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Running COMSOL in distributed-memory mode

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Hello everyone,

So far, I have only used a cluster for solving my COMSOL problems in shared-memory mode and then I use several processors but only one computational node. However, now I have a very large problem (almost 3,000,000 DOF) and I need more memory in order to get a solution. Then I am thinking of using the distributed-memory mode but I have some doubts about it:

1) I don't know if the license I have allows me to use this mode. Currently, I have a floating network license for 1 concurrent user and I can only execute a file at a time. Let me explain this: if I send a file to the cluster (shared-memory mode), it is going to be solved by one sole machine. However, I can't send a different file to be executed at the same time on another different machine because I get a license error. Then I am wondering if I will be able to use the distributed-memory mode since, to my knowledge, COMSOL will run in several physical nodes (machines). Then, can I use an unlimited number of nodes (I mean as many nodes as the cluster has)?

2) Do I have to build my models in a different way in order to solve them using the distributed-memory mode?

3) I don't want to make a parametric sweep, I only have a rather memory-consuming problem that I want to solve using a direct solver. Can I use any of the direct solvers? Do yo reccommend me one of them in particular?

4) I am still using COMSOL 3.5 because I am adapting to version 4.1. Would there be many differences (regarding calculation speed and so on) if I used version 4.1?.

Thank you very much for your help

3 Replies Last Post 17 mag 2011, 16:53 GMT-4

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Posted: 1 decade ago 17 mag 2011, 06:09 GMT-4
Regarding my question, the COMSOL distributor in my country tells me that I can't use COMSOL 3.5 in distributed-memory mode, which I don't believe because there is a section in the user's guide devoted to this topic. On the other hand, from COMSOL support they don't ask my question because they say that version 3.5 is not supported any longer. Has anybody used COMSOL 3.5 this way? Can you tell me what kind of license you use?

Regards,

Diego
Regarding my question, the COMSOL distributor in my country tells me that I can't use COMSOL 3.5 in distributed-memory mode, which I don't believe because there is a section in the user's guide devoted to this topic. On the other hand, from COMSOL support they don't ask my question because they say that version 3.5 is not supported any longer. Has anybody used COMSOL 3.5 this way? Can you tell me what kind of license you use? Regards, Diego

Jeff Hiller COMSOL Employee

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Posted: 1 decade ago 17 mag 2011, 07:39 GMT-4
Hello Diego,
Before version 4, cluster computing was not a feature that was included by default with floating network licenses: it required the purchase of a special license type ("SMP" license). Starting at version 4, cluster computing is offered as part of the standard FNL license.
Best,
Jeff
Hello Diego, Before version 4, cluster computing was not a feature that was included by default with floating network licenses: it required the purchase of a special license type ("SMP" license). Starting at version 4, cluster computing is offered as part of the standard FNL license. Best, Jeff

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Posted: 1 decade ago 17 mag 2011, 16:53 GMT-4
3: There is a tutorial model that you should study, in the model library of version 4.1: Model Library path: COMSOL_Multiphysics/Tutorial_Models/
micromixer_cluster

4: V 3.5 has no support for distributed solves. You need to upgrade to 4.1.

Niklas



3) I don't want to make a parametric sweep, I only have a rather memory-consuming problem that I want to solve using a direct solver. Can I use any of the direct solvers? Do yo reccommend me one of them in particular?

4) I am still using COMSOL 3.5 because I am adapting to version 4.1. Would there be many differences (regarding calculation speed and so on) if I used version 4.1?.

Thank you very much for your help

3: There is a tutorial model that you should study, in the model library of version 4.1: Model Library path: COMSOL_Multiphysics/Tutorial_Models/ micromixer_cluster 4: V 3.5 has no support for distributed solves. You need to upgrade to 4.1. Niklas [QUOTE] 3) I don't want to make a parametric sweep, I only have a rather memory-consuming problem that I want to solve using a direct solver. Can I use any of the direct solvers? Do yo reccommend me one of them in particular? 4) I am still using COMSOL 3.5 because I am adapting to version 4.1. Would there be many differences (regarding calculation speed and so on) if I used version 4.1?. Thank you very much for your help [/QUOTE]

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