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# Exclude Land Processes in NEMO
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The **E**xclude **L**and **P**rocesses **i**n **N**EMO tool is a tool to find proper namelist parameters to exclude Land-only processes in NEMO simulations.
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The first time that you run the tool it will install it. After that, with the resolution and the maximum number of processes to use.
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As an example, once the tool is installed, the command ``./Launcher ORCA025 512`` will produce :
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512 26 25
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The first number corresponds to **jpnij** ( total number of subdomains containing sea-points), the second number corresponds **jpni** (number of division in x axis) and the third corresponds to **jpnj** (number of domain divisions in y axis).
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![result](/uploads/14436bb19990e5ab7563134a40c950fe/RemovedProcesses.png)
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### ORCA025 comparison
The next plots are both ORCA025 simulations where the land-only processes have been removed, the first one using 120 processes and the second one using 950 processes.
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As can be seen, when more processes are used the size of the subdomains is smaller and therefore it is possible to adjust better to the continental shape and delete a bigger proportion of the land grid-points.
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From domain decomposition resulting in 136 sub-domains 16 are land-only and therefore removed, an 11% of the total grid.

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![O025_120p](/uploads/775d2de2a2ade97dc9a54b56ff7e4ebf/RemovedProcessesORCA025_120.png)
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From domain decomposition resulting in 1287 sub-domains 312 are land-only and therefore removed, a 24% of the total grid.
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![O025_120p](/uploads/42cd6b018eefc525f9349b0d9d5101ef/RemovedProcessesORCA025_950.png)
## Impact on Performance
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For the ORCA025 resolution, the advantadge of using ELPiN is massive as can be seen in the next figure:\\

![simple_plot](/uploads/898820c14fb18e569e372b2223d44f6d/simple_plot.png)

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Further details can be found in [this paper](https://www.sciencedirect.com/science/article/pii/S1877050917308888/pdf?md5=d7e6c16ad4156c9d09cad2d8eafc327f&pid=1-s2.0-S1877050917308888-main.pdf&_valck=1)