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Octave 
======

  

GNU Octave is a high-level interpreted language, primarily intended for
numerical computations. It provides capabilities for the numerical
solution of linear and nonlinear problems, and for performing other
numerical experiments. It also provides extensive graphics capabilities
for data visualization and manipulation. Octave is normally used through
its interactive command line interface, but it can also be used to write
non-interactive programs. The Octave language is quite similar to Matlab
so that most programs are easily portable. Read more on
<http://www.gnu.org/software/octave/>***

Two versions of octave are available on the cluster, via module

  Status       Version        module
  ------  |---|---|---- --------
  **Stable**   Octave 3.8.2   Octave

 

    $ module load Octave

The octave on the cluster is linked to highly optimized MKL mathematical
library. This provides threaded parallelization to many octave kernels,
notably the linear algebra subroutines. Octave runs these heavy
calculation kernels without any penalty. By default, octave would
parallelize to 24 threads. You may control the threads by setting the
OMP_NUM_THREADS environment variable.

To run octave interactively, log in with ssh -X parameter for X11
forwarding. Run octave:

    $ octave

To run octave in batch mode, write an octave script, then write a bash
jobscript and execute via the qsub command. By default, octave will use
16 threads when running MKL kernels.

    #!/bin/bash

    # change to local scratch directory
    mkdir -p /scratch/work/user/$USER/$PBS_JOBID
    cd /scratch/work/user/$USER/$PBS_JOBID || exit

    # copy input file to scratch 
    cp $PBS_O_WORKDIR/octcode.m .

    # load octave module
    module load Octave

    # execute the calculation
    octave -q --eval octcode > output.out

    # copy output file to home
    cp output.out $PBS_O_WORKDIR/.

    #exit
    exit

This script may be submitted directly to the PBS workload manager via
the qsub command.  The inputs are in octcode.m file, outputs in
output.out file. See the single node jobscript example in the [Job
execution
section](../../resource-allocation-and-job-execution.html).

The octave c compiler mkoctfile calls the GNU gcc 4.8.1 for compiling
native c code. This is very useful for running native c subroutines in
octave environment.

$ mkoctfile -v

Octave may use MPI for interprocess communication
This functionality is currently not supported on the cluster cluster. In
case you require the octave interface to MPI, please contact our
[cluster support](https://support.it4i.cz/rt/).