The files in this directory support making a modified version of
quantum espresso that includes the pw2qmcpack converter.

The download_and_patch_qe6.4.1.sh script will automatically download
and patch quantum espresso. Similarly named scripts are provided for
earlier versions. After patching you can move the espresso directory
anywhere convenient. There is no need to keep it within the QMCPACK
source tree. However, if you are using NEXUS you should update your
PATH so that the correct executables are found.

If you have already downloaded quantum espresso you can, e.g.,

patch -p1 -i ../add_pw2qmcpack_to_qe-6.4.1.diff

from within the top level quantum espresso directory.

Due to internal changes in quantum espresso, generally the patch and
pw2qmcpack files only work for one specific version.

Notes for maintainers:

1. Update the new version of QE. Hopefully the old patch
works. Typically there are small makefile updates. If install/configure.ac is
updated, be sure to run autoconf to generate a new install/configure.

2. Create a new patch.

diff -urN qe-x.y_original qe-x.y_updated >add_pw2qmcpack_to_qe-x.y.diff
or
git diff release-branch..patched-release-branch >add_pw2qmcpack_to_qe-x.y.diff

3. Update the download_and_patch script. Change the version number and
directory location on QE Forge. The latter varies with no clear logic.

4. Check that QE patches and builds correctly using the download script.

5. Add the new patch and download script to git and commit.