"""
The converter module defines code for converting between Sage objects
and MongoDB documents.
DBConverter is a class whose methods are for converting native Sage
objects into MongoDB documents (JSON-like dictionaries), and
conversely. In addition to the DBConverter, this module defines two
objects: db_converter and to_db. The first, db_converter, is simply
an instance of the DBConverter class. The second, to_db is the method
of the DBConverter class that converts a native Sage object to a
document. Conversion in the other direction, from document to Sage
object, must be done by explicitly calling a method of db_converter.
This is because no type codes are stored in the database document, in
order to not tie the database too tightly to Sage.
"""
class DBConverter:
def from_dirichlet_character(self, e):
zeta_order = int(e.parent().base_ring().zeta_order())
return {'modulus':int(e.modulus()),
'order':int(e.order()),
'even':e.is_even(),
'element':[int(a) for a in e.element()],
'zeta_order':zeta_order}
def to_dirichlet_character(self, character):
if character['order'] == 1:
from sage.all import trivial_character
return trivial_character(character['modulus'])
from sage.all import DirichletGroup, CyclotomicField, QQ
from sage.modular.dirichlet import DirichletCharacter
zeta_order = character['zeta_order']
R = QQ if zeta_order == 2 else CyclotomicField(zeta_order)
G = DirichletGroup(character['modulus'], R, zeta_order=zeta_order)
v = G.an_element().element().parent()(character['element'])
return DirichletCharacter(G, v)
def to_db(self, x):
from sage.modular.dirichlet import DirichletCharacter
from sage.all import Integer
if isinstance(x, DirichletCharacter):
return self.from_dirichlet_character(x)
elif isinstance(x, (Integer, int, long)):
return int(x)
elif x is None:
return x
raise NotImplementedError
db_converter = DBConverter()
to_db = db_converter.to_db
