#12499: The density() function of a sparse matrix looks at every matrix entry
------------------------------+---------------------------------------------
Reporter: jason | Owner: jason, was
Type: defect | Status: new
Priority: major | Milestone: sage-5.0
Component: linear algebra | Keywords:
Work_issues: | Upstream: N/A
Reviewer: | Author:
Merged: | Dependencies:
------------------------------+---------------------------------------------
The implementation of the density method for a sparse matrix is insane.
It loops through every single index possible and asks if each entry is
zero or nonzero:
{{{
sage: A=matrix(5000,5000,{(1,2): 1})
sage: A.density()
1/25000000
}}}
An implementation that instead relied on `A.nonzero_positions()` would be
orders of magnitude faster.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12499>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en.
