Trac #34409: remove experimental warning for composite elliptic-curve…

… isogenies

The code from #32744 was released with Sage 9.5 and has since been real-
world tested by numerous people. It is exceedingly unlikely that we'll
want to remove it, and I'm reasonably convinced that there are no
disastrous bugs.

Therefore I propose to remove the experimental warning in the next
release. See also comment:18:ticket:34303.

In the future, we should also change the default composition method to
`EllipticCurveHom_composite`: See #34410.

URL: https://trac.sagemath.org/34409
Reported by: lorenz
Ticket author(s): Lorenz Panny
Reviewer(s): Kwankyu Lee

src/sage/schemes/elliptic_curves/ell_field.py

@@ -1098,7 +1098,7 @@ def isogeny(self, kernel, codomain=None, degree=None, model=None, check=True, al
           kernel point of odd order `\geq 5`.
           This algorithm is selected using ``algorithm="velusqrt"``.
 
-        - Factored Isogenies (*experimental* --- see
+        - Factored Isogenies (see
           :mod:`~sage.schemes.elliptic_curves.hom_composite`):
           Given a list of points which generate a composite-order
           subgroup, decomposes the isogeny into prime-degree steps.
@@ -1200,9 +1200,7 @@ def isogeny(self, kernel, codomain=None, degree=None, model=None, check=True, al
 
             sage: E = EllipticCurve(GF(2^32-5), [170246996, 2036646110])
             sage: P = E.lift_x(2)
-            sage: E.isogeny(P, algorithm="factored")    # experimental
-            doctest:warning
-            ...
+            sage: E.isogeny(P, algorithm="factored")
             Composite morphism of degree 1073721825 = 3^4*5^2*11*19*43*59:
               From: Elliptic Curve defined by y^2 = x^3 + 170246996*x + 2036646110 over Finite Field of size 4294967291
               To:   Elliptic Curve defined by y^2 = x^3 + 272790262*x + 1903695400 over Finite Field of size 4294967291

src/sage/schemes/elliptic_curves/hom.py

@@ -221,7 +221,6 @@ def degree(self):
         is the product of the degrees of the individual factors::
 
             sage: from sage.schemes.elliptic_curves.hom_composite import EllipticCurveHom_composite
-            doctest:warning ...
             sage: E = EllipticCurve(GF(419), [1,0])
             sage: P, = E.gens()
             sage: phi = EllipticCurveHom_composite(E, P+P)

src/sage/schemes/elliptic_curves/hom_composite.py

@@ -7,21 +7,13 @@
 while exposing (close to) the same interface as "normal", unfactored
 elliptic-curve isogenies.
 
-.. WARNING::
-
-    This module is currently considered experimental.
-    It may change in a future release without prior warning, or even
-    be removed altogether if things turn out to be unfixably broken.
-
 EXAMPLES:
 
 The following example would take quite literally forever with the
 straightforward :class:`EllipticCurveIsogeny` implementation, but
 decomposing into prime steps is exponentially faster::
 
     sage: from sage.schemes.elliptic_curves.hom_composite import EllipticCurveHom_composite
-    doctest:warning
-    ...
     sage: p = 3 * 2^143 - 1
     sage: GF(p^2).inject_variables()
     Defining z2
@@ -90,9 +82,6 @@
 from sage.schemes.elliptic_curves.ell_curve_isogeny import EllipticCurveIsogeny
 from sage.schemes.elliptic_curves.weierstrass_morphism import WeierstrassIsomorphism
 
-from sage.misc.superseded import experimental_warning
-experimental_warning(32744, 'EllipticCurveHom_composite is experimental code.')
-
 #TODO: implement sparse strategies? (cf. the SIKE cryptosystem)
 
 def _eval_factored_isogeny(phis, P):
@@ -789,7 +778,7 @@ def make_default():
 
             This method exists only temporarily to make testing more
             convenient while :class:`EllipticCurveHom_composite` is
-            experimental.
+            not yet the default.
 
         EXAMPLES::