Merge pull request dftbplus#64 from vanderhe/readmeExtension

Extend readme to include libXC installation

README.rst

@@ -11,8 +11,8 @@ robust. Make sure, you check results as careful as possible. Use at your own
 risk!
 
 
-Installing
-==========
+Installation
+============
 
 |build status|
 
@@ -30,16 +30,42 @@ Prerequisites
 * libXC library with f03 interface (version >=6.0.0)
 
 
-Building the code
------------------
+Obtaining via Conda
+-------------------
+
+The preferred way of obtaining SkProgs is to install it via the conda package
+management framework using `Miniconda
+<https://docs.conda.io/en/latest/miniconda.html>`_ or `Anaconda
+<https://www.anaconda.com/products/individual>`_. Make sure to add/enable the
+``conda-forge`` channel in order to be able to access SkProgs::
+
+  conda config --add channels conda-forge
+  conda config --set channel_priority strict
+
+We recommend to set up a dedicated conda environment and to use the
+`mamba solver <https://mamba.readthedocs.io/>`_ ::
+
+  conda create --name skprogs
+  conda activate skprogs
+  conda install conda-libmamba-solver
+  conda config --set solver libmamba
+
+to install the latest stable release of SkProgs (Fortran and Python
+components)::
+
+  mamba install skprogs skprogs-python
+
+
+Building from source
+--------------------
 
 Follow the usual CMake build workflow:
 
 * Configure the project, specify your compilers (e.g. ``gfortran``),
-  the install location (e.g. ``$HOME/opt/skprogs``) and the build directory
-  (e.g. ``_build``)::
+  the install location (i.e. path stored in ``YOUR_SKPROGS_INSTALL_FOLDER``,
+  e.g. ``$HOME/opt/skprogs``) and the build directory (e.g. ``_build``)::
 
-    FC=gfortran cmake -DCMAKE_INSTALL_PREFIX=$HOME/opt/skprogs -B _build .
+    FC=gfortran cmake -DCMAKE_INSTALL_PREFIX=YOUR_SKPROGS_INSTALL_FOLDER -B _build .
 
   If libXC is installed in a non-standard location, you may need to specify
   either the ``CMAKE_PREFIX_PATH`` environment variable (if libXC was built with
@@ -65,6 +91,39 @@ Follow the usual CMake build workflow:
     cmake --install _build
 
 
+Building libXC from source
+--------------------------
+
+Follow the usual CMake build workflow:
+
+* Clone the official libXC repository and checkout the latest release tag, e.g.
+  ``6.2.2``::
+
+    git clone https://gitlab.com/libxc/libxc.git libxc
+    cd libxc/
+    git checkout 6.2.2
+
+* Configure the project, specify your compilers (e.g. ``gfortran`` and ``gcc``),
+  the install location (i.e. path stored in ``YOUR_LIBXC_INSTALL_FOLDER``, e.g.
+  ``$HOME/opt/libxc``) and the build directory (e.g. ``_build``)::
+
+      FC=gfortran CC=gcc cmake -DENABLE_FORTRAN=True -DCMAKE_INSTALL_PREFIX=YOUR_LIBXC_INSTALL_FOLDER -B _build .
+
+* If the configuration was successful, build the code ::
+
+    cmake --build _build -- -j
+
+* After successful build, you should test the code by running ::
+
+    pushd _build
+    ctest -j
+    popd
+
+* If the tests were successful, install the package via ::
+
+    cmake --install _build
+
+
 Advanced build configuration
 ============================
 
@@ -85,7 +144,7 @@ variable. If you want to load an external toolchain file instead of one from the
 source tree, you can specify the file path with the ``-DTOOLCHAIN_FILE`` option
 ::
 
-  -DTOOLCHAIN_FILE=/some/path/myintel.cmake
+  -DTOOLCHAIN_FILE=/path/to/myintel.cmake
 
 or with the ``SKPROGS_TOOLCHAIN_FILE`` environment variable.
 
@@ -101,9 +160,10 @@ Generating SK-files
 The basic steps of generating the electronic part of the SK-tables are as
 follows:
 
-* Initialize the necessary environment variables by sourceing the
-  ``skprogs-activate.sh`` script (provided you have BASH or compatible shell,
-  otherwise inspect the script and set up the environment variables manually)::
+* If you have build SkProgs from source, initialize the necessary environment
+  variables by sourceing the ``skprogs-activate.sh`` script (provided you have
+  BASH or a compatible shell, otherwise inspect the script and set up the
+  environment variables manually)::
 
     source <SKPROGS_INSTALL_FOLDER>/bin/skprogs-activate.sh