ELM Functional Physics Model

This project is in active development.

Description

This library contains land-surface physics functions derived from E3SM's land model, ELM.

https://github.com/E3SM-Project/E3SM

This library's cell-by-cell physics implementation is designed to expose a general interface for use with hydrology models and data/task-parallel programming models. We rely on programming models (currently Kokkos) to provide performance portability. Templated data types are used to provide flexibility and allow simple switching between programming models

This library currently includes tools for automating data management, I/O, and time/date keeping. An interface for the Kokkos programming model is nearing completion. The included physics kernels can simulate the entire water cycle (assuming flow is provided by external hydrology model) and energy cycle at the land surface. The test suite tests many of the physics kernels against output from ELM using included forcing data.

Ongoing development tasks include the completion of verification testing, physics-informed functional decomposition of kernels, creation of a general interface for hydrology models, and performance optimization.

Installation

Building this library is simple and should only take a few minutes.

I recommend setting up the following directory structure:

export KOKKOS_DIR=/path/to/kokkos/install
export ELM_DIR=/path/to/ELMKernels
export ELM_INPUT_DIR=/path/to/ELM/inout/for/driver     ## input data not yet included - will update soon

Add these directory definitions to your environment and include them in a place where they will be sourced by new shells.

Then clone Kokkos

git clone -b master "https://github.com/kokkos/kokkos.git" $KOKKOS_DIR

And this repository

git clone -b main "https://github.com/CANGA/ELMKernels.git" $ELM_DIR

Build Kokkos

Your build options may differ from those shown here

cd $KOKKOS_DIR
mkdir "build"; cd "build"
cmake ..\
  -DCMAKE_CXX_COMPILER=$path_to_compiler \
  -DCMAKE_INSTALL_PREFIX=${KOKKOS_DIR} \
  -DKokkos_ENABLE_OPENMP=ON \
  -DKokkos_ARCH_HSW=On \
  -DKokkos_HWLOC_DIR=$path_to_hwloc
make -j6 install

And now we can build this library

cd $ELM_DIR
sh buildELMphys.sh

If you set up your environment as decribed above, the build script should work without issue.

Run some tests

./install/bin/test_*

This code has been built with various minor versions of GCC 11.xx - 13.xx and the past year of Clang versions. Device simulation is not currently tested, only CPU computation. The Kokkos driver at driver/kokkos/kokkos_driver.cc demonstrates simple usage of these kernels.