bugGNU Octave - Bugs: bug #42646, Error in implementation of logm

 
 

bug #42646: Error in implementation of logm

Submitted by:  None
Submitted on:  Sun 29 Jun 2014 07:05:51 PM UTC  
 
Category: Octave FunctionSeverity: 3 - Normal
Priority: 5 - NormalItem Group: None
Status: Works For MeAssigned to: None
Originator Name: uhlmannjOriginator Email: -unavailable-
Open/Closed: ClosedRelease: 3.8.1
Operating System: Any

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Sun 29 Jun 2014 08:17:32 PM UTC, comment #2:

Works for me on Windows 7 with Octave-3.8.0, 3.8.2-rc1, 3.9.0+ & 4.1.0+

Philip Nienhuis <philipnienhuis>
Project Member
Sun 29 Jun 2014 07:24:29 PM UTC, comment #1:

This works fine for me on a Linux, x86_64 system.

The bug is filed with Operating System = "any", but is this actually on a Windows or Mac system?

Rik <rik5>
Project Administrator
Sun 29 Jun 2014 07:05:51 PM UTC, original submission:

The logm function fails for many types of matrix, e.g., any triangular matrix of ones.

> M = tril(ones(2));

ans =

1 0
1 1

> logm(M)

warning: inverse: matrix singular to machine precision
ans =

0 0
0 0

M is nonsingular unit eigenvalues and thus has a logarithm, e.g.:

> expm([0 0; 1 0])

ans =

1 0
1 1

Anonymous

 

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    Follow 2 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Sat 05 Jul 2014 06:44:11 PM UTCrik5Open/ClosedOpen=>Closed
    Sun 29 Jun 2014 07:24:29 PM UTCrik5StatusNone=>Works For Me

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