falfilfa4py 1.0.5

FA/LFI/LFA for Python

FALFILFA

Externalized FA - LFI - LFA Formats from IAL

• LFI : "Logiciel de Fichiers Indexes"
• FA : "Format Arpege" - overlay on top of LFI
• LFA : format used for DDH outputs

Installing FALFILFA

Supported Platforms

• Linux

Requirements

• Fortran and C compiler( tested On Intel & GNU 11.3.0 and later )
• CMake (see https://cmake.org)
• ecbuild (see https://github.com/ecmwf/ecbuild)
• fiat (see https://github.com/ecmwf-ifs/fiat)

Building FALFILFA

Environment variables

$ export ecbuild_ROOT=`<path-to-ecbuild>`
$ export fiat_ROOT=`<path-to-fiat>`
$ export eccodes_ROOT=`<path-to-eccodes>`

Compilers could be set while building the libraries or with thoses env variables :

$ export CC=`<path-to-C-compiler>`
$ export FC=`<path-to-Fortran-compiler>`

Since, we are using ecbuild, you must compile FALFILFA out-of-source, so create a build-directory

$ mkdir build

Configuration of the build happens through standard CMake

$ cmake -S FALFILFA -B build

Extra options can be added to the cmake command to control the build:

• -DCMAKE_BUILD_TYPE=<Debug|RelWithDebInfo|Release|Bit> default=RelWithDebInfo (typically -O2 -g)
• -DBUILD_SHARED_LIBS=<BOTH|ON|OFF> default=ON
• -DENABLE_SINGLE_PRECISION=<ON|OFF> default=OFF
• -DENABLE_DOUBLE_PRECISION=<ON|OFF> default=ON
• -DCMAKE_INSTALL_PREFIX=<install-prefix> default=/usr/local (You will need permission to install)
• -DCMAKE_Fortran_COMPILER=< fortran compiler> default=gfortran or the set FC env variable
• -DCMAKE_C_COMPILER=< C compiler> default=gcc or the set CC env variable

More options to control compilation flags, only when defaults are not sufficient

• -DCMAKE_Fortran_FLAGS=<fortran-flags>
• -DCMAKE_C_FLAGS=<c-flags>

Once this has finished successfully, run cmake --build . and cmake --install ..

Building falfilfa4py

To build the falfilfa4py python package (wheel):

export ecbuild_ROOT=`<path-to-ecbuild>`
export gribex_ROOT=`<path-to-your-gribex-root>`
export fiat_ROOT=`<path-to-fiat>`
export eccodes_ROOT=`<path-to-eccodes>`

pip install build
pip install auditwheel
python -m build --sdist --wheel
python -m auditwheel repair dist/falfilfa4py-*-linux_x86_64.whl

Build helper

The script singularity_build.sh, together with sub-scripts in bld/, is designed to help build the libraries and/or the falfilfa4py python package (wheel) within a manylinux container using singularity.

See variables in the header of the script to tune dependencies versions in particular.

• singularity_build.sh get gets the container image and dependencies clones
• singularity_build.sh deps builds the dependencies (fiat, eccodes...) (req. to have done get)
• singularity_build.sh lib builds the libfa_[dp|sp].so (req. to have done get&deps)
• singularity_build.sh wheel builds falfilfa4py wheels for several versions of python (req. to have done get&deps)
• singularity_build.sh all does all of the above

Caveats

The current version relies on a copy of the GRIB_API_INTERFACE module (grib_api_interface.F90) from IAL, renamed ECCODES_INTERFACE (src/fa/module/eccodes_interface.F90).

This is a temporary workaround, several options are considered to fix this caveat in a near future:

• relying directly on ECCODES library
• moving this module in a lower-level library, e.g. eccodes or fiat

Reporting Bugs

Issues: https://github.com/ACCORD-NWP/FALFILFA/Issues Contributions: https://github.com/ACCORD-NWP/FALFILFA/Pulls