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[Octave-bug-tracker] [bug #48686] Copy of columns of the matrix
From: |
anonymous |
Subject: |
[Octave-bug-tracker] [bug #48686] Copy of columns of the matrix |
Date: |
Wed, 3 Aug 2016 10:38:28 +0000 (UTC) |
User-agent: |
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.106 Safari/537.36 |
URL:
<http://savannah.gnu.org/bugs/?48686>
Summary: Copy of columns of the matrix
Project: GNU Octave
Submitted by: None
Submitted on: Wed 03 Aug 2016 10:38:26 AM UTC
Category: Performance
Severity: 3 - Normal
Priority: 5 - Normal
Item Group: None
Status: None
Assigned to: None
Originator Name: Polina
Originator Email: address@hidden
Open/Closed: Open
Discussion Lock: Any
Release: 4.0.3
Operating System: Microsoft Windows
_______________________________________________________
Details:
Dear Developers!
Thank you for your work on Octave! It's really useful soft for me nowdays.
I noticed a problem and decided to report hoping that this could improve
Octave even more.
It seems that implementation of column copy in matrices has some leakage. When
I try to copy columns like
T(:, i+1) = T(:, i);
it takes increadibly long time for the whole matrix.
For my programming I wanted to optimize code like
T(:, i+1) = T(:, i) + v * T(:, i);
for the case when v = 0.
In the end that did slowed my code instead.
I attach a simple test.
It takes 6 minutes for copying of the columns (flag = 0) and less than one
second for analogos copy with addition of 0 * column.
P.S. I tested both with Octave for WIndows and with Octave installed in CygWin
environment.
P.P.S. I tested the same on copying of rows and it seems to be fine.
Kind regards,
Polina
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Wed 03 Aug 2016 10:38:26 AM UTC Name: test_matrix_copy.m Size: 464B
By: None
<http://savannah.gnu.org/bugs/download.php?file_id=38084>
_______________________________________________________
Reply to this item at:
<http://savannah.gnu.org/bugs/?48686>
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