hyper.py 文件源码

def get_period(self):
        """
        Return a number P such that G(x*exp(I*P)) == G(x).

        >>> from sympy.functions.special.hyper import meijerg
        >>> from sympy.abc import z
        >>> from sympy import pi, S

        >>> meijerg([1], [], [], [], z).get_period()
        2*pi
        >>> meijerg([pi], [], [], [], z).get_period()
        oo
        >>> meijerg([1, 2], [], [], [], z).get_period()
        oo
        >>> meijerg([1,1], [2], [1, S(1)/2, S(1)/3], [1], z).get_period()
        12*pi
        """
        # This follows from slater's theorem.
        def compute(l):
            # first check that no two differ by an integer
            for i, b in enumerate(l):
                if not b.is_Rational:
                    return oo
                for j in range(i + 1, len(l)):
                    if not Mod((b - l[j]).simplify(), 1):
                        return oo
            return reduce(ilcm, (x.q for x in l), 1)
        beta = compute(self.bm)
        alpha = compute(self.an)
        p, q = len(self.ap), len(self.bq)
        if p == q:
            if beta == oo or alpha == oo:
                return oo
            return 2*pi*ilcm(alpha, beta)
        elif p < q:
            return 2*pi*beta
        else:
            return 2*pi*alpha