This is a collection of libraries commonly known as NCEPLIBS that are required for several NCEP applications, e.g., UFS, GSI, UPP, etc. For general information about NCEPLIBS, the user is referred to the Wiki.

For full documentation of each package see https://noaa-emc.github.io/NCEPLIBS/.

For installing NCEPLIBS on NOAA HPC systems, see the documentation for the spack-stack project. The documentation 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. Note that 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 for applications that spack-stack is intended to support, namely, UFS applications, Global Workflow, and JEDI applications (i.e., users developing the UFS Weather Model on a personal machine are recommended to use their own installation 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.

NCEPLIBS is comprised of the following libraries:

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.

The following projects are also related to the NCEPLIBS project:

• NCEPLIBS-grib_util ('grib-util' in Spack)
• NCEPLIBS-prod_util ('prod-util' in Spack)
• UFS_UTILS ('ufs-utils' in Spack)

• A supported C/C++ and Fortran compiler (see table below). Other versions may work, in particular if close to the versions listed below.

• A supported MPI library (see table below). Other versions may work, in particular if close to the versions listed below.

• A software stack consisting of the following third-party libraries, compiled with the same compiler and MPI library (where applicable). Other versions may work, in particular if close to the versions listed below. To install the third-party libraries needed by NCEPLIBS, see NCEPLIBS-external.

The NCEPLIBS-external project provides an convenient way to install the required third-party libraries on supported platforms such as generic Linux/macOS systems.

All of the NCEPLIBS 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, or 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 along with any needed 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 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 # find external packages to save time
spack install ip@develop precision=4 ^[email protected] precision=4
spack load ip

The spack load command configures the $CMAKE_PREFIX_PATH variable, in this example making the ip library available to downstream CMake builds.

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 appropriate NCEPLIBS repository.

See NCEPLIBS-external for building external dependencies.

Clone the repository:

git clone https://github.com/NOAA-EMC/NCEPLIBS

CMake employs an out-of-source build. Create a directory for configuring the build and cd into it:

mkdir -p build && cd build

Set the compilers, if needed, to match those being used for compiling the third-party libraries listed above: FC, CC, and CXX environment variables can be used to point to the desired Fortran, C, and C++ compilers.

Execute cmake from inside your build directory.

cmake -DCMAKE_INSTALL_PREFIX=<nceplibs-prefix> ../NCEPLIBS

If the third-party libraries are not located in a path recognized by cmake e.g. /usr/local, it may be necessary to provide the appropriate environment variables e.g. <package_ROOT> or CMAKE_PREFIX_PATH so that cmake is able to locate these dependencies.

The installation prefix for NCEPLIBS is provided by the cmake command-line argument -DCMAKE_INSTALL_PREFIX=<nceplibs-prefix>

To build and install:

make -j<x>

This will build and install all the NCEPLIBS and place them into the installation prefix <nceplibs-prefix>.

Additional cmake command-line options while configuring NCEPLIBS:

-DFLAT=ON|OFF - determines the installation tree heirarchy

-DDEPLOY=ON|OFF - prepares and deploys Lua modulefiles for each of the NCEPLIBS libraries. To deploy modulefiles:

make deploy

LMod Environment module system is required to load/unload these modules.

Some HPC systems use Tcl based Environment modules. NCEPLIBS provides a means to deploy Tcl module files and can be exercised as follows:

-DTCLMOD=ON - enables option to change Lua modulefiles to Tcl modulefiles for each of the NCEPLIBS libraries. To make the change:

make tcl

On machines that do not provide access to Github, a DOWNLOAD_ONLY and USE_LOCAL option is provided. To download the NCEPLIBS without building them use the cmake command line option -DDOWNLOAD_ONLY=ON. This will download all the NCEPLIBS in a local download folder. make tarball will tar and zip this folder into nceplibs.tgz which can then be transferred to the machine without GitHub access. Untar the tarball, and use the cmake command line option USE_LOCAL as -DUSE_LOCAL=ON. This will use the source code from the download directory.

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 are installed through Spack, loading the packages, either through Spack-built environment modules or using the spack load command, will populate the $CMAKE_PREFIX_PATH environment variable with the appropriate paths.

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