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Software Module Toolchains

The YCRC uses a framework called EasyBuild to build and install the software you access via the module system.


When we install software, we use pre-defined build environment modules called toolchains. These are modules that include dependencies like compilers and libraries such as GCC, OpenMPI, CUDA, etc. We do this to keep our build process simpler, and to ensure that sets of software modules loaded together function properly. The two groups of toolchains we use on the YCRC clusters are foss and intel, which hierarchically include some shared sub-toolchains. Toolchains will have versions associated with the version of the compiler and/or when the toolchain was composed. Toolchain names and versions are appended as suffixes in module names. This tells you that a module was built with that toolchain and which other modules are compatible with it. The YCRC maintains a rolling two toolchain version support model. The toolchain versions supported on each cluster are listed in the Module Lifecycle documentation.

Free Open Source Software (foss)

The foss toolchains are versioned with a yearletter scheme, e.g. foss/2020b is the second foss toolchain composed in 2020. Software modules that were built with a sub-toolchain, e.g. GCCcore, are still safe to load with their parents as long as their versions match. The major difference between foss and fosscuda is that fosscuda includes CUDA and builds applications for GPUs by default. You shoould only use fosscuda modules on nodes with GPUs. Below is a tree depicting which toolchains inherit each other.

foss: gompi + FFTW, OpenBLAS, ScaLAPACK
└── gompi: GCC + OpenMPI
    └── GCC: GCCcore + zlib, binutils
        └── GCCcore: GNU Compiler Collection

fosscuda: gompic + FFTW, OpenBLAS, ScaLAPACK
└── gompic: gcccuda + CUDA-enabled OpenMPI
    └── gcccuda: GCC + CUDA
        └── GCC: GCCcore + zlib, binutils
            └── GCCcore: GNU Compiler Collection


The YCRC licenses Intel Parallel Studio XE (Intel oneAPI Base & HPC Toolkit coming soon). The intel and iomkl toolchains are versioned with a yearletter scheme, e.g. intel/2020b is the second intel toolchain composed in 2020. The major difference between iomkl and intel is MPI - intel uses Intel's MPI implementation and iomkl uses OpenMPI. Below is a tree depicting which toolchains inherit each other.

iomkl: iompi + Intel Math Kernel Library
└── iompi: iccifort + OpenMPI
    └── iccifort: Intel compilers
        └── GCCcore: GNU Compiler Collection

intel: iimpi + Intel Math Kernel Library
└── iimpi: iccifort + Intel MPI
    └── iccifort: Intel C/C++/Fortran compilers
        └── GCCcore: GNU Compiler Collection

What Versions Match?

To see what versions of sub-toolchains are compatible with their parents, load a foss or intel module of interest and run module list.

[netid@node ~]$ module load foss/2020b
[netid@node ~]$ module list

Currently Loaded Modules:
  1) StdEnv                        (S)   7) XZ/5.2.5-GCCcore-10.2.0           13) OpenMPI/4.0.5-GCC-10.2.0
  2) GCCcore/10.2.0                      8) libxml2/2.9.10-GCCcore-10.2.0     14) OpenBLAS/0.3.12-GCC-10.2.0
  3) zlib/1.2.11-GCCcore-10.2.0          9) libpciaccess/0.16-GCCcore-10.2.0  15) gompi/2020b
  4) binutils/2.35-GCCcore-10.2.0       10) hwloc/2.2.0-GCCcore-10.2.0        16) FFTW/3.3.8-gompi-2020b
  5) GCC/10.2.0                         11) UCX/1.9.0-GCCcore-10.2.0          17) ScaLAPACK/2.1.0-gompi-2020b
  6) numactl/2.0.13-GCCcore-10.2.0      12) libfabric/1.11.0-GCCcore-10.2.0   18) foss/2020b

   S:  Module is Sticky, requires --force to unload or purge

Here you see that foss/2020b includes GCCcore/10.2.0, so modules with either the foss-2020b or GCCcore-10.2.0 should be compatible.

Last update: August 17, 2023