Prerequisites
===================================

Compilers
...................

For building ComFLOW and/or ComFLOW plug-ins a recent Fortran and C compiler are required.
Using a recent compiler version may be beneficial for program performance and reduces the risk of (internal) compiler errors.

ComFLOW uses parts of the Fortran 2003 and Fortran 2008 standards.
As a rule-of-thumb ComFLOW supports the latest two major versions of a compiler.

====================    ===========================
Compiler                Minimum version
====================    ===========================
GNU Fortran/C(++)       **6.3**
Intel Fortran/C(++)     **2017**
PGI Fortran             currently not supported
NAG Fortran             status unknown
====================    ===========================


.. _installing_cmake:

CMake
...................

The ComFLOW software is designed to run on multiple operating systems and to support various Fortran and C compilers.
To ensure cross-platform and cross-compiler compatibility the *CMake* build system is used.
This system is capable of producing native build environments such as GNU make files on Linux or Visual Studio solutions on Windows.

The latest version of CMake may be downloaded from https://cmake.org/download/.

Note that the minimum required version may change in time and can be found
in the preamble of the file ``CMakeLists.txt``:

.. code-block:: cmake

    cmake_minimum_required(VERSION 3.0)

If CMake is not installed, or if the installed version is out-of-date, it is recommended to perform
a local installation of CMake. This can be done as follows (replacing version numbers if necessary):

.. code-block:: bash

    mkdir ~/bin/cmake
    wget https://cmake.org/files/v3.13/cmake-3.13.0-rc2-Linux-x86_64.sh
    ./cmake-3.13.0-rc2-Linux-x86_64.sh

Make sure the local installation is found *before* the original version. This can be done by including
the following statements in the startup script (typically ``~/.bashrc``):

.. code-block:: bash

    export PATH="~/bin/cmake/bin:$PATH"

Git
...................

Git is used for version management of the ComFLOW source code including all of its (third-party) dependencies.

On Windows TortoiseGit may be used, which can be downloaded from https://tortoisegit.org/download/.
On most Linux systems Git is already installed. If otherwise, it may be installed using the command ``sudo apt-get install git``.