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Thomas Ibbotson


MathWorks

35 total contributions since 2012

Professional Interests: Parallel computing

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Answered
How to disable MDCS cluster discovery
The MATLAB Job Scheduler uses multicast to make the cluster discoverable. You could block multicast traffic on your head node fi...

10 months ago | 2

Answered
Heterogeneous nodes architectures in Matlab Parallel Computing Toolbox
No, mixing 64-bit and 32-bit workers in the same MJS cluster will not work. All workers must have the same bitness as the MATLAB...

3 years ago | 0

Answered
Submit job to specified workers in an MJS cluster
Unfortunately, this is not possible. You could temporarily reduce the number of workers on each node to 5. The MJS startworker a...

4 years ago | 0

| accepted

Answered
Parpool Java exception occurred: 2014a & Mac - Only when wifi at home turned on?
A patch has been released for this bug see: <http://www.mathworks.com/support/bugreports/1119179 Bug report 1119179>

5 years ago | 2

Answered
Getting output from parallel jobs that would regularly go to a diary
Remove the line with: wait(j, 'finished') Then this allows you to get the tasks' diary output while the job is still r...

5 years ago | 0

Answered
Batch Processing of a Function with Different Arguments
I think code that looks something like this will work: for jobIdx = 1:length(nVector) jobs(jobIdx) = batch('long...

5 years ago | 2

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Answered
How can I use 30-50 workers instead of only the 12 maximum allowed in Parallel Computing Toolbox?
As of R2014a the number of local workers is no longer restricted. <http://www.mathworks.com/help/distcomp/release-notes.html See...

5 years ago | 2

Answered
Maximizing the number of workers used in a parfor loop using the "batch" command
I think it might help to explain how batch with the 'matlabpool' argument works. This causes 1 worker to run 'myTest' as the cli...

5 years ago | 1

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Answered
Help with parcluster, createJob, and createTask
It looks like the number of processes you can run in your user account is limited. You can find out what it is set to by running...

5 years ago | 1

| accepted

Answered
Parallel computing on a cluster
We would need to see the code for 'submat', but my guess is that an independent job is being created rather than a communicating...

5 years ago | 0

Answered
A few questions on running MATLAB on Amazon EC2 cloud
If you want to use the Parallel Computing Toolbox with Amazon EC2, have a look at <http://www.mathworks.com/ec2>. There is on-de...

5 years ago | 1

Answered
Setting password when connecting to mjs
If you need to you can reset the user's password as the 'admin' user by using 'changePassword' with the username to change as th...

5 years ago | 0

Answered
Matlab 2014a not using all logical cores
See Edric's answer to another question about hyperthreading here: <http://www.mathworks.com/matlabcentral/answers/80129#answer_...

5 years ago | 1

Answered
Accessing Matlab Cluster from outside the network
I'm assuming you're using MJS. This is what the documentation has to say: BASE_PORT. The mdce_def file specifies and describ...

5 years ago | 2

Answered
JVM out of memory when running parfor on cluster
It's possible that the worker JVMs are not picking up the java.opts file. Workers have a different startup folder to the client ...

6 years ago | 2

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Answered
How can I set the password while using the MDCS job scheduling feature on Linux.
The user can change their password using the changePassword method of the MJS cluster object: mjs = parcluster; changePa...

6 years ago | 0

Answered
Cannot connect to MJS with parcluster
I can't see anything obviously wrong there. I suggest you contact technical support, we have support engineers that can help you...

6 years ago | 0

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Answered
Using MATLAB in a client/server configuration
You need the MATLAB Distributed Computing Server ( <http://www.mathworks.co.uk/products/distriben/> ) to use the Parallel Comput...

6 years ago | 1

Answered
How can I send a batch job with empty workspace ?
Hi Rafael, Unfortunately the error message you are receiving is misleading. The problem is that you are using the incorrect s...

6 years ago | 2

Answered
Two different interacting programs on parallel computing toolbox
Hi Gav, I think you want the labsend, labreceive functionality. You can use the labindex function to switch between server be...

6 years ago | 0

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Answered
not able to start Matlabpool
This is a known issue with the newer versions of the Java Virtual Machine. There is a patch available at: <http://www.mathwor...

7 years ago | 0

Answered
matlabpool line 134 error.
It's possible that you have ended up with a corrupt profile somehow. We can try cleaning it up and see if that helps. In MATL...

7 years ago | 1

| accepted

Answered
Parallel programming: defining tasks
Hi Daniel, See my answer to your other related question: http://www.mathworks.com/matlabcentral/answers/62944-parallel-progr...

7 years ago | 0

Answered
Parallel programming with createJob
Hi Daniel, The problem is in the first line of code where you open a matlabpool. This is not required when using jobs and tas...

7 years ago | 2

| accepted

Answered
Is it okay to use matlabpool in multiple matlab sessions?
By default matlabpool will try and use all the workers available in a cluster. For example if you have 16 workers in a cluster a...

7 years ago | 0

Answered
error using matlabpool open local in a cluster
Hi Jhih-An If I understand correctly, you are submitting jobs to a cluster, which attempt to open a matlabpool on the cluster...

7 years ago | 0

Answered
Differences createCommunicatingJob( ..., 'Type','pool') and ...'Type', 'SPMD')
Both spmd and parfor require a matlabpool to be open to send their work to each worker in the pool. You can create the matlabpoo...

7 years ago | 1

| accepted

Answered
CUDA missing library libcuda.so.1
When you open a matlabpool and use 'spmd', the code in that block is run on all the workers in the pool. As your workers are run...

7 years ago | 1

Answered
help with passing cell array argument to function running on worker with batch
Thanks for reporting this issue, unfortunately you have uncovered a bug in the Parallel Computing Toolbox. For now I'm afraid yo...

7 years ago | 0

Answered
There is no such file as mdce but I have 'glnxa64/mdced'
This looks like there might be a problem with your installation, you should have the 'mdce' file in your $matlabhome/toolbox/dis...

7 years ago | 1

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