Bug #1080
intersect: problem with zero generators
Description
There are still problems with zero generators:
use R ::= QQ[x,y]; I1 := ideal(x,zero(R)); I2 := ideal(y); intersect(I1,I2); --> ERROR
I thought this had been fixed :-(
Related issues
History
#1 Updated by John Abbott almost 7 years ago
- Related to Bug #446: intersection fails with zero ideal added
#2 Updated by John Abbott almost 7 years ago
The problem appears to be the ctor for a GPoly
which does not allow GPoly
of 0 to be created.
Location TMPGreductor.C:1563
inside fn EmbedPoly
.
Anna, are you able to read Max's code?
#3 Updated by Anna Maria Bigatti almost 7 years ago
- Description updated (diff)
- Assignee set to Anna Maria Bigatti
#4 Updated by John Abbott almost 7 years ago
We must remember to add some tests for various failing cases when this has been resolved.
PS it is a little tedious that CoCoA does not accept ideal(x,0,y)
because it wants a RINGELEM
instead of an INT
; of course, it is no often that one wants to give explicitly an INT
as a generator, so perhaps the error message is a "feature"?
#5 Updated by Anna Maria Bigatti over 6 years ago
- Status changed from New to Feedback
- Estimated time set to 1.01 h
I added the function EmbedPolyListNo0
in TmpGReductor.C
.
It does the same as EmbedPolyList
but skipping zero polynomials.
This should indeed be used always, instead of EmbedPolyList
, but it'd better checked case by case (for example for syzygies one should be careful....)
#6 Updated by Anna Maria Bigatti over 6 years ago
- % Done changed from 0 to 90
#7 Updated by Anna Maria Bigatti over 6 years ago
- Status changed from Feedback to Closed
- % Done changed from 90 to 100
#8 Updated by Anna Maria Bigatti over 6 years ago
- Estimated time changed from 1.01 h to 1.71 h
added test in exbugs.