(ctx, x, **kwargs)
Negates the number *x*, giving a floating-point result, optionally
        using a custom precision and rounding mode.

        See the documentation of :func:`~mpmath.fadd` for a detailed description
        of how to specify precision and rounding.

        **Examples**

        An mpmath number is returned::

            >>> from sympy.mpmath import *
            >>> mp.dps = 15; mp.pretty = False
            >>> fneg(2.5)
            mpf('-2.5')
            >>> fneg(-5+2j)
            mpc(real='5.0', imag='-2.0')

        Precise control over rounding is possible::

            >>> x = fadd(2, 1e-100, exact=True)
            >>> fneg(x)
            mpf('-2.0')
            >>> fneg(x, rounding='f')
            mpf('-2.0000000000000004')

        Negating with and without roundoff::

            >>> n = 200000000000000000000001
            >>> print(int(-mpf(n)))
            -200000000000000016777216
            >>> print(int(fneg(n)))
            -200000000000000016777216
            >>> print(int(fneg(n, prec=log(n,2)+1)))
            -200000000000000000000001
            >>> print(int(fneg(n, dps=log(n,10)+1)))
            -200000000000000000000001
            >>> print(int(fneg(n, prec=inf)))
            -200000000000000000000001
            >>> print(int(fneg(n, dps=inf)))
            -200000000000000000000001
            >>> print(int(fneg(n, exact=True)))
            -200000000000000000000001
Negates the number *x*, giving a floating-point result, optionally
        using a custom precision and rounding mode.
Negates the number * x * giving a floating - point result optionally using a custom precision and rounding mode .
def fneg(ctx, x, **kwargs):
        """
        Negates the number *x*, giving a floating-point result, optionally
        using a custom precision and rounding mode.

        See the documentation of :func:`~mpmath.fadd` for a detailed description
        of how to specify precision and rounding.

        **Examples**

        An mpmath number is returned::

            >>> from sympy.mpmath import *
            >>> mp.dps = 15; mp.pretty = False
            >>> fneg(2.5)
            mpf('-2.5')
            >>> fneg(-5+2j)
            mpc(real='5.0', imag='-2.0')

        Precise control over rounding is possible::

            >>> x = fadd(2, 1e-100, exact=True)
            >>> fneg(x)
            mpf('-2.0')
            >>> fneg(x, rounding='f')
            mpf('-2.0000000000000004')

        Negating with and without roundoff::

            >>> n = 200000000000000000000001
            >>> print(int(-mpf(n)))
            -200000000000000016777216
            >>> print(int(fneg(n)))
            -200000000000000016777216
            >>> print(int(fneg(n, prec=log(n,2)+1)))
            -200000000000000000000001
            >>> print(int(fneg(n, dps=log(n,10)+1)))
            -200000000000000000000001
            >>> print(int(fneg(n, prec=inf)))
            -200000000000000000000001
            >>> print(int(fneg(n, dps=inf)))
            -200000000000000000000001
            >>> print(int(fneg(n, exact=True)))
            -200000000000000000000001

        """
        prec, rounding = ctx._parse_prec(kwargs)
        x = ctx.convert(x)
        if hasattr(x, '_mpf_'):
            return ctx.make_mpf(mpf_neg(x._mpf_, prec, rounding))
        if hasattr(x, '_mpc_'):
            return ctx.make_mpc(mpc_neg(x._mpc_, prec, rounding))
        raise ValueError("Arguments need to be mpf or mpc compatible numbers")
def fneg ( ctx , x , * * kwargs ) : prec , rounding = ctx . _parse_prec ( kwargs ) x = ctx . convert ( x ) if hasattr ( x , '_mpf_' ) : return ctx . make_mpf ( mpf_neg ( x . _mpf_ , prec , rounding ) ) if hasattr ( x , '_mpc_' ) : return ctx . make_mpc ( mpc_neg ( x . _mpc_ , prec , rounding ) ) raise ValueError ( "Arguments need to be mpf or mpc compatible numbers" )