) # This one cannot be done numerically, since it comes out as a g-function # of argument 4*pi # NOTE This also tests a bug in inverse mellin transform (which used to # turn exp(4*pi*I*t) into a factor of exp(4*pi*I)**t instead of # exp_polar). #u(exp(x)*sin(x), x) assert _rewrite_single(exp(x)*sin(x), x) == \ ([(-sqrt(2)/(2*sqrt(pi)), 0, meijerg(((Rational(-1, 2), 0, Rational(1, 4), S.Half, Rational(3, 4)), (1,)), ((), (Rational(-1, 2), 0)), 64*exp_polar(-4*I*pi)/x**4))], True)
def test_polarify(): from sympy.functions.elementary.complexes import (polar_lift, polarify) x = Symbol('x') z = Symbol('z', polar=True) f = Function('f') ES = {} assert polarify(-1) == (polar_lift(-1), ES) assert polarify(1 + I) == (polar_lift(1 + I), ES) assert polarify(exp(x), subs=False) == exp(x) assert polarify(1 + x, subs=False) == 1 + x assert polarify(f(I) + x, subs=False) == f(polar_lift(I)) + x assert polarify(x, lift=True) == polar_lift(x) assert polarify(z, lift=True) == z assert polarify(f(x), lift=True) == f(polar_lift(x)) assert polarify(1 + x, lift=True) == polar_lift(1 + x) assert polarify(1 + f(x), lift=True) == polar_lift(1 + f(polar_lift(x))) newex, subs = polarify(f(x) + z) assert newex.subs(subs) == f(x) + z mu = Symbol("mu") sigma = Symbol("sigma", positive=True) # Make sure polarify(lift=True) doesn't try to lift the integration # variable assert polarify( Integral( sqrt(2) * x * exp(-(-mu + x)**2 / (2 * sigma**2)) / (2 * sqrt(pi) * sigma), (x, -oo, oo)), lift=True) == Integral( sqrt(2) * (sigma * exp_polar(0))**exp_polar(I * pi) * exp( (sigma * exp_polar(0))**(2 * exp_polar(I * pi)) * exp_polar( I * pi) * polar_lift(-mu + x)**(2 * exp_polar(0)) / 2) * exp_polar(0) * polar_lift(x) / (2 * sqrt(pi)), (x, -oo, oo))
def test_simplify_relational(): assert simplify(x * (y + 1) - x * y - x + 1 < x) == (x > 1) assert simplify(x * (y + 1) - x * y - x - 1 < x) == (x > -1) assert simplify(x < x * (y + 1) - x * y - x + 1) == (x < 1) q, r = symbols("q r") assert (((-q + r) - (q - r)) <= 0).simplify() == (q >= r) root2 = sqrt(2) equation = ((root2 * (-q + r) - root2 * (q - r)) <= 0).simplify() assert equation == (q >= r) r = S.One < x # canonical operations are not the same as simplification, # so if there is no simplification, canonicalization will # be done unless the measure forbids it assert simplify(r) == r.canonical assert simplify(r, ratio=0) != r.canonical # this is not a random test; in _eval_simplify # this will simplify to S.false and that is the # reason for the 'if r.is_Relational' in Relational's # _eval_simplify routine assert simplify(-(2**(pi * Rational(3, 2)) + 6**pi)**(1 / pi) + 2 * (2**(pi / 2) + 3**pi)**(1 / pi) < 0) is S.false # canonical at least assert Eq(y, x).simplify() == Eq(x, y) assert Eq(x - 1, 0).simplify() == Eq(x, 1) assert Eq(x - 1, x).simplify() == S.false assert Eq(2 * x - 1, x).simplify() == Eq(x, 1) assert Eq(2 * x, 4).simplify() == Eq(x, 2) z = cos(1)**2 + sin(1)**2 - 1 # z.is_zero is None assert Eq(z * x, 0).simplify() == S.true assert Ne(y, x).simplify() == Ne(x, y) assert Ne(x - 1, 0).simplify() == Ne(x, 1) assert Ne(x - 1, x).simplify() == S.true assert Ne(2 * x - 1, x).simplify() == Ne(x, 1) assert Ne(2 * x, 4).simplify() == Ne(x, 2) assert Ne(z * x, 0).simplify() == S.false # No real-valued assumptions assert Ge(y, x).simplify() == Le(x, y) assert Ge(x - 1, 0).simplify() == Ge(x, 1) assert Ge(x - 1, x).simplify() == S.false assert Ge(2 * x - 1, x).simplify() == Ge(x, 1) assert Ge(2 * x, 4).simplify() == Ge(x, 2) assert Ge(z * x, 0).simplify() == S.true assert Ge(x, -2).simplify() == Ge(x, -2) assert Ge(-x, -2).simplify() == Le(x, 2) assert Ge(x, 2).simplify() == Ge(x, 2) assert Ge(-x, 2).simplify() == Le(x, -2) assert Le(y, x).simplify() == Ge(x, y) assert Le(x - 1, 0).simplify() == Le(x, 1) assert Le(x - 1, x).simplify() == S.true assert Le(2 * x - 1, x).simplify() == Le(x, 1) assert Le(2 * x, 4).simplify() == Le(x, 2) assert Le(z * x, 0).simplify() == S.true assert Le(x, -2).simplify() == Le(x, -2) assert Le(-x, -2).simplify() == Ge(x, 2) assert Le(x, 2).simplify() == Le(x, 2) assert Le(-x, 2).simplify() == Ge(x, -2) assert Gt(y, x).simplify() == Lt(x, y) assert Gt(x - 1, 0).simplify() == Gt(x, 1) assert Gt(x - 1, x).simplify() == S.false assert Gt(2 * x - 1, x).simplify() == Gt(x, 1) assert Gt(2 * x, 4).simplify() == Gt(x, 2) assert Gt(z * x, 0).simplify() == S.false assert Gt(x, -2).simplify() == Gt(x, -2) assert Gt(-x, -2).simplify() == Lt(x, 2) assert Gt(x, 2).simplify() == Gt(x, 2) assert Gt(-x, 2).simplify() == Lt(x, -2) assert Lt(y, x).simplify() == Gt(x, y) assert Lt(x - 1, 0).simplify() == Lt(x, 1) assert Lt(x - 1, x).simplify() == S.true assert Lt(2 * x - 1, x).simplify() == Lt(x, 1) assert Lt(2 * x, 4).simplify() == Lt(x, 2) assert Lt(z * x, 0).simplify() == S.false assert Lt(x, -2).simplify() == Lt(x, -2) assert Lt(-x, -2).simplify() == Gt(x, 2) assert Lt(x, 2).simplify() == Lt(x, 2) assert Lt(-x, 2).simplify() == Gt(x, -2) # Test particulat branches of _eval_simplify m = exp(1) - exp_polar(1) assert simplify(m * x > 1) is S.false # These two tests the same branch assert simplify(m * x + 2 * m * y > 1) is S.false assert simplify(m * x + y > 1 + y) is S.false
def test_sympy__functions__elementary__exponential__exp_polar(): from sympy.functions.elementary.exponential import exp_polar assert _test_args(exp_polar(2))