Copyright (C) 2018-2022 ENVIRON (www.quantum-environ.org)

This file is part of Environ version 3.0

Environ 3.0 is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 2 of the License, or
(at your option) any later version.

Environ 3.0 is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more detail, either the file
`License' in the root directory of the present distribution, or
online at <http://www.gnu.org/licenses/>.

Authors

Name	Institution
Oliviero Andreussi	Department of Physics, University of North Texas
Francesco Nattino	THEOS and NCCR-MARVEL, Ecole Polytechnique Federale de Lausanne
Iurii Timrov	THEOS and NCCR-MARVEL, Ecole Polytechnique Federale de Lausanne
Ismaila Dabo	Department of Materials Science and Engineering, Penn State
Nicola Marzari	THEOS and NCCR-MARVEL, Ecole Polytechnique Federale de Lausanne
Quinn Campbell	Sandia National Labs
Edan Bainglass	Department of Physics, University of North Texas
Matthew Truscott	Department of Physics, University of North Texas
Gabriel Medrano	Department of Physics, University of North Texas

Compilation instructions for Environ module

This distribution of the Environ module is intended for Quantum ESPRESSO.
The steps below will cover the following:

- configuration of QE and Environ
- QE compilation
- Environ compilation
- QE patching, dependency updating, and recompilation

Note that Environ now uses its own FFTXlib and UtilXlib libraries modeled
respectively after the FFTXlib and UtilXlib libraries of QE 6.7

If there are any problems with the QE compilation step, look for solutions
on the PW-forum, or refer to the Quantum ESPRESSO documentation and/or website:

  http://www.quantum-espresso.org/

QE + Environ 3.0 Installation

The following instructions refer to Environ 3.0 installed on QE >= 7.1
For previous versions, please refer to the instructions on the website:

  https://environ.readthedocs.io/en/latest/install/install.html

From Environ root:

1. configure Environ with

   • ./configure --with-qe=<absolute_path_to_QE>
   • the script will attempt to find the necessary libraries/compilers
     • if it fails, the user may need to manually modify make.inc

2. compile Environ with

   • make -jN compile
   • N = number of cores for compilation (default = 1)
     • if issues arise, retry with N = 1

From QE root:

using make

1. configure QE with

   • ./configure --with-environ=<absolute_path_to_Environ>
   • the script will attempt to find the necessary libraries/compilers
     • if it fails, the user may need to manually modify make.inc

2. compile desired QE package with

   • make -jN <package>
   • N = number of cores for compilation (default = 1)
     • if issues arise, retry with N = 1
   • Environ supports the following QE packages: PW, CP, TDDFPT, XSpectra, NEB

using cmake

1. create and navigate to a new directory (build/ is a common choice)

2. generate build environment with

   • cmake -DCMAKE_Fortran_COMPILER=<...> -DCMAKE_C_COMPILER=<...> -DENVIRON_ROOT=<absolute_path_to_Environ> ..
   • more information can be found at https://gitlab.com/QEF/q-e/-/wikis/Developers/CMake-build-system

3. compile desired QE package as described above

If using cmake, modify the ESPRESSO_ROOT variable in the following files to reflect the build dir:

• Environ/tests/environment
• Environ/examples/qe/environment

Uninstall Environ 3.0

From Environ root:

• make clean

• (OPTIONAL) make veryclean to also remove configuration files

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