NCEPLIBS is a collection of libraries used by a range of NCEP R&D and operational applications, including UFS (Weather Model, SRW, etc.), GSI/Global Workflow, UFS_UTILS, and UPP. General information about NCEPLIBS, including code best practices, contributor expectations, and continuous integration methods, can be found in the NCEPLIBS wiki.
For using NCEPLIBS on NOAA HPC systems, see the spack-stack project's Getting Started documentation and wiki. The spack-stack framework is used to install a range of libraries, including all currently supported NCEPLIBS codes, on RDHPCS systems in locations available to all users. The documentation also provides instructions for using spack-stack to build software stacks from scratch, as well as to build stacks that are chained to existing environments in order to re-use dependencies already provided by official spack-stack deployments.
Warning
This repository contains long disused scripts for compiling NCEPLIBS. These are not in any way maintained or supported. Use as at your own risk. See instructions below for obtaining NCEPLIBS.
NCEPLIBS is comprised of the following libraries. Italicization indicates a repository that as of Summer 2025 is no longer actively developed, therefore NOAA developers are suggested to avoid using them, or to confer with the NCEPLIBS team before beginning any development work with them.
| NCEP library | Spack package name | Description |
|---|---|---|
| NCEPLIBS-bacio | bacio | Binary I/O for the NCEP models |
| NCEPLIBS-bufr | bufr | Working with the BUFR format |
| NCEPLIBS-g2 | g2 | Coding/decoding GRIB2 messages |
| NCEPLIBS-g2c | g2c | C decoder/encoder routines for GRIB edition 2 |
| NCEPLIBS-g2tmpl | g2tmpl | Utilities for GRIB2 templates |
| NCEPLIBS-gfsio | gfsio | Convert GFS Gaussian output into grib output |
| NCEPLIBS-grib_util | grib-util | Utilities for working with GRIB2 files |
| NCEPLIBS-ip | ip | General interpolation library |
| NCEPLIBS-landsfcutil | landsfcutil | Initializing land-surface states |
| NCEPLIBS-ncio | ncio | Read the GFS forecast files |
| NCEPLIBS-nemsio | nemsio | I/O for the NCEP models using NEMS |
| NCEPLIBS-nemsiogfs | nemsiogfs | I/O for the NEMS-GFS model |
| NCEPLIBS-prod_util | prod-util | EMC copy of NCO's utilities for misc. date & file manipulation |
| NCEPLIBS-sfcio | sfcio | Surface files I/O |
| NCEPLIBS-sigio | sigio | I/O on the sigma restart file of the global spectral model |
| NCEPLIBS-w3emc | w3emc | Decoder/encoder routines for GRIB edition 1 |
| NCEPLIBS-wrf_io | wrf-io | Lightweight WRF-IO API library for Unified Post Processor (UPP) |
| wgrib2 | wgrib2 | Utility for working with GRIB2 files |
For information on maintainers, documentation, and bug and feature requests, refer to each package repository listed above.
The NCEPLIBS-w3nco, NCEPLIBS-ip2, and NCEPLIBS-sp libraries ('w3nco', 'ip2', and 'sp' in Spack, respectively) are deprecated. NCEPLIBS-w3emc replaces NCEPLIBS-w3nco, and NCEPLIBS-ip replaces NCEPLIBS-ip2 and NCEPLIBS-sp.
NCEPLIBS codes are tested with and intended to support GCC, Intel Classic, and Intel oneAPI compilers. Older versions of each of these may not be compatible. Refer to individual code repositories (including GitHub Issues) for more specific information on compiler conflicts, and please submit issues if previously unknown conflicts emerge. Contributions of modified code and CMake configurations to allow for the use of other compilers are welcome, but compilers other than those listed above are not officially supported.
All NCEPLIBS codes use the CMake build system, therefore CMake and at least one of GMake and Ninja are necessary to build them.
Note
Users are recommended to use existing spack-stack installations as much as possible when using NOAA R&D systems, and to use spack-stack as much as possible when developing the applications that spack-stack is intended to support, namely, UFS applications, Global Workflow, and JEDI applications (for instance, users developing the UFS Weather Model on a personal machine are recommended to build a local copy of spack-stack). Outside of these platforms and applications, users are recommended to install NCEPLIBS either through CMake or through regular Spack (not spack-stack); see instructions below.
All of the NCEPLIBS codes can be installed through the Spack package manager. One significant benefit of using Spack is that it will automatically install any dependencies needed, including CMake, and even compilers. See the Spack documentation for details of configuring and executing Spack installations. Spack also has extensive capabilities including source and build caching, parallel installation, dynamically generating Tcl and Lmod environment modules, and creating Docker and Singularity container images.
In the simplest case, with the spack command loaded into the current
environment, run, for example, spack install ip to install the latest release
of the NCEPLIBS-ip library; Spack will take care of installing all necessary
dependencies. See the above table for each package's name in Spack. The develop
branch for each library can be installed by specifying the 'develop' version,
i.e., spack install w3emc@develop.
Here is a typical set of steps for installing and using NCEPLIBS using Spack, assuming that Spack's own prerequisites are already installed:
git clone https://github.com/spack/spack
. spack/share/spack/setup-env.sh # assuming bash, zsh, or dash shell
spack external find cmake gmake openblas # optionally find external packages to save time
spack install ip@develop precision=4,d,8
spack load ip
The spack load command configures the $CMAKE_PREFIX_PATH variable, in this
example making the ip library available to downstream CMake projects (e.g., UFS
Weather Model).
For any bugs or other issues with Spack-based installations, such as incorrect dependencies in a package's recipe, please file an issue under the main Spack repository.
For CMake build instructions, including software prerequisities and build options, refer to each NCEPLIBS repository's README and ReadTheDocs page. The GitHub Actions workflows under .github/workflows/ in each NCEPLIBS repository may be useful references for possible approaches to obtaining software prerequisites.
NCEPLIBS can be used in any application that uses cmake to configure and
build by adding -DCMAKE_PREFIX_PATH=<nceplibs-prefix> to the CMake command
line during configuration. Note that if NCEPLIBS codes are installed through
Spack, loading the packages, either through Spack-built environment modules or
using the spack load command, will by default populate the
$CMAKE_PREFIX_PATH environment variable with the appropriate paths.
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