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Normally, number of $ProcessorCount should be the same as LaunchKernels[], but if they are not the same, what is the problem?

enter image description here


Update

I just tried to manually launch kernel as this

LaunchKernels[24]

And test parallel computation, surprisingly, it indeed use 24 cores at the same time

enter image description here

Than why $ConfiguredKernels is 16 by default? I tried setting $ConfiguredKernels=24, but LaunchKernels[] still gives 16 kernels. What is wrong?

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  • $\begingroup$ You may want to check your $ConfiguredKernels value, as well as the configuration in Preferences -> Parallel -> Local Kernels. The licensing limitations will of course depend on the actual license being used. $\endgroup$
    – ilian
    Nov 17 '15 at 17:59
  • $\begingroup$ @ilian You are right. $ConfiguredKernels shows 16. But what does this mean "The licensing limitations will of course depend on the actual license being used.“? $MaxLicenseSubprocesses shows infinity $\endgroup$
    – matheorem
    Nov 18 '15 at 0:47
  • $\begingroup$ You are probably using a MathLM license server, so you can launch as many kernels as you like, as long as there are network licenses available for them; monitorlm can be used to query the server for the number of authorized/available/in use processes. $\endgroup$
    – ilian
    Nov 18 '15 at 2:12
  • $\begingroup$ @ilian I didn't install MathLM. So I think this may not be the right point. $\endgroup$
    – matheorem
    Nov 18 '15 at 8:05
  • $\begingroup$ @ilian I add new phenomena in the post $\endgroup$
    – matheorem
    Nov 18 '15 at 8:29
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Your license may only allow 16 subkernels. You can check this by evaluating

$MaxLicenseSubprocesses
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  • $\begingroup$ Well, it is actually infinity... $\endgroup$
    – matheorem
    Nov 17 '15 at 13:12
  • $\begingroup$ @matheorem Well, what happens if you try to launch more than 16? $\endgroup$
    – Szabolcs
    Nov 17 '15 at 15:20
  • $\begingroup$ Yeah, I just feel confused about that. No matter on my laptop or on HPC, if I run LaunchKernels[num], num greater than processorcount, It will give a kernel list of exactly num, I don't understand what does that mean. $\endgroup$
    – matheorem
    Nov 17 '15 at 15:39

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