Ticket #12768: 12768-review.patch

sage/databases/cremona.py

@@ -280 +280 @@
     label = chr(k)*int(n//26 + 1)
     return label
 
-cremona_label_regex = re.compile(r'(\d+)([a-z]*)(\d*)')
-lmfdb_label_regex = re.compile(r'(\d+)\.([a-z]+)(\d*)')
+cremona_label_regex = re.compile(r'(\d+)([a-z]*)(\d*)$')
+lmfdb_label_regex = re.compile(r'(\d+)\.([a-z]+)(\d*)$')
 
 def parse_cremona_label(label):
     """
@@ -292 +292 @@
     For this function, the curve number may be omitted, in which case
     it defaults to 1.  If the curve number and isogeny class are both
     omitted (label is just a string representing a conductor), then
-    the isogeny class defaults to 'a' and the number to 1.
+    the isogeny class defaults to 'a' and the number to 1.  Valid
+    labels consist of one or more digits, followed by zero or more
+    letters (in either upper or lower case, which will be lowered),
+    followed by zero or more digits.
 
     INPUT:
 
@@ -313 +316 @@
         (37, 'b', 1)
         sage: parse_cremona_label('10bb2')
         (10, 'bb', 2)
+        sage: parse_cremona_label('11a')
+        (11, 'a', 1)
+        sage: parse_cremona_label('11')
+        (11, 'a', 1)
+
+    TESTS::
+
+        sage: from sage.databases.cremona import parse_cremona_label
+        sage: parse_cremona_label('x11')
+        Traceback (most recent call last):
+        ...
+        ValueError: x11 is not a valid Cremona label
     """
     m = cremona_label_regex.match(str(label).lower())
     if m is None:
@@ -362 +377 @@
     EXAMPLES::
 
         sage: from sage.databases.cremona import parse_lmfdb_label
-        sage: parse_cremona_label('37.a2')
+        sage: parse_lmfdb_label('37.a2')
         (37, 'a', 2)
-        sage: parse_cremona_label('37.b')
+        sage: parse_lmfdb_label('37.b')
         (37, 'b', 1)
-        sage: parse_cremona_label('10.bb2')
+        sage: parse_lmfdb_label('10.bb2')
         (10, 'bb', 2)
     """
     m = lmfdb_label_regex.match(str(label).lower())

sage/schemes/elliptic_curves/ell_rational_field.py

@@ -3796 +3796 @@
             lexicographically by a-invariants.
 
           - if ``order`` is a list of curves, then the curves in the
-            class are reordered to be isogenous with the specified
+            class are reordered to be isomorphic with the specified
             list of curves.
 
         - ``use_tuple`` -- bool (default: True).  Controls the output
@@ -3806 +3806 @@
 
         If ``use_tuple`` is False, returns a
         :class:`sage.schemes.elliptic_curves.isogeny_class.IsogenyClass_EC_Rational`
-        instace.  This object models a list of minimal models (with
+        instance.  This object models a list of minimal models (with
         containment, index, etc based on isomorphism classes).  It
         also has methods for computing the isogeny matrix and the list
         of isogenies between curves in this class.
@@ -3977 +3977 @@
             deprecation("""For elliptic curves E over Q, isogeny_class(use_tuple=False) returns a class
 that has methods producing the isogeny graph and list of lists of isogenies.
 use_tuple=True (currently default) is deprecated.""", "Sage Version 5.0")
-            # After a year or so we should switch the default to use_tuple=False as the default and deprecate
+            # After a year or so (in May 2013) we should switch the default to use_tuple=False as the default and deprecate
             # the keyword argument
             if return_maps:
                 return isoclass, isoclass.matrix(fill_matrix), isoclass.isogenies()
@@ -4405 +4405 @@
 
         E = self.minimal_model()
         C = self.optimal_curve()
-        _, m = C.isogeny_class()
+        m = C.isogeny_class(use_tuple=False).matrix()
         ma = max(max(x) for x in m)
         OmC = C.period_lattice().basis()
         OmE = E.period_lattice().basis()

sage/schemes/elliptic_curves/isogeny_class.py

@@ -29 +29 @@
 from sage.rings.all import ZZ
 from sage.misc.cachefunc import cached_method
 from sage.misc.abstract_method import abstract_method
-from sage.schemes.elliptic_curves.ell_generic import EllipticCurve_generic
+from sage.schemes.elliptic_curves.ell_rational_field import EllipticCurve_rational_field
 
 class IsogenyClass_EC(SageObject):
     """
     Isogeny class of an elliptic curve.
 
     The current implementation chooses a curve from each isomorphism
-    class in the isogeny class, since over Q there is a unique minimal
-    model in each isomorphism class.
+    class in the isogeny class, since over Q there is a unique reduced
+    minimal model in each isomorphism class.
 
     EXAMPLES::
 
@@ -122 +122 @@
             2
         """
         # This will need updating once we start talking about curves over more general number fields
-        if not isinstance(C, EllipticCurve_generic):
+        if not isinstance(C, EllipticCurve_rational_field):
             raise ValueError("x not in isogeny class")
         return self.curves.index(C.minimal_model())
 
@@ -219 +219 @@
             sage: E.short_weierstrass_model() in cls
             True
         """
-        if not isinstance(x, EllipticCurve_generic):
+        if not isinstance(x, EllipticCurve_rational_field):
             return False
         return x.minimal_model() in self.curves
 
@@ -571 +571 @@
 
             sage: isocls = EllipticCurve('389a1').isogeny_class(use_tuple=False); isocls
             Elliptic curve isogeny class 389a
+            sage: E = EllipticCurve([1, -1, 0, -53594, 4788959]) # conductor 10001
+            sage: E.isogeny_class(use_tuple=False, order='database')
+            Traceback (most recent call last):
+            ...
+            RuntimeError: unable to to find Elliptic Curve defined by y^2 + x*y = x^3 - x^2 - 53594*x + 4788959 over Rational Field in the database
             sage: TestSuite(isocls).run()
         """
         self._algorithm = algorithm
@@ -632 +637 @@
             try:
                 label = self.E.cremona_label(space=False)
             except RuntimeError:
-                raise RuntimeError("unable to to find %s in the database"%self)
+                raise RuntimeError("unable to to find %s in the database"%self.E)
             db = sage.databases.cremona.CremonaDatabase()
             curves = db.isogeny_class(label)
             if len(curves) == 0:
-                raise RuntimeError("unable to to find %s in the database"%self)
+                raise RuntimeError("unable to to find %s in the database"%self.E)
             # All curves will have the same conductor and isogeny class,
             # and there are are most 8 of them, so lexicographic sorting is okay.
             self.curves = tuple(sorted(curves, key = lambda E: E.cremona_label()))