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authorPierrick-Dartois <pierrickdartois@icloud.com>2025-05-22 18:51:58 +0200
committerPierrick-Dartois <pierrickdartois@icloud.com>2025-05-22 18:51:58 +0200
commitcb6080eaa4f326d9fce5f0a9157be46e91d55e09 (patch)
tree4d080ade8db9faa0da5268ab420dad2b02a4e248 /theta_lib/isogenies/Kani_gluing_isogeny_chain_dim4.py
parentd40de259097c5e8d8fd35539560ca7c3d47523e7 (diff)
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Clean up PEGASIS submodule inclusion
Diffstat (limited to 'theta_lib/isogenies/Kani_gluing_isogeny_chain_dim4.py')
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diff --git a/theta_lib/isogenies/Kani_gluing_isogeny_chain_dim4.py b/theta_lib/isogenies/Kani_gluing_isogeny_chain_dim4.py
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--- a/theta_lib/isogenies/Kani_gluing_isogeny_chain_dim4.py
+++ /dev/null
@@ -1,567 +0,0 @@
-from sage.all import *
-from ..utilities.discrete_log import weil_pairing_pari
-from ..basis_change.canonical_basis_dim1 import make_canonical
-from ..basis_change.kani_base_change import (
- fixed_deg_gluing_matrix_Phi1,
- fixed_deg_gluing_matrix_Phi2,
- fixed_deg_gluing_matrix_dim4,
- clapoti_cob_matrix_dim2,
- clapoti_cob_matrix_dim2_dim4,
- gluing_base_change_matrix_dim2,
- gluing_base_change_matrix_dim2_dim4,
- gluing_base_change_matrix_dim2_F1,
- gluing_base_change_matrix_dim2_F2,
- kernel_basis,
-)
-from ..basis_change.base_change_dim2 import base_change_theta_dim2
-from ..basis_change.base_change_dim4 import base_change_theta_dim4
-from ..theta_structures.Theta_dim1 import ThetaStructureDim1
-from ..theta_structures.Theta_dim2 import ProductThetaStructureDim2
-from ..theta_structures.Tuple_point import TuplePoint
-from ..theta_structures.Theta_dim4 import ProductThetaStructureDim2To4, ThetaPointDim4
-from ..isogenies_dim2.isogeny_chain_dim2 import IsogenyChainDim2
-from .gluing_isogeny_dim4 import GluingIsogenyDim4
-
-class KaniFixedDegDim2Gluing:
- def __init__(self,P_mp3,Q_mp3,a,b,c,d,u,f,m,strategy_dim2=None):
- r"""
- INPUT:
- - P_mp3, Q_mp3: basis of E[2^(m+3)] such that pi(P_mp3)=P_mp3 and pi(Q_mp3)=-Q_mp3.
- - a,b,c,d,u,f: integers such that a**2+c**2+p*(b**2+d**2)=u*(2**f-u), where p is
- ths characteristic of the base field.
- - m: integer such that m=min(v_2(a-b),v_2(a+b)).
-
- OUTPUT: Gluing isogeny chain F_{m+1}\circ...\circ F_1 containing the first m+1 steps of
- the isogeny F: E^4 --> A*A' representing a u-isogeny in dimension 2.
- """
-
- P_mp2 = 2*P_mp3
- Q_mp2 = 2*Q_mp3
- P_4 = 2**m*P_mp2
- Q_4 = 2**m*Q_mp2
-
- E = P_mp3.curve()
-
- # Canonical basis with S_4=(1,0)
- _, _, R_4, S_4, M_dim1 = make_canonical(P_4,Q_4,4,preserve_pairing=True)
-
- Z4 = Integers(4)
- M0 = matrix(Z4,[[M_dim1[0,0],0,M_dim1[0,1],0],
- [0,M_dim1[0,0],0,M_dim1[0,1]],
- [M_dim1[1,0],0,M_dim1[1,1],0],
- [0,M_dim1[1,0],0,M_dim1[1,1]]])
-
- # Theta structures
- Theta_E = ThetaStructureDim1(E,R_4,S_4)
- Theta_EE = ProductThetaStructureDim2(Theta_E,Theta_E)
-
- # Gluing change of basis in dimension 2
- M1 = fixed_deg_gluing_matrix_Phi1(u,a,b,c,d)
- M2 = fixed_deg_gluing_matrix_Phi2(u,a,b,c,d)
-
- M10 = M0*M1
- M20 = M0*M2
-
- Fp2 = E.base_field()
- e4 = Fp2(weil_pairing_pari(R_4,S_4,4))
-
- N_Phi1 = base_change_theta_dim2(M10,e4)
- N_Phi2 = base_change_theta_dim2(M20,e4)
-
- # Gluing change of basis dimension 2 * dimension 2 --> dimension 4
- M_dim4 = fixed_deg_gluing_matrix_dim4(u,a,b,c,d,m)
-
- self.N_dim4 = base_change_theta_dim4(M_dim4,e4)
-
- # Kernel of Phi1 : E^2 --> A_m1 and Phi2 : E^2 --> A_m2
- two_mp2 = 2**(m+2)
- two_mp3 = 2*two_mp2
- mu = inverse_mod(u,two_mp3)
-
- B_K_Phi1 = [TuplePoint((u%two_mp2)*P_mp2,((c+d)%two_mp2)*P_mp2),
- TuplePoint((((d**2-c**2)*mu)%two_mp2)*Q_mp2,((c-d)%two_mp2)*Q_mp2)]
-
- B_K_Phi2 = [TuplePoint((u%two_mp2)*P_mp2,((d-c)%two_mp2)*P_mp2),
- TuplePoint((((d**2-c**2)*mu)%two_mp2)*Q_mp2,(-(c+d)%two_mp2)*Q_mp2)]
-
- # Computation of the 2**m-isogenies Phi1 and Phi2
- self._Phi1=IsogenyChainDim2(B_K_Phi1,Theta_EE,N_Phi1,m,strategy_dim2)
- self._Phi2=IsogenyChainDim2(B_K_Phi2,Theta_EE,N_Phi2,m,strategy_dim2)
-
- # Kernel of the (m+1)-th isogeny in dimension 4 F_{m+1}: A_m1*A_m2 --> B (gluing isogeny)
-
- B_K_dim4 =[TuplePoint((u%two_mp3)*P_mp3,E(0),((a+b)%two_mp3)*P_mp3,((c+d)%two_mp3)*P_mp3),
- TuplePoint(E(0),(u%two_mp3)*P_mp3,((d-c)%two_mp3)*P_mp3,((a-b)%two_mp3)*P_mp3),
- TuplePoint(((u-2**f)%two_mp3)*Q_mp3,E(0),((a-b)%two_mp3)*Q_mp3,((c-d)%two_mp3)*Q_mp3),
- TuplePoint(E(0),((u-2**f)%two_mp3)*Q_mp3,((-c-d)%two_mp3)*Q_mp3,((a+b)%two_mp3)*Q_mp3)]
-
- L_K_dim4=B_K_dim4+[B_K_dim4[0]+B_K_dim4[1]]
-
- L_K_dim4=[[self._Phi1(TuplePoint(T[0],T[3])),self._Phi2(TuplePoint(T[1],T[2]))] for T in L_K_dim4]
-
- # Product Theta structure on A_m1*A_m2
- self.domain_product=ProductThetaStructureDim2To4(self._Phi1._codomain,self._Phi2._codomain)
-
- # Theta structure on A_m1*A_m2 after change of theta coordinates
- self.domain_base_change=self.domain_product.base_change_struct(self.N_dim4)
-
- # Converting the kernel to the Theta structure domain_base_change
- L_K_dim4=[self.domain_product.product_theta_point(T[0],T[1]) for T in L_K_dim4]
- L_K_dim4=[self.domain_base_change.base_change_coords(self.N_dim4,T) for T in L_K_dim4]
-
- # Computing the gluing isogeny in dimension 4
- self._gluing_isogeny_dim4=GluingIsogenyDim4(self.domain_base_change,L_K_dim4,[(1,0,0,0),(0,1,0,0),(0,0,1,0),(0,0,0,1),(1,1,0,0)])
-
- # Translates for the evaluation of the gluing isogeny in dimension 4
- self.L_trans=[2*B_K_dim4[k] for k in range(2)]
- self.L_trans_ind=[1,2] # Corresponds to multi indices (1,0,0,0) and (0,1,0,0)
-
- self._codomain=self._gluing_isogeny_dim4._codomain
-
- def evaluate(self,P):
- if not isinstance(P, TuplePoint):
- raise TypeError("KaniGluingIsogenyChainDim4 isogeny expects as input a TuplePoint on the domain product E^4")
-
- # Translating P
- L_P_trans=[P+T for T in self.L_trans]
-
- # dim4 --> dim2 x dim2
- eval_P=[TuplePoint(P[0],P[3]),TuplePoint(P[1],P[2])]
- eval_L_P_trans=[[TuplePoint(Q[0],Q[3]),TuplePoint(Q[1],Q[2])] for Q in L_P_trans]
-
- # evaluating through the dimension 2 isogenies
- eval_P=[self._Phi1(eval_P[0]),self._Phi2(eval_P[1])]
- eval_L_P_trans=[[self._Phi1(Q[0]),self._Phi2(Q[1])] for Q in eval_L_P_trans]
-
- # Product Theta structure and base change
- eval_P=self.domain_product.product_theta_point(eval_P[0],eval_P[1])
- eval_P=self.domain_base_change.base_change_coords(self.N_dim4,eval_P)
-
- eval_L_P_trans=[self.domain_product.product_theta_point(Q[0],Q[1]) for Q in eval_L_P_trans]
- eval_L_P_trans=[self.domain_base_change.base_change_coords(self.N_dim4,Q) for Q in eval_L_P_trans]
-
- return self._gluing_isogeny_dim4.special_image(eval_P,eval_L_P_trans,self.L_trans_ind)
-
- def __call__(self,P):
- return self.evaluate(P)
-
-
-class KaniClapotiGluing:
- def __init__(self,points_mp3,points_mp2,points_4,integers,strategy_dim2=None,coerce=None):
- self._coerce=coerce
- Pu_mp3,Qu_mp3,Pv_mp3,Qv_mp3 = points_mp3
- Pu_mp2,Qu_mp2,Pv_mp2,Qv_mp2 = points_mp2
- Pu_4,Qu_4,Pv_4,Qv_4 = points_4
- gu,xu,yu,gv,xv,yv,Nbk,Nck,e,m = integers
-
- Eu=Pu_4.curve()
- Ev=Pv_4.curve()
-
- lamb_u = inverse_mod(ZZ(gu),4)
- lamb_v = inverse_mod(ZZ(gv*Nbk*Nck),4)
-
-
- # 4-torsion canonical change of basis in Eu and Ev (Su=(1,0), Sv=(1,0))
- _,_,Ru,Su,Mu=make_canonical(Pu_4,lamb_u*Qu_4,4,preserve_pairing=True)
- _,_,Rv,Sv,Mv=make_canonical(Pv_4,lamb_v*Qv_4,4,preserve_pairing=True)
-
- Z4 = Integers(4)
- M0=matrix(Z4,[[Mu[0,0],0,Mu[1,0],0],
- [0,Mv[0,0],0,Mv[1,0]],
- [Mu[0,1],0,Mu[1,1],0],
- [0,Mv[0,1],0,Mv[1,1]]])
-
- self.M_product_dim2=M0
-
- # Theta structures in dimension 1 and 2
- Theta_u=ThetaStructureDim1(Eu,Ru,Su)
- Theta_v=ThetaStructureDim1(Ev,Rv,Sv)
-
- Theta_uv=ProductThetaStructureDim2(Theta_u,Theta_v)
-
- # Gluing change of basis in dimension 2
- M1 = clapoti_cob_matrix_dim2(integers)
- M10 = M0*M1
-
- Fp2 = Eu.base_field()
- e4 = Fp2(weil_pairing_pari(Ru,Su,4))
- self.e4 = e4
-
- N_dim2 = base_change_theta_dim2(M10,e4)
-
- # Gluing change of basis dimension 2 * dimension 2 --> dimension 4
- M2 = clapoti_cob_matrix_dim2_dim4(integers)
-
- self.N_dim4 = base_change_theta_dim4(M2,e4)
-
- # Kernel of the 2**m-isogeny chain in dimension 2
- two_mp2=2**(m+2)
- two_mp3=2*two_mp2
- u=ZZ(gu*(xu**2+yu**2))
- mu=inverse_mod(u,two_mp2)
- suv=ZZ(xu*xv+yu*yv)
- duv=ZZ(xv*yu-xu*yv)
- uNbk=(u*Nbk)%two_mp2
- gusuv=(gu*suv)%two_mp2
- xK2=(uNbk+gu*gv*mu*Nck*duv**2)%two_mp2
- B_K_dim2 = [TuplePoint(uNbk*Pu_mp2,gusuv*Pv_mp2),TuplePoint(xK2*Qu_mp2,gusuv*Qv_mp2)]
-
- # Computation of the 2**m-isogeny chain in dimension 2
- self._isogenies_dim2=IsogenyChainDim2(B_K_dim2,Theta_uv,N_dim2,m,strategy_dim2)
-
- # Kernel of the (m+1)-th isogeny in dimension 4 f_{m+1}: A_m^2 --> B (gluing isogeny)
- xuNbk = (xu*Nbk)%two_mp3
- yuNbk = (yu*Nbk)%two_mp3
- inv_Nbk = inverse_mod(Nbk,two_mp3)
- lambxu = ((1-2**e)*xu)%two_mp3 # extreme case m=e-2, 2^e = 2^(m+2) so 2^e/(u*Nbk) = 2^e mod 2^(m+3).
- lambyu = ((1-2**e)*yu)%two_mp3
- xv_Nbk = (xv*inv_Nbk)%two_mp3
- yv_Nbk = (yv*inv_Nbk)%two_mp3
-
- B_K_dim4 = [TuplePoint(xuNbk*Pu_mp3,yuNbk*Pu_mp3,xv*Pv_mp3,yv*Pv_mp3),
- TuplePoint(-yuNbk*Pu_mp3,xuNbk*Pu_mp3,-yv*Pv_mp3,xv*Pv_mp3),
- TuplePoint(lambxu*Qu_mp3,lambyu*Qu_mp3,xv_Nbk*Qv_mp3,yv_Nbk*Qv_mp3),
- TuplePoint(-lambyu*Qu_mp3,lambxu*Qu_mp3,-yv_Nbk*Qv_mp3,xv_Nbk*Qv_mp3)]
-
- L_K_dim4=B_K_dim4+[B_K_dim4[0]+B_K_dim4[1]]
-
- L_K_dim4=[[self._isogenies_dim2(TuplePoint(L_K_dim4[k][0],L_K_dim4[k][2])),self._isogenies_dim2(TuplePoint(L_K_dim4[k][1],L_K_dim4[k][3]))] for k in range(5)]
-
- # Product Theta structure on A_m^2
- self.domain_product=ProductThetaStructureDim2To4(self._isogenies_dim2._codomain,self._isogenies_dim2._codomain)
-
- # Theta structure on A_m^2 after change of theta coordinates
- self.domain_base_change=self.domain_product.base_change_struct(self.N_dim4)
-
- # Converting the kernel to the Theta structure domain_base_change
- L_K_dim4=[self.domain_product.product_theta_point(L_K_dim4[k][0],L_K_dim4[k][1]) for k in range(5)]
- L_K_dim4=[self.domain_base_change.base_change_coords(self.N_dim4,L_K_dim4[k]) for k in range(5)]
-
- # Computing the gluing isogeny in dimension 4
- self._gluing_isogeny_dim4=GluingIsogenyDim4(self.domain_base_change,L_K_dim4,[(1,0,0,0),(0,1,0,0),(0,0,1,0),(0,0,0,1),(1,1,0,0)], coerce=self._coerce)
-
- # Translates for the evaluation of the gluing isogeny in dimension 4
- self.L_trans=[2*B_K_dim4[k] for k in range(2)]
- self.L_trans_ind=[1,2] # Corresponds to multi indices (1,0,0,0) and (0,1,0,0)
-
- self._codomain=self._gluing_isogeny_dim4._codomain
-
- def evaluate(self,P):
- if not isinstance(P, TuplePoint):
- raise TypeError("KaniGluingIsogenyChainDim4 isogeny expects as input a TuplePoint on the domain product Eu^2 x Ev^2")
-
- # Translating P
- L_P_trans=[P+T for T in self.L_trans]
-
- # dim4 --> dim2 x dim2
- eval_P=[TuplePoint(P[0],P[2]),TuplePoint(P[1],P[3])]
- eval_L_P_trans=[[TuplePoint(Q[0],Q[2]),TuplePoint(Q[1],Q[3])] for Q in L_P_trans]
-
- # evaluating through the dimension 2 isogenies
- eval_P=[self._isogenies_dim2(eval_P[0]),self._isogenies_dim2(eval_P[1])]
- eval_L_P_trans=[[self._isogenies_dim2(Q[0]),self._isogenies_dim2(Q[1])] for Q in eval_L_P_trans]
-
- # Product Theta structure and base change
- eval_P=self.domain_product.product_theta_point(eval_P[0],eval_P[1])
- eval_P=self.domain_base_change.base_change_coords(self.N_dim4,eval_P)
-
- eval_L_P_trans=[self.domain_product.product_theta_point(Q[0],Q[1]) for Q in eval_L_P_trans]
- eval_L_P_trans=[self.domain_base_change.base_change_coords(self.N_dim4,Q) for Q in eval_L_P_trans]
-
- return self._gluing_isogeny_dim4.special_image(eval_P,eval_L_P_trans,self.L_trans_ind)
-
- def __call__(self,P):
- return self.evaluate(P)
-
-
-
-class KaniGluingIsogenyChainDim4:
- def __init__(self,points_m,points_4,a1,a2,q,m,strategy_dim2=None):
- r"""
-
- INPUT:
- - points_m: list of 4 points P1_m, Q1_m, R2_m, S2_m of order 2**(m+3)
- such that (P1_m,Q1_m) generates E1[2**(m+3)] and (R2_m,S2_m) is
- its image by sigma: E1 --> E2.
- - points_4: list of 4 points P1_4, Q1_4, R2_4, S2_4 of order 4 obtained by
- multiplying P1_m, Q1_m, R2_m, S2_m by 2**(m+1).
- - a1, a2, q: integers such that a1**2+a2**2+q=2**e.
- - m: 2-adic valuation of a2.
-
- OUTPUT: Composition of the m+1 first isogenies in the isogeny chained
- E1^2*E1^2 --> E1^2*E2^2 parametrized by a1, a2 and sigma via Kani's lemma.
- """
-
- P1_m, Q1_m, R2_m, S2_m = points_m
- P1_4, Q1_4, R2_4, S2_4 = points_4
-
- E1=P1_m.curve()
- E2=R2_m.curve()
-
- Fp2=E1.base_field()
-
- lamb=inverse_mod(q,4)
-
- _,_,T1,T2,MT=make_canonical(P1_4,Q1_4,4,preserve_pairing=True)
- _,_,U1,U2,MU=make_canonical(R2_4,lamb*S2_4,4,preserve_pairing=True)
-
- Z4=Integers(4)
- M0=matrix(Z4,[[MT[0,0],0,MT[1,0],0],
- [0,MU[0,0],0,MU[1,0]],
- [MT[0,1],0,MT[1,1],0],
- [0,MU[0,1],0,MU[1,1]]])
-
- self.M_product_dim2=M0
-
- # Theta structures in dimension 1 and 2
- Theta1=ThetaStructureDim1(E1,T1,T2)
- Theta2=ThetaStructureDim1(E2,U1,U2)
-
- Theta12=ProductThetaStructureDim2(Theta1,Theta2)
-
- self.Theta1=Theta1
- self.Theta2=Theta2
- self.Theta12=Theta12
-
- # Gluing base change in dimension 2
- M1=gluing_base_change_matrix_dim2(a1,a2,q)
- M10=M0*M1
-
- self.M_gluing_dim2=M1
-
- e4=Fp2(weil_pairing_pari(T1,T2,4))
-
- self.e4=e4
-
- N_dim2=base_change_theta_dim2(M10,e4)
- #N_dim2=montgomery_to_theta_matrix_dim2(Theta12.zero().coords(),N1)
-
- # Gluing base change in dimension 4
- mua2=-M1[3,1]
- M2=gluing_base_change_matrix_dim2_dim4(a1,a2,m,mua2)
-
- self.M_gluing_dim4=M2
-
- self.N_dim4=base_change_theta_dim4(M2,e4)
-
- # Kernel of the 2**m-isogeny chain in dimension 2
- a1_red=a1%(2**(m+2))
- a2_red=a2%(2**(m+2))
- B_K_dim2=[TuplePoint(2*a1_red*P1_m-2*a2_red*Q1_m,2*R2_m),TuplePoint(2*a1_red*Q1_m+2*a2_red*P1_m,2*S2_m)]
-
- # Computation of the 2**m-isogeny chain in dimension 2
- self._isogenies_dim2=IsogenyChainDim2(B_K_dim2,Theta12,N_dim2,m,strategy_dim2)
-
- # Kernel of the (m+1)-th isogeny in dimension 4 f_{m+1}: A_m^2 --> B (gluing isogeny)
- a1_red=a1%(2**(m+3))
- a2_red=a2%(2**(m+3))
-
- a1P1_m=(a1_red)*P1_m
- a2P1_m=(a2_red)*P1_m
- a1Q1_m=(a1_red)*Q1_m
- a2Q1_m=(a2_red)*Q1_m
-
- OE2=E2(0)
-
- B_K_dim4=[TuplePoint(a1P1_m,a2P1_m,R2_m,OE2),TuplePoint(a1Q1_m,a2Q1_m,S2_m,OE2),
- TuplePoint(-a2P1_m,a1P1_m,OE2,R2_m),TuplePoint(-a2Q1_m,a1Q1_m,OE2,S2_m)]
- L_K_dim4=B_K_dim4+[B_K_dim4[0]+B_K_dim4[1]]
-
- L_K_dim4=[[self._isogenies_dim2(TuplePoint(L_K_dim4[k][0],L_K_dim4[k][2])),self._isogenies_dim2(TuplePoint(L_K_dim4[k][1],L_K_dim4[k][3]))] for k in range(5)]
-
- # Product Theta structure on A_m^2
- self.domain_product=ProductThetaStructureDim2To4(self._isogenies_dim2._codomain,self._isogenies_dim2._codomain)
-
- # Theta structure on A_m^2 after base change
- self.domain_base_change=self.domain_product.base_change_struct(self.N_dim4)
-
- # Converting the kernel to the Theta structure domain_base_change
- L_K_dim4=[self.domain_product.product_theta_point(L_K_dim4[k][0],L_K_dim4[k][1]) for k in range(5)]
- L_K_dim4=[self.domain_base_change.base_change_coords(self.N_dim4,L_K_dim4[k]) for k in range(5)]
-
- # Computing the gluing isogeny in dimension 4
- self._gluing_isogeny_dim4=GluingIsogenyDim4(self.domain_base_change,L_K_dim4,[(1,0,0,0),(0,1,0,0),(0,0,1,0),(0,0,0,1),(1,1,0,0)])
-
- # Translates for the evaluation of the gluing isogeny in dimension 4
- self.L_trans=[2*B_K_dim4[k] for k in range(2)]
- self.L_trans_ind=[1,2] # Corresponds to multi indices (1,0,0,0) and (0,1,0,0)
-
- self._codomain=self._gluing_isogeny_dim4._codomain
-
- def evaluate(self,P):
- if not isinstance(P, TuplePoint):
- raise TypeError("KaniGluingIsogenyChainDim4 isogeny expects as input a TuplePoint on the domain product E1^2 x E2^2")
-
- # Translating P
- L_P_trans=[P+T for T in self.L_trans]
-
- # dim4 --> dim2 x dim2
- eval_P=[TuplePoint(P[0],P[2]),TuplePoint(P[1],P[3])]
- eval_L_P_trans=[[TuplePoint(Q[0],Q[2]),TuplePoint(Q[1],Q[3])] for Q in L_P_trans]
-
- # evaluating through the dimension 2 isogenies
- eval_P=[self._isogenies_dim2(eval_P[0]),self._isogenies_dim2(eval_P[1])]
- eval_L_P_trans=[[self._isogenies_dim2(Q[0]),self._isogenies_dim2(Q[1])] for Q in eval_L_P_trans]
-
- # Product Theta structure and base change
- eval_P=self.domain_product.product_theta_point(eval_P[0],eval_P[1])
- eval_P=self.domain_base_change.base_change_coords(self.N_dim4,eval_P)
-
- eval_L_P_trans=[self.domain_product.product_theta_point(Q[0],Q[1]) for Q in eval_L_P_trans]
- eval_L_P_trans=[self.domain_base_change.base_change_coords(self.N_dim4,Q) for Q in eval_L_P_trans]
-
- return self._gluing_isogeny_dim4.special_image(eval_P,eval_L_P_trans,self.L_trans_ind)
-
- def __call__(self,P):
- return self.evaluate(P)
-
-class KaniGluingIsogenyChainDim4Half:
- def __init__(self, points_m, a1, a2, q, m, Theta12, M_product_dim2, M_start_dim4, M_gluing_dim4, e4, dual=False,strategy_dim2=None):#points_m,points_4,a1,a2,q,m,precomputed_data=None,dual=False,strategy_dim2=None):
- r"""
-
- INPUT:
- - points_m: list of 4 points P1_m, Q1_m, R2_m, S2_m of order 2**(m+3)
- such that (P1_m,Q1_m) generates E1[2**(m+3)] and (R2_m,S2_m) is
- its image by sigma: E1 --> E2.
- - points_4: list of 4 points P1_4, Q1_4, R2_4, S2_4 of order 4 obtained by
- multiplying P1_m, Q1_m, R2_m, S2_m by 2**(m+1).
- - a1, a2, q: integers such that a1**2+a2**2+q=2**e.
- - m: 2-adic valuation of a2.
-
- OUTPUT: Composition of the m+1 first isogenies in the isogeny chained
- E1^2*E1^2 --> E1^2*E2^2 parametrized by a1, a2 and sigma via Kani's lemma.
- """
-
- P1_m, Q1_m, R2_m, S2_m = points_m
-
- E1=P1_m.curve()
- E2=R2_m.curve()
-
- Fp2=E1.base_field()
-
- self.M_product_dim2 = M_product_dim2
-
- self.Theta12=Theta12
-
- self.e4=e4
-
- # Gluing base change in dimension 2
- if not dual:
- M1=gluing_base_change_matrix_dim2_F1(a1,a2,q)
- else:
- M1=gluing_base_change_matrix_dim2_F2(a1,a2,q)
-
- M10=M_product_dim2*M1
-
- self.M_gluing_dim2=M1
-
- self.e4=e4
-
- N_dim2=base_change_theta_dim2(M10,e4)
- #N_dim2=montgomery_to_theta_matrix_dim2(Theta12.zero().coords(),N1)
-
- # Gluing base change in dimension 4
-
- self.M_gluing_dim4 = M_gluing_dim4
-
- self.N_dim4 = base_change_theta_dim4(M_gluing_dim4, e4)
-
- # Kernel of the 2**m-isogeny chain in dimension 2
- a1_red=a1%(2**(m+2))
- a2_red=a2%(2**(m+2))
- if not dual:
- B_K_dim2=[TuplePoint(2*a1_red*P1_m-2*a2_red*Q1_m,2*R2_m),TuplePoint(2*a1_red*Q1_m+2*a2_red*P1_m,2*S2_m)]
- else:
- B_K_dim2=[TuplePoint(2*a1_red*P1_m+2*a2_red*Q1_m,-2*R2_m),TuplePoint(2*a1_red*Q1_m-2*a2_red*P1_m,-2*S2_m)]
-
- # Computation of the 2**m-isogeny chain in dimension 2
- self._isogenies_dim2=IsogenyChainDim2(B_K_dim2,Theta12,N_dim2,m,strategy_dim2)
-
- # Kernel of the (m+1)-th isogeny in dimension 4 f_{m+1}: A_m^2 --> B (gluing isogeny)
- lamb=inverse_mod(q,2**(m+3))
- B_K_dim4=kernel_basis(M_start_dim4,m+1,P1_m,Q1_m,R2_m,lamb*S2_m)
- L_K_dim4=B_K_dim4+[B_K_dim4[0]+B_K_dim4[1]]
-
- L_K_dim4=[[self._isogenies_dim2(TuplePoint(L_K_dim4[k][0],L_K_dim4[k][2])),self._isogenies_dim2(TuplePoint(L_K_dim4[k][1],L_K_dim4[k][3]))] for k in range(5)]
-
- # Product Theta structure on A_m^2
- self.domain_product=ProductThetaStructureDim2To4(self._isogenies_dim2._codomain,self._isogenies_dim2._codomain)
-
- # Theta structure on A_m^2 after base change
- self.domain_base_change=self.domain_product.base_change_struct(self.N_dim4)
-
- # Converting the kernel to the Theta structure domain_base_change
- L_K_dim4=[self.domain_product.product_theta_point(L_K_dim4[k][0],L_K_dim4[k][1]) for k in range(5)]
- L_K_dim4=[self.domain_base_change.base_change_coords(self.N_dim4,L_K_dim4[k]) for k in range(5)]
-
- # Computing the gluing isogeny in dimension 4
- self._gluing_isogeny_dim4=GluingIsogenyDim4(self.domain_base_change,L_K_dim4,[(1,0,0,0),(0,1,0,0),(0,0,1,0),(0,0,0,1),(1,1,0,0)])
-
- # Translates for the evaluation of the gluing isogeny in dimension 4
- self.L_trans=[2*B_K_dim4[k] for k in range(2)]
- self.L_trans_ind=[1,2] # Corresponds to multi indices (1,0,0,0) and (0,1,0,0)
-
- self._codomain=self._gluing_isogeny_dim4._codomain
-
- def evaluate(self,P):
- if not isinstance(P, TuplePoint):
- raise TypeError("KaniGluingIsogenyChainDim4 isogeny expects as input a TuplePoint on the domain product E1^2 x E2^2")
-
- # Translating P
- L_P_trans=[P+T for T in self.L_trans]
-
- # dim4 --> dim2 x dim2
- eval_P=[TuplePoint(P[0],P[2]),TuplePoint(P[1],P[3])]
- eval_L_P_trans=[[TuplePoint(Q[0],Q[2]),TuplePoint(Q[1],Q[3])] for Q in L_P_trans]
-
- # evaluating through the dimension 2 isogenies
- eval_P=[self._isogenies_dim2(eval_P[0]),self._isogenies_dim2(eval_P[1])]
- eval_L_P_trans=[[self._isogenies_dim2(Q[0]),self._isogenies_dim2(Q[1])] for Q in eval_L_P_trans]
-
- # Product Theta structure and base change
- eval_P=self.domain_product.product_theta_point(eval_P[0],eval_P[1])
- eval_P=self.domain_base_change.base_change_coords(self.N_dim4,eval_P)
-
- eval_L_P_trans=[self.domain_product.product_theta_point(Q[0],Q[1]) for Q in eval_L_P_trans]
- eval_L_P_trans=[self.domain_base_change.base_change_coords(self.N_dim4,Q) for Q in eval_L_P_trans]
-
- return self._gluing_isogeny_dim4.special_image(eval_P,eval_L_P_trans,self.L_trans_ind)
-
- def __call__(self,P):
- return self.evaluate(P)
-
- def dual(self):
- domain = self._codomain.hadamard()
- codomain_base_change = self.domain_base_change
- codomain_product = self.domain_product
- N_dim4 = self.N_dim4.inverse()
- isogenies_dim2 = self._isogenies_dim2.dual()
- splitting_isogeny_dim4 = self._gluing_isogeny_dim4.dual()
-
- return KaniSplittingIsogenyChainDim4(domain, codomain_base_change, codomain_product, N_dim4, isogenies_dim2, splitting_isogeny_dim4)
-
-class KaniSplittingIsogenyChainDim4:
- def __init__(self, domain, codomain_base_change, codomain_product, N_dim4, isogenies_dim2, splitting_isogeny_dim4):
- self._domain = domain
- self.codomain_base_change = codomain_base_change
- self.codomain_product = codomain_product
- self.N_dim4 = N_dim4
- self._isogenies_dim2 = isogenies_dim2
- self._splitting_isogeny_dim4 = splitting_isogeny_dim4
-
- def evaluate(self,P):
- if not isinstance(P, ThetaPointDim4):
- raise TypeError("KaniSplittingIsogenyChainDim4 isogeny expects as input a ThetaPointDim4")
-
- Q = self._splitting_isogeny_dim4(P)
- Q = self.codomain_product.base_change_coords(self.N_dim4, Q)
- Q1, Q2 = self.codomain_product.to_theta_points(Q)
- Q1, Q2 = self._isogenies_dim2._domain(Q1.hadamard()), self._isogenies_dim2._domain(Q2.hadamard())
-
- Q1 = self._isogenies_dim2(Q1)
- Q2 = self._isogenies_dim2(Q2)
-
- return TuplePoint(Q1[0],Q2[0],Q1[1],Q2[1])
-
- def __call__(self,P):
- return self.evaluate(P)