(x)
return polygamma(0, x)
r"""
    The digamma function is the first derivative of the loggamma function i.e,

    .. math::
        \psi(x) := \frac{\mathrm{d}}{\mathrm{d} z} \log\Gamma(z)
                = \frac{\Gamma'(z)}{\Gamma(z) }

    In this case, ``digamma(z) = polygamma(0, z)``.

    See Also
    ========

    gamma: Gamma function.
    lowergamma: Lower incomplete gamma function.
    uppergamma: Upper incomplete gamma function.
    polygamma: Polygamma function.
    loggamma: Log Gamma function.
    trigamma: Trigamma function.
    sympy.functions.special.beta_functions.beta: Euler Beta function.

    References
    ==========

    .. [1] http://en.wikipedia.org/wiki/Digamma_function
    .. [2] http://mathworld.wolfram.com/DigammaFunction.html
    .. [3] http://functions.wolfram.com/GammaBetaErf/PolyGamma2/
r"""
    The digamma function is the first derivative of the loggamma function i.e,
r The digamma function is the first derivative of the loggamma function i . e
def digamma(x):
    r"""
    The digamma function is the first derivative of the loggamma function i.e,

    .. math::
        \psi(x) := \frac{\mathrm{d}}{\mathrm{d} z} \log\Gamma(z)
                = \frac{\Gamma'(z)}{\Gamma(z) }

    In this case, ``digamma(z) = polygamma(0, z)``.

    See Also
    ========

    gamma: Gamma function.
    lowergamma: Lower incomplete gamma function.
    uppergamma: Upper incomplete gamma function.
    polygamma: Polygamma function.
    loggamma: Log Gamma function.
    trigamma: Trigamma function.
    sympy.functions.special.beta_functions.beta: Euler Beta function.

    References
    ==========

    .. [1] http://en.wikipedia.org/wiki/Digamma_function
    .. [2] http://mathworld.wolfram.com/DigammaFunction.html
    .. [3] http://functions.wolfram.com/GammaBetaErf/PolyGamma2/
    """
    return polygamma(0, x)
def digamma ( x ) : return polygamma ( 0 , x )