Installing the library
======================

The installation is performed via ``cmake`` and requires:

* a Fortran and a C compiler
* a Python 3 interpreter
* the ``numpy``, ``cffi`` and optionally ``pyscf`` python libraries.
  PySCF is used for evaluating orbitals and is thus required for
  integral calculation.
* BLAS and LAPACK Fortran libraries
* optionally, an MPI library for parallelization
* optionally, the HDF5 library for HDF5 formatted and parallel I/O
  (requires a parallel fortran build of HDF5)
* optionally, the TREXIO library for I/O

For reference, these requirements can be installed on some
Debian-based GNU/Linux systems with:

.. code-block:: bash

  sudo apt install cmake gcc gfortran python3 python3-pip libblas-dev liblapack-dev
  pip3 install --user numpy scipy cffi "h5py==3.0.*" pyscf

Build instructions
^^^^^^^^^^^^^^^^^^

To install, create a build directory:

.. code-block:: bash

  mkdir build && cd build

and invoke ``cmake``:

.. code-block:: bash

  cmake ..

Optional cmake arguments are:

* ``-DCMAKE_BUILD_TYPE=DEBUG/RELEASE`` to set the build type, no
  default
* ``-DPYSCF=ON/OFF`` to enable/disable using pyscf for orbitals,
  defaults to ``ON``
* ``-DPARALLEL=ON/OFF`` to enable/disable using MPI for
  parallelization, defaults to ``ON``
* ``-DUSE_OMP=ON/OFF`` to enable/disable using OpenMP for
  parallelization, defaults to ``OFF``

Then, call ``make`` to build the library components and executables:

.. code-block:: bash

  make
  make install

For further details and tips on the build process see :ref:`faq`.

Afterwards, the build directory should include the following content
(not a complete list):

.. code-block:: none

  build
  ├── bin/
       └── tchint_standalone
  ├── include/
       └── <module files>
  ├── lib/
       ├── <internal shared libraries>
       └── libtchint.so
  ├── python/
       ├── tchint.py
       └── libplugin.so
  └── tests/
       └── tchint_unit_tests

A source encyclopedia can be created by running ``cmake`` in the
``doc`` subdirectory and then building the ``doxy`` target:

.. code-block:: bash

  mkdir doc/build
  cd doc/build
  cmake ..
  make doxy

Testing
^^^^^^^

All current tests are standalone unit/regression tests that are part
of the ``tests/tchint_unit_tests`` and ``tests/tchint_ints_tests``.
executables in the build directory.  They can be run by invoking
``ctest`` in the build directory.