def from_polynomial(cls, pol): pol = PolynomialRing(QQ, 'x')(str(pol)) pol *= pol.denominator() R = pol.parent() pol = R(pari(pol).polredbest().polredabs()) return cls.from_coeffs( [int(c) for c in pol.coefficients(sparse=False)])
def polredabs(self): if "polredabs" in self._data.keys(): return self._data["polredabs"] else: pol = PolynomialRing(QQ, 'x')(self.polynomial()) pol *= pol.denominator() R = pol.parent() from sage.all import pari pol = R(pari(pol).polredabs()) self._data["polredabs"] = pol return pol
def polredabs(self): if "polredabs" in self._data.keys(): return self._data["polredabs"] else: pol = PolynomialRing(QQ, 'x')(map(str, self.polynomial())) # Need to map because the coefficients are given as unicode, which does not convert to QQ pol *= pol.denominator() R = pol.parent() from sage.all import pari pol = R(pari(pol).polredabs()) self._data["polredabs"] = pol return pol
def polredabs(self): if "polredabs" in self._data.keys(): return self._data["polredabs"] else: pol = PolynomialRing(QQ, 'x')(map(str,self.polynomial())) # Need to map because the coefficients are given as unicode, which does not convert to QQ pol *= pol.denominator() R = pol.parent() from sage.all import pari pol = R(pari(pol).polredabs()) self._data["polredabs"] = pol return pol
def from_polynomial(cls, pol): try: # try to cast to ring pol = PolynomialRing(QQ, 'x')(pol) except Exception: # try again as a string pol = PolynomialRing(QQ, 'x')(str(pol)) pol *= pol.denominator() R = pol.parent() pol = R(pari(pol).polredbest().polredabs()) return cls.from_coeffs( [int(c) for c in pol.coefficients(sparse=False)])
def from_polynomial(cls, pol): try: # try to cast to ring pol = PolynomialRing(QQ, 'x')(pol) except Exception: # try again as a string pol = PolynomialRing(QQ, 'x')(str(pol)) pol *= pol.denominator() # For some reason the error raised by Pari on a constant polynomial is not being caught if pol.degree() < 1: raise ValueError("Polynomial cannot be constant") R = pol.parent() pol = R(pari(pol).polredbest().polredabs()) return cls.from_coeffs([int(c) for c in pol.coefficients(sparse=False)])
def poly_to_field_label(pol): try: pol = PolynomialRing(QQ, 'x')(str(pol)) pol *= pol.denominator() R = pol.parent() pol = R(pari(pol).polredabs()) except: return None coeffs = list2string([int(c) for c in pol.coeffs()]) d = int(pol.degree()) query = {'coeffs': coeffs} C = base.getDBConnection() one = C.numberfields.fields.find_one(query) if one: return one['label'] return None
def from_polynomial(cls, pol): pol = PolynomialRing(QQ, 'x')(str(pol)) pol *= pol.denominator() R = pol.parent() pol = R(pari(pol).polredbest().polredabs()) return cls.from_coeffs([int(c) for c in pol.coefficients(sparse=False)])
def input_to_subfield(inp): def finish(result): return '.'.join([str(z) for z in result]) def notq(): raise SearchParsingError(r"The rational numbers $\Q$ cannot be a proper intermediate field.") # Change unicode dash with minus sign inp = inp.replace(u'\u2212', '-') # remove non-ascii characters from inp # we need to encode and decode for Python 3, as 'str' object has no attribute 'decode' inp = re.sub(r'[^\x00-\x7f]', r'', inp) if len(inp) == 0: return None # Do we have a nf label if re.match(r'\d+\.\d+\.[0-9e_]+\.\d+',inp): from lmfdb import db myfield = db.nf_fields.lookup(inp) if myfield: return finish(myfield['coeffs']) else: raise SearchParsingError("It is not the label for a subfield in the database.") F = inp.lower() # keep original if needed # Is it a polynomial if 'x' in F: F1 = F.replace('^', '**') R = PolynomialRing(ZZ, 'x') pol = PolynomialRing(QQ,'x')(str(F1)) pol *= pol.denominator() if not pol.is_irreducible(): raise SearchParsingError("It is not an irreducible polynomial.") coeffs = R(pari(pol).polredabs()).coefficients(sparse=False) if coeffs == [0,1]: notq() return finish(coeffs) # Nicknames if F == 'q': notq() if F in ['qi', 'q(i)']: return '1.0.1' if F[0] == 'q': if '(' in F and ')' in F: F=F.replace('(','').replace(')','') inp=inp.replace('(','').replace(')','') if F[1:5] in ['sqrt', 'root']: try: d = ZZ(str(F[5:])).squarefree_part() except (TypeError, ValueError): d = 0 if d == 0 or d == 1: raise SearchParsingError("After {0}, the remainder must be a nonzero integer which is not a perfect square. Use {0}5 or {0}-11 for example.".format(inp[:5])) # Recursion has it use polredabs to get the polynomial return input_to_subfield("x^2 - (%s)" % d) # Look for cyclotomic if F[0:5] == 'qzeta': if '_' in F: F = F.replace('_','') match_obj = re.match(r'^qzeta(\d+)(\+|plus)?$', F) if not match_obj: raise SearchParsingError("After {0}, the remainder must be a positive integer or a positive integer followed by '+'. Use {0}5 or {0}19+, for example.".format(F[:5])) d = ZZ(str(match_obj.group(1))) if d % 4 == 2: d /= 2 # Q(zeta_6)=Q(zeta_3), etc) if d < 1: raise SearchParsingError("After {0}, the remainder must be a positive integer or a positive integer followed by '+'. Use {0}5 or {0}19+, for example.".format(F[:5])) if d==1: # asking for Q notq() if match_obj.group(2): # asking for the totally real field from lmfdb.number_fields.web_number_field import rcyclolookup if d < 5: # again, asking for subfield Q notq() if d in rcyclolookup: return input_to_subfield(rcyclolookup[d]) else: raise SearchParsingError("Subfield %s is not available." % F) f = pari.polcyclo(d) return input_to_subfield(str(f)) # Want polcyclo here raise SearchParsingError('%s is not in the database.' % F) f = pari.polcyclo(d) return input_to_subfield(str(f)) raise SearchParsingError('It is not a valid field nickname or label, or a defining polynomial.')