Ticket #7575: trac_7575-followup.patch

File trac_7575-followup.patch, 3.6 KB (added by Robert Miller, 13 years ago)

Fixes default search bounds

  • sage/schemes/elliptic_curves/ell_rational_field.py

    # HG changeset patch
    # User Robert L. Miller <rlm@rlmiller.org>
    # Date 1265491875 28800
    # Node ID a2682bbcd97636b40c3c88ef662a8c8849d3afb9
    # Parent  8a90b87fca0ce33dded2bd986d413441ac42ff0f
    #7575: Set height bound to 12, fix documentation
    
    diff -r 8a90b87fca0c -r a2682bbcd976 sage/schemes/elliptic_curves/ell_rational_field.py
    a b  
    17961796        -  ``verbose`` - (default: None), if specified changes
    17971797           the verbosity of mwrank computations.
    17981798       
    1799         -  ``rank1_search`` - (default: 16), if the curve has
     1799        -  ``rank1_search`` - (default: 10), if the curve has
    18001800           analytic rank 1, try to find a generator by a direct search up to
    18011801           this logarithmic height. If this fails the usual mwrank procedure
    18021802           is called. algorithm -
     
    18161816        -  ``use_database`` - bool (default True) if True,
    18171817           attempts to find curve and gens in the (optional) database
    18181818       
    1819         -  ``descent_second_limit`` - (default: 16)- used in 2-descent
     1819        -  ``descent_second_limit`` - (default: 12)- used in 2-descent
    18201820       
    18211821        OUTPUT:
    18221822       
     
    20352035        -  ``precision`` - int or None (default: None): the
    20362036           precision in bits of the result (default real precision if None)
    20372037       
    2038         -  ``descent_second_limit`` - (default: 16)- used in 2-descent
     2038        -  ``descent_second_limit`` - (default: 12)- used in 2-descent
    20392039       
    20402040        -  ``verbose`` - whether to print mwrank's verbose output
    20412041       
  • sage/schemes/elliptic_curves/heegner.py

    diff -r 8a90b87fca0c -r a2682bbcd976 sage/schemes/elliptic_curves/heegner.py
    a b  
    63296329        return IR(alpha-MIN_ERR,alpha+MIN_ERR) * IR(LE1-err_E,LE1+err_E) * IR(LF1-err_F,LF1+err_F)
    63306330
    63316331
    6332 def heegner_index(self, D,  min_p=2, prec=5, descent_second_limit=16, verbose_mwrank=False):
     6332def heegner_index(self, D,  min_p=2, prec=5, descent_second_limit=12, verbose_mwrank=False):
    63336333    r"""
    63346334    Return an interval that contains the index of the Heegner
    63356335    point `y_K` in the group of `K`-rational points modulo torsion
     
    63586358    -  ``prec (int)`` - (default: 5), use prec\*sqrt(N) +
    63596359       20 terms of L-series in computations, where N is the conductor.
    63606360
    6361     -  ``descent_second_limit`` - (default: 16)- used in 2-descent
     6361    -  ``descent_second_limit`` - (default: 12)- used in 2-descent
    63626362       when computing regulator of the twist
    63636363
    63646364    OUTPUT: an interval that contains the index
     
    64116411
    64126412    This example demonstrates the `descent_second_limit` option,
    64136413    which can be used to fine tune the 2-descent used to compute
    6414     the regulator of the twist. If we set the parameter lower than
    6415     its usual value, then the point search is not high enough to
    6416     find what it is looking for::
     6414    the regulator of the twist::
    64176415   
    64186416        sage: E = EllipticCurve([0, 0, 1, -34874, -2506691])
    6419         sage: E.heegner_index(-8, descent_second_limit=10)
     6417        sage: E.heegner_index(-8)
    64206418        Traceback (most recent call last):
    64216419        ...
    64226420        RuntimeError: ...
    64236421
    6424     However when we use the default values, we find the points we need::
    6425 
    6426         sage: E.heegner_index(-8)
     6422    However when we search higher, we find the points we need::
     6423
     6424        sage: E.heegner_index(-8, descent_second_limit=16)
    64276425        1.00000?
    64286426
    64296427    """