bugGNU Octave - Bugs: bug #50194, Norm -Inf for matrices

 
 

bug #50194: Norm -Inf for matrices

Submitter:  Ernst Reissner <ernstreissner>
Submitted:  Tue 31 Jan 2017 10:37:10 AM UTC
   
 
Category:  None Severity:  2 - Minor
Priority:  5 - Normal Item Group:  Feature Request
Status:  Fixed Assigned to:  None
Originator Name:  Ernst Reissner Open/Closed:  * Closed
Release:  * 4.2.0 Operating System:  * Any
Fixed Release:  None Planned Release:  None
* Mandatory Fields

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Fri 03 Feb 2017 04:49:53 AM UTC, comment #2: 

Checking in the literature, there doesn't seem to be a defined concept of a matrix norm with a p-value of -Inf.  For a vector, yes, but not for a matrix.

Hence, I changed Octave to issue an error, as Matlab does, for a matrix input and p-value of -Inf.  See this cset http://hg.savannah.gnu.org/hgweb/octave/rev/bfa4ad642fa0.

Fixed, closing report.

Rik <rik5>
Group administrator
Fri 03 Feb 2017 02:11:44 AM UTC, comment #1: 

So you would like norm(A, -inf) to return something different from norm(A, inf) in Octave, even though norm(A, -inf) throws an error in Matlab when A is a matrix?

Observing that -inf is not documented as a valid argument when A is a matrix, it just happens to be treated internally the same as +inf for convenience.

Mike Miller <mtmiller>
Group Member
Tue 31 Jan 2017 10:37:10 AM UTC, original submission:  

norm([1 2;2 3],-Inf) yields 5
which is not allowed in matlab and which is wrong
if extending naturally from norm of vector as for
norm([1 2;2 3],Inf)

Ernst Reissner <ernstreissner>

 

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    Follow 6 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2017-02-03 rik5 StatusNeed Info Fixed
        Open/ClosedOpen Closed
    2017-02-03 mtmiller Severity3 - Normal 2 - Minor
        Item GroupNone Feature Request
        StatusNone Need Info
    2017-01-31 ernstreissner Carbon-Copy- Added -email is unavailable-

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