Revision as of 09:39, 22 November 2022

Application Details

• Description: MATLAB is a numerical computing environment and programming language developed by MathWorks, MATLAB allows matrix manipulations, plotting of functions and data, and implementation of algorithms. A range of toolboxes is available to extend functionality.
• Versions: 2016a, 2016b, 2017a, 2018a, 2019a, 2020a
• Module names: matlab/2016a matlab/2016b matlab/2017a matlab/2018a matlab/2019a matlab/2020a
• License: University of Hull Total Academic Headcount license, available to members of the university for research use

Toolboxes

Matlab on Viper has the following toolboxes available:

Usage Examples

By default Matlab will make use of multithreading for certain functions, with the maximum number of computational threads equal to the number of computational cores on the node. If a job or session hasn't requested an appropriate resource, this multithreading can cause contention for CPU resources and negatively impact other users. For this reason when using the standard matlab command please make sure you request appropriate resources by either: Using an exclusive session, e.g. use interactive --exclusive or submit a task with the #SBATCH --exclusive option Starting matlab using matlab ‑singleCompThread which limits Matlab to using a single CPU core

Interactive

Interactive with full graphical interface (note the use of --exclusive when starting the interactive session):

[username@login01 ~]$ interactive --exclusive
salloc: Granted job allocation 289663
Job ID 289663 connecting to c170, please wait...
Last login: Thu Jan 26 12:59:11 2017 from 10.254.5.246
[username@c170 ~]$ module add matlab/2020a
[username@c170 ~]$ matlab 

Interactive with command line only:

[username@c170 ~]$ matlab -nodisplay

                                                    < M A T L A B (R) >
                                          Copyright 1984-2020 The MathWorks, Inc.
                                           R2020a Update 4 (9.8.0.1417392) 64-bit (glnxa64)
                                                     June 24, 2020

To get started, type one of these: helpwin, helpdesk, or demo.
For product information, visit www.mathworks.com.

        Academic License

>>

Batch Submission

To submit a batch job for Matlab, put your code in a .m script file and refer to this in your batch submission script, as shown below in the example MATLABtest.job job script. Remember to leave the .m extension from the script name in the Matlab command line.

#!/bin/bash
#SBATCH -J MATLAB           
#SBATCH -N 1                
#SBATCH -o %N.%j.out       
#SBATCH -e %N.%j.err        
#SBATCH -p compute          
#SBATCH --exclusive 
 
module purge
module add matlab/2020a
 
matlab -nodisplay -r my_matlab_m_file

To submit the Matlab job, use sbatch as shown below:

[username@login01 ~]$ sbatch MATLABtest.job
Submitted batch job 289522

Parallel Matlab

By default Matlab on Viper will run on a single core as multi-threading conflicts with the schedulers resource management, however, there are two ways in which Matlab can utilize multiple processors:

Multi-threading

Matlab can use multiple threads for certain built-in functions for example linear algebra and numerical functions such as fft, \ (mldivide), eig, svd, and sort. These functions automatically execute on multiple computational threads in a single MATLAB session, allowing them to execute faster on multicore-enabled machines. Additionally, many functions in the Image Processing Toolbox are multithreaded.

Firstly, using the matlab command with the -singleCompThread option:

[username@c170 ~]$ matlab -singleCompThread -nodisplay -nojvm -nodesktop -nosplash -r "maxNumCompThreads , exit"

                                                    < M A T L A B (R) >
                                          Copyright 1984-2016 The MathWorks, Inc.
                                           R2016a (9.0.0.341360) 64-bit (glnxa64)
                                                     February 11, 2016

For online documentation, see http://www.mathworks.com/support
For product information, visit www.mathworks.com.

        Academic License

Warning: maxNumCompThreads will be removed in a future release. Please remove any instances of this function from your code.
> In maxNumCompThreads (line 26)

ans =

     1

Using the standard matlab command, on Viper this starts Matlab with multithreading support enabled:

[username@c170 ~]$ matlab -nodisplay -nojvm -nodesktop -nosplash -r "maxNumCompThreads , exit"

                                                    < M A T L A B (R) >
                                          Copyright 1984-2016 The MathWorks, Inc.
                                           R2016a (9.0.0.341360) 64-bit (glnxa64)
                                                     February 11, 2016

For online documentation, see http://www.mathworks.com/support
For product information, visit www.mathworks.com.

        Academic License

Warning: maxNumCompThreads will be removed in a future release. Please remove any instances of this function from your code.
> In maxNumCompThreads (line 26)

ans =

     28

When using Matlab with multicore enabled, please ensure you have exclusive access to the node, see Exclusive interactive or Exclusive batch jobs.

Parallel Computing Toolbox

The Parallel Computing Toolbox allows you to open a number of workers (separate Matlab engines) on the local node, up to the number of cores on that node (28 for standard nodes in an exclusive session).

>> parpool('local',28)
Starting parallel pool (parpool) using the 'local' profile ... connected to 28 workers.

ans = 

 Pool with properties: 

            Connected: true
           NumWorkers: 28
              Cluster: local
        AttachedFiles: {}
          IdleTimeout: 30 minute(s) (30 minutes remaining)
          SpmdEnabled: true

When using Matlab with the Parallel Computing Toolbox, please ensure you have exclusive access to the node, see Exclusive interactive or Exclusive batch jobs.

Next Steps

• Matlab website
• Useful Matlab tutorials
• Matlab multicore

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