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where graph_file is something like https://acme-svn2.ornl.gov/acme-repo/acme/inputdata/ocn/mpas-o/oRRS15to5/mpas-o.graph.info.151209 and # pes is the number of cores you want to use for that component.
A Note about Layouts for Single-Component Simulations
The above discussion is mostly relevant to coupled runs involving all model components (aka "b" or "A_WCYCL" compsets). For simulations where most components are just reading in data (e.g. atmosphere "F" compsets or ocean/ice "G" compsets) it doesn't make sense to assign lots of cores to those inactive components. A natural choice in these cases is to run all components sequentially with all components asking for the same number of cores. This layout naturally avoids load balancing issues which might arise from some components doing all the work an others not doing anything. A complication with this approach is that some components may not scale to the core size used for the main components and may actually slow down as they are given too many components. Here is a table of the maximum number of cores each component can handle: NOTE - I DON'T KNOW THESE NUMBERS, WHETHER THIS IS EVEN TRUE, OR HOW THREADING COMPLICATES THIS PICTURE. HELP?
| atm | lnd | ocn | ice | rof | cpl | |
|---|---|---|---|---|---|---|
| ne30 | 5400 | |||||
| ne120 | 86400 |
There may also be advantages to running with some components in parallel... ALSO NOT SURE IF THIS IS TRUE.
About Parallel I/O (PIO) Layout:
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