Opened 14 months ago
Closed 13 months ago
#22265 closed defect (fixed)
Fix Dynatomic Polynomials
Reported by:  rlmiller  Owned by:  

Priority:  minor  Milestone:  sage7.6 
Component:  algebra  Keywords:  
Cc:  Ben, Hutz  Merged in:  
Authors:  Rebecca Lauren Miller  Reviewers:  Ben Hutz 
Report Upstream:  N/A  Work issues:  
Branch:  994717c (Commits)  Commit:  994717c9c79f27c32abca28cd00d07b423934da7 
Dependencies:  Stopgaps: 
Description
Need to add NotImplementedError? to try/except in homogenize in affine_morphism. Need to fix dynatomic error that returns wrong parent in projective_morphsim. Current examples of failure:
R.<c>=QQ[] A.<z>=AffineSpace(R,1) H=End(A) f=H([z^2+c]) f.dynatomic_polynomial([1,2])
R.<c>=QQ[] P.<x,y>=ProjectiveSpace(R,1) H=End(P) f=H([x^2+c*y^2,y^2]) f.dynatomic_polynomial([1,2]).parent()
R.<c>=QQ[] P.<x,y>=ProjectiveSpace(ZZ,1) H=End(P) f=H([x^2+y^2,(1)*y^2 + (1)*x*y]) f.dynatomic_polynomial([1,2]).parent()
Change History (16)
comment:1 Changed 14 months ago by
comment:2 Changed 14 months ago by
What is happening in that example is that the quo_rem fails to return a nonzero reminder, so then maxima is tried. The division in maxima (line 964) is not checked to see if the remainder is zero (which it is not).
This example is unable to be exactly divided, so it should return the rational function.
comment:3 Changed 13 months ago by
 Branch set to u/rlmiller/master
comment:4 Changed 13 months ago by
 Branch changed from u/rlmiller/master to u/rlmiller/22265
 Commit set to 940a51be5fa4e9dc54b558bd19de41ff9a845c90
 Status changed from new to needs_review
New commits:
940a51b  22265 fixed errors in dynatomic polynomial

comment:5 Changed 13 months ago by
 Reviewers set to Ben Hutz
 Status changed from needs_review to needs_work
Both examples where the base ring is a polynomial ring still do not work.
The example you added with
f.dynatomic_polynomial([0,1]).parent()
is still the m=0 case, which is not what you changed. I would choose a different period for the example.
You need to add some readability spacing such as around = and ==
The complex example is fixed. I think it would be good to also add an example where the division succeeds, CC.0/2 or some other finite decimal expansion.
comment:6 Changed 13 months ago by
 Commit changed from 940a51be5fa4e9dc54b558bd19de41ff9a845c90 to 288c766caf640e52d1e5650927f02bbc5929950a
Branch pushed to git repo; I updated commit sha1. New commits:
288c766  22265 error fixes for dynatomic polynomials

comment:7 Changed 13 months ago by
 Status changed from needs_work to needs_review
comment:8 Changed 13 months ago by
 Status changed from needs_review to needs_work
The original failures listed in the ticket now work. However, I found a number of additional examples that fail. Mostly it is for the affine computation, but apparently there is also no input checking done on the n
parameter in both affine and projective.
Needs input checking:
P.<x,y> = ProjectiveSpace(ZZ, 1) H = Hom(P,P) f = H([x^25*y^2, y^2]) D=f.dynatomic_polynomial(3) print D.parent(),D F=f.dehomogenize(1) D=F.dynatomic_polynomial(3) D.parent(),D
P.<x,y> = ProjectiveSpace(ZZ, 1) H = Hom(P,P) f = H([x^25*y^2, y^2]) D=f.dynatomic_polynomial([1,0]) print D.parent(),D F=f.dehomogenize(1) D=F.dynatomic_polynomial([1,0]) D.parent(),D
Other failures:
R.<x>=QQ[] K.<i>=R.quo(x^2+1) P.<x,y> = ProjectiveSpace(K, 1) H = Hom(P,P) f = H([x^2i/3*y^2, y^2]) D=f.dynatomic_polynomial([2,1]) print D.parent(),D F=f.dehomogenize(1) D=F.dynatomic_polynomial([2,1]) D.parent(),D Traceback (click to the left of this block for traceback) ... TypeError: lift() takes exactly 2 arguments (1 given)
P.<x,y> = ProjectiveSpace(Zp(3), 1) H = Hom(P,P) f = H([x^25*y^2, y^2]) D=f.dynatomic_polynomial([1,2]) print D.parent(),D F=f.dehomogenize(1) D=F.dynatomic_polynomial([1,2]) D.parent(),D Traceback (click to the left of this block for traceback) ... TypeError: not a constant polynomial
R.<c,d>=QQbar[] P.<x,y>=ProjectiveSpace(R,1) H=End(P) f=H([x^2+c*y^2,d*y^2]) D=f.dynatomic_polynomial([1,2]) print D.parent(),D F=f.dehomogenize(1) D=F.dynatomic_polynomial([1,2]) D.parent(),D Traceback (click to the left of this block for traceback) ... TypeError: no conversion of this ring to a Singular ring defined
R.<c,d>=QQbar[] P.<x,y>=ProjectiveSpace(QQbar,1) H=End(P) f=H([x^2+QQbar(sqrt(3))*y^2,2*y^2]) D=f.dynatomic_polynomial([1,2]) print D.parent(),D F=f.dehomogenize(1) D=F.dynatomic_polynomial([1,2]) D.parent(),D Traceback (click to the left of this block for traceback) ... TypeError: not a constant polynomial
comment:9 Changed 13 months ago by
 Commit changed from 288c766caf640e52d1e5650927f02bbc5929950a to e270735e739017a412fbd93408d2f4d3e6aa5be8
Branch pushed to git repo; I updated commit sha1. New commits:
e270735  22265 Fixed Dynatomic Polynomial failures and added examples

comment:10 Changed 13 months ago by
 Status changed from needs_work to needs_review
comment:11 Changed 13 months ago by
 Status changed from needs_review to needs_work
Looks like these are all fixed except the input checking. The following should also be returning 0
P.<x,y> = ProjectiveSpace(ZZ, 1) H = Hom(P,P) f = H([x^25*y^2, y^2]) f.dynatomic_polynomial([3,0])
comment:12 Changed 13 months ago by
 Commit changed from e270735e739017a412fbd93408d2f4d3e6aa5be8 to d10f4e067329939cba9bfc156c6e6410c34b74b1
Branch pushed to git repo; I updated commit sha1. New commits:
d10f4e0  22265 Fixed error when n=0

comment:13 Changed 13 months ago by
 Status changed from needs_work to needs_review
comment:14 Changed 13 months ago by
 Commit changed from d10f4e067329939cba9bfc156c6e6410c34b74b1 to 994717c9c79f27c32abca28cd00d07b423934da7
Branch pushed to git repo; I updated commit sha1. New commits:
994717c  22265 Code Beautification

comment:15 Changed 13 months ago by
 Status changed from needs_review to positive_review
comment:16 Changed 13 months ago by
 Branch changed from u/rlmiller/22265 to 994717c9c79f27c32abca28cd00d07b423934da7
 Resolution set to fixed
 Status changed from positive_review to closed
Another failure as of 7.6.beta2
this is line 853 in the projective_morphism.py file. The expected value is also wrong.