Installation

You will need to download and compile the code before you can use it; we do not supply binaries.

Downloading

CONQUEST is accessed from the GitHub repository; it can be cloned:

git clone https://github.com/OrderN/CONQUEST-release destination-directory

where destination-directory should be set by the user. Alternatively, it can be downloaded from GitHub as a zip file and unpacked:

https://github.com/OrderN/CONQUEST-release/archive/master.zip

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Compiling

Once you have the distribution, you will need to compile the main Conquest code (found in the src/ directory), along with the ion file generation code (found in the tools/ directory). Conquest requires a working MPI installation including a Fortran90 compiler (often mpif90 but this can vary), along with a few standard libraries:

  • BLAS and LAPACK (normally provided by the system vendor)

  • FFTW 3.x (more detail can be found at http://www.fftw.org/)

  • ScaLAPACK (often provided as part of an HPC system; the source code can be obtained from the netlib repository if you need to compile it)

Additionally, Conquest can use LibXC if it is available (v4.x or later).

The library locations are set in the system.make file in the src/system directory, along with other parameters needed for compilation. The default file name is system.make but you can select another file with make SYSTEM=label which would then use the file system.label.make in the src/system directory. system.<systemname>.make files are provided for some HPC systems used by the community, but if you want to run locally or on a different system, you will need to create an appropriate system.make file. Use src/system/system.example.make as a starting point.

  • FC (typically FC=mpif90 will be all that is required)

  • COMPFLAGS (set these to specify compiler options such as optimisation)

  • BLAS (specify the BLAS and LAPACK libraries)

  • SCALAPACK (specify the ScaLAPACK library)

  • FFT_LIB (must be left as FFTW)

  • XC_LIBRARY (choose XC_LIBRARY=CQ for the internal Conquest library, otherwise XC_LIBRARY=LibXC_v4 for LibXC v4.x, or XC_LIBRARY=LibXC_v5 for LibXC v5.x and v6.x)

  • Two further options need to be set for LibXC:

    • XC_LIB (specify the XC libraries)

    • XC_COMPFLAGS (specify the location of the LibXC include and module files, e.g. -I/usr/local/include)

Once these are set, you should make the executable using make.

The ion file generation code is compiled using the same options required for the main code.

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Multi-threading

CONQUEST can use OpenMP for multi-threading; some multi-threading is available throughout the code, while there are specific matrix multiplication routines which can use multi-threading for the linear scaling solver. The number of threads is set via the environment variable OMP_NUM_THREADS.

Compiler flags to enable OpenMP are dependent on the vendor, but should be specified via OMPFLAGS in the system.make file. If compiling with OpenMP then you should also change the variable OMP_DUMMY in the same file to be blank to enable the number of threads to be included in the output.

On some systems, the default stack size for OpenMP is set to be rather small, and this can cause a segmentation fault when running with multiple threads. We recommend testing the effect of the environment variable OMP_STACKSIZE (and suggest setting it to 50M or larger as a first test).

Most OpenMP multi-threading in CONQUEST uses the runtime schedule. This means the type of scheduling of work to threads can be set by the user by setting the OMP_SCHEDULE `variable<https://www.openmp.org/spec-html/5.0/openmpse49.html>`_. If the variable is unset, OpenMP will use a default implementation defined schedule.

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Installing with Spack

CONQUEST and all of its dependencies can be installed with Spack. The CONQUEST package requires Spack v0.21 or later. If Spack isn’t available or up to date on your system, it is relatively straightforward to install it with user permissions following the install instructions. When setting up Spack on a new system, it is recommended to configure it to use available system compilers and system packages. Once spack is installed and set up, install CONQUEST with:

spack install conquest

and load the Conquest executable to PATH with

spack load conquest

The build can be customized by adding options to the Spack spec conquest. The CONQUEST package includes variants for OpenMP support and different matrix multiplication kernels; more details can be found in the Spack CONQUEST package.

Installing on Ubuntu

CONQUEST can be compiled on Ubuntu after installing the required packages. The below instructions are given for Ubuntu 22.04 LTS and Ubuntu 24.04 LTS. The source files will be downloaded into the ${USER}/local/src directory. The ${USER} variable will be automatically replaced by the current username. If compilation is successful, the executable file can be found in ${USER}/local/src/conquest_master/bin.

Install needed packages

sudo apt update
sudo apt upgrade

sudo apt install -y build-essential libtool                            # GCC and other tools for software development
sudo apt install -y openmpi-bin libopenmpi-dev                         # MPI
sudo apt install -y libfftw3-dev                                       # FFT
sudo apt install -y libblas-dev liblapack-dev libscalapack-openmpi-dev # Linear algebra

Install libxc

cd $HOME
mkdir -p ${HOME}/local/src
cd ${HOME}/local/src

wget https://gitlab.com/libxc/libxc/-/archive/6.2.2/libxc-6.2.2.tar.bz2 -O libxc.tar.bz2
tar -xf libxc.tar.bz2
cd libxc-6.2.2 && autoreconf -i && ./configure --prefix=$HOME/local
make
make check && make install

Download CONQUEST

cd ${HOME}/local/src
git clone https://github.com/OrderN/CONQUEST-release.git conquest_master
cd conquest_master/src

Prepare makefile

# Prepare system.make file for Ubuntu.
cat > system/system.make << EOF

# Set compilers
FC=mpif90

# OpenMP flags
# Set this to "OMPFLAGS= " if compiling without openmp
# Set this to "OMPFLAGS= -fopenmp" if compiling with openmp
OMPFLAGS=
# Set this to "OMP_DUMMY = DUMMY" if compiling without openmp
# Set this to "OMP_DUMMY = " if compiling with openmp
OMP_DUMMY = DUMMY

# Set BLAS and LAPACK libraries
# MacOS X
# BLAS= -lvecLibFort
# Intel MKL use the Intel tool
# Generic
BLAS= -llapack -lblas
# Full scalapack library call; remove -lscalapack if using dummy diag module.
# If using OpenMPI, use -lscalapack-openmpi instead.
# If using Cray-libsci, use -llibsci_cray_mpi instead.
SCALAPACK = -lscalapack-openmpi

# LibXC compatibility
# Choose LibXC version: v4 (deprecated) or v5/6 (v5 and v6 have the same interface)
# XC_LIBRARY = LibXC_v4
XC_LIBRARY = LibXC_v5
XC_LIB = -lxcf90 -lxc
XC_COMPFLAGS = -I\${HOME}/local/include -I/usr/local/include

# Set FFT library
FFT_LIB=-lfftw3
FFT_OBJ=fft_fftw3.o

LIBS= \$(FFT_LIB) \$(XC_LIB)  \$(SCALAPACK) \$(BLAS)

# Compilation flags
# NB for gcc10 you need to add -fallow-argument-mismatch
COMPFLAGS= -O3 \$(OMPFLAGS) \$(XC_COMPFLAGS) -fallow-argument-mismatch

# Linking flags
LINKFLAGS= -L\${HOME}/local/lib -L/usr/local/lib \$(OMPFLAGS)

# Matrix multiplication kernel type
MULT_KERN = default
# Use dummy DiagModule or not
DIAG_DUMMY =

EOF

Compile CONQUEST

dos2unix ./makedeps       # For Windows Subsystem for Linux (WSL), there may be some incompatibilities thus file conversion is recommended.
make                      # Or make -j`nproc` for parallel compilation using all available cores

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