Libxc (Exchange-Correlation Functionals Library)

Libxc is a library of exchange-correlation functionals for density-functional theory (DFT). It provides a comprehensive collection of local and semi-local functionals, hybrid functionals, and meta-GGA functionals, widely used in quantum chemistry and solid-state physics applications.

Libxc is available through the Spack package manager with support for multiple compiler toolchains including AMD AOCC, Intel OneAPI, and Intel Classic compilers.

Quick Start

Note

For the value of ${SPACK_ROOT}, please refer to Spack Instances for the installation path.

# Modify this path accordingly
export SPACK_ROOT="/path/to/spack"

# Activate Spack environment
source "${SPACK_ROOT}/dist/bin/setup-env.sh" -y

# Load a supported compiler
module load intel-oneapi-compilers

# Check available Libxc versions
module avail libxc

# Load Libxc
module load libxc

# Verify installation
module list | grep libxc

Note

Module names may include a 7-digit hash suffix (e.g., libxc/7.0.0-abc1234). You do NOT need to include this hash when loading - the version alone (e.g., 7.0.0) is sufficient.

Building Applications with Libxc

Using CMake

Using find_package:

# Libxc provides CMake config files
find_package(Libxc REQUIRED)

# For C/C++ programs
target_link_libraries(myprogram PRIVATE Libxc::xc)

# For Fortran programs
target_link_libraries(myfortranprogram PRIVATE Libxc::xcf03)

Using pkg-config in CMake:

find_package(PkgConfig REQUIRED)
pkg_check_modules(LIBXC REQUIRED IMPORTED_TARGET libxc)

# For C/C++ programs
target_link_libraries(myprogram PRIVATE PkgConfig::LIBXC)

# For Fortran programs
pkg_check_modules(LIBXCF03 REQUIRED IMPORTED_TARGET libxcf03)
target_link_libraries(myfortranprogram PRIVATE PkgConfig::LIBXCF03)

Using pkg-config

# Query flags for Libxc (C/C++)
pkg-config --cflags libxc
pkg-config --libs libxc

# Query flags for Libxc Fortran interface
pkg-config --cflags libxcf03
pkg-config --libs libxcf03

# Use in compilation
export CC=gcc
export CFLAGS="$(pkg-config --cflags libxc)"
export LDFLAGS="$(pkg-config --libs libxc)"

# Compile
$CC -o myprogram myprogram.c $CFLAGS $LDFLAGS

Integration with DFT Codes

Libxc is commonly integrated with various density-functional theory codes. Below are examples for popular scientific computing applications.

Features and Capabilities

Exchange-Correlation Functionals

Libxc provides a comprehensive collection of exchange-correlation functionals:

Category

Description

Available

LDA Functionals

Local Density Approximation functionals

✓

GGA Functionals

Generalized Gradient Approximation functionals

✓

Hybrid Functionals

Hybrid functionals (e.g., B3LYP, PBE0)

✓

Meta-GGA Functionals

Meta-GGA functionals (e.g., TPSS, SCAN)

✓

3rd Order Derivatives

Third-order functional derivatives

✓

4th Order Derivatives

Fourth-order functional derivatives

✓

Supported Interfaces

Interface

Description

Available

C Interface

Native C API

✓

C++ Interface

C++ wrapper (uses C interface)

✓

Fortran 2003 Interface

Modern Fortran 2003 API

✓

Python Interface

Python bindings

pylibxc

Library Variants

Variant

Description

Available

Shared Libraries

Dynamic linking support (.so files)

✓

Static Libraries

Static linking support (.a files)

✗

MPI Support

Direct MPI integration

Not required

Compiling from Source

For users who need specific build options or want to compile Libxc from source, please refer to the compilation guide:

Libxc Compilation Guide

The compilation guide provides detailed instructions for building Libxc with various compiler toolchains (AMD AOCC, Intel OneAPI, Intel Classic) and custom configurations.

Support and Resources

Official Documentation

Citations

If you use Libxc in your research, please cite the following papers: