Project

General

Profile

Slug #1110

Determinant of matrix over QQ (whose entries are actually integers)

Added by John Abbott over 6 years ago. Updated over 5 years ago.

Status:
Closed
Priority:
Normal
Assignee:
John Abbott
Category:
Improving
Target version:
CoCoALib-0.99600
Start date:
25 Oct 2017
Due date:
% Done:

100%

Estimated time:
19.90 h
Spent time:
20.00 h

Description

CoCoA-5 can be much faster as computing det(M) if RingOf(M) is ZZ than the same matrix but over the ring QQ.

In one test (using RandomUnimodularMatrix(ZZ, 100, 100000)) the times were: 10s over ZZ, and 125s over QQ even though the matrices had the same entries!

[REJECTED] Perhaps add a special case where all entries are over ZZ?
[IMPLEMENTED] Perhaps even do something clever to clear denoms, then compute over ZZ?

Related issues

Related to CoCoALib - Slug #691: Matrix determinant over ZZClosed2015-04-29

History

#1 Updated by John Abbott over 6 years ago

  • Related to Slug #691: Matrix determinant over ZZ added

#2 Updated by John Abbott almost 6 years ago

  • Status changed from New to Feedback
  • Assignee set to John Abbott
  • Target version changed from CoCoALib-1.0 to CoCoALib-0.99600
  • % Done changed from 0 to 90
  • Estimated time set to 19.90 h

Done as part of work on Habilitationsschrift.
Now both dets take about 1.8s

#3 Updated by John Abbott over 5 years ago

  • Description updated (diff)
  • Status changed from Feedback to Closed
  • % Done changed from 90 to 100

Also available in: Atom PDF