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Feature #1033

Split poly into homog parts

Added by John Abbott over 7 years ago. Updated over 6 years ago.

Status:
Closed
Priority:
Normal
Assignee:
John Abbott
Category:
New Function
Target version:
CoCoALib-0.99560
Start date:
17 Mar 2017
Due date:
% Done:

100%

Estimated time:
0.55 h
Spent time:
0.30 h

Description

Introduce new function to split a poly into its homog parts.

What should the result be?
  • vector<RingElem> where v[k] contains part of degree k? But what about multigradings?
  • vector<RingElem> where each entry in vector is non-zero and homog (in decr/incr oredr of degree?)

Related issues

Related to CoCoALib - Feature #1030: IsInRadical: case of homog idealClosed2017-03-14

Related to CoCoALib - Slug #1042: LF curiously slow (breaking a poly into homog pieces)Closed2017-04-10

History

#1 Updated by John Abbott over 7 years ago

  • Related to Feature #1030: IsInRadical: case of homog ideal added

#2 Updated by John Abbott over 7 years ago

If we do choose to introduce such a function, what should its name be?

#3 Updated by Anna Maria Bigatti over 7 years ago

I'm against this idea, because I think it might be badly misused.

I see you want to apply it to IsInRadical for a homogeneous ideal:
in this case one should (we still have to see if it's worth it) take LF (which works the same for simple or multigrading), if it is in radical, then try LF of the remaining, .. and so on.
Since orderings are degree compatible, this is not an expensive function.

I do not see any reason to store the whole decomposition in one step.
(with an obvious problem in dealing with multigradings)

#4 Updated by John Abbott over 7 years ago

  • Status changed from New to In Progress
  • % Done changed from 0 to 10

In some ways the "eat up" version appeals to me more; though it might discourage casual use... (would that matter?)

MoveLF?

#5 Updated by John Abbott over 6 years ago

  • Status changed from In Progress to Feedback
  • Assignee set to John Abbott
  • Target version changed from CoCoALib-1.0 to CoCoALib-0.99560
  • % Done changed from 10 to 90
  • Estimated time set to 0.55 h

I think the CutLF function solves this issue.
Do you agree? If so, we can close the issue :-)

#6 Updated by John Abbott over 6 years ago

  • Related to Slug #1042: LF curiously slow (breaking a poly into homog pieces) added

#7 Updated by John Abbott over 6 years ago

  • Status changed from Feedback to Closed
  • % Done changed from 90 to 100

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