[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Octave-bug-tracker] [bug #51950] sparse qr may return a malformed spars
From: |
Rik |
Subject: |
[Octave-bug-tracker] [bug #51950] sparse qr may return a malformed sparse matrix R with out of bounds entries |
Date: |
Wed, 6 Sep 2017 18:50:16 -0400 (EDT) |
User-agent: |
Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:55.0) Gecko/20100101 Firefox/55.0 |
Follow-up Comment #8, bug #51950 (project octave):
I tested some old versions of Octave with Marco's test case and the problem
exists all the way back to Octave 3.2.4, and probably before that as well but
I don't have any earlier versions.
The code is in liboctave/numeric/sparse-qr.[h|cc]. This doesn't appear to be
a problem with the full version which is in liboctave/numeric/qr.[h|cc].
I tried the full version
A=zeros(5,6);A(3,1)=0.8;A(2,2)=1.4;A(1,6)=-0.5;[q r]=qr(A);r
r =
-0.80000 0.00000 0.00000 0.00000 0.00000 0.00000
0.00000 1.40000 0.00000 0.00000 0.00000 0.00000
0.00000 0.00000 0.00000 0.00000 0.00000 0.50000
0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
The difference is element (3,6) which is missing in the sparse version
A=sparse(5,6);A(3,1)=0.8;A(2,2)=1.4;A(1,6)=-0.5;[q r]=qr(A);r
r =
Compressed Column Sparse (rows = 5, cols = 6, nnz = 3 [10%])
(1, 1) -> -0.80000
(2, 2) -> -1.4000
(6, 6) -> 0.50000
full (r)
ans =
-0.80000 0.00000 0.00000 0.00000 0.00000 0.00000
0.00000 -1.40000 0.00000 0.00000 0.00000 0.00000
0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
_______________________________________________________
Reply to this item at:
<http://savannah.gnu.org/bugs/?51950>
_______________________________________________
Message sent via/by Savannah
http://savannah.gnu.org/
- [Octave-bug-tracker] [bug #51950] Segfault during a sparse QR factorization, Joseph Young, 2017/09/05
- [Octave-bug-tracker] [bug #51950] Segfault during a sparse QR factorization, Doug Stewart, 2017/09/05
- [Octave-bug-tracker] [bug #51950] Segfault during a sparse QR factorization, Dmitri A. Sergatskov, 2017/09/05
- [Octave-bug-tracker] [bug #51950] Segfault during a sparse QR factorization, Marco Caliari, 2017/09/06
- [Octave-bug-tracker] [bug #51950] Segfault during a sparse QR factorization, Mike Miller, 2017/09/06
- [Octave-bug-tracker] [bug #51950] Segfault during a sparse QR factorization, Mike Miller, 2017/09/06
- [Octave-bug-tracker] [bug #51950] Segfault during a sparse QR factorization, Mike Miller, 2017/09/06
- [Octave-bug-tracker] [bug #51950] sparse qr may return a malformed sparse matrix R with out of bounds entries, Mike Miller, 2017/09/06
- [Octave-bug-tracker] [bug #51950] sparse qr may return a malformed sparse matrix R with out of bounds entries, Marco Caliari, 2017/09/06
- [Octave-bug-tracker] [bug #51950] sparse qr may return a malformed sparse matrix R with out of bounds entries,
Rik <=
- [Octave-bug-tracker] [bug #51950] sparse qr may return a malformed sparse matrix R with out of bounds entries, Rik, 2017/09/06
- [Octave-bug-tracker] [bug #51950] sparse qr may return a malformed sparse matrix R with out of bounds entries, Rik, 2017/09/06
- [Octave-bug-tracker] [bug #51950] sparse qr may return a malformed sparse matrix R with out of bounds entries, Dmitri A. Sergatskov, 2017/09/07
- [Octave-bug-tracker] [bug #51950] sparse qr may return a malformed sparse matrix R with out of bounds entries, Joseph Young, 2017/09/07
- [Octave-bug-tracker] [bug #51950] sparse qr may return a malformed sparse matrix R with out of bounds entries, Marco Caliari, 2017/09/07
- [Octave-bug-tracker] [bug #51950] sparse qr may return a malformed sparse matrix R with out of bounds entries, Joseph Young, 2017/09/09
- [Octave-bug-tracker] [bug #51950] sparse qr may return a malformed sparse matrix R with out of bounds entries, Rik, 2017/09/09
- [Octave-bug-tracker] [bug #51950] sparse qr may return a malformed sparse matrix R with out of bounds entries, Dmitri A. Sergatskov, 2017/09/09
- [Octave-bug-tracker] [bug #51950] sparse qr may return a malformed sparse matrix R with out of bounds entries, Dmitri A. Sergatskov, 2017/09/09
- [Octave-bug-tracker] [bug #51950] sparse qr may return a malformed sparse matrix R with out of bounds entries, Rik, 2017/09/24