Ejemplo n.º 1
0
def insert_dirichlet_L_functions(start, end):
    print "Putting Dirichlet L-functions into database."
    start = max(3, start)
    for q in range(start, end):
        print "Working on modulus", q
        sys.stdout.flush()
        G = DirichletGroup(q)
        for n in range(len(G)):
            chi = G[n]
            if chi.is_primitive():
                L = lc.Lfunction_from_character(chi)
                z = L.find_zeros_via_N(1)[0]
                Lfunction_data = {}
                Lfunction_data['first_zero'] = float(z)
                Lfunction_data[
                    'description'] = "Dirichlet L-function for character number " + str(
                        n) + " modulo " + str(q)
                Lfunction_data['degree'] = 1
                Lfunction_data['signature'] = (1, 0)
                if chi.is_odd():
                    Lfunction_data['mu'] = [
                        (1.0, 0.0),
                    ]
                else:
                    Lfunction_data['mu'] = [
                        (0.0, 0.0),
                    ]

                Lfunction_data['level'] = q

                coeffs = []

                for k in range(0, 10):
                    coeffs.append(CC(chi(k)))

                Lfunction_data['coeffs'] = [(float(x.real()), float(x.imag()))
                                            for x in coeffs]
                Lfunction_data['special'] = {
                    'type': 'dirichlet',
                    'modulus': q,
                    'number': n
                }

                Lfunctions.insert(Lfunction_data)
Ejemplo n.º 2
0
import sys

from sage.all import DirichletGroup

import pymongo
from pymongo import Connection
import sage.libs.lcalc.lcalc_Lfunction as lc

from lmfdb import base
C = base.getDBConnection()
db = C.Lfunctions

first_zeros = db.first_zeros_testing

first_zeros.drop()

for q in range(3, 1500):
    print q
    sys.stdout.flush()
    G = DirichletGroup(q)
    for n in range(len(G)):
        if G[n].is_primitive():
            L = lc.Lfunction_from_character(G[n])
            z = L.find_zeros_via_N(1)[0]
            first_zeros.insert({
                'zero': float(z),
                'modulus': int(q),
                'character': int(n)
            })
Ejemplo n.º 3
0
    def __init__(self, **args):

        #Check for compulsory arguments
        if not ('charactermodulus' in args.keys() and 'characternumber' in args.keys()):
            raise KeyError, "You have to supply charactermodulus and characternumber for the L-function of a Dirichlet character"
        
        # Initialize default values
        self.numcoeff = 30    # set default to 30 coefficients

        # Put the arguments into the object dictionary
        self.__dict__.update(args)
        self.charactermodulus = int(self.charactermodulus)
        self.characternumber = int(self.characternumber)
        self.numcoeff = int(self.numcoeff)

        # Create the Dirichlet character
        chi = DirichletGroup(self.charactermodulus)[self.characternumber]

        if chi.is_primitive():

            # Extract the L-function information from the Dirichlet character
            # Warning: will give nonsense if character is not primitive
            aa = int((1-chi(-1))/2)   # usually denoted \frak a
            self.quasidegree = 1
            self.Q_fe = float(sqrt(self.charactermodulus)/sqrt(math.pi))
            self.sign = 1/(I**aa * float(sqrt(self.charactermodulus))/(chi.gauss_sum_numerical()))
            self.kappa_fe = [0.5]
            self.lambda_fe = [0.5*aa]
            self.mu_fe = [aa]
            self.nu_fe = []
            self.langlands = True
            self.primitive = True
            self.degree = 1
            self.level = self.charactermodulus

            self.dirichlet_coefficients = []
            for n in range(1,self.numcoeff):
                self.dirichlet_coefficients.append(chi(n).n())
                                
            self.poles = []
            self.residues = []
            self.coefficient_period = self.charactermodulus

            # Determine if the character is real (i.e., if the L-function is selfdual)
            chivals=chi.values_on_gens()
            self.selfdual = True
            for v in chivals:
                if abs(imag_part(v)) > 0.0001:
                    self.selfdual = False
      
            if self.selfdual:
                self.coefficient_type = 1
            else:
                self.coefficient_type = 2

            self.texname = "L(s,\\chi)"
            self.texnamecompleteds = "\\Lambda(s,\\chi)"
                                
            if self.selfdual:
                self.texnamecompleted1ms = "\\Lambda(1-s,\\chi)"
            else:
                self.texnamecompleted1ms = "\\Lambda(1-s,\\overline{\\chi})"

            self.credit = 'Sage'
            self.citation = ''
            self.title = "Dirichlet L-function: $L(s,\\chi)$"
            self.title = (self.title+", where $\\chi$ is the character modulo "+
                              str(self.charactermodulus) + ", number " +
                              str(self.characternumber))
            
            self.sageLfunction = lc.Lfunction_from_character(chi)

        else:  #Character not primitive
            raise Exception("The dirichlet character you choose is " +
                            "not primitive so it's Dirichlet series " +
                            "is not an L-function." ,"UserError")

        constructor_logger(self,args)