[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Octave-bug-tracker] [bug #51401] inv() function gives incorrect results
From: |
anonymous |
Subject: |
[Octave-bug-tracker] [bug #51401] inv() function gives incorrect results, even for invertible 2x2 matrix |
Date: |
Thu, 6 Jul 2017 06:51:31 -0400 (EDT) |
User-agent: |
Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36 |
URL:
<http://savannah.gnu.org/bugs/?51401>
Summary: inv() function gives incorrect results, even for
invertible 2x2 matrix
Project: GNU Octave
Submitted by: None
Submitted on: Thu 06 Jul 2017 10:51:30 AM UTC
Category: Octave Function
Severity: 3 - Normal
Priority: 5 - Normal
Item Group: None
Status: None
Assigned to: None
Originator Name: Harry
Originator Email: address@hidden
Open/Closed: Open
Discussion Lock: Any
Release: 4.2.0
Operating System: Microsoft Windows
_______________________________________________________
Details:
There is a clear bug in the inv() function, which I particularly see for
Hermitian matrices.
Example:
A = [1,1+1j;1-1j,3];
>> inv(A)
ans =
3 + 0i -1 - 1i
-1 - 1i 1 + 0i
The correct answer should be:
ans =
3 + 0i -1 - 1i
-1 + 1i 1 + 0i
(i.e. ans(2,1) is conjugated). Matlab gives the correct answer. Or for a 2x2
matrix, we can check it as:
detA = A(1,1)*A(2,2) - A(1,2)*A(2,1);
invA = [A(2,2),-A(1,2); -A(2,1),A(1,1)] / detA;
_______________________________________________________
Reply to this item at:
<http://savannah.gnu.org/bugs/?51401>
_______________________________________________
Message sent via/by Savannah
http://savannah.gnu.org/
- [Octave-bug-tracker] [bug #51401] inv() function gives incorrect results, even for invertible 2x2 matrix,
anonymous <=