I am computing Monte-Carlo simulations using GNU Octave 4.0.0 on my 4-core PC. The simulation takes almost 4 hours to compute the script for 50,000 times (specific to my problem), which is a lot of time spent for computation. I was wondering if there is a way to run Octave on multiple cores simultaneously to reduce the time of computations. Thanks in advance.

When I try to plot anything in GNU Octave, I get this error.

octave:1> plot(linspace(1,2,30),linspace(1,1,30))
error: feval: /usr/lib/octave/5.2.0/oct/x86_64-pc-linux-gnu/__init_fltk__.oct: failed to load: libfltk_gl.so.1.3: cannot open shared object file: No such file or directory
error: called from
    graphics_toolkit at line 91 column 5
    figure at line 91 column 7
    newplot at line 117 column 10
    plot at line 222 column 9

One workaround is to use gnuplot instead of fltk, but the plots look better with fltk. It turned out that blas was replaced by openblas during installing Julia, and after installing blas (by removing julia and openblas) it works again. So, how to make fltk work with openblas?

In the question, https://unix.stackexchange.com/questions/579164/detecting-bad-images-from-the-command-line , there is an Octave script to detect bad images. I'm trying to run on Mac OSX with a homebrew Octave installation.

#!/usr/bin/octave -qf

threshold = 0.25;

usage = "Usage is: badfiles  OR badfiles   \n";
files\n";
assert(nargin>0, usage);
dryrun = isfile(argv{1});
if !dryrun
  errdir = argv{1};
  baddir = argv{2};
  assert(isfolder(errdir) && isfolder(baddir) && isfile(argv{3}), usage);
endif

start = 1 + 2*(!dryrun);
for fname = argv()(start:end)'
  q = [];
  f = fname{};

  warning error
  try
    q = imread(fname{});
  catch err
  end_try_catch
  warning on

  if isempty(q)
    printf("error\t");
    dryrun || movefile(f, errdir);
  else
    qt = all(q == q(end,1,:) ,2);
    qtt = squeeze(all(qt, 3));
    r = 1 - find(qtt==0, 1, 'last') / size(q, 1);
    if (r > threshold)
      printf("bad--%02d\t", ceil(100*r));
      dryrun || movefile(f, baddir);
    else
      printf("good-%02d\t", ceil(100*r));
    endif
  endif

  disp(f);
endfor

However I cannot get it to run and it gives a sourcing error. Is there a typo at line 4 as below? files\n"; What should this line be? If I comment it out, I get "error: invalid empty index expression" at line 18 which is f = fname{};

###Context My uname -rv is 4.4.0-64-generic #85~14.04.1-Ubuntu SMP Mon Feb 20 12:10:54 UTC 2017 --- My compiler is GNU gcc 6.3.0 --- I am compiling GNU Octave from source. I have been trying to compile the Octave versions 4.0.2, 4.2.0 and 4.2.1 I configure the build with the invocation ${srcdir}/configure \ --prefix=/opt/octave/4.2.1 \ --with-java-homedir=/usr/lib/jvm/default-java \ --with-java-libdir=/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/server ###Issue# In all cases the make stage fails with the following error libinterp/.libs/liboctinterp.so: undefined reference to `Magick::Image::ping(std::__cxx11::basic_string, std::allocator > const&)' libinterp/.libs/liboctinterp.so: undefined reference to `Magick::Image::attribute(std::__cxx11::basic_string, std::allocator >)' libinterp/.libs/liboctinterp.so: undefined reference to `Magick::CoderInfo::description[abi:cxx11]() const' libinterp/.libs/liboctinterp.so: undefined reference to `Magick::Image::comment[abi:cxx11]() const' libinterp/.libs/liboctinterp.so: undefined reference to `Magick::Image::magick[abi:cxx11]() const' libinterp/.libs/liboctinterp.so: undefined reference to `Magick::CoderInfo::CoderInfo(std::__cxx11::basic_string, std::allocator > const&)' collect2: error: ld returned 1 exit status ###Evidence# In preparation of the manual installation, I had run sudo apt-get build-dep octave. This relates to version 3.8.1 which is the one currently supported by Ubuntu 14.04. Yet, I thought it could be no harm. (Suggestion from the file INSTALL.OCTAVE in the source directory) To stay on the safe side, I installed the libraries libmagickcore-dev, libmagickwand-dev, libmagick++-dev from the Ubuntu repository 8:6.7.7.10-6ubuntu3.4). The issue arises with or without them. Hence, dpkg -l | grep magick shows ii imagemagick 8:6.7.7.10-6ubuntu3.4 amd64 image manipulation programs ii imagemagick-common 8:6.7.7.10-6ubuntu3.4 all image manipulation programs -- infrastructure ii libgraphicsmagick++1-dev 1.3.18-1ubuntu3 amd64 format-independent image processing - C++ development files ii libgraphicsmagick++3 1.3.18-1ubuntu3 amd64 format-independent image processing - C++ shared library ii libgraphicsmagick1-dev 1.3.18-1ubuntu3 amd64 format-independent image processing - C development files ii libgraphicsmagick3 1.3.18-1ubuntu3 amd64 format-independent image processing - C shared library ii libmagick++-dev 8:6.7.7.10-6ubuntu3.4 amd64 object-oriented C++ interface to ImageMagick - development files ii libmagick++5:amd64 8:6.7.7.10-6ubuntu3.4 amd64 object-oriented C++ interface to ImageMagick ii libmagickcore-dev 8:6.7.7.10-6ubuntu3.4 amd64 low-level image manipulation library - development files ii libmagickcore5:amd64 8:6.7.7.10-6ubuntu3.4 amd64 low-level image manipulation library ii libmagickcore5-extra:amd64 8:6.7.7.10-6ubuntu3.4 amd64 low-level image manipulation library - extra codecs ii libmagickwand-dev 8:6.7.7.10-6ubuntu3.4 amd64 image manipulation library - development files ii libmagickwand5:amd64 8:6.7.7.10-6ubuntu3.4 amd64 image manipulation library The configuration stage exits nicely with status 0. (Note the configure stage is not 100% foolproof: one previous attempt to build failed because I had no gnulib installed, which had not been caught by configure) https://stackoverflow.com/questions/39228019/error-while-compiling-octave-with-gcc says that undefined references are a known trait of liboctinterp.so, as of of Octave 4.0.2. Either this buggy behaviour persists in 4.2.0, or there are hidden requirements that I am missing. ###Question# What should I do to complete the compilation of Octave successfully?

I need to install octave-octcdf package to work with Octave in Ubuntu 18.04 LTS. I tried, sudo apt-get install -y octave-octcdf. But this receives an error as following;

user@PowerEdge-R540:~/user/tools$ sudo apt-get install -y octave-octcdf
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package octave-octcdf is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'octave-octcdf' has no installation candidate

Can anyone help to properly install octave-octcdf package?

I am really angry. Just installed the new ubuntu and run apt-get install octave. I got tons of crap installed (like Java, some QT libraries, and other pollution). How can I install Octave in Ubuntu 16.04 without the dependency to any GUI stuff? If the latest version of Octave does not have a "clean" package, then how to install an old version which does not have the GUI?

I am running GNU Octave from flatpak and I have an issue with the edit command. In Octave's CLI when I run edit file.m I got the following issue: sh: vim: command not found I have the following set in my octaverc configuration file (from [GNU Octave Wiki: vim](https://wiki.octave.org/Vim)) : EDITOR('vim > /dev/tty 2>&1 < /dev/tty %s') vim is installed on my system. I don't have any error if I replace vim by nano in the previous command. I wonder if the problem isn't that I'm using flatpak.

How can I install Octave 4.2.0 or latest? I have tried: - Installing latest version of GNU Octave when I have already installed other version : does not give flathub command not found - Installing Octave 4.2.0 from source on ubuntu? : does not work - Installing Octave 4.2.0 from source on ubuntu? : does not work configure: error: BLAS and LAPACK libraries are required - Installing Octave 4.2.0 from source on ubuntu? : not work installed 4.0.3 instead This is my PC version: $ lsb_release -a No LSB modules are available. Distributor ID: Debian Description: Debian GNU/Linux 9.6 (stretch) Release: 9.6 Codename: stretch I ran the command sudo -i to enter root then the following commands. I am not sure if it is correct. $ sudo -i # echo deb http://deb.debian.org/debian stretch-backports main > /etc/apt/sources.list.d/stretch-backports.list # apt update Ign:1 http://deb.debian.org/debian stretch InRelease Hit:2 http://security.debian.org stretch/updates InRelease Hit:3 http://deb.debian.org/debian stretch-updates InRelease Hit:4 http://deb.debian.org/debian stretch-backports InRelease Hit:5 http://deb.debian.org/debian stretch Release Hit:7 http://packages.cloud.google.com/apt cloud-sdk-stretch InRelease Hit:8 https://download.docker.com/linux/debian stretch InRelease Hit:9 https://nvidia.github.io/libnvidia-container/debian9/amd64 InRelease Hit:10 http://packages.cloud.google.com/apt google-compute-engine-stretch-stable InRelease Hit:11 https://nvidia.github.io/nvidia-container-runtime/debian9/amd64 InRelease Hit:12 http://packages.cloud.google.com/apt google-cloud-packages-archive-keyring-stretch InRelease Hit:6 https://packages.cloud.google.com/apt kubernetes-xenial InRelease Ign:13 http://ppa.launchpad.net/alexlarsson/flatpak/ubuntu disco InRelease Hit:14 https://nvidia.github.io/nvidia-docker/debian9/amd64 InRelease Ign:16 http://ppa.launchpad.net/octave/stable/ubuntu disco InRelease Ign:17 http://ppa.launchpad.net/picaso/octave/ubuntu disco InRelease Err:18 http://ppa.launchpad.net/alexlarsson/flatpak/ubuntu disco Release 404 Not Found Err:19 http://ppa.launchpad.net/octave/stable/ubuntu disco Release 404 Not Found Err:20 http://ppa.launchpad.net/picaso/octave/ubuntu disco Release 404 Not Found Reading package lists... Done W: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list.d/backports.list:1 and /etc/apt/sources.list.d/stretch-backports.list:1 W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list.d/backports.list:1 and /etc/apt/sources.list.d/stretch-backports.list:1 W: Target Translations (main/i18n/Translation-en_US) is configured multiple times in /etc/apt/sources.list.d/backports.list:1 and /etc/apt/sources.list.d/stretch-backports.list:1 W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list.d/backports.list:1 and /etc/apt/sources.list.d/stretch-backports.list:1 W: Target DEP-11 (main/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list.d/backports.list:1 and /etc/apt/sources.list.d/stretch-backports.list:1 W: Target DEP-11 (main/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list.d/backports.list:1 and /etc/apt/sources.list.d/stretch-backports.list:1W: Target DEP-11-icons (main/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list.d/backports.list:1 and /etc/apt/sources.list.d/stretch-backports.list:1 E: The repository 'http://ppa.launchpad.net/alexlarsson/flatpak/ubuntu disco Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://ppa.launchpad.net/octave/stable/ubuntu disco Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://ppa.launchpad.net/picaso/octave/ubuntu disco Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. W: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list.d/backports.list:1 and /etc/apt/sources.list.d/stretch-backports.list:1 W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list.d/backports.list:1 and /etc/apt/sources.list.d/stretch-backports.list:1 W: Target Translations (main/i18n/Translation-en_US) is configured multiple times in /etc/apt/sources.list.d/backports.list:1 and /etc/apt/sources.list.d/stretch-backports.list:1 W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list.d/backports.list:1 and /etc/apt/sources.list.d/stretch-backports.list:1 W: Target DEP-11 (main/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list.d/backports.list:1 and /etc/apt/sources.list.d/stretch-backports.list:1 W: Target DEP-11 (main/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list.d/backports.list:1 and /etc/apt/sources.list.d/stretch-backports.list:1W: Target DEP-11-icons (main/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list.d/backports.list:1 and /etc/apt/sources.list.d/stretch-backports.list:1

Octave .m files are seen as some sort of text files in the Dolphin file manager on my Debian 9 system. They do not show the Octave icon. I'd like to be able to open the Octave script directly by clicking on them which is currently not happening.

I am using octave under debian. Everything is working ok. I would like the octave-programs to finish faster. My "CPU usage monitor"-icon (LXDE) shows that, while octave is calculating, only about one third of my CPU is used. Is there a way to configure the system to use more CPU for octave's calculations? **-- UPDATE --** Extra info: Looking at htop as my program run I have the following: 0. the CPU has 4 cores and 7.71GiB RAM. 1. from the beginning until before plotting, one core (apparently random selected) is used at 100% and the others at below 2%. 2. after plotting begins, another core (apparently also random selected, sometimes the same) is used to 100% and the other ones kept below 2%. 3. there is a little change in MEM usage (max difference ~0.1GiB). 4. there is no change in swap.

>$ sudo apt-get install octave Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: gnupg : Breaks: software-properties-common (= 2.8.4) but it is not going to be installed Depends: libqt5gui5 (>= 5.7.0) but it is not going to be installed Depends: libqt5opengl5 (>= 5.0.2) but it is not going to be installed Depends: libqt5printsupport5 (>= 5.0.2) but it is not going to be installed Depends: libqt5widgets5 (>= 5.6.0~beta) but it is not going to be installed Recommends: gnuplot-qt but it is not going to be installed or gnuplot-x11 but it is not going to be installed or gnuplot-nox E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.

I use GNU Octave 4.4.1 (x86_64-pc-linux-gnu on Arch Linux), and I have problem with fplot function. I would like to know why fplot(@(x) 1/(1+25*x.^2),[-1,1]) Have a different result of fplot(@(x) (1+25*x.^2).^-1,[-1,1]) (the latter returns the correct graphic) Had the **exact same problem** with my students in a windows version of Octave 4.4.1. I would like to know if it is an actual error or there's a fancy explanation for why the latter command is correct and the first one is wrong (so I can try to convince my students that they should use GNU Octave. OK, I'll try it anyway).

I am using the following version of linux. e130167@instance-1:~$ lsb_release -a No LSB modules are available. Distributor ID: Debian Description: Debian GNU/Linux 9.6 (stretch) Release: 9.6 Codename: stretch I have Octave version 4.4.1 and am trying to install the Image package for Octave https://octave.sourceforge.io/image/index.html . I downloaded the tar.gz file and ran the following command and got an error octave:2> pkg install image-2.8.0.tar.gz pkg: please install the Debian package "liboctave-dev" to get the mkoctfile command error: called from __gripe_missing_component__ at line 53 column 3 configure_make at line 44 column 7 install at line 186 column 7 pkg at line 437 column 9 octave:2> So I then tried installing liboctave-dev but I now receive this error. e130167@instance-1:~$ sudo apt-get install liboctave-dev Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: liboctave-dev : Depends: liboctave3v5 (= 4.0.3-3) but it is not going to be installed Depends: octave (= 4.0.3-3) but 4.4.1-2~bpo9+1 is to be installed E: Unable to correct problems, you have held broken packages.

I just followed the answer in: https://unix.stackexchange.com/questions/280195/how-to-install-octave-without-gui-in-ubuntu-16-04#new-answer?newreg=a3e30a76cc184b50ae80b8c39bf2463d to install octave in ubuntu 16.04 and apparently it worked fine. Running octave-cli in terminal apparently works But when I went to run octave clicking on its icon I got the following error: > The settings file /home/user/.config/octave/qt-settings does not exist and can not be created. > Make sure you have read and write permissions to /home/user/.config/octave > Octave GUI must be closed now. Can anyone please help me fix this, so I can run octave?

I'm using 'termux'(android terminal emulator ). I've recently installed Ubuntu inside it in a 'proot' environment. When I searched for octave package using 'apt search octave' , I can't find any result. Then I manually searched for octave in Ubuntu packages to verify whether it is available for 'armhf'. To my surprise it is available for 'armhf' . I'm really dying to use octave on my android . Why is it not showing up in apt search ? What can I do to fix it?  Ubuntu package search:https://packages.ubuntu.com/search?suite=artful&arch=armhf&searchon=names&keywords=Octave Output of "cat /etc/apt/sources.list" # See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to # newer versions of the distribution. deb http://ports.ubuntu.com/ubuntu-ports/ artful main restricted # deb-src http://ports.ubuntu.com/ubuntu-ports/ artful main restricted ## Major bug fix updates produced after the final release of the ## distribution. deb http://ports.ubuntu.com/ubuntu-ports/ artful-updates main restricted # deb-src http://ports.ubuntu.com/ubuntu-ports/ artful-updates main restricted ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team. Also, please note that software in universe WILL NOT receive any ## review or updates from the Ubuntu security team. deb http://ports.ubuntu.com/ubuntu-ports/ artful universe # deb-src http://ports.ubuntu.com/ubuntu-ports/ artful universe deb http://ports.ubuntu.com/ubuntu-ports/ artful-updates universe # deb-src http://ports.ubuntu.com/ubuntu-ports/ artful-updates universe ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team, and may not be under a free licence. Please satisfy yourself as to ## your rights to use the software. Also, please note that software in ## multiverse WILL NOT receive any review or updates from the Ubuntu ## security team. deb http://ports.ubuntu.com/ubuntu-ports/ artful multiverse # deb-src http://ports.ubuntu.com/ubuntu-ports/ artful multiverse deb http://ports.ubuntu.com/ubuntu-ports/ artful-updates multiverse # deb-src http://ports.ubuntu.com/ubuntu-ports/ artful-updates multiverse ## N.B. software from this repository may not have been tested as ## extensively as that contained in the main release, although it includes ## newer versions of some applications which may provide useful features. ## Also, please note that software in backports WILL NOT receive any review ## or updates from the Ubuntu security team. deb http://ports.ubuntu.com/ubuntu-ports/ artful-backports main restricted universe multiverse # deb-src http://ports.ubuntu.com/ubuntu-ports/ artful-backports main restricted universe multiverse ## Uncomment the following two lines to add software from Canonical's ## 'partner' repository. ## This software is not part of Ubuntu, but is offered by Canonical and the ## respective vendors as a service to Ubuntu users. # deb http://archive.canonical.com/ubuntu artful partner # deb-src http://archive.canonical.com/ubuntu artful partner deb http://ports.ubuntu.com/ubuntu-ports/ artful-security main restricted # deb-src http://ports.ubuntu.com/ubuntu-ports/ artful-security main restricted deb http://ports.ubuntu.com/ubuntu-ports/ artful-security universe # deb-src http://ports.ubuntu.com/ubuntu-ports/ artful-security universe deb http://ports.ubuntu.com/ubuntu-ports/ artful-security multiverse # deb-src http://ports.ubuntu.com/ubuntu-ports/ artful-security multiverse

I have done a shortcut to open LTSpice simulator on terminal, to open the program typing "ltspice", I used the alias command and the path of the program and saved to bashrc. It's working pretty good on terminal, but when I try to use the command on octave: system('ltspice'); it returns, sh: 1: ltspice: not found

I have an Octave code that among other things outputs: (x - 5)⋅(x - 4)⋅(x - 3)⋅(x - 2) ─────────────────────────────── 24 When using publish function from Octave miscellaneous package, the corresponding latex code look like this: (x - 5)â‹…(x - 4)â‹…(x - 3)â‹…(x - 2) ─────────────────────────────── 24 I tried using sed to replace the weird characters: sed -i -e 's/â‹…/$\cdot$/g' file.tex sed -i -e 's/─/-/g' file.tex But nothing happens... Any help is appreciated.

As per Wiki page of GNU software octave latest version is 4.2.1 (Released in february 2017). I am using fedora 25 and the octave in my system is version 4.0.3 . I tried upgrading it to the latest version by using both dnf upgrade octave and dnf update octave but both showed Last metadata expiration check: 1:29:36 ago on Sat Sep 23 16:02:26 2017. Dependencies resolved. Nothing to do. Complete! Why am I not able to update to latest version, is it because fedora 25 doesn't support latest octave version? or any other reason?

I'm running Debian stretch and want to be able to run my MATLAB code, using the GNU Octave packages. I type this into terminal pkg install -forge general and it gives me this error bash: pkg: command not found Any ideas? I've attempted to install this before, so maybe I did something weird last time, but as far as I can remember, I had the same problem the first time. I've had a look around the forums, but I didn't find anything that I understood enough to be helpful.

I have installed Octave using the following commands: sudo apt-add-repository ppa:octave/stable sudo apt-get update sudo apt-get install octave Typing octave --no-gui in the shell launches Octave command line. However, if I try opening octave GUI by typing octave or octave --force-gui, octave icon appears in the sidebar, and nothing else happens (no error message, either) and octave doesn't launch. Clicking on the icon doesn't do anything either. I have tried following the accepted answer to this similar question, but when I write > cd .config/octave I get the following message: > bash: cd: .config/octave: No such file or directory Thanks.