ESL Demonstrator

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LGPL-2.1 ESL-demo ESL team

The ESL-demo is a self-contained density functional theory (DFT) code with the purpose of being a “playground” for library maintainers and code developorse.

Its inception was created with the intention of demonstrating 1) how fast a fully functional DFT code could be developed, 2) that ESL components could be glued together and 3) a framework for future developments using a common framework.

At the 5th year of ESL inception the ESL-demonstrator was born and (largely) developed in a fortnight at a workshop with roughly 10-15 coders. The ESL-demo is implemented using only ESL components ESL and thus have very little low-level implementations. Almost everything is leveraged by external libraries.

The DFT implemented is comprising two components both using the pseudopotential methodology for core states:

  1. Plane waves
  2. Localized atomic basis orbital

The purpose will not be to replace other DFT codes, but rather testing libraries, checking interoperability and finding bugs.

Since this uses a large fraction of the libraries shipped in the ESL bundle it also acts as a test facility for the compatibility of the bundle libraries.



  • A C compiler (e.g. gcc, icc, pgcc, xlc, …)
  • A Fortran compiler (e.g. gfortran, ifort, pgif90, xlf, …)
  • A recent Python interpreter (Python 2 >= 2.7.13 or Python 3 >= 3.5.1)
  • GNU Make >= 2.80 (other versions may work but have not been tested)


  1. Create a build directory, and cd into it
  2. Run cmake ..
  3. Run make -j, this will create the bin/esl-demo.X executable

There are some optional flags for the compilation which may be useful for certain functionalities.

  • MPI support: -DWITH_MPI=ON|OFF
  • ELSI support: -DWITH_ELSI=ON|OFF
  • Shared libraries: -DBUILD_SHARED_LIBS=ON|OFF
  • API documentation: -DWITH_DOC=ON|OFF


In the tests directory there are a set of tests that could be runned. Both atomic orbitals and plane wave tests are added. Please run at least one of them to see that it runs without problems.


The ESL-demo and ESL initiative are described here1.


  1. M.J.T Oliveira, N. Papior, Y. Pouillon,, The CECAM electronic structure library and the modular software development paradigm J. Chem. Phys. 153, 024117 (2020), DOI: 10.1063/5.0012901 ↩︎