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Using CAM6 to run the same experiment with different cores, the results vary greatly

ybb

lichun
New Member
Hello! I have a problem about cam6.
I used cam6 to run the same experiment with different cores,but the results are quite different.Is that right?
What should I do if it is wrong?
I'm glad I got the answer.
 

cacraig

Cheryl Craig
CSEG and Liaisons
Staff member
What compset are you using (i.e is it a CAM-only F compset or a fully coupled compset like a B compset?) CAM F compsets are intended to give identical results independent of the PE layout. If you are experiencing this with a F compset, please give us the details requested in:https://bb.cgd.ucar.edu/cesm/threads/information-to-include-in-help-requests.4974/

If this is a B compset, changing PE layout is expected to change answers. If you want to control this behavior, there is a bfbflag documented at: 3.5. Bit-for-bit flag — CIME master documentation
 

ybb

lichun
New Member
I am very glad and honored to receive your reply.This is the first time I've posted a question. I am sorry that some of the content is not very clear.

I use the compset F2000climo(CAM-only F compset) to run a case.I changed nothing and ran the same case with different numbers of nodes(each node has 28 cores).Their results vary widely. For example, temperatures can vary by five degrees or more in winter.The version is CESM2.1.3.

I don't know what to do about it.Looking forward to your reply.THANK U,sir.
 

Attachments

  • version_info.txt
    7.3 KB · Views: 1

ybb

lichun
New Member
What compset are you using (i.e is it a CAM-only F compset or a fully coupled compset like a B compset?) CAM F compsets are intended to give identical results independent of the PE layout. If you are experiencing this with a F compset, please give us the details requested in:https://bb.cgd.ucar.edu/cesm/threads/information-to-include-in-help-requests.4974/

If this is a B compset, changing PE layout is expected to change answers. If you want to control this behavior, there is a bfbflag documented at: 3.5. Bit-for-bit flag — CIME master documentation
am very glad and honored to receive your reply.This is the first time I've posted a question. I am sorry that some of the content is not very clear.

I use the compset F2000climo(CAM-only F compset) to run a case.I changed nothing and ran the same case with different numbers of nodes(each node has 28 cores).Their results vary widely. For example, temperatures can vary by five degrees or more in winter.The version is CESM2.1.3.

I don't know what to do about it.Looking forward to your reply.THANK U,sir.
 

Attachments

  • version_info.txt
    7.3 KB · Views: 2

cacraig

Cheryl Craig
CSEG and Liaisons
Staff member
Sorry to have not replied sooner. Are you still having issues with this?
 
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