Bug #1101
Bug in MinPolyModular (insufficient rational reconstruction)
Status:
Closed
Priority:
High
Assignee:
Category:
Maths Bugs
Target version:
Description
Rational reconstruction succeeds "too early"
/**/ L:=[3*x^3*y +3*y*z^3 +1, 2*x*y*z^2 +3*x, 2*y^3*z +1]; /**/ I := ideal(L); /**/ mp := MinPolyQuot(x, I, x); /**/ mp isin I; false /**/ mp; x^16 +(15/2)*x^10 +(45/4)*x^4 +(-1/2028)*x
Related issues
History
#1 Updated by Anna Maria Bigatti over 6 years ago
- Project changed from CoCoA-5 to CoCoALib
- Category changed from enhancing/improving to Maths Bugs
- Target version changed from CoCoA-5.2.2 to CoCoALib-0.99560
- % Done changed from 0 to 20
Adding Horner evaluation to check minpoly correct reconstruction.
#2 Updated by Anna Maria Bigatti over 6 years ago
- Related to Bug #1100: PrimaryDecomposition0: says not 0-dim but IsZeroDim says ideal is zero-dim! added
#3 Updated by Anna Maria Bigatti over 6 years ago
- Status changed from New to Resolved
- Priority changed from Normal to High
- % Done changed from 20 to 70
- Estimated time set to 3.00 h
Fixed. I implemented a Horner evaluation in MinPoly.C
which may be improved, and maybe moved into some other file (and also exported to cocoa5, so we can delete it from PrimaryDecomposition0.cpkg5
).
/**/ L:=[3*x^3*y +3*y*z^3 +1, 2*x*y*z^2 +3*x, 2*y^3*z +1]; /**/ I := ideal(L); /**/ mp := MinPolyQuot(x, I, x); /**/ mp isin I; /**/ /**/ /**/ true /**/ mp; x^16 +(15/2)*x^10 +(45/4)*x^4 +(1594195/5184)*x
#4 Updated by John Abbott over 6 years ago
Here are some more examples which the computer found during the night:
[3*x*y*z^3 +z^2 +1, 3*y^3*z +z^2, 2*x*y^2*z^2 +3*x*y*z^2] [x^2*y^2 +3*y^3*z +1, x*y*z^2 +x*y^2, 2*y^3 +3]
#5 Updated by John Abbott over 6 years ago
JAA has added test-MinPoly1.C
including the 3 examples listed here.
Checking in now.
#6 Updated by John Abbott over 6 years ago
- Status changed from Resolved to Feedback
- % Done changed from 70 to 90
#7 Updated by John Abbott over 6 years ago
- Status changed from Feedback to Closed
- % Done changed from 90 to 100
#8 Updated by Anna Maria Bigatti about 6 years ago
- Related to Slug #1165: MinPoly over QQ: verification may be very slow added