예제 #1
0
    def _eval_power(self, other, terms=False):
        #         n          n          n
        # (-3 + y)   ->  (-1)  * (3 - y)
        #
        # If terms=True then return the arguments that should be
        # multiplied together rather than multiplying them.
        #
        # At present, as_coeff_terms return +/-1 but the
        # following should work even if that changes.
        if Basic.keep_sign:
            return None

        rv = None
        c, t = self.as_coeff_mul()
        if c.is_negative and not other.is_integer:
            if c is not S.NegativeOne and self.is_positive:
                coeff = C.Pow(-c, other)
                assert len(t) == 1, 't'
                b = -t[0]
                rv = (coeff, C.Pow(b, other))
        elif c is not S.One:
            coeff = C.Pow(c, other)
            assert len(t) == 1, 't'
            b = t[0]
            rv = (coeff, C.Pow(b, other))
        if not rv or terms:
            return rv
        else:
            return C.Mul(*rv)
예제 #2
0
파일: evalf.py 프로젝트: nthorne/sympy
def _create_evalf_table():
    global evalf_table
    evalf_table = {
        C.Symbol: evalf_symbol,
        C.Dummy: evalf_symbol,
        C.Float: lambda x, prec, options: (x._mpf_, None, prec, None),
        C.Rational: lambda x, prec, options: (from_rational(x.p, x.q, prec), None, prec, None),
        C.Integer: lambda x, prec, options: (from_int(x.p, prec), None, prec, None),
        C.Zero: lambda x, prec, options: (None, None, prec, None),
        C.One: lambda x, prec, options: (fone, None, prec, None),
        C.Half: lambda x, prec, options: (fhalf, None, prec, None),
        C.Pi: lambda x, prec, options: (mpf_pi(prec), None, prec, None),
        C.Exp1: lambda x, prec, options: (mpf_e(prec), None, prec, None),
        C.ImaginaryUnit: lambda x, prec, options: (None, fone, None, prec),
        C.NegativeOne: lambda x, prec, options: (fnone, None, prec, None),
        C.NaN : lambda x, prec, options: (fnan, None, prec, None),

        C.exp: lambda x, prec, options: evalf_pow(C.Pow(S.Exp1, x.args[0],
        evaluate=False), prec, options),

        C.cos: evalf_trig,
        C.sin: evalf_trig,

        C.Add: evalf_add,
        C.Mul: evalf_mul,
        C.Pow: evalf_pow,

        C.log: evalf_log,
        C.atan: evalf_atan,
        C.Abs: evalf_abs,

        C.re: evalf_re,
        C.im: evalf_im,
        C.floor: evalf_floor,
        C.ceiling: evalf_ceiling,

        C.Integral: evalf_integral,
        C.Sum: evalf_sum,
        C.Piecewise: evalf_piecewise,

        C.bernoulli: evalf_bernoulli,
    }