reflect deprecation of mutable isogenies in doctests

sagemath · Aug 17, 2021 · 69a15a2 · 69a15a2
1 parent 3e10548
commit 69a15a2
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diff --git a/src/sage/schemes/elliptic_curves/ell_curve_isogeny.py b/src/sage/schemes/elliptic_curves/ell_curve_isogeny.py
@@ -779,7 +779,7 @@ class EllipticCurveIsogeny(EllipticCurveHom):
         sage: f = X^2 - 2/5*i + 1/5
         sage: phi= E.isogeny(f)
         sage: isom = phi.codomain().isomorphism_to(E)
-        sage: phi.set_post_isomorphism(isom)
+        sage: phi = isom * phi
         sage: phi.codomain() == phi.domain()
         True
         sage: phi.rational_maps()
@@ -1385,6 +1385,7 @@ def __clear_cached_values(self):
             sage: old_hash = hash(phi)
             sage: from sage.schemes.elliptic_curves.weierstrass_morphism import WeierstrassIsomorphism
             sage: phi.set_post_isomorphism(WeierstrassIsomorphism(phi.codomain(), (-1,2,-3,4)))
+            ...
             sage: hash(phi) == old_hash
             False
 
@@ -1394,6 +1395,7 @@ def __clear_cached_values(self):
             sage: old_ratl_maps = phi.rational_maps()
             sage: from sage.schemes.elliptic_curves.weierstrass_morphism import WeierstrassIsomorphism
             sage: phi.set_post_isomorphism(WeierstrassIsomorphism(phi.codomain(), (-1,0,0,0)))
+            ...
             sage: old_ratl_maps == phi.rational_maps()
             False
             sage: old_ratl_maps[1] == -phi.rational_maps()[1]
@@ -1407,6 +1409,7 @@ def __clear_cached_values(self):
             sage: old_ratl_maps = phi.rational_maps()
             sage: from sage.schemes.elliptic_curves.weierstrass_morphism import WeierstrassIsomorphism
             sage: phi.set_post_isomorphism(WeierstrassIsomorphism(phi.codomain(), (-13,13,-13,13)))
+            ...
             sage: old_hash == hash(phi)
             False
             sage: old_ratl_maps == phi.rational_maps()
@@ -1439,9 +1442,11 @@ def __perform_inheritance_housekeeping(self):
             sage: E2 = phi.codomain()
             sage: post_isom = WeierstrassIsomorphism(E2, (41, 37, 31, 29))
             sage: phi.set_post_isomorphism(post_isom)
+            ...
             sage: E1pr = WeierstrassIsomorphism(E, (-1, 2, -3, 4)).codomain()
             sage: pre_isom = E1pr.isomorphism_to(E)
             sage: phi.set_pre_isomorphism(pre_isom)
+            ...
 
         """
         # one of the superclasses uses these fields
@@ -1664,6 +1669,7 @@ def __set_pre_isomorphism(self, domain, isomorphism):
             sage: E1pr = WeierstrassIsomorphism(E, (-1, 2, -3, 4)).codomain()
             sage: pre_isom = E1pr.isomorphism_to(E)
             sage: phi.set_pre_isomorphism(pre_isom)
+            ...
             sage: phi._EllipticCurveIsogeny__set_pre_isomorphism(E, WeierstrassIsomorphism(E, (-1, 3, -3, 4)))
             sage: E == phi.domain()
             True
@@ -1712,6 +1718,7 @@ def __set_post_isomorphism(self, codomain, isomorphism):
             sage: E2 = phi.codomain()
             sage: isom = WeierstrassIsomorphism(E2, (-1,2,-3,4))
             sage: phi.set_post_isomorphism(isom)
+            ...
             sage: phi._EllipticCurveIsogeny__set_post_isomorphism(E2, WeierstrassIsomorphism(phi.codomain(), (1,-2,3,-4)))
             sage: E2 == phi.codomain()
             True
@@ -2891,6 +2898,7 @@ def set_pre_isomorphism(self, preWI):
             sage: Epr = E.short_weierstrass_model()
             sage: isom = Epr.isomorphism_to(E)
             sage: phi.set_pre_isomorphism(isom)
+            ...
             sage: phi.rational_maps()
             ((-6*x^4 - 3*x^3 + 12*x^2 + 10*x - 1)/(x^3 + x - 12), (3*x^7 + x^6*y - 14*x^6 - 3*x^5 + 5*x^4*y + 7*x^4 + 8*x^3*y - 8*x^3 - 5*x^2*y + 5*x^2 - 14*x*y + 14*x - 6*y - 6)/(x^6 + 2*x^4 + 7*x^3 + x^2 + 7*x - 11))
             sage: phi(Epr((0,22)))
@@ -2908,7 +2916,9 @@ def set_pre_isomorphism(self, preWI):
             sage: inv_isom = WeierstrassIsomorphism(E, (1,-2,5,10))
             sage: Epr = inv_isom.codomain()
             sage: isom = Epr.isomorphism_to(E)
-            sage: phi.set_pre_isomorphism(isom); phi
+            sage: phi.set_pre_isomorphism(isom)
+            ...
+            sage: phi
             Isogeny of degree 5 from Elliptic Curve defined by y^2 + 10*x*y + 20*y = x^3 + 27*x^2 + 6 over Finite Field of size 29 to Elliptic Curve defined by y^2 = x^3 + 20*x over Finite Field of size 29
             sage: phi(Epr((12,1)))
             (26 : 0 : 1)
@@ -2928,6 +2938,7 @@ def set_pre_isomorphism(self, preWI):
             sage: Epr = E.short_weierstrass_model()
             sage: isom = Epr.isomorphism_to(E)
             sage: phi.set_pre_isomorphism(isom)
+            ...
             sage: phi
             Isogeny of degree 5 from Elliptic Curve defined by y^2 = x^3 - 13392*x - 1080432 over Rational Field to Elliptic Curve defined by y^2 + y = x^3 - x^2 - 7820*x - 263580 over Rational Field
             sage: phi(Epr((168,1188)))
@@ -2982,6 +2993,7 @@ def set_post_isomorphism(self, postWI):
             sage: phi = EllipticCurveIsogeny(E, x+18)
             sage: from sage.schemes.elliptic_curves.weierstrass_morphism import WeierstrassIsomorphism
             sage: phi.set_post_isomorphism(WeierstrassIsomorphism(phi.codomain(), (6,8,10,12)))
+            ...
             sage: phi
             Isogeny of degree 3 from Elliptic Curve defined by y^2 = x^3 + 1 over Finite Field of size 31 to Elliptic Curve defined by y^2 + 24*x*y + 7*y = x^3 + 22*x^2 + 16*x + 20 over Finite Field of size 31
 
@@ -2991,9 +3003,11 @@ def set_post_isomorphism(self, postWI):
             sage: E2 = phi.codomain()
             sage: post_isom = E2.isomorphism_to(E)
             sage: phi.set_post_isomorphism(post_isom)
+            ...
             sage: phi.rational_maps() == E.multiplication_by_m(3)
             False
             sage: phi.switch_sign()
+            ...
             sage: phi.rational_maps() == E.multiplication_by_m(3)
             True
 
@@ -3056,6 +3070,7 @@ def get_pre_isomorphism(self):
             sage: Epr = E.short_weierstrass_model()
             sage: isom = Epr.isomorphism_to(E)
             sage: phi.set_pre_isomorphism(isom)
+            ...
             sage: isom == phi.get_pre_isomorphism()
             True
 
@@ -3085,6 +3100,7 @@ def get_post_isomorphism(self):
             sage: from sage.schemes.elliptic_curves.weierstrass_morphism import WeierstrassIsomorphism
             sage: isom = WeierstrassIsomorphism(phi.codomain(), (6,8,10,12))
             sage: phi.set_post_isomorphism(isom)
+            ...
             sage: isom == phi.get_post_isomorphism()
             True
 
@@ -3120,6 +3136,7 @@ def switch_sign(self):
             sage: phi.rational_maps() == E.multiplication_by_m(3)
             False
             sage: phi.switch_sign()
+            ...
             sage: phi.rational_maps() == E.multiplication_by_m(3)
             True
 
@@ -3132,6 +3149,7 @@ def switch_sign(self):
             sage: phi.rational_maps()
             ((x^2 + 6*x + 4)/(x + 6), (x^2*y - 5*x*y + 8*x - 2*y)/(x^2 - 5*x + 2))
             sage: phi.switch_sign()
+            ...
             sage: phi
             Isogeny of degree 2 from Elliptic Curve defined by y^2 + 15*x*y + 12*y = x^3 + 3*x^2 + 7*x + 6 over Finite Field of size 17 to Elliptic Curve defined by y^2 + 15*x*y + 12*y = x^3 + 3*x^2 + 4*x + 8 over Finite Field of size 17
             sage: phi.rational_maps()
@@ -3144,6 +3162,7 @@ def switch_sign(self):
             sage: phi = EllipticCurveIsogeny(E, f)
             sage: (xmap1, ymap1) = phi.rational_maps()
             sage: phi.switch_sign()
+            ...
             sage: (xmap2, ymap2) = phi.rational_maps()
             sage: xmap1 == xmap2
             True
@@ -3157,6 +3176,7 @@ def switch_sign(self):
             sage: phi.rational_maps()
             ((x^2 + (-a)*x - 2)/(x + (-a)), (x^2*y + (-2*a)*x*y + y)/(x^2 + (-2*a)*x - 1))
             sage: phi.switch_sign()
+            ...
             sage: phi.rational_maps()
             ((x^2 + (-a)*x - 2)/(x + (-a)), (-x^2*y + (2*a)*x*y - y)/(x^2 + (-2*a)*x - 1))
 
@@ -3203,15 +3223,15 @@ def is_normalized(self, via_formal=True, check_by_pullback=True):
             sage: phi.is_normalized()
             True
             sage: isom = WeierstrassIsomorphism(phi.codomain(), (3, 0, 0, 0))
-            sage: phi.set_post_isomorphism(isom)
+            sage: phi = isom * phi
             sage: phi.is_normalized()
             False
             sage: isom = WeierstrassIsomorphism(phi.codomain(), (5, 0, 0, 0))
-            sage: phi.set_post_isomorphism(isom)
+            sage: phi = isom * phi
             sage: phi.is_normalized()
             True
             sage: isom = WeierstrassIsomorphism(phi.codomain(), (1, 1, 1, 1))
-            sage: phi.set_post_isomorphism(isom)
+            sage: phi = isom * phi
             sage: phi.is_normalized()
             True
 
@@ -3222,15 +3242,15 @@ def is_normalized(self, via_formal=True, check_by_pullback=True):
             sage: isom = WeierstrassIsomorphism(phi.codomain(), (alpha, 0, 0, 0))
             sage: phi.is_normalized()
             True
-            sage: phi.set_post_isomorphism(isom)
+            sage: phi = isom * phi
             sage: phi.is_normalized()
             False
             sage: isom = WeierstrassIsomorphism(phi.codomain(), (1/alpha, 0, 0, 0))
-            sage: phi.set_post_isomorphism(isom)
+            sage: phi = isom * phi
             sage: phi.is_normalized()
             True
             sage: isom = WeierstrassIsomorphism(phi.codomain(), (1, 1, 1, 1))
-            sage: phi.set_post_isomorphism(isom)
+            sage: phi = isom * phi
             sage: phi.is_normalized()
             True
 
@@ -3241,15 +3261,15 @@ def is_normalized(self, via_formal=True, check_by_pullback=True):
             sage: isom = WeierstrassIsomorphism(phi.codomain(), (2, 0, 0, 0))
             sage: phi.is_normalized()
             True
-            sage: phi.set_post_isomorphism(isom)
+            sage: phi = isom * phi
             sage: phi.is_normalized()
             False
             sage: isom = WeierstrassIsomorphism(phi.codomain(), (1/2, 0, 0, 0))
-            sage: phi.set_post_isomorphism(isom)
+            sage: phi = isom * phi
             sage: phi.is_normalized()
             True
             sage: isom = WeierstrassIsomorphism(phi.codomain(), (1, 1, 1, 1))
-            sage: phi.set_post_isomorphism(isom)
+            sage: phi = isom * phi
             sage: phi.is_normalized()
             True
         """
@@ -3415,7 +3435,7 @@ def dual(self):
             sage: phi
             Isogeny of degree 5 from Elliptic Curve defined by y^2 = x^3 + 11*x + 11 over Finite Field of size 103 to Elliptic Curve defined by y^2 = x^3 + 25*x + 80 over Finite Field of size 103
             sage: from sage.schemes.elliptic_curves.weierstrass_morphism import WeierstrassIsomorphism
-            sage: phi.set_post_isomorphism(WeierstrassIsomorphism(phi.codomain(),(5,0,1,2)))
+            sage: phi = WeierstrassIsomorphism(phi.codomain(),(5,0,1,2)) * phi
             sage: phi.dual().dual() == phi
             True
 

diff --git a/src/sage/schemes/elliptic_curves/isogeny_class.py b/src/sage/schemes/elliptic_curves/isogeny_class.py
@@ -840,8 +840,7 @@ def add_tup(t):
                 if js: # seen codomain already -- up to isomorphism
                     j = js[0]
                     if phi.codomain()!=curves[j]:
-                        iso = E2.isomorphism_to(curves[j])
-                        phi.set_post_isomorphism(iso)
+                        phi = E2.isomorphism_to(curves[j]) * phi
                     assert phi.domain()==curves[i] and phi.codomain()==curves[j]
                     add_tup([i,j,d,phi])
                 else:

diff --git a/src/sage/schemes/elliptic_curves/isogeny_small_degree.py b/src/sage/schemes/elliptic_curves/isogeny_small_degree.py
@@ -324,7 +324,7 @@ def isogenies_prime_degree_genus_0(E, l=None, minimal_models=True):
         from sage.rings.number_field.number_field_base import is_NumberField
         model = "minimal" if minimal_models and is_NumberField(F) else None
         isogs = [E1.isogeny(kernel=ker, model=model) for ker in kernels]
-        [isog.set_pre_isomorphism(w) for isog in isogs]
+        isogs = [isog * w for isog in isogs]
         return isogs
 
     if l is None:
@@ -660,7 +660,7 @@ def isogenies_sporadic_Q(E, l=None, minimal_models=True):
     from sage.rings.number_field.number_field_base import is_NumberField
     model = "minimal" if minimal_models and is_NumberField(F) else None
     isog = Ew.isogeny(kernel=ker, degree=l, model=model, check=False)
-    isog.set_pre_isomorphism(E_to_Ew)
+    isog = isog * E_to_Ew
     return [isog]
 
 
@@ -822,7 +822,7 @@ def isogenies_5_0(E, minimal_models=True):
     model = "minimal" if minimal_models and is_NumberField(F) else None
     isogs = [Ew.isogeny(x**2+beta*x+gamma, model=model) for beta,gamma in zip(betas,gammas)]
     iso = E.isomorphism_to(Ew)
-    [isog.set_pre_isomorphism(iso) for isog in isogs]
+    isogs = [isog * iso for isog in isogs]
     return isogs
 
 def isogenies_5_1728(E, minimal_models=True):
@@ -921,13 +921,13 @@ def isogenies_5_1728(E, minimal_models=True):
     if square1:
         i = F(-1).sqrt()
         isogs = [Ew.isogeny(f) for f in [x**2+a/(1+2*i), x**2+a/(1-2*i)]]
-        [isog.set_post_isomorphism(isog.codomain().isomorphism_to(E)) for isog in isogs]
+        isogs = [isog.codomain().isomorphism_to(E) * isog for isog in isogs]
     # Type 2: if 5 is a square we have up to 4 (non-endomorphism) isogenies
     if square5:
         betas = sorted((x**4+20*a*x**2-80*a**2).roots(multiplicities=False))
         gammas = [(beta**2-2*a)/6 for beta in betas]
         isogs += [Ew.isogeny(x**2+beta*x+gamma, model=model) for beta,gamma in zip(betas,gammas)]
-    [isog.set_pre_isomorphism(iso) for isog in isogs]
+    isogs = [isog * iso for isog in isogs]
     return isogs
 
 def isogenies_7_0(E, minimal_models=True):
@@ -1026,8 +1026,7 @@ def isogenies_7_0(E, minimal_models=True):
     kers = [7*x-(2+6*t) for t in ts]
     kers = [k(x**3/a).monic() for k in kers]
     isogs = [Ew.isogeny(k,model=model) for k in kers]
-    if isogs:
-        [endo.set_post_isomorphism(endo.codomain().isomorphism_to(E)) for endo in isogs]
+    isogs = [endo.codomain().isomorphism_to(E) * endo for endo in isogs]
 
     # we may have up to 6 other isogenies:
     ts = (x**2-21).roots(multiplicities=False)
@@ -1038,7 +1037,7 @@ def isogenies_7_0(E, minimal_models=True):
         kers = [ker(x/s).monic() for s in ss]
         isogs += [Ew.isogeny(k, model=model) for k in kers]
 
-    [isog.set_pre_isomorphism(iso) for isog in isogs]
+    isogs = [isog * iso for isog in isogs]
     return isogs
 
 def isogenies_7_1728(E, minimal_models=True):
@@ -1127,7 +1126,7 @@ def isogenies_7_1728(E, minimal_models=True):
 
         kers = [ker(x/s) for s in ss]
         isogs += [Ew.isogeny(k.monic(), model=model) for k in kers]
-    [isog.set_pre_isomorphism(iso) for isog in isogs]
+    isogs = [isog * iso for isog in isogs]
     return isogs
 
 def isogenies_13_0(E, minimal_models=True):
@@ -1236,8 +1235,7 @@ def isogenies_13_0(E, minimal_models=True):
     kers = [13*x**2 + (78*t + 26)*x + 24*t + 40 for t in ts]
     kers = [k(x**3/a).monic() for k in kers]
     isogs = [Ew.isogeny(k,model=model) for k in kers]
-    if isogs:
-        [endo.set_post_isomorphism(endo.codomain().isomorphism_to(E)) for endo in isogs]
+    isogs = [endo.codomain().isomorphism_to(E) * endo for endo in isogs]
 
     # we may have up to 12 other isogenies:
     ts = sorted((x**4 + 7*x**3 + 20*x**2 + 19*x + 1).roots(multiplicities=False))
@@ -1253,7 +1251,7 @@ def isogenies_13_0(E, minimal_models=True):
         kers = [ker(x/s).monic() for s in ss]
         isogs += [Ew.isogeny(k, model=model) for k in kers]
 
-    [isog.set_pre_isomorphism(iso) for isog in isogs]
+    isogs = [isog * iso for isog in isogs]
 
     return isogs
 
@@ -1355,8 +1353,7 @@ def isogenies_13_1728(E, minimal_models=True):
     kers = [13*x**3 + (-26*i - 13)*x**2 + (-52*i - 13)*x - 2*i - 3 for i in ts]
     kers = [k(x**2/a).monic() for k in kers]
     isogs = [Ew.isogeny(k,model=model) for k in kers]
-    if isogs:
-        [endo.set_post_isomorphism(endo.codomain().isomorphism_to(E)) for endo in isogs]
+    isogs = [endo.codomain().isomorphism_to(E) * endo for endo in isogs]
 
     # we may have up to 12 other isogenies:
 
@@ -1380,7 +1377,7 @@ def isogenies_13_1728(E, minimal_models=True):
         kers = [ker(x/s).monic() for s in ss]
         isogs += [Ew.isogeny(k, model=model) for k in kers]
 
-    [isog.set_pre_isomorphism(iso) for isog in isogs]
+    isogs = [isog * iso for isog in isogs]
 
     return isogs