当前位置: 首页>>代码示例>>Python>>正文


Python EllipticCurve.discriminant方法代码示例

本文整理汇总了Python中constructor.EllipticCurve.discriminant方法的典型用法代码示例。如果您正苦于以下问题:Python EllipticCurve.discriminant方法的具体用法?Python EllipticCurve.discriminant怎么用?Python EllipticCurve.discriminant使用的例子?那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在constructor.EllipticCurve的用法示例。


在下文中一共展示了EllipticCurve.discriminant方法的1个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的Python代码示例。

示例1: _tate

# 需要导入模块: from constructor import EllipticCurve [as 别名]
# 或者: from constructor.EllipticCurve import discriminant [as 别名]
    def _tate(self, proof = None, globally = False):
        r"""
        Tate's algorithm for an elliptic curve over a number field.

        Computes both local reduction data at a prime ideal and a
        local minimal model.

        The model is not required to be integral on input.  If `P` is
        principal, uses a generator as uniformizer, so it will not
        affect integrality or minimality at other primes.  If `P` is not
        principal, the minimal model returned will preserve
        integrality at other primes, but not minimality.

        The optional argument globally, when set to True, tells the algorithm to use the generator of the prime ideal if it is principal. Otherwise just any uniformizer will be used.

        .. note:: 

           Called only by ``EllipticCurveLocalData.__init__()``.

        OUTPUT:

        (tuple) ``(Emin, p, val_disc, fp, KS, cp)`` where:

        - ``Emin`` (EllipticCurve) is a model (integral and) minimal at P
        - ``p`` (int) is the residue characteristic
        - ``val_disc`` (int) is the valuation of the local minimal discriminant
        - ``fp`` (int) is the valuation of the conductor
        - ``KS`` (string) is the Kodaira symbol
        - ``cp`` (int) is the Tamagawa number


        EXAMPLES (this raised a type error in sage prior to 4.4.4, see :trac:`7930`) ::

            sage: E = EllipticCurve('99d1')

            sage: R.<X> = QQ[]
            sage: K.<t> = NumberField(X^3 + X^2 - 2*X - 1)
            sage: L.<s> = NumberField(X^3 + X^2 - 36*X - 4)

            sage: EK = E.base_extend(K)
            sage: toK = EK.torsion_order()
            sage: da = EK.local_data()  # indirect doctest

            sage: EL = E.base_extend(L)
            sage: da = EL.local_data()  # indirect doctest

        EXAMPLES:

        The following example shows that the bug at :trac:`9324` is fixed::

            sage: K.<a> = NumberField(x^2-x+6)
            sage: E = EllipticCurve([0,0,0,-53160*a-43995,-5067640*a+19402006])
            sage: E.conductor() # indirect doctest
            Fractional ideal (18, 6*a)

        The following example shows that the bug at :trac:`9417` is fixed::

            sage: K.<a> = NumberField(x^2+18*x+1)
            sage: E = EllipticCurve(K, [0, -36, 0, 320, 0])
            sage: E.tamagawa_number(K.ideal(2))
            4

        This is to show that the bug :trac: `11630` is fixed. (The computation of the class group would produce a warning)::
        
            sage: K.<t> = NumberField(x^7-2*x+177)
            sage: E = EllipticCurve([0,1,0,t,t])
            sage: P = K.ideal(2,t^3 + t + 1)
            sage: E.local_data(P).kodaira_symbol()
            II

        """
        E = self._curve
        P = self._prime
        K = E.base_ring()
        OK = K.maximal_order()
        t = verbose("Running Tate's algorithm with P = %s"%P, level=1)
        F = OK.residue_field(P)
        p = F.characteristic()

        # In case P is not principal we mostly use a uniformiser which
        # is globally integral (with positive valuation at some other
        # primes); for this to work, it is essential that we can
        # reduce (mod P) elements of K which are not integral (but are
        # P-integral).  However, if the model is non-minimal and we
        # end up dividing a_i by pi^i then at that point we use a
        # uniformiser pi which has non-positive valuation at all other
        # primes, so that we can divide by it without losing
        # integrality at other primes.
           
        if globally:
            principal_flag = P.is_principal()
        else: 
            principal_flag = False
            
        if (K is QQ) or principal_flag :
            pi = P.gens_reduced()[0]
            verbose("P is principal, generator pi = %s"%pi, t, 1)
        else:
            pi = K.uniformizer(P, 'positive')
            verbose("uniformizer pi = %s"%pi, t, 1)
#.........这里部分代码省略.........
开发者ID:amitjamadagni,项目名称:sage,代码行数:103,代码来源:ell_local_data.py


注:本文中的constructor.EllipticCurve.discriminant方法示例由纯净天空整理自Github/MSDocs等开源代码及文档管理平台,相关代码片段筛选自各路编程大神贡献的开源项目,源码版权归原作者所有,传播和使用请参考对应项目的License;未经允许,请勿转载。