Feature #384: IsZero for matrix - CoCoA-5 - CoCoA Project

Feature #384

IsZero for matrix

Added by John Abbott almost 11 years ago. Updated almost 10 years ago.

Status:

Closed

Priority:

Normal

Assignee:

Anna Maria Bigatti

Category:

Incomplete function

Target version:

CoCoA-5.1.0 Easter14

Start date:

05 Jul 2013

Due date:

% Done:

100%

Estimated time:

2.50 h

Spent time:

3.50 h

Description

The built-in fn IsZero works for many types (INT, RAT, RINGELEM, MODULEELEM and IDEAL).
Should it work for matrices (type MAT) too?

However I do not think it should be applicable to LIST.

Related issues

History

#1 Updated by Anna Maria Bigatti about 10 years ago

Category set to Incomplete function
Target version set to CoCoA-5.1.0 Easter14

I think we should have IsZero for MAT

#2 Updated by Anna Maria Bigatti about 10 years ago

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

I tried implementing it in a clever way but got stuck.
(clever = ZeroImpl gives true, IdentityImpl gives false, ...)

But I had a brilliant(?) idea: should we just implement IsZero as return M = ZeroMat(R, NR, NC) and let the equality test to be clever? (I think it is clever)

#3 Updated by Anna Maria Bigatti about 10 years ago

Assignee set to Anna Maria Bigatti
% Done changed from 10 to 50
Estimated time set to 2.50 h

Implemented as described above.
Seems to work (added test IsZero(ZeroMat(R, 12345,67890)) and is fast).
But where should the implementation go? matrix.C or MatrixViews.C?
Now the prototype is in matrix.H and the implementation in MatrixViews.C...