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

 
 

bug #50194: Norm -Inf for matrices

Submitted by:  Ernst Reissner <ernstreissner>
Submitted on:  Tue 31 Jan 2017 10:37:10 AM UTC  
 
Category: NoneSeverity: 2 - Minor
Priority: 5 - NormalItem Group: Feature Request
Status: FixedAssigned to: None
Originator Name: Ernst ReissnerOpen/Closed: Closed
Release: 4.2.0Operating System: Any

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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>
Project 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>
Project Administrator
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
    Fri 03 Feb 2017 04:49:53 AM UTCrik5StatusNeed Info=>Fixed
      Open/ClosedOpen=>Closed
    Fri 03 Feb 2017 02:11:44 AM UTCmtmillerSeverity3 - Normal=>2 - Minor
      Item GroupNone=>Feature Request
      StatusNone=>Need Info
    Tue 31 Jan 2017 10:37:10 AM UTCernstreissnerCarbon-Copy-=>Added -unavailable-

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