Building singularity-eos
The singularity-eos build system is designed with two goals in mind
Portability to a wide range of host codes, system layouts, and underlying hardware
Ease of code development, and flexibility for developers
These considerations continue to guide development of the tools and
workflows in working with singularity-eos.
Basics
The build of singularity-eos can take two forms:
Submodule mode
Standalone mode
These will be described in more detail below, but in brief submodule
mode is intended for downstream codes that build singularity-eos
source code directly in the build (sometimes referred to as “in-tree”),
while standalone mode will build singularity-eos as an independent
library that can be installed onto the system.
The most important distinction between the modes is how dependencies are
handled. submodule mode will use internal source clones of key
dependencies (located in utils\), effectively building these
dependencies as part of the overall singularity-eos build procedure.
It should be noted, however, that there are optional dependencies that
are not provided internally and must be separately available.
In standalone mode, all dependencies must be available in the
environment, and be discoverable to CMake. While not required, it is
encouraged to use the dependency management tool spack to help
facilitate constructing a build environment, as well as deploying
singularity-eos. Example uses of spack for these purposes are
provided below.
A CMake configuration option is provided that allows developers to
select a specific mode (SINGULARITY_FORCE_SUBMODULE_MODE), however
this is intended for internal development only. The intended workflow is
to let singularity-eos decide the appropriate mode, which it
decides based on inspecting the project directory that the source
resides in.
Dependencies
singularity-eos has a number of required and optional depdencies.
Package Name |
Distribution |
Comment |
|---|---|---|
submodule / external |
Required |
|
submodule / external |
Required |
|
Optional; enhanced backend for EOS tables |
||
external only |
Optional; used for table I/O |
|
external only |
Optional; used for sesame tables. |
|
submodule / external |
Optional; enables GPU offloading. |
|
submodule / external |
Optional; used for linear algebra on the CPU when doing mixed-cell closures. |
|
submodule / external |
Optional; used for linear algebra on the GPU when doing mixed-cell closures. |
|
external / fetchable [‡] |
Optional |
A FORTRAN compiler is required if fortran bindings are enabled.
Options for configuring the build
Most configuration options are the same between the two builds. standalone / submodule specific options are touched on in the sections detailing those build modes.
The main CMake options to configure building are in the following table:
Option |
Default |
Comment |
|---|---|---|
|
ON |
Enables EOS objects that use |
|
ON |
Enable Fortran API for equation of state. |
|
OFF |
Uses Kokkos as the portability backend. Currently only Kokkos is supported for GPUs. |
|
OFF |
Link against EOSPAC. Needed for sesame2spiner and some tests. |
|
OFF |
Build the mixed cell closure models |
|
OFF |
Build test infrastructure. |
|
OFF |
Build Python bindings. |
|
OFF |
Build examples of |
|
OFF |
For tests, pre-invert eospac tables. |
|
ON |
Enables nicer GPU debug flags. May interfere with in-tree builds as a submodule. |
|
OFF |
Makes warnings less verbose. May interfere with in-tree builds as a submodule. |
|
OFF |
Force build in _submodule_ mode. |
|
OFF |
Use single precision logarithms (may degrade accuracy). |
|
OFF |
Use grids that conform to logarithmic spacing. |
More options are available to modify only if certain other options or variables satisfy certain conditions (dependent options). Dependent options can only be accessed if their precondition is satisfied.
If the precondition is satisfied, they take on a default value, although they can be changed. If the precondition is not satisfied, then their value is fixed and cannot be changed. For instance,
# in <top-level>/build
cmake .. -DSINGULARITY_USE_KOKKOS=OFF -DSINGULARITY_USE_CUDA=ON
will have no effect (i.e. SINGULARITY_USE_CUDA will be set to
OFF), because the precondition of SINGULARITY_USE_CUDA is for
SINGULARITY_USE_KOKKOS=ON.
Generally, dependent options should only be used for specific
use-cases where the defaults are not applicable. For most scenarios, the
preconditions and defaults are logically constructed and the most
natural in practice (SINGULARITY_TEST_* are only available if
SINGLARITY_BUILD_TESTS is enabled, for instance).
These options are listed in the following table, along with their preconditions:
Option |
Precondition |
Comment |
|---|---|---|
|
|
Requests that |
|
|
Target nvidia GPUs for |
|
|
Use Kokkos Kernels for linear algebra. Needed for mixed cell closure models on GPU. |
|
|
Builds the conversion tool sesame2spiner which makes files readable by SpinerEOS. |
|
|
Builds the conversion tool stellarcollapse2spiner which optionally makes stellar collapse files faster to read. |
|
|
Test the Sesame table readers. |
|
|
Test the Stellar Collapse table readers. |
|
|
Test the Python bindings. |
|
|
Use Helmholtz equation of state. |
|
|
Build Helmholtz equation of state tests. |
When installing singularity-eos, data files are also installed. The
follwing options control where the data files are installed:
Option |
Default |
Comment |
|---|---|---|
|
<none> |
Install directory for data files. |
|
share |
Fallback data install directory. |
The paths specified by these options are relative to the install prefix.
CMake presets
To further aid the developer, singularity-eos is distributed with
Presets, a list of common build options with naturally named labels
that when used can reduce the need to input and remember the many
options singularity-eos uses. For a general overview of CMake
presets, see the cmake documentation on
presets
Warning
CMake presets are only available if singularity-eos is the
top-level project.
Predefined presets
Predefined presets are described with a json schema in the file
CMakePresets.json. As an example:
# in <top-level>/build
$> cmake .. --preset="basic_with_testing"
Preset CMake variables:
CMAKE_EXPORT_COMPILE_COMMANDS="ON"
SINGULARITY_BUILD_TESTS="ON"
SINGULARITY_USE_EOSPAC="ON"
SINGULARITY_USE_SPINER="ON"
# ...
As you can see, CMake reports the configuration variables that the preset has used, and their values. A list of presets can be easily examined with:
# in <top-level>/build
$> cmake .. --list-presets
Available configure presets:
"basic"
"basic_with_testing"
"kokkos_nogpu"
"kokkos_nogpu_with_testing"
"kokkos_gpu"
"kokkos_gpu_with_testing"
When using presets, additional options may be readily appended to
augment the required build. For example, suppose that the basic
preset is mostly sufficient, but you would like to enable building the
closure models:
# in <top-level>/build
$> cmake .. --preset="basic_with_testing" -DSINGULARITY_BUILD_CLOSURE=ON
# ...
User defined presets
The CMake preset functionality includes the ability of developers to
define local presets in CMakeUserPresets.json. singularity-eos
explicitly does not track this file in Git, so developers can construct
their own presets. All presets in the predefined CMakePresets.json
are automatically included by CMake, so developers can build off of
those if needed.
For instance, suppose you have a local checkout of the kokkos and
kokkos-kernels codes that you’re using to debug a GPU build, and you
have these installed in ~/scratch/. Your CMakeUserPresets.json
could look like:
{
"version": 1,
"cmakeMinimumRequired": {
"major": 3,
"minor": 19
},
"configurePresets": [
{
"name": "my_local_build",
"description": "submodule build using a local scratch install of kokkos",
"inherits": [
"kokkos_gpu_with_testing"
],
"cacheVariables": {
"Kokkos_DIR": "$env{HOME}/scratch/kokkos/lib/cmake/Kokkos",
"KokkosKernels_DIR": "$env{HOME}/scratch/kokkoskernels/lib/cmake/KokkosKernels",
"SINGULARITY_BUILD_PYTHON": "ON",
"SINGULARITY_TEST_PYTHON": "OFF"
}
}
]
}
This inherits the predefined kokkos_gpu_with_testing preset, sets
the Kokkos*_DIR cache variables to point find_package() to use
these directories, and finally enables building the python bindings
without including the python tests.
Building in submodule mode
For submodule mode to activate, a clone of the singularity-eos
source should be placed below the top-level of a host project
# An example directory layout when using singularity-eos in submodule mode
my_project
|_CMakeLists.txt
|_README.md
|_src
|_include
|_tpl/singularity-eos
singularity-eos is then imported using the add_subdirectory()
command in CMake
# In your CMakeLists.txt
cmake_minimum_required(VERSION 3.19)
project(my_project)
add_executable(my_exec src/main.cc)
target_include_directories(my_exec include)
add_subdirectory(tpl/singularity-eos)
target_link_libraries(my_exec singularity-eos::singularity-eos)
This will expose the singularity-eos interface and library to your
code, along with the interfaces of the internal dependencies
// in source of my_project
#include<singularity-eos/eos/eos.hpp>
// from the internal ports-of-call submodule
#include<ports-of-call/portability>
// ...
using namespace singularity;
singularity-eos will build (along with internal dependencies) and be
linked directly to your executable.
The git submoudles may change during development, either by changing the pinned hash, addition or removal of submodules. If you have errors that appear to be the result of incompatible code, make sure you have updated your submodules with
git submodule update --init --recursive
Building in standalone mode
For standalone mode, all required and optional dependencies are expected to be discoverable by CMake. This can be done several ways
(preferred) Use Spack to configure and install all the dependencies needed to build.
Use a system package manager (
apt-get,yum, &t) to install dependencies.Hand-build to a local filesystem, and configure your shell or CMake invocation to be aware of these installs
standalone mode is the mode used to install singularity-eos to a
system as a common library. If, for example, you use Spack to install
packages, singularity-eos will be built and installed in
standalone mode.
Building with Spack
Spack is a package management tool that is designed specifically for HPC environments, but may be used in any compute environment. It is useful for gathering, configuring and installing software and it’s dependencies self-consistently, and can use existing software installed on the system or do a “full” install of all required (even system) packages in a local directory.
Spack remains under active development, and is subject to rapid change
in interface, design, and functionality. Here we will provide an
overview of how to use Spack to develop and deploy singularigy-eos,
but for more in-depth information, please refer to the official Spack
documentation.
Preparation
First, we need to clone the Spack repository. You can place this anywhere, but note that by default Spack will download and install software under this directory. This default behavior can be changed, please refer to the documentation for information of customizing your Spack instance.
$> cd ~
$> git clone https://github.com/spack/spack.git
To start using Spack, we use the provided activation script
# equivalent scripts for tcsh, fish are located here as well
$> source ~/spack/share/spack/setup-env.sh
You will always need to activate spack for each new shell. You may find it convienant to invoke this Spack setup in your login script, though be aware that Spack will prepend paths to your environment which may cause conflicts with other package tools and software.
The first time a Spack command is invoked, it will need to bootstrap
itself to be able to start concretizing package specs. This will
download pre-built packages and create a ${HOME}/.spack directory.
This directory is important and is where your primary Spack
configuration data will be located. If at any point this configuration
becomes corrupted or too complicated to easily fix, you may safely
remove this directory to restore the default configuration, or just to
try a new approach. Again, refer to the Spack documentaion for more
information.
Setup compilers
To use Spack effectively, we need to configure it for the HPC
environment we’re using. This can be done manually (by editing
packages.yaml, compilers.yaml, and perhaps a few others). This
is ideal if you understand how your software environment is installed on
the HPC system, and you are fluent in the Spack configuration schema.
However, Spack has put in a lot of effort to be able to automatically discover the available tools and software on any given system. While not perfect, we can get a fairly robust starting point.
Assume we are on an HPC system that has Envionrmental Modules that provides compilers, MPI implementations, and sundry other common tools. To help Spack find these, let’s load a specific configuration into the active shell environment.
$> module load cmake/3.19.2 gcc/11.2.0 openmpi/4.1.1 python/3.10
$> module list
Currently Loaded Modules:
1) cmake/3.19.2 2) gcc/11.2.0 3) openmpi/4.1.1 4) python/3.10-anaconda-2023.03
First, let’s find the available compilers. (If this is the first Spack command you’ve run, it will need to bootstrap)
$> spack compiler find
==> Added 2 new compilers to ${HOME}/.spack/linux/compilers.yaml
gcc@4.8.5 gcc@11.2.0
==> Compilers are defined in the following files:
${HOME}/.spack/linux/compilers.yaml
Here, we find the default system compiler (gcc@4.8.5), along with
the compiler from the module we loaded. Also notice that the
${HOME}/.spack directory has been modified with some new YAML config
files. These are information on the compilers and how Spack will use
them. You are free to modify these files, but for now let’s leave them
as is.
NB: You can repeat this procedure for other compilers and packages, though if you need to use many different combinations of compiler/software, you will find using Spack environments more convenient.
Setup system-provided packages
Next, we will try and find system software (e.g.
ncurses,git,zlib) that we can use instead of needing to
build our own. This will also find the module software we loaded
(cmake,openmpi,python). (This command will take a couple
minutes to complete).
$> spack external find --all --not-buildable
==> The following specs have been detected on this system and added to ${HOME}/.spack/packages.yaml
autoconf@2.69 bzip2@1.0.6 coreutils@8.22 dos2unix@6.0.3 gcc@11.2.0 go@1.16.5 hdf5@1.8.12 libfuse@3.6.1 ncurses@6.4.20221231 openssl@1.1.1t python@3.10.9 sqlite@3.7.17 texlive@20130530
automake@1.13.4 bzip2@1.0.8 cpio@2.11 doxygen@1.8.5 gettext@0.19.8.1 go@1.18.4 hdf5@1.10.6 libtool@2.4.2 ninja@1.10.2 perl@5.16.3 rdma-core@22.4 sqlite@3.40.1 which@2.20
bash@4.2.46 ccache@3.7.7 curl@7.29.0 file@5.11 ghostscript@9.25 go-bootstrap@1.16.5 krb5@1.15.1 lustre@2.12.9 opencv@2.4.5 pkg-config@0.27.1 rsync@3.1.2 subversion@1.7.14 xz@5.2.2
berkeley-db@5.3.21 cmake@2.8.12.2 curl@7.87.0 findutils@4.5.11 git@2.18.4 go-bootstrap@1.18.4 krb5@1.19.4 m4@1.4.16 openjdk@1.8.0_372-b07 python@2.7.5 ruby@2.0.0 swig@2.0.10 xz@5.2.10
binutils@2.27.44 cmake@3.17.5 cvs@1.11.23 flex@2.5.37 git-lfs@2.10.0 gpgme@1.3.2 libfabric@1.7.2 maven@3.0.5 openssh@7.4p1 python@3.4.10 sed@4.2.2 tar@1.26 zip@3.0
bison@3.0.4 cmake@3.19.2 diffutils@3.3 gawk@4.0.2 gmake@3.82 groff@1.22.2 libfuse@2.9.2 ncurses@5.9.20130511 openssl@1.0.2k-fips python@3.6.8 slurm@23.02.1 texinfo@5.1
-- no arch / gcc@11.2.0 -----------------------------------------
openmpi@4.1.1
Generally you will want to use as much system-provided software as you
can get away with (in Spack speak, these are called externals, though
external packages are not limited to system provided ones and can
point to, e.g., a manual install). In the above command, we told Spack
to mark any packages it can find as not-buildable, which means that
Spack will never attempt to build that package and will always use the
external one. This may cause issues in resolving packages specs when
the external is not compatible with the requirements of an downstream
package.
As a first pass, we will use --not-buildable for
spack external find, but if you have any issues with concretizing
then start this guide over (remove ${HOME}/.spack and go back to
compilers) and do not use --not-buildable in the previous command.
You may also manually edit the packages.yaml file to switch the
buildable flag for the troublesome package, but you will need to be
a least familiar with YAML schema.
First install with Spack
Let’s walk through a simple Spack workflow for installing. First, we
want to look at the options available for a package. The Spack team and
package developers have worked over the years to provide an impressive
selection of packages. This example will use hypre, a parallel
library for multigrid methods.
$> spack info hypre
AutotoolsPackage: hypre
Description:
Hypre is a library of high performance preconditioners that features
parallel multigrid methods for both structured and unstructured grid
problems.
Homepage: https://llnl.gov/casc/hypre
Preferred version:
2.28.0 https://github.com/hypre-space/hypre/archive/v2.28.0.tar.gz
Safe versions:
develop [git] https://github.com/hypre-space/hypre.git on branch master
2.28.0 https://github.com/hypre-space/hypre/archive/v2.28.0.tar.gz
# ... more versions listed
Variants:
Name [Default] When Allowed values Description
======================== ======= ==================== ==============================================
amdgpu_target [none] [+rocm] none, gfx900, AMD GPU architecture
gfx1030, gfx90c,
gfx90a, gfx1101,
gfx908, gfx1010,
# ... lots of amd targets listed
build_system [autotools] -- autotools Build systems supported by the package
caliper [off] -- on, off Enable Caliper support
complex [off] -- on, off Use complex values
cuda [off] -- on, off Build with CUDA
cuda_arch [none] [+cuda] none, 62, 80, 90, CUDA architecture
20, 32, 35, 37, 87,
10, 21, 30, 12, 61,
11, 72, 13, 60, 53,
52, 75, 70, 89, 86,
50
debug [off] -- on, off Build debug instead of optimized version
fortran [on] -- on, off Enables fortran bindings
gptune [off] -- on, off Add the GPTune hookup code
int64 [off] -- on, off Use 64bit integers
internal-superlu [off] -- on, off Use internal SuperLU routines
mixedint [off] -- on, off Use 64bit integers while reducing memory use
mpi [on] -- on, off Enable MPI support
openmp [off] -- on, off Enable OpenMP support
rocm [off] -- on, off Enable ROCm support
shared [on] -- on, off Build shared library (disables static library)
superlu-dist [off] -- on, off Activates support for SuperLU_Dist library
sycl [off] -- on, off Enable SYCL support
umpire [off] -- on, off Enable Umpire support
unified-memory [off] -- on, off Use unified memory
Build Dependencies:
blas caliper cuda gnuconfig hip hsa-rocr-dev lapack llvm-amdgpu mpi rocprim rocrand rocsparse rocthrust superlu-dist umpire
Link Dependencies:
blas caliper cuda hip hsa-rocr-dev lapack llvm-amdgpu mpi rocprim rocrand rocsparse rocthrust superlu-dist umpire
Run Dependencies:
None
The spack info commands gives us three important data-points we
need. First, it tells the versions available. If you do not specify a
version, the preferred version is default.
Next and most important are the variants. These are used to control how to build the package, i.e. to build with MPI, to build a fortran interface, and so on. These will have default values, and in practice you will only need to provide a small number for any particular system.
Finally, we are given the dependencies of the package. The
dependencies listed are for all configurations, so some dependencies
may not be necessary for your particular install. (For instance, if you
do not build with cuda, then cuda will not be necessary to
install)
Let’s look at what Spack will do when we want to install. We will start
with the default configuration (that is, all variants are left to
default). The spack spec command will try to use the active Spack
configuration to determine which packages are needed to install
hypre, and will print the dependency tree out.
$> spack spec hypre
Input spec
--------------------------------
- hypre
Concretized
--------------------------------
- hypre@2.28.0%gcc@11.2.0~caliper~complex~cuda~debug+fortran~gptune~int64~internal-superlu~mixedint+mpi~openmp~rocm+shared~superlu-dist~sycl~umpire~unified-memory build_system=autotools arch=linux-rhel7-broadwell
- ^openblas@0.3.23%gcc@11.2.0~bignuma~consistent_fpcsr+fortran~ilp64+locking+pic+shared build_system=makefile symbol_suffix=none threads=none arch=linux-rhel7-broadwell
[e] ^perl@5.16.3%gcc@11.2.0+cpanm+opcode+open+shared+threads build_system=generic patches=0eac10e,3bbd7d6 arch=linux-rhel7-broadwell
[e] ^openmpi@4.1.1%gcc@11.2.0~atomics~cuda~cxx~cxx_exceptions~gpfs~internal-hwloc~internal-pmix~java~legacylaunchers~lustre~memchecker~openshmem~orterunprefix+pmi+romio+rsh~singularity+static+vt~wrapper-rpath build_system=autotools fabrics=ofi,psm,psm2 schedulers=slurm arch=linux-rhel7-broadwell
Here, we see the full default Spack spec, which as a rough guide is
structured as
<package>@<version>%<compiler>@<compiler_version>{[+/~]variants} <arch_info>.
The +,~ variant prefixes are used to turn on/off variants with
binary values, while variants with a set of values are given similar to
keyword values (e.g. +cuda cuda_arch=70 ~shared)
If we wanted to install a different configuration, in this case say we
want complex and openmp enabled, but we don’t need fortran.
$> spack spec hypre+complex+openmp~fortran
Input spec
--------------------------------
- hypre+complex~fortran+openmp
Concretized
--------------------------------
- hypre@2.28.0%gcc@11.2.0~caliper+complex~cuda~debug~fortran~gptune~int64~internal-superlu~mixedint+mpi+openmp~rocm+shared~superlu-dist~sycl~umpire~unified-memory build_system=autotools arch=linux-rhel7-broadwell
- ^openblas@0.3.23%gcc@11.2.0~bignuma~consistent_fpcsr+fortran~ilp64+locking+pic+shared build_system=makefile symbol_suffix=none threads=none arch=linux-rhel7-broadwell
[e] ^perl@5.16.3%gcc@11.2.0+cpanm+opcode+open+shared+threads build_system=generic patches=0eac10e,3bbd7d6 arch=linux-rhel7-broadwell
[e] ^openmpi@4.1.1%gcc@11.2.0~atomics~cuda~cxx~cxx_exceptions~gpfs~internal-hwloc~internal-pmix~java~legacylaunchers~lustre~memchecker~openshmem~orterunprefix+pmi+romio+rsh~singularity+static+vt~wrapper-rpath build_system=autotools fabrics=ofi,psm,psm2 schedulers=slurm arch=linux-rhel7-broadwell
Here, you can see the full spec has out supplied variants. In general, variants can control build options and features, and can change which dependencies are needed.
Notice also the left-aligned string starting each line for a package.
- indicates that Spack isn’t aware that this package is installed
(which is expected). [+] indicates that the package has been
previously installed. [e] indicates that the package has been marked
as externally installed.
Finally, we can install it. Because perl and openmpi are already
present, Spack will not need to download, build, and install these
packages. This can save lots of time! Note, however, that external
packages are loosely constrained and may not be correctly configured for
the requested package.
Note
By default, Spack will try to download the package source from the repository associated with the package. This behavior can be overrided with Spack mirrors , but that is beyond the scope of this doc.
Now, we can use Spack similarly to module load,
$> spack load hypre
$> spack find --loaded
Other options are available for integrating Spack installed packages into your environment. For more, head over to https://spack.readthedocs.io
Installing singularity-eos using Spack
- . warning::
The spack build is currently experimental. Please report problems you havee as github issues.
The spackage is available in the main Spack
repositories, and we provide a spackage for singularity-eos witin the
the singularity-eos source repository. The distributed spackage may be
more up-to-date than the one in the main Spack repository. If you
have spack installed, simply call
git clone --recursive git@github.com:lanl/singularity-eos.git
spack repo add singularity-eos/spack-repo
spack install singularity-eos
to install singularity-eos into your spack instance. The spackage
supports a number of relevant variants:
Variant Name [default] |
Allowed Values |
Description |
|---|---|---|
build_extra [none] |
none, sesame, stellarcollapse |
Build sesame2spiner or stellarcollapse2spiner |
build_type [RelWithDebInfo] |
Debug, Release, RelWitHDebInfo, MinSizeRel |
Equivalent to -DCMAKE_BUILD_TYPE in cmake build |
cuda [off] |
on, off |
Build with cuda |
cuda_arch [none] |
see kokkos spec |
The target GPU architecture |
doc [off] |
on, off |
Build sphinx docs |
format [off] |
on, off |
Support for clang-format |
fortran [on] |
on, off |
Provide fortran bindings |
hdf5 [off] |
on, off |
Enable HDF5 I/O for tables |
ipo [off] |
on, off |
CMake interprocedural optimization |
kokkos [off] |
on, off |
Enable Kokkos backend Required for cuda support |
kokkos-kernels [off] |
on, off |
Use kokkos-kernels for linear algebra suport, which is needed with mixed-cell closures on GPU |
mpi [off] |
on, off |
Build with parallel HDF5 otherwise build with serial |
openmp [off] |
on, off |
Build Kokkos openmp backend |
tests [off] |
on, off |
Build tests |
Developing singularity-eos using Spack
Spack is a powerful tool that can help develop singularity-eos for a
variety of platforms and hardware.
Install the dependencies
singularity-eosneeds using Spack
$> spack install -u cmake singularity-eos@main%gcc@13+hdf5+eospac+mpi+kokkos+kokkos-kernels+openmp^eospac@6.4.0
This command will initiate an install of singularity-eos using
Spack, but will stop right before singularity-eos starts to build
(-u cmake means until cmake). This ensures all the necessary
dependencies are installed and visible to Spack
Use Spack to construct an ad-hoc shell environment
$> spack build-env singularity-eos@main%gcc@13+hdf5+eospac+mpi+kokkos+kokkos-kernels+openmp^eospac@6.4.0 -- bash
This command will construct a shell environment in bash that has all
the dependency information populated (e.g. PREFIX_PATH,
CMAKE_PREFIX_PATH, LD_LIBRARY_PATH, and so on). Even external
packages from a module system will be correctly loaded. Thus, we can
build for a specific combination of dependencies, compilers, and
portability strategies.
$> salloc -p scaling
# ...
$> source ~/spack/share/spack/setup-env.sh
$> spack build-env singularity-eos@main%gcc@12+hdf5+eospac+mpi+kokkos+kokkos-kernels+openmp^eospac@6.4.0 -- bash
$> mkdir -p build_gpu_mpi ; cd build_gpu_mpi
$> cmake .. --preset="kokkos_nogpu_with_testing"