Python sympy.meijerg函数代码示例

def test_meijerg_eval():
    from sympy import besseli, exp_polar
    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, S(1)/3, 0.25, 0.75, S(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_cosine_transform():
    from sympy import sinh, cosh, Si, Ci

    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)*(-sinh(a*w) + cosh(a*w))/(2*a)

    assert cosine_transform(t**(-a), t, w) == 2**(-a + S(1)/2)*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(1)/2)/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) == -sinh(a*t) + cosh(a*t)

    assert cosine_transform(exp(-a*sqrt(t))*cos(a*sqrt(t)), t, w) == a*(-sinh(a**2/(2*w)) + cosh(a**2/(2*w)))/(2*w**(S(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))/(2*sqrt(pi))
    assert inverse_cosine_transform(sqrt(2)*meijerg(((S(1)/2, 0), ()), ((S(1)/2, 0, 0), (S(1)/2,)), 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(1)/2,), ()), ((0, 0), (S(1)/2,)), a**2*w**2/4)/(2*sqrt(pi))
    assert inverse_cosine_transform(sqrt(2)*meijerg(((S(1)/2,), ()), ((0, 0), (S(1)/2,)), a**2*w**2/4)/(2*sqrt(pi)), w, t) == 1/(t*sqrt(a**2/t**2 + 1))

def test_K():
    assert K(0) == pi / 2
    assert K(S(1) / 2) == 8 * pi ** (S(3) / 2) / gamma(-S(1) / 4) ** 2
    assert K(1) == zoo
    assert K(-1) == gamma(S(1) / 4) ** 2 / (4 * sqrt(2 * pi))
    assert K(oo) == 0
    assert K(-oo) == 0
    assert K(I * oo) == 0
    assert K(-I * oo) == 0
    assert K(zoo) == 0

    assert K(z).diff(z) == (E(z) - (1 - z) * K(z)) / (2 * z * (1 - z))
    assert td(K(z), z)

    zi = Symbol("z", real=False)
    assert K(zi).conjugate() == K(zi.conjugate())
    zr = Symbol("z", real=True, negative=True)
    assert K(zr).conjugate() == K(zr)

    assert K(z).rewrite(hyper) == (pi / 2) * hyper((S.Half, S.Half), (S.One,), z)
    assert tn(K(z), (pi / 2) * hyper((S.Half, S.Half), (S.One,), z))
    assert K(z).rewrite(meijerg) == meijerg(((S.Half, S.Half), []), ((S.Zero,), (S.Zero,)), -z) / 2
    assert tn(K(z), meijerg(((S.Half, S.Half), []), ((S.Zero,), (S.Zero,)), -z) / 2)

    assert K(z).series(
        z
    ) == pi / 2 + pi * z / 8 + 9 * pi * z ** 2 / 128 + 25 * pi * z ** 3 / 512 + 1225 * pi * z ** 4 / 32768 + 3969 * pi * z ** 5 / 131072 + O(
        z ** 6
    )

def test_rewrite1():
    assert _rewrite1(x ** 3 * meijerg([a], [b], [c], [d], x ** 2 + y * x ** 2) * 5, x) == (
        5,
        x ** 3,
        [(1, 0, meijerg([a], [b], [c], [d], x ** 2 * (y + 1)))],
        True,
    )

def can_do_meijer(a1, a2, b1, b2, numeric=True):
    """
    This helper function tries to hyperexpand() the meijer g-function
    corresponding to the parameters a1, a2, b1, b2.
    It returns False if this expansion still contains g-functions.
    If numeric is True, it also tests the so-obtained formula numerically
    (at random values) and returns False if the test fails.
    Else it returns True.
    """
    from sympy import unpolarify, expand
    r = hyperexpand(meijerg(a1, a2, b1, b2, z))
    if r.has(meijerg):
        return False
    # NOTE hyperexpand() returns a truly branched function, whereas numerical
    #      evaluation only works on the main branch. Since we are evaluating on
    #      the main branch, this should not be a problem, but expressions like
    #      exp_polar(I*pi/2*x)**a are evaluated incorrectly. We thus have to get
    #      rid of them. The expand heuristically does this...
    r = unpolarify(expand(r, force=True, power_base=True, power_exp=False,
                          mul=False, log=False, multinomial=False, basic=False))

    if not numeric:
        return True

    repl = {}
    for n, a in enumerate(meijerg(a1, a2, b1, b2, z).free_symbols - set([z])):
        repl[a] = randcplx(n)
    return tn(meijerg(a1, a2, b1, b2, z).subs(repl), r.subs(repl), z)

def test_E():
    assert E(z, 0) == z
    assert E(0, m) == 0
    assert E(i*pi/2, m) == i*E(m)
    assert E(z, oo) == zoo
    assert E(z, -oo) == zoo
    assert E(0) == pi/2
    assert E(1) == 1
    assert E(oo) == I*oo
    assert E(-oo) == oo
    assert E(zoo) == zoo

    assert E(-z, m) == -E(z, m)

    assert E(z, m).diff(z) == sqrt(1 - m*sin(z)**2)
    assert E(z, m).diff(m) == (E(z, m) - F(z, m))/(2*m)
    assert E(z).diff(z) == (E(z) - K(z))/(2*z)
    r = randcplx()
    assert td(E(r, m), m)
    assert td(E(z, r), z)
    assert td(E(z), z)

    mi = Symbol('m', real=False)
    assert E(z, mi).conjugate() == E(z.conjugate(), mi.conjugate())
    mr = Symbol('m', real=True, negative=True)
    assert E(z, mr).conjugate() == E(z.conjugate(), mr)

    assert E(z).rewrite(hyper) == (pi/2)*hyper((-S.Half, S.Half), (S.One,), z)
    assert tn(E(z), (pi/2)*hyper((-S.Half, S.Half), (S.One,), z))
    assert E(z).rewrite(meijerg) == \
        -meijerg(((S.Half, S(3)/2), []), ((S.Zero,), (S.Zero,)), -z)/4
    assert tn(E(z), -meijerg(((S.Half, S(3)/2), []), ((S.Zero,), (S.Zero,)), -z)/4)

def test_K():
    assert K(0) == pi/2
    assert K(S(1)/2) == 8*pi**(S(3)/2)/gamma(-S(1)/4)**2
    assert K(1) == zoo
    assert K(-1) == gamma(S(1)/4)**2/(4*sqrt(2*pi))
    assert K(oo) == 0
    assert K(-oo) == 0
    assert K(I*oo) == 0
    assert K(-I*oo) == 0
    assert K(zoo) == 0

    assert K(z).diff(z) == (E(z) - (1 - z)*K(z))/(2*z*(1 - z))
    assert td(K(z), z)

    zi = Symbol('z', real=False)
    assert K(zi).conjugate() == K(zi.conjugate())
    zr = Symbol('z', real=True, negative=True)
    assert K(zr).conjugate() == K(zr)

    assert K(z).rewrite(hyper) == \
        (pi/2)*hyper((S.Half, S.Half), (S.One,), z)
    assert tn(K(z), (pi/2)*hyper((S.Half, S.Half), (S.One,), z))
    assert K(z).rewrite(meijerg) == \
        meijerg(((S.Half, S.Half), []), ((S.Zero,), (S.Zero,)), -z)/2
    assert tn(K(z), meijerg(((S.Half, S.Half), []), ((S.Zero,), (S.Zero,)), -z)/2)

def test_issue_10798():
    from sympy import integrate, pi, I, log, polylog, exp_polar, Piecewise, meijerg, Abs
    from sympy.abc import x, y
    assert integrate(1/(1-(x*y)**2), (x, 0, 1), y) == \
        -Piecewise((I*pi*log(y) - polylog(2, y), Abs(y) < 1), (-I*pi*log(1/y) - polylog(2, y), Abs(1/y) < 1), \
                   (-I*pi*meijerg(((), (1, 1)), ((0, 0), ()), y) + I*pi*meijerg(((1, 1), ()), ((), (0, 0)), y) - polylog(2, y), True))/2 \
                   - log(y)*log(1 - 1/y)/2 + log(y)*log(1 + 1/y)/2 + log(y)*log(y - 1)/2 \
                   - log(y)*log(y + 1)/2 + I*pi*log(y)/2 - polylog(2, y*exp_polar(I*pi))/2

def test_meijerg_lookup():
    from sympy 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], [])

def test_limits():
    k, x = symbols('k, x')
    assert hyper((1,), (S(4)/3, S(5)/3), k**2).series(k) == \
           hyper((1,), (S(4)/3, S(5)/3), 0) + \
           9*k**2*hyper((2,), (S(7)/3, S(8)/3), 0)/20 + \
           81*k**4*hyper((3,), (S(10)/3, S(11)/3), 0)/1120 + \
           O(k**6) # issue 6350
    assert limit(meijerg((), (), (1,), (0,), -x), x, 0) == \
            meijerg(((), ()), ((1,), (0,)), 0) # issue 6052

def test_meijerint():
    from sympy import symbols, expand, arg

    s, t, mu = symbols("s t mu", real=True)
    assert integrate(
        meijerg([], [], [0], [], s * t) * meijerg([], [], [mu / 2], [-mu / 2], t ** 2 / 4), (t, 0, oo)
    ).is_Piecewise
    s = symbols("s", positive=True)
    assert integrate(x ** s * meijerg([[], []], [[0], []], x), (x, 0, oo)) == gamma(s + 1)
    assert integrate(x ** s * meijerg([[], []], [[0], []], x), (x, 0, oo), meijerg=True) == gamma(s + 1)
    assert isinstance(integrate(x ** s * meijerg([[], []], [[0], []], x), (x, 0, oo), meijerg=False), Integral)

    assert meijerint_indefinite(exp(x), x) == exp(x)

    # TODO what simplifications should be done automatically?
    # This tests "extra case" for antecedents_1.
    a, b = symbols("a b", positive=True)
    assert simplify(meijerint_definite(x ** a, x, 0, b)[0]) == b ** (a + 1) / (a + 1)

    # This tests various conditions and expansions:
    meijerint_definite((x + 1) ** 3 * exp(-x), x, 0, oo) == (16, True)

    # Again, how about simplifications?
    sigma, mu = symbols("sigma mu", positive=True)
    i, c = meijerint_definite(exp(-((x - mu) / (2 * sigma)) ** 2), x, 0, oo)
    assert simplify(i) == sqrt(pi) * sigma * (erf(mu / (2 * sigma)) + 1)
    assert c is True

    i, _ = meijerint_definite(exp(-mu * x) * exp(sigma * x), x, 0, oo)
    # TODO it would be nice to test the condition
    assert simplify(i) == 1 / (mu - sigma)

    # Test substitutions to change limits
    assert meijerint_definite(exp(x), x, -oo, 2) == (exp(2), True)
    assert expand(meijerint_definite(exp(x), x, 0, I)[0]) == exp(I) - 1
    assert expand(meijerint_definite(exp(-x), x, 0, x)[0]) == 1 - exp(-exp(I * arg(x)) * abs(x))

    # Test -oo to oo
    assert meijerint_definite(exp(-x ** 2), x, -oo, oo) == (sqrt(pi), True)
    assert meijerint_definite(exp(-abs(x)), x, -oo, oo) == (2, True)
    assert meijerint_definite(exp(-(2 * x - 3) ** 2), x, -oo, oo) == (sqrt(pi) / 2, True)
    assert meijerint_definite(exp(-abs(2 * x - 3)), x, -oo, oo) == (1, True)
    assert meijerint_definite(exp(-((x - mu) / sigma) ** 2 / 2) / sqrt(2 * pi * sigma ** 2), x, -oo, oo) == (1, True)

    # Test one of the extra conditions for 2 g-functinos
    assert meijerint_definite(exp(-x) * sin(x), x, 0, oo) == (S(1) / 2, True)

    # Test a bug
    def res(n):
        return (1 / (1 + x ** 2)).diff(x, n).subs(x, 1) * (-1) ** n

    for n in range(6):
        assert integrate(exp(-x) * sin(x) * x ** n, (x, 0, oo), meijerg=True) == res(n)

    # Test trigexpand:
    assert integrate(exp(-x) * sin(x + a), (x, 0, oo), meijerg=True) == sin(a) / 2 + cos(a) / 2

def test_meijerg_shift_operators():
    # carefully set up the parameters. XXX this still fails sometimes
    a1, a2, a3, a4, a5, b1, b2, b3, b4, b5 = \
        map(lambda n: randcplx(n), range(10))
    g = meijerg([a1], [a3, a4], [b1], [b3, b4], z)

    assert tn(MeijerShiftA(b1).apply(g, op),
              meijerg([a1], [a3, a4], [b1 + 1], [b3, b4], z), z)
    assert tn(MeijerShiftB(a1).apply(g, op),
              meijerg([a1 - 1], [a3, a4], [b1], [b3, b4], z), z)
    assert tn(MeijerShiftC(b3).apply(g, op),
              meijerg([a1], [a3, a4], [b1], [b3 + 1, b4], z), z)
    assert tn(MeijerShiftD(a3).apply(g, op),
              meijerg([a1], [a3 - 1, a4], [b1], [b3, b4], z), z)

    s = MeijerUnShiftA([a1], [a3, a4], [b1], [b3, b4], 0, z)
    assert tn(
        s.apply(g, op), meijerg([a1], [a3, a4], [b1 - 1], [b3, b4], z), z)

    s = MeijerUnShiftC([a1], [a3, a4], [b1], [b3, b4], 0, z)
    assert tn(
        s.apply(g, op), meijerg([a1], [a3, a4], [b1], [b3 - 1, b4], z), z)

    s = MeijerUnShiftB([a1], [a3, a4], [b1], [b3, b4], 0, z)
    assert tn(
        s.apply(g, op), meijerg([a1 + 1], [a3, a4], [b1], [b3, b4], z), z)

    s = MeijerUnShiftD([a1], [a3, a4], [b1], [b3, b4], 0, z)
    assert tn(
        s.apply(g, op), meijerg([a1], [a3 + 1, a4], [b1], [b3, b4], z), z)

def test_meijerg():
    expr = meijerg([pi, pi, x], [1], [0, 1], [1, 2, 3], z)
    ucode_str = \
u"""\
╭─╮2, 3 ⎛π, π, x     1    │  ⎞\n\
│╶┐     ⎜                 │ z⎟\n\
╰─╯4, 5 ⎝ 0, 1    1, 2, 3 │  ⎠\
"""
    ascii_str = \
"""\
 __2, 3 /pi, pi, x     1    |  \\\n\
/__     |                   | z|\n\
\_|4, 5 \\  0, 1     1, 2, 3 |  /\
"""
    assert pretty(expr) == ascii_str
    assert upretty(expr) == ucode_str

    expr = meijerg([1, pi/7], [2, pi, 5], [], [], z**2)
    ucode_str = \
u"""\
        ⎛   π          │   ⎞\n\
╭─╮0, 2 ⎜1, ─  2, π, 5 │  2⎟\n\
│╶┐     ⎜   7          │ z ⎟\n\
╰─╯5, 0 ⎜              │   ⎟\n\
        ⎝              │   ⎠\
"""
    ascii_str = \
"""\
        /   pi           |   \\\n\
 __0, 2 |1, --  2, pi, 5 |  2|\n\
/__     |   7            | z |\n\
\_|5, 0 |                |   |\n\
        \\                |   /\
"""
    assert pretty(expr) == ascii_str
    assert upretty(expr) == ucode_str


    ucode_str = \
u"""\
╭─╮ 1, 10 ⎛1, 1, 1, 1, 1, 1, 1, 1, 1, 1  1 │  ⎞\n\
│╶┐       ⎜                                │ z⎟\n\
╰─╯11,  2 ⎝             1                1 │  ⎠\
"""
    ascii_str = \
"""\
 __ 1, 10 /1, 1, 1, 1, 1, 1, 1, 1, 1, 1  1 |  \\\n\
/__       |                                | z|\n\
\_|11,  2 \\             1                1 |  /\
"""

    expr = meijerg([1]*10, [1], [1], [1], z)
    assert pretty(expr) == ascii_str
    assert upretty(expr) == ucode_str

def test_gh_issue_2711():
    x = Symbol('x')
    f = meijerg(((), ()), ((0,), ()), x)
    a = Wild('a')
    b = Wild('b')

    assert f.find(a) == set([(S.Zero,), ((), ()), ((S.Zero,), ()), x, S.Zero,
                             (), meijerg(((), ()), ((S.Zero,), ()), x)])
    assert f.find(a + b) == \
        {meijerg(((), ()), ((S.Zero,), ()), x), x, S.Zero}
    assert f.find(a**2) == {meijerg(((), ()), ((S.Zero,), ()), x), x}

def test_expand_func():
    # evaluation at 1 of Gauss' hypergeometric function:
    from sympy.abc import a, b, c
    from sympy import gamma, expand_func

    a1, b1, c1 = randcplx(), randcplx(), randcplx() + 5
    assert expand_func(hyper([a, b], [c], 1)) == gamma(c) * gamma(-a - b + c) / (gamma(-a + c) * gamma(-b + c))
    assert abs(expand_func(hyper([a1, b1], [c1], 1)).n() - hyper([a1, b1], [c1], 1).n()) < 1e-10

    # hyperexpand wrapper for hyper:
    assert expand_func(hyper([], [], z)) == exp(z)
    assert expand_func(hyper([1, 2, 3], [], z)) == hyper([1, 2, 3], [], z)
    assert expand_func(meijerg([[1, 1], []], [[1], [0]], z)) == log(z + 1)
    assert expand_func(meijerg([[1, 1], []], [[], []], z)) == meijerg([[1, 1], []], [[], []], z)