Coverage for local/lib/python2.7/site-packages/sage/databases/db_class_polynomials.py : 34%

""" 

Database of Hilbert Polynomials 

""" 

####################################################################### 

# Copyright (C) 2006 David Kohel <kohel@maths.usyd.edu.au> 

# Copyright (C) 2016 Vincent Delecroix <vincent.delecroix@labri.fr> 

# 

# Distributed under the terms of the GNU General Public License (GPL) 

# as published by the Free Software Foundation; either version 2 of 

# the License, or (at your option) any later version. 

# http://www.gnu.org/licenses/ 

#***************************************************************************** 

from __future__ import print_function, absolute_import 

from .db_modular_polynomials import _dbz_to_integers 

disc_format = "%07d" # disc_length = 7 

level_format = "%03d" # level_length = 3 

class ClassPolynomialDatabase: 

def _dbpath(self, disc, level=1): 

""" 

TESTS:: 

sage: db = HilbertClassPolynomialDatabase() 

sage: db._dbpath(5, 1) 

'PolHeeg/Cls/0000001-0005000/pol.0000005.dbz' 

sage: db._dbpath(15000, 1) 

'PolHeeg/Cls/0010001-0015000/pol.0015000.dbz' 

sage: db._dbpath(3, 2) 

Traceback (most recent call last): 

... 

NotImplementedError: Level (= 2) > 1 not yet implemented 

""" 

if level != 1: 

raise NotImplementedError("Level (= %s) > 1 not yet implemented"%level) 

n1 = 5000*((abs(disc)-1)//5000) 

s1 = disc_format % (n1+1) #_pad_int(n1+1, disc_length) 

s2 = disc_format % (n1+5000) 

subdir = "%s-%s"%(s1,s2) 

discstr = disc_format % abs(disc) 

return "PolHeeg/%s/%s/pol.%s.dbz"%(self.model, subdir, discstr) 

def __getitem__(self, disc): 

r""" 

TESTS:: 

sage: db = HilbertClassPolynomialDatabase() 

sage: db[32] # optional - database_kohel 

x^2 - 52250000*x + 12167000000 

sage: db[123913912] 

Traceback (most recent call last): 

... 

LookupError: filename .../kohel/PolHeeg/Cls/123910001-123915000/pol.123913912.dbz does not exist 

""" 

from sage.rings.integer_ring import ZZ 

from sage.rings.polynomial.polynomial_ring_constructor import PolynomialRing 

classpol = self._dbpath(disc) 

coeff_list = _dbz_to_integers(classpol) 

return PolynomialRing(ZZ, 'x')(coeff_list) 

class HilbertClassPolynomialDatabase(ClassPolynomialDatabase): 

""" 

The database of Hilbert class polynomials. 

EXAMPLES:: 

sage: db = HilbertClassPolynomialDatabase() 

sage: db[-4] # optional - database_kohel 

x - 1728 

sage: db[-7] # optional - database_kohel 

x + 3375 

sage: f = db[-23]; f # optional - database_kohel 

x^3 + 3491750*x^2 - 5151296875*x + 12771880859375 

sage: f.discriminant().factor() # optional - database_kohel 

-1 * 5^18 * 7^12 * 11^4 * 17^2 * 19^2 * 23 

sage: db[-23] # optional - database_kohel 

x^3 + 3491750*x^2 - 5151296875*x + 12771880859375 

""" 

model = "Cls" 

def __repr__(self): 

return "Hilbert class polynomial database" 

###################################################### 

# None of the following are implemented yet. 

###################################################### 

class AtkinClassPolynomialDatabase(ClassPolynomialDatabase): 

""" 

The database of Atkin class polynomials. 

""" 

model = "Atk" 

def __repr__(self): 

return "Atkin class polynomial database" 

class WeberClassPolynomialDatabase(ClassPolynomialDatabase): 

""" 

The database of Weber class polynomials. 

""" 

def __repr__(self): 

return "Weber class polynomial database" 

class DedekindEtaClassPolynomialDatabase(ClassPolynomialDatabase): 

""" 

The database of Dedekind eta class polynomials. 

""" 

model = "Eta" 

def __repr__(self): 

return "Dedekind eta class polynomial database"