Пример #1
0
    def _eval_expand_log(self, deep=True, **hints):
        from sympy import unpolarify
        force = hints.get('force', False)
        arg = self.args[0]
        if arg.is_Mul:
            expr = []
            nonpos = []
            for x in arg.args:
                if force or x.is_positive or x.is_polar:
                    a = self.func(x)
                    if isinstance(a, log):
                        expr.append(self.func(x)._eval_expand_log(**hints))
                    else:
                        expr.append(a)
                else:
                    nonpos.append(x)
            return Add(*expr) + log(Mul(*nonpos))
        elif arg.is_Pow:
            if force or (arg.exp.is_real and arg.base.is_positive) or \
                    arg.base.is_polar:
                b = arg.base
                e = arg.exp
                a = self.func(b)
                if isinstance(a, log):
                    return unpolarify(e) * a._eval_expand_log(**hints)
                else:
                    return unpolarify(e) * a

        return self.func(arg)
Пример #2
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    def eval(cls, nu, z):
        if z.is_zero:
            if nu.is_zero:
                return S.One
            elif (nu.is_integer and nu.is_zero is False) or re(nu).is_positive:
                return S.Zero
            elif re(nu).is_negative and not (nu.is_integer is True):
                return S.ComplexInfinity
            elif nu.is_imaginary:
                return S.NaN
        if z is S.Infinity or (z is S.NegativeInfinity):
            return S.Zero

        if z.could_extract_minus_sign():
            return (z)**nu*(-z)**(-nu)*besselj(nu, -z)
        if nu.is_integer:
            if nu.could_extract_minus_sign():
                return S(-1)**(-nu)*besselj(-nu, z)
            newz = z.extract_multiplicatively(I)
            if newz:  # NOTE we don't want to change the function if z==0
                return I**(nu)*besseli(nu, newz)

        # branch handling:
        from sympy import unpolarify, exp
        if nu.is_integer:
            newz = unpolarify(z)
            if newz != z:
                return besselj(nu, newz)
        else:
            newz, n = z.extract_branch_factor()
            if n != 0:
                return exp(2*n*pi*nu*I)*besselj(nu, newz)
        nnu = unpolarify(nu)
        if nu != nnu:
            return besselj(nnu, z)
Пример #3
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def test_expint():
    """ Test various exponential integrals. """
    from sympy import (expint, unpolarify, Symbol, Ci, Si, Shi, Chi,
                       sin, cos, sinh, cosh, Ei)
    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
Пример #4
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 xrange(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 xrange(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 xrange(n)])

        # TODO use minpoly instead of ad-hoc methods when issue 2789 is fixed
        if z.func is 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 xrange(q)])

        return lerchphi(z, s, a)
Пример #5
0
    def _eval_expand_log(self, deep=True, **hints):
        from sympy import unpolarify
        force = hints.get('force', False)
        if deep:
            arg = self.args[0].expand(deep=deep, **hints)
        else:
            arg = self.args[0]
        if arg.is_Mul:
            expr = []
            nonpos = []
            for x in arg.args:
                if deep:
                    x = x.expand(deep=deep, **hints)
                if force or x.is_positive or x.is_polar:
                    expr.append(self.func(x)._eval_expand_log(deep=deep, **hints))
                else:
                    nonpos.append(x)
            return Add(*expr) + log(Mul(*nonpos))
        elif arg.is_Pow:
            if force or (arg.exp.is_real and arg.base.is_positive) or \
                        arg.base.is_polar:
                if deep:
                    b = arg.base.expand(deep=deep, **hints)
                    e = arg.exp.expand(deep=deep, **hints)
                else:
                    b = arg.base
                    e = arg.exp
                return unpolarify(e) * self.func(b)._eval_expand_log(deep=deep,\
                **hints)

        return self.func(arg)
Пример #6
0
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)
Пример #7
0
 def fdiff(self, argindex=1):
     from sympy import unpolarify
     arg = unpolarify(self.args[0])
     if argindex == 1:
         return C.exp(arg)/arg
     else:
         raise ArgumentIndexError(self, argindex)
Пример #8
0
 def eval(cls, s, z):
     s, z = sympify((s, z))
     if z == 1:
         return zeta(s)
     elif z == -1:
         return -dirichlet_eta(s)
     elif z == 0:
         return S.Zero
     elif s == 2:
         if z == S.Half:
             return pi**2/12 - log(2)**2/2
         elif z == 2:
             return pi**2/4 - I*pi*log(2)
         elif z == -(sqrt(5) - 1)/2:
             return -pi**2/15 + log((sqrt(5)-1)/2)**2/2
         elif z == -(sqrt(5) + 1)/2:
             return -pi**2/10 - log((sqrt(5)+1)/2)**2
         elif z == (3 - sqrt(5))/2:
             return pi**2/15 - log((sqrt(5)-1)/2)**2
         elif z == (sqrt(5) - 1)/2:
             return pi**2/10 - log((sqrt(5)-1)/2)**2
     # For s = 0 or -1 use explicit formulas to evaluate, but
     # automatically expanding polylog(1, z) to -log(1-z) seems undesirable
     # for summation methods based on hypergeometric functions
     elif s == 0:
         return z/(1 - z)
     elif s == -1:
         return z/(1 - z)**2
     # polylog is branched, but not over the unit disk
     from sympy.functions.elementary.complexes import (Abs, unpolarify,
         polar_lift)
     if z.has(exp_polar, polar_lift) and (Abs(z) <= S.One) == True:
         return cls(s, unpolarify(z))
Пример #9
0
    def eval(cls, arg, base=None):
        from sympy import unpolarify
        if base is not None:
            base = sympify(base)

            if arg.is_positive and arg.is_Integer and \
               base.is_positive and base.is_Integer:
                base = int(base)
                arg = int(arg)
                n = multiplicity(base, arg)
                return S(n) + log(arg // base ** n) / log(base)
            if base is not S.Exp1:
                return cls(arg)/cls(base)
            else:
                return cls(arg)

        arg = sympify(arg)

        if arg.is_Number:
            if arg is S.Zero:
                return S.ComplexInfinity
            elif arg is S.One:
                return S.Zero
            elif arg is S.Infinity:
                return S.Infinity
            elif arg is S.NegativeInfinity:
                return S.Infinity
            elif arg is S.NaN:
                return S.NaN
            elif arg.is_negative:
                return S.Pi * S.ImaginaryUnit + cls(-arg)
            elif arg.is_Rational:
                if arg.q != 1:
                    return cls(arg.p) - cls(arg.q)
                # remove perfect powers automatically
                p = perfect_power(int(arg))
                if p is not False:
                    return p[1]*cls(p[0])
        elif arg is S.ComplexInfinity:
            return S.ComplexInfinity
        elif arg is S.Exp1:
            return S.One
        elif arg.func is exp and arg.args[0].is_real:
            return arg.args[0]
        elif arg.func is exp_polar:
            return unpolarify(arg.exp)
        #don't autoexpand Pow or Mul (see the issue 252):
        elif not arg.is_Add:
            coeff = arg.as_coefficient(S.ImaginaryUnit)

            if coeff is not None:
                if coeff is S.Infinity:
                    return S.Infinity
                elif coeff is S.NegativeInfinity:
                    return S.Infinity
                elif coeff.is_Rational:
                    if coeff.is_nonnegative:
                        return S.Pi * S.ImaginaryUnit * S.Half + cls(coeff)
                    else:
                        return -S.Pi * S.ImaginaryUnit * S.Half + cls(-coeff)
Пример #10
0
    def eval(cls, n, z):
        n, z = list(map(sympify, (n, z)))
        from sympy import unpolarify

        if n.is_integer:
            if n.is_nonnegative:
                nz = unpolarify(z)
                if z != nz:
                    return polygamma(n, nz)

            if n == -1:
                return loggamma(z)
            else:
                if z.is_Number:
                    if z is S.NaN:
                        return S.NaN
                    elif z is S.Infinity:
                        if n.is_Number:
                            if n is S.Zero:
                                return S.Infinity
                            else:
                                return S.Zero
                    elif z.is_Integer:
                        if z.is_nonpositive:
                            return S.ComplexInfinity
                        else:
                            if n is S.Zero:
                                return -S.EulerGamma + C.harmonic(z - 1, 1)
                            elif n.is_odd:
                                return (-1) ** (n + 1) * C.factorial(n) * zeta(n + 1, z)

        if n == 0:
            if z is S.NaN:
                return S.NaN
            elif z.is_Rational:
                # TODO actually *any* n/m can be done, but that is messy
                lookup = {
                    S(1) / 2: -2 * log(2) - S.EulerGamma,
                    S(1) / 3: -S.Pi / 2 / sqrt(3) - 3 * log(3) / 2 - S.EulerGamma,
                    S(1) / 4: -S.Pi / 2 - 3 * log(2) - S.EulerGamma,
                    S(3) / 4: -3 * log(2) - S.EulerGamma + S.Pi / 2,
                    S(2) / 3: -3 * log(3) / 2 + S.Pi / 2 / sqrt(3) - S.EulerGamma,
                }
                if z > 0:
                    n = floor(z)
                    z0 = z - n
                    if z0 in lookup:
                        return lookup[z0] + Add(*[1 / (z0 + k) for k in range(n)])
                elif z < 0:
                    n = floor(1 - z)
                    z0 = z + n
                    if z0 in lookup:
                        return lookup[z0] - Add(*[1 / (z0 - 1 - k) for k in range(n)])
            elif z in (S.Infinity, S.NegativeInfinity):
                return S.Infinity
            else:
                t = z.extract_multiplicatively(S.ImaginaryUnit)
                if t in (S.Infinity, S.NegativeInfinity):
                    return S.Infinity
Пример #11
0
    def _eval_expand_log(self, deep=True, **hints):
        from sympy import unpolarify, expand_log
        from sympy.concrete import Sum, Product
        force = hints.get('force', False)
        if (len(self.args) == 2):
            return expand_log(self.func(*self.args), deep=deep, force=force)
        arg = self.args[0]
        if arg.is_Integer:
            # remove perfect powers
            p = perfect_power(int(arg))
            if p is not False:
                return p[1]*self.func(p[0])
        elif arg.is_Rational:
            return log(arg.p) - log(arg.q)
        elif arg.is_Mul:
            expr = []
            nonpos = []
            for x in arg.args:
                if force or x.is_positive or x.is_polar:
                    a = self.func(x)
                    if isinstance(a, log):
                        expr.append(self.func(x)._eval_expand_log(**hints))
                    else:
                        expr.append(a)
                elif x.is_negative:
                    a = self.func(-x)
                    expr.append(a)
                    nonpos.append(S.NegativeOne)
                else:
                    nonpos.append(x)
            return Add(*expr) + log(Mul(*nonpos))
        elif arg.is_Pow or isinstance(arg, exp):
            if force or (arg.exp.is_real and (arg.base.is_positive or ((arg.exp+1)
                .is_positive and (arg.exp-1).is_nonpositive))) or arg.base.is_polar:
                b = arg.base
                e = arg.exp
                a = self.func(b)
                if isinstance(a, log):
                    return unpolarify(e) * a._eval_expand_log(**hints)
                else:
                    return unpolarify(e) * a
        elif isinstance(arg, Product):
            if arg.function.is_positive:
                return Sum(log(arg.function), *arg.limits)

        return self.func(arg)
Пример #12
0
 def fdiff(self, argindex=2):
     from sympy import meijerg, unpolarify
     if argindex == 2:
         a, z = self.args
         return -C.exp(-unpolarify(z))*z**(a - 1)
     elif argindex == 1:
         a, z = self.args
         return uppergamma(a, z)*log(z) + meijerg([], [1, 1], [0, 0, a], [], z)
     else:
         raise ArgumentIndexError(self, argindex)
Пример #13
0
    def eval(cls, nu, z):
        if nu.is_Integer:
            newz = z.extract_multiplicatively(I)
            if newz:  # NOTE we don't want to change the function if z==0
                return I**(-nu)*besselj(nu, -newz)

        # branch handling:
        from sympy import unpolarify, exp
        if nu.is_integer:
            newz = unpolarify(z)
            if newz != z:
                return besseli(nu, newz)
        else:
            newz, n = z.extract_branch_factor()
            if n != 0:
                return exp(2*n*pi*nu*I)*besseli(nu, newz)
        nnu = unpolarify(nu)
        if nu != nnu:
            return besseli(nnu, z)
Пример #14
0
    def eval(cls, nu, z):
        from sympy import unpolarify, expand_mul, uppergamma, exp, gamma, factorial

        nu2 = unpolarify(nu)
        if nu != nu2:
            return expint(nu2, z)
        if nu.is_Integer and nu <= 0 or (not nu.is_Integer and (2 * nu).is_Integer):
            return unpolarify(expand_mul(z ** (nu - 1) * uppergamma(1 - nu, z)))

        # Extract branching information. This can be deduced from what is
        # explained in lowergamma.eval().
        z, n = z.extract_branch_factor()
        if n == 0:
            return
        if nu.is_integer:
            if (nu > 0) is not True:
                return
            return expint(nu, z) - 2 * pi * I * n * (-1) ** (nu - 1) / factorial(nu - 1) * unpolarify(z) ** (nu - 1)
        else:
            return (exp(2 * I * pi * nu * n) - 1) * z ** (nu - 1) * gamma(1 - nu) + expint(nu, z)
Пример #15
0
    def eval(cls, a, z):
        from sympy import unpolarify, I, expint
        if z.is_Number:
            if z is S.NaN:
                return S.NaN
            elif z is S.Infinity:
                return S.Zero
            elif z is S.Zero:
                # TODO: Holds only for Re(a) > 0:
                return gamma(a)

        # We extract branching information here. C/f lowergamma.
        nx, n = z.extract_branch_factor()
        if a.is_integer and (a > 0) == True:
            nx = unpolarify(z)
            if z != nx:
                return uppergamma(a, nx)
        elif a.is_integer and (a <= 0) == True:
            if n != 0:
                return -2*pi*I*n*(-1)**(-a)/factorial(-a) + uppergamma(a, nx)
        elif n != 0:
            return gamma(a)*(1 - exp(2*pi*I*n*a)) + exp(2*pi*I*n*a)*uppergamma(a, nx)

        # Special values.
        if a.is_Number:
            if a is S.One:
                return exp(-z)
            elif a is S.Half:
                return sqrt(pi)*erfc(sqrt(z))
            elif a.is_Integer or (2*a).is_Integer:
                b = a - 1
                if b.is_positive:
                    if a.is_integer:
                        return exp(-z) * factorial(b) * Add(*[z**k / factorial(k) for k in range(a)])
                    else:
                        return gamma(a) * erfc(sqrt(z)) + (-1)**(a - S(3)/2) * exp(-z) * sqrt(z) * Add(*[gamma(-S.Half - k) * (-z)**k / gamma(1-a) for k in range(a - S.Half)])
                elif b.is_Integer:
                    return expint(-b, z)*unpolarify(z)**(b + 1)

                if not a.is_Integer:
                    return (-1)**(S.Half - a) * pi*erfc(sqrt(z))/gamma(1-a) - z**a * exp(-z) * Add(*[z**k * gamma(a) / gamma(a+k+1) for k in range(S.Half - a)])
Пример #16
0
 def _eval_rewrite_as_Ei(self, nu, z):
     from sympy import exp_polar, unpolarify, exp, factorial
     if nu == 1:
         return -Ei(z*exp_polar(-I*pi)) - I*pi
     elif nu.is_Integer and nu > 1:
         # DLMF, 8.19.7
         x = -unpolarify(z)
         return x**(nu - 1)/factorial(nu - 1)*E1(z).rewrite(Ei) + \
             exp(x)/factorial(nu - 1) * \
             Add(*[factorial(nu - k - 2)*x**k for k in range(nu - 1)])
     else:
         return self
Пример #17
0
    def eval(cls, a, z):
        from sympy import unpolarify, I, factorial, exp, expint

        if z.is_Number:
            if z is S.NaN:
                return S.NaN
            elif z is S.Infinity:
                return S.Zero
            elif z is S.Zero:
                # TODO: Holds only for Re(a) > 0:
                return gamma(a)

        # We extract branching information here. C/f lowergamma.
        nx, n = z.extract_branch_factor()
        if a.is_integer and (a > 0) == True:
            nx = unpolarify(z)
            if z != nx:
                return uppergamma(a, nx)
        elif a.is_integer and (a <= 0) == True:
            if n != 0:
                return -2 * pi * I * n * (-1) ** (-a) / factorial(-a) + uppergamma(a, nx)
        elif n != 0:
            return gamma(a) * (1 - exp(2 * pi * I * n * a)) + exp(2 * pi * I * n * a) * uppergamma(a, nx)

        # Special values.
        if a.is_Number:
            # TODO this should be non-recursive
            if a is S.One:
                return C.exp(-z)
            elif a is S.Half:
                return sqrt(pi) * (1 - erf(sqrt(z)))  # TODO could use erfc...
            elif a.is_Integer or (2 * a).is_Integer:
                b = a - 1
                if b.is_positive:
                    return b * cls(b, z) + z ** b * C.exp(-z)
                elif b.is_Integer:
                    return expint(-b, z) * unpolarify(z) ** (b + 1)

                if not a.is_Integer:
                    return (cls(a + 1, z) - z ** a * C.exp(-z)) / a
Пример #18
0
    def eval(cls, a, z):
        from sympy import unpolarify, I, expint
        if z.is_Number:
            if z is S.NaN:
                return S.NaN
            elif z is S.Infinity:
                return S.Zero
            elif z is S.Zero:
                # TODO: Holds only for Re(a) > 0:
                return gamma(a)

        # We extract branching information here. C/f lowergamma.
        nx, n = z.extract_branch_factor()
        if a.is_integer and (a > 0) == True:
            nx = unpolarify(z)
            if z != nx:
                return uppergamma(a, nx)
        elif a.is_integer and (a <= 0) == True:
            if n != 0:
                return -2*pi*I*n*(-1)**(-a)/factorial(-a) + uppergamma(a, nx)
        elif n != 0:
            return gamma(a)*(1 - exp(2*pi*I*n*a)) + exp(2*pi*I*n*a)*uppergamma(a, nx)

        # Special values.
        if a.is_Number:
            # TODO this should be non-recursive
            if a is S.One:
                return exp(-z)
            elif a is S.Half:
                return sqrt(pi)*erfc(sqrt(z))
            elif a.is_Integer or (2*a).is_Integer:
                b = a - 1
                if b.is_positive:
                    return b*cls(b, z) + z**b * exp(-z)
                elif b.is_Integer:
                    return expint(-b, z)*unpolarify(z)**(b + 1)

                if not a.is_Integer:
                    return (cls(a + 1, z) - z**a * exp(-z))/a
Пример #19
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    def eval(cls, n, z):
        n, z = map(sympify, (n, z))
        from sympy import unpolarify

        if n.is_integer:
            if n.is_nonnegative:
                nz = unpolarify(z)
                if z != nz:
                    return polygamma(n, nz)

            if n is S.NegativeOne:
                return loggamma(z)
            else:
                if z.is_Number:
                    if z is S.NaN:
                        return S.NaN
                    elif z is S.Infinity:
                        if n.is_Number:
                            if n.is_zero:
                                return S.Infinity
                            else:
                                return S.Zero
                        if n.is_zero:
                            return S.Infinity
                    elif z.is_Integer:
                        if z.is_nonpositive:
                            return S.ComplexInfinity
                        else:
                            if n.is_zero:
                                return -S.EulerGamma + harmonic(z - 1, 1)
                            elif n.is_odd:
                                return (-1)**(n + 1) * factorial(n) * zeta(
                                    n + 1, z)

        if n.is_zero:
            if z is S.NaN:
                return S.NaN
            elif z.is_Rational:

                p, q = z.as_numer_denom()

                # only expand for small denominators to avoid creating long expressions
                if q <= 5:
                    return expand_func(polygamma(S.Zero, z, evaluate=False))

            elif z in (S.Infinity, S.NegativeInfinity):
                return S.Infinity
            else:
                t = z.extract_multiplicatively(S.ImaginaryUnit)
                if t in (S.Infinity, S.NegativeInfinity):
                    return S.Infinity
Пример #20
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    def _eval_expand_log(self, deep=True, **hints):
        from sympy import unpolarify
        from sympy.concrete import Sum, Product
        force = hints.get('force', False)
        arg = self.args[0]
        if arg.is_Integer:
            # remove perfect powers
            p = perfect_power(int(arg))
            if p is not False:
                return p[1] * self.func(p[0])
        elif arg.is_Mul:
            expr = []
            nonpos = []
            for x in arg.args:
                if force or x.is_positive or x.is_polar:
                    a = self.func(x)
                    if isinstance(a, log):
                        expr.append(self.func(x)._eval_expand_log(**hints))
                    else:
                        expr.append(a)
                else:
                    nonpos.append(x)
            return Add(*expr) + log(Mul(*nonpos))
        elif arg.is_Pow:
            if force or (arg.exp.is_real and arg.base.is_positive) or \
                    arg.base.is_polar:
                b = arg.base
                e = arg.exp
                a = self.func(b)
                if isinstance(a, log):
                    return unpolarify(e) * a._eval_expand_log(**hints)
                else:
                    return unpolarify(e) * a
        elif isinstance(arg, Product):
            if arg.function.is_positive:
                return Sum(log(arg.function), *arg.limits)

        return self.func(arg)
Пример #21
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    def _eval_expand_log(self, deep=True, **hints):
        from sympy import unpolarify
        from sympy.concrete import Sum, Product
        force = hints.get('force', False)
        arg = self.args[0]
        if arg.is_Integer:
            # remove perfect powers
            p = perfect_power(int(arg))
            if p is not False:
                return p[1]*self.func(p[0])
        elif arg.is_Mul:
            expr = []
            nonpos = []
            for x in arg.args:
                if force or x.is_positive or x.is_polar:
                    a = self.func(x)
                    if isinstance(a, log):
                        expr.append(self.func(x)._eval_expand_log(**hints))
                    else:
                        expr.append(a)
                else:
                    nonpos.append(x)
            return Add(*expr) + log(Mul(*nonpos))
        elif arg.is_Pow:
            if force or (arg.exp.is_real and arg.base.is_positive) or \
                    arg.base.is_polar:
                b = arg.base
                e = arg.exp
                a = self.func(b)
                if isinstance(a, log):
                    return unpolarify(e) * a._eval_expand_log(**hints)
                else:
                    return unpolarify(e) * a
        elif isinstance(arg, Product):
            if arg.function.is_positive:
                return Sum(log(arg.function), *arg.limits)

        return self.func(arg)
Пример #22
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    def eval(cls, nu, z):
        if nu.is_Integer:
            if nu < 0:
                return S(-1)**nu * besselj(-nu, z)
            if z.could_extract_minus_sign():
                return S(-1)**nu * besselj(nu, -z)
            newz = z.extract_multiplicatively(I)
            if newz:  # NOTE we don't want to change the function if z==0
                return I**(nu) * besseli(nu, newz)

        # branch handling:
        from sympy import unpolarify, exp
        if nu.is_integer:
            newz = unpolarify(z)
            if newz != z:
                return besselj(nu, newz)
        else:
            newz, n = z.extract_branch_factor()
            if n != 0:
                return exp(2 * n * pi * nu * I) * besselj(nu, newz)
        nnu = unpolarify(nu)
        if nu != nnu:
            return besselj(nnu, z)
Пример #23
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    def eval(cls, nu, z):
        from sympy import (unpolarify, expand_mul, uppergamma, exp, gamma,
                           factorial)
        nu2 = unpolarify(nu)
        if nu != nu2:
            return expint(nu2, z)
        if nu.is_Integer and nu <= 0 or (not nu.is_Integer and
                                         (2 * nu).is_Integer):
            return unpolarify(expand_mul(z**(nu - 1) * uppergamma(1 - nu, z)))

        # Extract branching information. This can be deduced from what is
        # explained in lowergamma.eval().
        z, n = z.extract_branch_factor()
        if n == 0:
            return
        if nu.is_integer:
            if (nu > 0) is not True:
                return
            return expint(nu, z) \
                - 2*pi*I*n*(-1)**(nu - 1)/factorial(nu - 1)*unpolarify(z)**(nu - 1)
        else:
            return (exp(2 * I * pi * nu * n) -
                    1) * z**(nu - 1) * gamma(1 - nu) + expint(nu, z)
Пример #24
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    def eval(cls, a, x):
        # For lack of a better place, we use this one to extract branching
        # information. The following can be
        # found in the literature (c/f references given above), albeit scattered:
        # 1) For fixed x != 0, lowergamma(s, x) is an entire function of s
        # 2) For fixed positive integers s, lowergamma(s, x) is an entire
        #    function of x.
        # 3) For fixed non-positive integers s,
        #    lowergamma(s, exp(I*2*pi*n)*x) =
        #              2*pi*I*n*(-1)**(-s)/factorial(-s) + lowergamma(s, x)
        #    (this follows from lowergamma(s, x).diff(x) = x**(s-1)*exp(-x)).
        # 4) For fixed non-integral s,
        #    lowergamma(s, x) = x**s*gamma(s)*lowergamma_unbranched(s, x),
        #    where lowergamma_unbranched(s, x) is an entire function (in fact
        #    of both s and x), i.e.
        #    lowergamma(s, exp(2*I*pi*n)*x) = exp(2*pi*I*n*a)*lowergamma(a, x)
        from sympy import unpolarify, I
        if x is S.Zero:
            return S.Zero
        nx, n = x.extract_branch_factor()
        if a.is_integer and a.is_positive:
            nx = unpolarify(x)
            if nx != x:
                return lowergamma(a, nx)
        elif a.is_integer and a.is_nonpositive:
            if n != 0:
                return 2*pi*I*n*(-1)**(-a)/factorial(-a) + lowergamma(a, nx)
        elif n != 0:
            return exp(2*pi*I*n*a)*lowergamma(a, nx)

        # Special values.
        if a.is_Number:
            if a is S.One:
                return S.One - exp(-x)
            elif a is S.Half:
                return sqrt(pi)*erf(sqrt(x))
            elif a.is_Integer or (2*a).is_Integer:
                b = a - 1
                if b.is_positive:
                    if a.is_integer:
                        return factorial(b) - exp(-x) * factorial(b) * Add(*[x ** k / factorial(k) for k in range(a)])
                    else:
                        return gamma(a)*(lowergamma(S.Half, x)/sqrt(pi) - exp(-x)*Add(*[x**(k - S.Half)/gamma(S.Half + k) for k in range(1, a + S.Half)]))

                if not a.is_Integer:
                    return (-1)**(S.Half - a)*pi*erf(sqrt(x))/gamma(1 - a) + exp(-x)*Add(*[x**(k + a - 1)*gamma(a)/gamma(a + k) for k in range(1, Rational(3, 2) - a)])

        if x.is_zero:
            return S.Zero
Пример #25
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    def eval(cls, s, z):
        s, z = sympify((s, z))
        if z is S.One:
            return zeta(s)
        elif z is S.NegativeOne:
            return -dirichlet_eta(s)
        elif z is S.Zero:
            return S.Zero
        elif s == 2:
            if z == S.Half:
                return pi**2 / 12 - log(2)**2 / 2
            elif z == 2:
                return pi**2 / 4 - I * pi * log(2)
            elif z == -(sqrt(5) - 1) / 2:
                return -pi**2 / 15 + log((sqrt(5) - 1) / 2)**2 / 2
            elif z == -(sqrt(5) + 1) / 2:
                return -pi**2 / 10 - log((sqrt(5) + 1) / 2)**2
            elif z == (3 - sqrt(5)) / 2:
                return pi**2 / 15 - log((sqrt(5) - 1) / 2)**2
            elif z == (sqrt(5) - 1) / 2:
                return pi**2 / 10 - log((sqrt(5) - 1) / 2)**2

        if z.is_zero:
            return S.Zero

        # Make an effort to determine if z is 1 to avoid replacing into
        # expression with singularity
        zone = z.equals(S.One)

        if zone:
            return zeta(s)
        elif zone is False:
            # For s = 0 or -1 use explicit formulas to evaluate, but
            # automatically expanding polylog(1, z) to -log(1-z) seems
            # undesirable for summation methods based on hypergeometric
            # functions
            if s is S.Zero:
                return z / (1 - z)
            elif s is S.NegativeOne:
                return z / (1 - z)**2
            if s.is_zero:
                return z / (1 - z)

        # polylog is branched, but not over the unit disk
        from sympy.functions.elementary.complexes import (Abs, unpolarify,
                                                          polar_lift)
        if z.has(exp_polar, polar_lift) and (zone or
                                             (Abs(z) <= S.One) == True):
            return cls(s, unpolarify(z))
Пример #26
0
    def eval(cls, nu, z):
        if z.is_zero:
            if nu.is_zero:
                return S.One
            elif (nu.is_integer and nu.is_zero == False) or re(nu).is_positive:
                return S.Zero
            elif re(nu).is_negative and not (nu.is_integer == True):
                return S.ComplexInfinity
            elif nu.is_imaginary:
                return S.NaN
        if z.is_imaginary:
            if im(z) is S.Infinity or im(z) is S.NegativeInfinity:
                return S.Zero

        if z.could_extract_minus_sign():
            return (z)**nu * (-z)**(-nu) * besseli(nu, -z)
        if nu.is_integer:
            if nu.could_extract_minus_sign():
                return besseli(-nu, z)
            newz = z.extract_multiplicatively(I)
            if newz:  # NOTE we don't want to change the function if z==0
                return I**(-nu) * besselj(nu, -newz)

        # branch handling:
        from sympy import unpolarify, exp
        if nu.is_integer:
            newz = unpolarify(z)
            if newz != z:
                return besseli(nu, newz)
        else:
            newz, n = z.extract_branch_factor()
            if n != 0:
                return exp(2 * n * pi * nu * I) * besseli(nu, newz)
        nnu = unpolarify(nu)
        if nu != nnu:
            return besseli(nnu, z)
Пример #27
0
    def eval(cls, n, z):
        n, z = map(sympify, (n, z))
        from sympy import unpolarify

        if n.is_integer:
            if n.is_nonnegative:
                nz = unpolarify(z)
                if z != nz:
                    return polygamma(n, nz)

            if n == -1:
                return loggamma(z)
            else:
                if z.is_Number:
                    if z is S.NaN:
                        return S.NaN
                    elif z is S.Infinity:
                        if n.is_Number:
                            if n is S.Zero:
                                return S.Infinity
                            else:
                                return S.Zero
                    elif z.is_Integer:
                        if z.is_nonpositive:
                            return S.ComplexInfinity
                        else:
                            if n is S.Zero:
                                return -S.EulerGamma + C.harmonic(z-1, 1)
                            elif n.is_odd:
                                return (-1)**(n+1)*C.factorial(n)*zeta(n+1, z)

        if n == 0 and z.is_Rational:
            # TODO actually *any* n/m can be done, but that is messy
            lookup = {S(1)/2: -2*log(2) - S.EulerGamma,
                      S(1)/3: -S.Pi/2/sqrt(3) - 3*log(3)/2 - S.EulerGamma,
                      S(1)/4: -S.Pi/2 - 3*log(2) - S.EulerGamma,
                      S(3)/4: -3*log(2) - S.EulerGamma + S.Pi/2,
                      S(2)/3: -3*log(3)/2 + S.Pi/2/sqrt(3) - S.EulerGamma}
            if z > 0:
                n = floor(z)
                z0 = z - n
                if z0 in lookup:
                    return lookup[z0] + Add(*[1/(z0 + k) for k in range(n)])
            elif z < 0:
                n = floor(1 - z)
                z0 = z + n
                if z0 in lookup:
                    return lookup[z0] - Add(*[1/(z0 - 1 - k) for k in range(n)])
Пример #28
0
    def eval(cls, n, z):
        n, z = list(map(sympify, (n, z)))
        from sympy import unpolarify

        if n.is_integer:
            if n.is_nonnegative:
                nz = unpolarify(z)
                if z != nz:
                    return polygamma(n, nz)

            if n == -1:
                return loggamma(z)
            else:
                if z.is_Number:
                    if z is S.NaN:
                        return S.NaN
                    elif z is S.Infinity:
                        if n.is_Number:
                            if n is S.Zero:
                                return S.Infinity
                            else:
                                return S.Zero
                    elif z.is_Integer:
                        if z.is_nonpositive:
                            return S.ComplexInfinity
                        else:
                            if n is S.Zero:
                                return -S.EulerGamma + harmonic(z - 1, 1)
                            elif n.is_odd:
                                return (-1)**(n + 1)*factorial(n)*zeta(n + 1, z)

        if n == 0:
            if z is S.NaN:
                return S.NaN
            elif z.is_Rational:

                p, q = z.as_numer_denom()

                # only expand for small denominators to avoid creating long expressions
                if q <= 5:
                    return expand_func(polygamma(n, z, evaluate=False))

            elif z in (S.Infinity, S.NegativeInfinity):
                return S.Infinity
            else:
                t = z.extract_multiplicatively(S.ImaginaryUnit)
                if t in (S.Infinity, S.NegativeInfinity):
                    return S.Infinity
Пример #29
0
    def fdiff(self, argindex=2):
        from sympy import meijerg, unpolarify

        if argindex == 2:
            a, z = self.args
            return exp(-unpolarify(z)) * z ** (a - 1)
        elif argindex == 1:
            a, z = self.args
            return (
                gamma(a) * digamma(a)
                - log(z) * uppergamma(a, z)
                - meijerg([], [1, 1], [0, 0, a], [], z)
            )

        else:
            raise ArgumentIndexError(self, argindex)
Пример #30
0
    def eval(cls, a, x):
        # For lack of a better place, we use this one to extract branching
        # information. The following can be
        # found in the literature (c/f references given above), albeit scattered:
        # 1) For fixed x != 0, lowergamma(s, x) is an entire function of s
        # 2) For fixed positive integers s, lowergamma(s, x) is an entire
        #    function of x.
        # 3) For fixed non-positive integers s,
        #    lowergamma(s, exp(I*2*pi*n)*x) =
        #              2*pi*I*n*(-1)**(-s)/factorial(-s) + lowergamma(s, x)
        #    (this follows from lowergamma(s, x).diff(x) = x**(s-1)*exp(-x)).
        # 4) For fixed non-integral s,
        #    lowergamma(s, x) = x**s*gamma(s)*lowergamma_unbranched(s, x),
        #    where lowergamma_unbranched(s, x) is an entire function (in fact
        #    of both s and x), i.e.
        #    lowergamma(s, exp(2*I*pi*n)*x) = exp(2*pi*I*n*a)*lowergamma(a, x)
        from sympy import unpolarify, I
        if x == 0:
            return S.Zero
        nx, n = x.extract_branch_factor()
        if a.is_integer and a.is_positive:
            nx = unpolarify(x)
            if nx != x:
                return lowergamma(a, nx)
        elif a.is_integer and a.is_nonpositive:
            if n != 0:
                return 2*pi*I*n*(-1)**(-a)/factorial(-a) + lowergamma(a, nx)
        elif n != 0:
            return exp(2*pi*I*n*a)*lowergamma(a, nx)

        # Special values.
        if a.is_Number:
            if a is S.One:
                return S.One - exp(-x)
            elif a is S.Half:
                return sqrt(pi)*erf(sqrt(x))
            elif a.is_Integer or (2*a).is_Integer:
                b = a - 1
                if b.is_positive:
                    if a.is_integer:
                        return factorial(b) - exp(-x) * factorial(b) * Add(*[x ** k / factorial(k) for k in range(a)])
                    else:
                        return gamma(a) * (lowergamma(S.Half, x)/sqrt(pi) - exp(-x) * Add(*[x**(k-S.Half) / gamma(S.Half+k) for k in range(1, a+S.Half)]))

                if not a.is_Integer:
                    return (-1)**(S.Half - a) * pi*erf(sqrt(x)) / gamma(1-a) + exp(-x) * Add(*[x**(k+a-1)*gamma(a) / gamma(a+k) for k in range(1, S(3)/2-a)])
Пример #31
0
def test_expint():
    from sympy import E1, expint, Max, re, lerchphi, Symbol, simplify, Si, Ci, Ei

    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(1) / 2) / (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(1) / 2)),
        (0, 1),
        True,
    )
    assert inverse_mellin_transform(
        -4 ** s * sqrt(pi) * gamma(s) / (2 * s * gamma(-s + S(1) / 2)), 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 * polar_lift(-1), 1, a), 0, S(0) < re(a))
    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()
    )
Пример #32
0
    def eval(cls, a, x):
        # For lack of a better place, we use this one to extract branching
        # information. The following can be
        # found in the literature (c/f references given above), albeit scattered:
        # 1) For fixed x != 0, lowergamma(s, x) is an entire function of s
        # 2) For fixed positive integers s, lowergamma(s, x) is an entire
        #    function of x.
        # 3) For fixed non-positive integers s,
        #    lowergamma(s, exp(I*2*pi*n)*x) =
        #              2*pi*I*n*(-1)**(-s)/factorial(-s) + lowergamma(s, x)
        #    (this follows from lowergamma(s, x).diff(x) = x**(s-1)*exp(-x)).
        # 4) For fixed non-integral s,
        #    lowergamma(s, x) = x**s*gamma(s)*lowergamma_unbranched(s, x),
        #    where lowergamma_unbranched(s, x) is an entire function (in fact
        #    of both s and x), i.e.
        #    lowergamma(s, exp(2*I*pi*n)*x) = exp(2*pi*I*n*a)*lowergamma(a, x)
        from sympy import unpolarify, I
        if x == 0:
            return S.Zero
        nx, n = x.extract_branch_factor()
        if a.is_integer and a.is_positive:
            nx = unpolarify(x)
            if nx != x:
                return lowergamma(a, nx)
        elif a.is_integer and a.is_nonpositive:
            if n != 0:
                return 2 * pi * I * n * (-1)**(
                    -a) / factorial(-a) + lowergamma(a, nx)
        elif n != 0:
            return exp(2 * pi * I * n * a) * lowergamma(a, nx)

        # Special values.
        if a.is_Number:
            # TODO this should be non-recursive
            if a is S.One:
                return S.One - exp(-x)
            elif a is S.Half:
                return sqrt(pi) * erf(sqrt(x))
            elif a.is_Integer or (2 * a).is_Integer:
                b = a - 1
                if b.is_positive:
                    return b * cls(b, x) - x**b * exp(-x)

                if not a.is_Integer:
                    return (cls(a + 1, x) + x**a * exp(-x)) / a
Пример #33
0
def _prep_tuple(v):
    """
    Turn an iterable argument V into a Tuple and unpolarify, since both
    hypergeometric and meijer g-functions are unbranched in their parameters.

    Examples
    ========

    >>> from sympy.functions.special.hyper import _prep_tuple
    >>> _prep_tuple([1, 2, 3])
    (1, 2, 3)
    >>> _prep_tuple((4, 5))
    (4, 5)
    >>> _prep_tuple((7, 8, 9))
    (7, 8, 9)
    """
    from sympy import unpolarify
    return TupleArg(*[unpolarify(x) for x in v])
Пример #34
0
def _prep_tuple(v):
    """
    Turn an iterable argument V into a Tuple and unpolarify, since both
    hypergeometric and meijer g-functions are unbranched in their parameters.

    Examples
    ========

    >>> from sympy.functions.special.hyper import _prep_tuple
    >>> _prep_tuple([1, 2, 3])
    (1, 2, 3)
    >>> _prep_tuple((4, 5))
    (4, 5)
    >>> _prep_tuple((7, 8, 9))
    (7, 8, 9)
    """
    from sympy import unpolarify
    return TupleArg(*[unpolarify(x) for x in v])
Пример #35
0
def _make_tuple(v):
    """
    Turn an iterable argument V into a Tuple.
    Also unpolarify, since both hypergeometric and meijer g-functions are
    unbranched in their parameters.

    Examples:
    >>> from sympy.functions.special.hyper import _make_tuple as mt
    >>> from sympy.core.containers import Tuple
    >>> mt([1, 2, 3])
    (1, 2, 3)
    >>> mt((4, 5))
    (4, 5)
    >>> mt((7, 8, 9))
    (7, 8, 9)
    """
    from sympy import unpolarify
    return Tuple(*[unpolarify(sympify(x)) for x in v])
Пример #36
0
def _make_tuple(v):
    """
    Turn an iterable argument V into a Tuple.
    Also unpolarify, since both hypergeometric and meijer g-functions are
    unbranched in their parameters.

    Examples:
    >>> from sympy.functions.special.hyper import _make_tuple as mt
    >>> from sympy.core.containers import Tuple
    >>> mt([1, 2, 3])
    (1, 2, 3)
    >>> mt((4, 5))
    (4, 5)
    >>> mt((7, 8, 9))
    (7, 8, 9)
    """
    from sympy import unpolarify
    return Tuple(*[unpolarify(sympify(x)) for x in v])
Пример #37
0
def test_expint():
    from sympy import E1, expint, Max, re, lerchphi, Symbol, simplify, Si, Ci, Ei
    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(1)/2)/(
        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(1)/2)), (0, 1), True)
    assert inverse_mellin_transform(
        -4**s * sqrt(pi) * gamma(s) / (2 * s * gamma(-s + S(1) / 2)), 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*polar_lift(-1), 1, a), 0, S(0) < re(a))
    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()
Пример #38
0
    def eval(cls, a, x):
        # For lack of a better place, we use this one to extract branching
        # information. The following can be
        # found in the literature (c/f references given above), albeit scattered:
        # 1) For fixed x != 0, lowergamma(s, x) is an entire function of s
        # 2) For fixed positive integers s, lowergamma(s, x) is an entire
        #    function of x.
        # 3) For fixed non-positive integers s,
        #    lowergamma(s, exp(I*2*pi*n)*x) =
        #              2*pi*I*n*(-1)**(-s)/factorial(-s) + lowergamma(s, x)
        #    (this follows from lowergamma(s, x).diff(x) = x**(s-1)*exp(-x)).
        # 4) For fixed non-integral s,
        #    lowergamma(s, x) = x**s*gamma(s)*lowergamma_unbranched(s, x),
        #    where lowergamma_unbranched(s, x) is an entire function (in fact
        #    of both s and x), i.e.
        #    lowergamma(s, exp(2*I*pi*n)*x) = exp(2*pi*I*n*a)*lowergamma(a, x)
        from sympy import unpolarify, I
        if x == 0:
            return S.Zero
        nx, n = x.extract_branch_factor()
        if a.is_integer and a.is_positive:
            nx = unpolarify(x)
            if nx != x:
                return lowergamma(a, nx)
        elif a.is_integer and a.is_nonpositive:
            if n != 0:
                return 2*pi*I*n*(-1)**(-a)/factorial(-a) + lowergamma(a, nx)
        elif n != 0:
            return exp(2*pi*I*n*a)*lowergamma(a, nx)

        # Special values.
        if a.is_Number:
            # TODO this should be non-recursive
            if a is S.One:
                return S.One - exp(-x)
            elif a is S.Half:
                return sqrt(pi)*erf(sqrt(x))
            elif a.is_Integer or (2*a).is_Integer:
                b = a - 1
                if b.is_positive:
                    return b*cls(b, x) - x**b * exp(-x)

                if not a.is_Integer:
                    return (cls(a + 1, x) + x**a * exp(-x))/a
Пример #39
0
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, ai in enumerate(meijerg(a1, a2, b1, b2, z).free_symbols - {z}):
        repl[ai] = randcplx(n)
    return tn(meijerg(a1, a2, b1, b2, z).subs(repl), r.subs(repl), z)
Пример #40
0
def test_unpolarify():
    from sympy import (exp_polar, polar_lift, exp, unpolarify,
                       principal_branch)
    from sympy import gamma, erf, sin, tanh, uppergamma, Eq, Ne
    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
Пример #41
0
    def _eval_expand_log(self, deep=True, **hints):
        from sympy import unpolarify, expand_log, factorint
        from sympy.concrete import Sum, Product
        from sympy.functions.elementary.complexes import Abs
        force = hints.get('force', False)
        factor = hints.get('factor', False)
        if (len(self.args) == 2):
            return expand_log(self.func(*self.args), deep=deep, force=force)
        arg = self.args[0]
        if arg.is_Integer:
            # remove perfect powers
            p = perfect_power(arg)
            logarg = None
            coeff = 1
            if p is not False:
                arg, coeff = p
                logarg = self.func(arg)
            # expand as product of its prime factors if factor=True
            if factor:
                p = factorint(arg)
                if arg not in p.keys():
                    logarg = sum(n * log(val) for val, n in p.items())
            if logarg is not None:
                return coeff * logarg
        elif arg.is_Rational:
            return log(arg.p) - log(arg.q)
        elif arg.is_Mul:
            expr = []
            nonpos = []
            for x in arg.args:
                if force or (x.is_real and not x.is_negative) or x.is_polar:
                    a = self.func(x)
                    if isinstance(a, log):
                        expr.append(self.func(x)._eval_expand_log(**hints))
                    else:
                        expr.append(a)
                elif x.is_negative:
                    a = self.func(-x)
                    expr.append(a)
                    nonpos.append(S.NegativeOne)
                else:
                    nonpos.append(x)
            return Add(*expr) + log(Mul(*nonpos))
        elif arg.is_Pow or isinstance(arg, exp):
            # expanding log(b^e)
            b = arg.base
            e = arg.exp
            if e % 2 == 0 and b.is_real:
                # even power and real base obeys the power rule: log(b^e) = e log(Abs(b))
                return e * self.func(Abs(b))
            elif e % 2 == 1 and b.is_real:
                # odd power and real base obeys the power rule: log(b^e) = e log(b)
                return e * self.func(b)
            elif force or (e.is_extended_real and
                           (b.is_positive or
                            ((e + 1).is_positive and
                             (e - 1).is_nonpositive))) or b.is_polar:
                a = self.func(b)
                if isinstance(a, log):
                    return unpolarify(e) * a._eval_expand_log(**hints)
                else:
                    return unpolarify(e) * a
        elif isinstance(arg, Product):
            if force or arg.function.is_positive:
                return Sum(log(arg.function), *arg.limits)

        return self.func(arg)
Пример #42
0
    def eval(cls, arg, base=None):
        from sympy import unpolarify
        arg = sympify(arg)

        if base is not None:
            base = sympify(base)
            if base == 1:
                if arg == 1:
                    return S.NaN
                else:
                    return S.ComplexInfinity
            try:
                # handle extraction of powers of the base now
                # or else expand_log in Mul would have to handle this
                n = multiplicity(base, arg)
                if n:
                    den = base**n
                    if den.is_Integer:
                        return n + log(arg // den) / log(base)
                    else:
                        return n + log(arg / den) / log(base)
                else:
                    return log(arg)/log(base)
            except ValueError:
                pass
            if base is not S.Exp1:
                return cls(arg)/cls(base)
            else:
                return cls(arg)

        if arg.is_Number:
            if arg is S.Zero:
                return S.ComplexInfinity
            elif arg is S.One:
                return S.Zero
            elif arg is S.Infinity:
                return S.Infinity
            elif arg is S.NegativeInfinity:
                return S.Infinity
            elif arg is S.NaN:
                return S.NaN
            elif arg.is_negative:
                return S.Pi * S.ImaginaryUnit + cls(-arg)
            elif arg.is_Rational:
                if arg.q != 1:
                    return cls(arg.p) - cls(arg.q)
        elif arg is S.ComplexInfinity:
            return S.ComplexInfinity
        elif arg is S.Exp1:
            return S.One
        elif arg.func is exp and arg.args[0].is_real:
            return arg.args[0]
        elif arg.func is exp_polar:
            return unpolarify(arg.exp)
        #don't autoexpand Pow or Mul (see the issue 252):
        elif not arg.is_Add:
            coeff = arg.as_coefficient(S.ImaginaryUnit)

            if coeff is not None:
                if coeff is S.Infinity:
                    return S.Infinity
                elif coeff is S.NegativeInfinity:
                    return S.Infinity
                elif coeff.is_Rational:
                    if coeff.is_nonnegative:
                        return S.Pi * S.ImaginaryUnit * S.Half + cls(coeff)
                    else:
                        return -S.Pi * S.ImaginaryUnit * S.Half + cls(-coeff)
Пример #43
0
def test_unpolarify():
    from sympy import (exp_polar, polar_lift, exp, unpolarify,
                       principal_branch)
    from sympy import gamma, erf, sin, tanh, uppergamma, Eq, Ne
    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
Пример #44
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)
Пример #45
0
    def eval(cls, arg, base=None):
        from sympy import unpolarify
        from sympy.calculus import AccumBounds
        from sympy.sets.setexpr import SetExpr

        arg = sympify(arg)

        if base is not None:
            base = sympify(base)
            if base == 1:
                if arg == 1:
                    return S.NaN
                else:
                    return S.ComplexInfinity
            try:
                # handle extraction of powers of the base now
                # or else expand_log in Mul would have to handle this
                n = multiplicity(base, arg)
                if n:
                    den = base**n
                    if den.is_Integer:
                        return n + log(arg // den) / log(base)
                    else:
                        return n + log(arg / den) / log(base)
                else:
                    return log(arg)/log(base)
            except ValueError:
                pass
            if base is not S.Exp1:
                return cls(arg)/cls(base)
            else:
                return cls(arg)

        if arg.is_Number:
            if arg is S.Zero:
                return S.ComplexInfinity
            elif arg is S.One:
                return S.Zero
            elif arg is S.Infinity:
                return S.Infinity
            elif arg is S.NegativeInfinity:
                return S.Infinity
            elif arg is S.NaN:
                return S.NaN
            elif arg.is_Rational and arg.p == 1:
                return -cls(arg.q)

        if arg is S.ComplexInfinity:
                return S.ComplexInfinity
        if isinstance(arg, exp) and arg.args[0].is_real:
            return arg.args[0]
        elif isinstance(arg, exp_polar):
            return unpolarify(arg.exp)
        elif isinstance(arg, AccumBounds):
            if arg.min.is_positive:
                return AccumBounds(log(arg.min), log(arg.max))
            else:
                return
        elif isinstance(arg, SetExpr):
            return arg._eval_func(cls)

        if arg.is_number:
            if arg.is_negative:
                return S.Pi * S.ImaginaryUnit + cls(-arg)
            elif arg is S.ComplexInfinity:
                return S.ComplexInfinity
            elif arg is S.Exp1:
                return S.One

        # don't autoexpand Pow or Mul (see the issue 3351):
        if not arg.is_Add:
            coeff = arg.as_coefficient(S.ImaginaryUnit)

            if coeff is not None:
                if coeff is S.Infinity:
                    return S.Infinity
                elif coeff is S.NegativeInfinity:
                    return S.Infinity
                elif coeff.is_Rational:
                    if coeff.is_nonnegative:
                        return S.Pi * S.ImaginaryUnit * S.Half + cls(coeff)
                    else:
                        return -S.Pi * S.ImaginaryUnit * S.Half + cls(-coeff)
Пример #46
0
 def fdiff(self, argindex=1):
     from sympy import unpolarify
     arg = unpolarify(self.args[0])
     if argindex == 1:
         return self._trigfunc(arg)/arg
Пример #47
0
 def eval(cls, ap, bq, z):
     from sympy import unpolarify
     if len(ap) <= len(bq) or (len(ap) == len(bq) + 1 and (Abs(z) <= 1) == True):
         nz = unpolarify(z)
         if z != nz:
             return hyper(ap, bq, nz)
Пример #48
0
    def eval(cls, arg, base=None):
        from sympy import unpolarify
        arg = sympify(arg)

        if base is not None:
            base = sympify(base)
            if base == 1:
                if arg == 1:
                    return S.NaN
                else:
                    return S.ComplexInfinity
            try:
                if not (base.is_positive and arg.is_positive):
                    raise ValueError
                n = multiplicity(base, arg)
                if n:
                    den = base**n
                    if den.is_Integer:
                        return n + log(arg // den) / log(base)
                    else:
                        return n + log(arg / den) / log(base)
                else:
                    return log(arg)/log(base)
            except ValueError:
                pass
            if base is not S.Exp1:
                return cls(arg)/cls(base)
            else:
                return cls(arg)

        if arg.is_Number:
            if arg is S.Zero:
                return S.ComplexInfinity
            elif arg is S.One:
                return S.Zero
            elif arg is S.Infinity:
                return S.Infinity
            elif arg is S.NegativeInfinity:
                return S.Infinity
            elif arg is S.NaN:
                return S.NaN
            elif arg.is_negative:
                return S.Pi * S.ImaginaryUnit + cls(-arg)
            elif arg.is_Rational:
                if arg.q != 1:
                    return cls(arg.p) - cls(arg.q)
                # remove perfect powers automatically
                p = perfect_power(int(arg))
                if p is not False:
                    return p[1]*cls(p[0])
        elif arg is S.ComplexInfinity:
            return S.ComplexInfinity
        elif arg is S.Exp1:
            return S.One
        elif arg.func is exp and arg.args[0].is_real:
            return arg.args[0]
        elif arg.func is exp_polar:
            return unpolarify(arg.exp)
        #don't autoexpand Pow or Mul (see the issue 252):
        elif not arg.is_Add:
            coeff = arg.as_coefficient(S.ImaginaryUnit)

            if coeff is not None:
                if coeff is S.Infinity:
                    return S.Infinity
                elif coeff is S.NegativeInfinity:
                    return S.Infinity
                elif coeff.is_Rational:
                    if coeff.is_nonnegative:
                        return S.Pi * S.ImaginaryUnit * S.Half + cls(coeff)
                    else:
                        return -S.Pi * S.ImaginaryUnit * S.Half + cls(-coeff)
Пример #49
0
 def fdiff(self, argindex=1):
     from sympy import unpolarify
     arg = unpolarify(self.args[0])
     if argindex == 1:
         return self._trigfunc(arg)/arg
Пример #50
0
 def mysimp(expr):
     return expand(
         unpolarify(simplify(expand(expand_func(expr.rewrite(besselj))))))
Пример #51
0
def unpolarify(x):
    return diffify(sympy.unpolarify(x))
Пример #52
0
 def eval(cls, ap, bq, z):
     from sympy import unpolarify
     if len(ap) <= len(bq) or (len(ap) == len(bq) + 1 and (Abs(z) <= 1) == True):
         nz = unpolarify(z)
         if z != nz:
             return hyper(ap, bq, nz)
Пример #53
0
    def eval(cls, a, z):
        from sympy import unpolarify, I, expint

        if z.is_Number:
            if z is S.NaN:
                return S.NaN
            elif z is S.Infinity:
                return S.Zero
            elif z.is_zero:
                if re(a).is_positive:
                    return gamma(a)

        # We extract branching information here. C/f lowergamma.
        nx, n = z.extract_branch_factor()
        if a.is_integer and a.is_positive:
            nx = unpolarify(z)
            if z != nx:
                return uppergamma(a, nx)
        elif a.is_integer and a.is_nonpositive:
            if n != 0:
                return -2 * pi * I * n * (-1) ** (-a) / factorial(-a) + uppergamma(
                    a, nx
                )
        elif n != 0:
            return gamma(a) * (1 - exp(2 * pi * I * n * a)) + exp(
                2 * pi * I * n * a
            ) * uppergamma(a, nx)

        # Special values.
        if a.is_Number:
            if a is S.Zero and z.is_positive:
                return -Ei(-z)
            elif a is S.One:
                return exp(-z)
            elif a is S.Half:
                return sqrt(pi) * erfc(sqrt(z))
            elif a.is_Integer or (2 * a).is_Integer:
                b = a - 1
                if b.is_positive:
                    if a.is_integer:
                        return (
                            exp(-z)
                            * factorial(b)
                            * Add(*[z ** k / factorial(k) for k in range(a)])
                        )
                    else:
                        return gamma(a) * erfc(sqrt(z)) + (-1) ** (a - S(3) / 2) * exp(
                            -z
                        ) * sqrt(z) * Add(
                            *[
                                gamma(-S.Half - k) * (-z) ** k / gamma(1 - a)
                                for k in range(a - S.Half)
                            ]
                        )
                elif b.is_Integer:
                    return expint(-b, z) * unpolarify(z) ** (b + 1)

                if not a.is_Integer:
                    return (-1) ** (S.Half - a) * pi * erfc(sqrt(z)) / gamma(
                        1 - a
                    ) - z ** a * exp(-z) * Add(
                        *[
                            z ** k * gamma(a) / gamma(a + k + 1)
                            for k in range(S.Half - a)
                        ]
                    )

        if a.is_zero and z.is_positive:
            return -Ei(-z)

        if z.is_zero and re(a).is_positive:
            return gamma(a)
Пример #54
0
def test_issue_14216():
    from sympy.functions.elementary.complexes import unpolarify
    A = MatrixSymbol("A", 2, 2)
    assert unpolarify(A[0, 0]) == A[0, 0]
    assert unpolarify(A[0, 0] * A[1, 0]) == A[0, 0] * A[1, 0]
Пример #55
0
def test_expint():
    """ Test various exponential integrals. """
    from sympy import (
        expint,
        unpolarify,
        Symbol,
        Ci,
        Si,
        Shi,
        Chi,
        sin,
        cos,
        sinh,
        cosh,
        Ei,
    )

    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
Пример #56
0
    def eval(cls, arg, base=None):
        from sympy import unpolarify
        from sympy.calculus import AccumBounds
        from sympy.sets.setexpr import SetExpr
        from sympy.functions.elementary.complexes import Abs

        arg = sympify(arg)

        if base is not None:
            base = sympify(base)
            if base == 1:
                if arg == 1:
                    return S.NaN
                else:
                    return S.ComplexInfinity
            try:
                # handle extraction of powers of the base now
                # or else expand_log in Mul would have to handle this
                n = multiplicity(base, arg)
                if n:
                    return n + log(arg / base**n) / log(base)
                else:
                    return log(arg) / log(base)
            except ValueError:
                pass
            if base is not S.Exp1:
                return cls(arg) / cls(base)
            else:
                return cls(arg)

        if arg.is_Number:
            if arg.is_zero:
                return S.ComplexInfinity
            elif arg is S.One:
                return S.Zero
            elif arg is S.Infinity:
                return S.Infinity
            elif arg is S.NegativeInfinity:
                return S.Infinity
            elif arg is S.NaN:
                return S.NaN
            elif arg.is_Rational and arg.p == 1:
                return -cls(arg.q)

        if arg.is_Pow and arg.base is S.Exp1 and arg.exp.is_extended_real:
            return arg.exp
        I = S.ImaginaryUnit
        if isinstance(arg, exp) and arg.exp.is_extended_real:
            return arg.exp
        elif isinstance(arg, exp) and arg.exp.is_number:
            r_, i_ = match_real_imag(arg.exp)
            if i_ and i_.is_comparable:
                i_ %= 2 * S.Pi
                if i_ > S.Pi:
                    i_ -= 2 * S.Pi
                return r_ + expand_mul(i_ * I, deep=False)
        elif isinstance(arg, exp_polar):
            return unpolarify(arg.exp)
        elif isinstance(arg, AccumBounds):
            if arg.min.is_positive:
                return AccumBounds(log(arg.min), log(arg.max))
            else:
                return
        elif isinstance(arg, SetExpr):
            return arg._eval_func(cls)

        if arg.is_number:
            if arg.is_negative:
                return S.Pi * I + cls(-arg)
            elif arg is S.ComplexInfinity:
                return S.ComplexInfinity
            elif arg is S.Exp1:
                return S.One

        if arg.is_zero:
            return S.ComplexInfinity

        # don't autoexpand Pow or Mul (see the issue 3351):
        if not arg.is_Add:
            coeff = arg.as_coefficient(I)

            if coeff is not None:
                if coeff is S.Infinity:
                    return S.Infinity
                elif coeff is S.NegativeInfinity:
                    return S.Infinity
                elif coeff.is_Rational:
                    if coeff.is_nonnegative:
                        return S.Pi * I * S.Half + cls(coeff)
                    else:
                        return -S.Pi * I * S.Half + cls(-coeff)

        if arg.is_number and arg.is_algebraic:
            # Match arg = coeff*(r_ + i_*I) with coeff>0, r_ and i_ real.
            coeff, arg_ = arg.as_independent(I, as_Add=False)
            if coeff.is_negative:
                coeff *= -1
                arg_ *= -1
            arg_ = expand_mul(arg_, deep=False)
            r_, i_ = arg_.as_independent(I, as_Add=True)
            i_ = i_.as_coefficient(I)
            if coeff.is_real and i_ and i_.is_real and r_.is_real:
                if r_.is_zero:
                    if i_.is_positive:
                        return S.Pi * I * S.Half + cls(coeff * i_)
                    elif i_.is_negative:
                        return -S.Pi * I * S.Half + cls(coeff * -i_)
                else:
                    from sympy.simplify import ratsimp
                    # Check for arguments involving rational multiples of pi
                    t = (i_ / r_).cancel()
                    t1 = (-t).cancel()
                    atan_table = {
                        # first quadrant only
                        sqrt(3):
                        S.Pi / 3,
                        1:
                        S.Pi / 4,
                        sqrt(5 - 2 * sqrt(5)):
                        S.Pi / 5,
                        sqrt(2) * sqrt(5 - sqrt(5)) / (1 + sqrt(5)):
                        S.Pi / 5,
                        sqrt(5 + 2 * sqrt(5)):
                        S.Pi * Rational(2, 5),
                        sqrt(2) * sqrt(sqrt(5) + 5) / (-1 + sqrt(5)):
                        S.Pi * Rational(2, 5),
                        sqrt(3) / 3:
                        S.Pi / 6,
                        sqrt(2) - 1:
                        S.Pi / 8,
                        sqrt(2 - sqrt(2)) / sqrt(sqrt(2) + 2):
                        S.Pi / 8,
                        sqrt(2) + 1:
                        S.Pi * Rational(3, 8),
                        sqrt(sqrt(2) + 2) / sqrt(2 - sqrt(2)):
                        S.Pi * Rational(3, 8),
                        sqrt(1 - 2 * sqrt(5) / 5):
                        S.Pi / 10,
                        (-sqrt(2) + sqrt(10)) / (2 * sqrt(sqrt(5) + 5)):
                        S.Pi / 10,
                        sqrt(1 + 2 * sqrt(5) / 5):
                        S.Pi * Rational(3, 10),
                        (sqrt(2) + sqrt(10)) / (2 * sqrt(5 - sqrt(5))):
                        S.Pi * Rational(3, 10),
                        2 - sqrt(3):
                        S.Pi / 12,
                        (-1 + sqrt(3)) / (1 + sqrt(3)):
                        S.Pi / 12,
                        2 + sqrt(3):
                        S.Pi * Rational(5, 12),
                        (1 + sqrt(3)) / (-1 + sqrt(3)):
                        S.Pi * Rational(5, 12)
                    }
                    if t in atan_table:
                        modulus = ratsimp(coeff * Abs(arg_))
                        if r_.is_positive:
                            return cls(modulus) + I * atan_table[t]
                        else:
                            return cls(modulus) + I * (atan_table[t] - S.Pi)
                    elif t1 in atan_table:
                        modulus = ratsimp(coeff * Abs(arg_))
                        if r_.is_positive:
                            return cls(modulus) + I * (-atan_table[t1])
                        else:
                            return cls(modulus) + I * (S.Pi - atan_table[t1])
Пример #57
0
 def eval(cls, ap, bq, z):
     from sympy import unpolarify
     if len(ap) <= len(bq):
         nz = unpolarify(z)
         if z != nz:
             return hyper(ap, bq, nz)
Пример #58
0
 def eval(cls, ap, bq, z):
     from sympy import unpolarify
     if len(ap) <= len(bq):
         nz = unpolarify(z)
         if z != nz:
             return hyper(ap, bq, nz)
Пример #59
0
    def eval(cls, arg, base=None):
        from sympy import unpolarify
        from sympy.calculus import AccumBounds
        from sympy.sets.setexpr import SetExpr

        arg = sympify(arg)

        if base is not None:
            base = sympify(base)
            if base == 1:
                if arg == 1:
                    return S.NaN
                else:
                    return S.ComplexInfinity
            try:
                # handle extraction of powers of the base now
                # or else expand_log in Mul would have to handle this
                n = multiplicity(base, arg)
                if n:
                    den = base**n
                    if den.is_Integer:
                        return n + log(arg // den) / log(base)
                    else:
                        return n + log(arg / den) / log(base)
                else:
                    return log(arg) / log(base)
            except ValueError:
                pass
            if base is not S.Exp1:
                return cls(arg) / cls(base)
            else:
                return cls(arg)

        if arg.is_Number:
            if arg is S.Zero:
                return S.ComplexInfinity
            elif arg is S.One:
                return S.Zero
            elif arg is S.Infinity:
                return S.Infinity
            elif arg is S.NegativeInfinity:
                return S.Infinity
            elif arg is S.NaN:
                return S.NaN
            elif arg.is_Rational and arg.p == 1:
                return -cls(arg.q)

        if arg is S.ComplexInfinity:
            return S.ComplexInfinity
        if isinstance(arg, exp) and arg.args[0].is_real:
            return arg.args[0]
        elif isinstance(arg, exp_polar):
            return unpolarify(arg.exp)
        elif isinstance(arg, AccumBounds):
            if arg.min.is_positive:
                return AccumBounds(log(arg.min), log(arg.max))
            else:
                return
        elif isinstance(arg, SetExpr):
            return arg._eval_func(cls)

        if arg.is_number:
            if arg.is_negative:
                return S.Pi * S.ImaginaryUnit + cls(-arg)
            elif arg is S.ComplexInfinity:
                return S.ComplexInfinity
            elif arg is S.Exp1:
                return S.One

        # don't autoexpand Pow or Mul (see the issue 3351):
        if not arg.is_Add:
            coeff = arg.as_coefficient(S.ImaginaryUnit)

            if coeff is not None:
                if coeff is S.Infinity:
                    return S.Infinity
                elif coeff is S.NegativeInfinity:
                    return S.Infinity
                elif coeff.is_Rational:
                    if coeff.is_nonnegative:
                        return S.Pi * S.ImaginaryUnit * S.Half + cls(coeff)
                    else:
                        return -S.Pi * S.ImaginaryUnit * S.Half + cls(-coeff)