Compilation
###########

LMDZ-SACS is always compiled with a fixed grid (type and dimensions).
To use different grids type/resolution LMDZ-SACS need to compiled once per grid type/resolution.

How to compile
==============

LMDZ-SACS can be compiled by running the *makfile* in its sources directory ``model_sources/dispersion/``.
Here are some example commands to compile LMDZ-SACS for use on **GPU** with NVIDIA's compiler ``nvfortran``.

* Regular lat-lon grid:

.. code-block:: shell

    make -j FC=nvfortran TARGET=gpu GRID=regular NLON=96 NLAT=96 NLEV=39 clean
    make -j FC=nvfortran TARGET=gpu GRID=regular NLON=96 NLAT=96 NLEV=39

* Icosahedral grid dimensions:

.. code-block:: shell

    make -j FC=nvfortran TARGET=gpu GRID=dynamico NBP=80 NLEV=79 clean
    make -j FC=nvfortran TARGET=gpu GRID=dynamico NBP=80 NLEV=79


Two identical executable files are produced by the *makefile*:

* ``dispersion.e``: a file with simple name to use **immediatly** or **never**.

* ``dispersion_[FC]_[TARGET]_[DIMS].e``: a file with complete name to use whenever.

.. note::

    While LMDZ-SACS can be compiled manually, it is recommended to les CIF compile it for you.
    By doing that you will be sure the LMDZ-SACS executable used by CIF is compiled with appropriate
    grid, dimensions and more importantly with appropriate **platform specific options**.

All the arguments for ``make`` command 
======================================

Compiler options
----------------

* ``FC`` fortran compiler, "gfortran" or "nvfortran". By default "nvfortran".

* ``MODE`` compilation mode, "PROD" (production) or "DEBUG" (debugging). By default "PROD".

* ``TARGET`` OpenACC target device, "gpu" or "multicore". By default "multicore".

* ``CC`` Device compute capability option for ``nvfortran`` compiler. By default "cc70,cc80".

* ``NETCDF_LIB`` directory containing the NetCDF library.

* ``NETCDF_INC`` directory containing the NetCDF include.

Grid options
------------

* ``GRID`` grid type, "regular" (Regular lat-lon) or "dynamico" (icosahedral). By default "regular".

* ``NLEV`` vertical dimension. By default 79.

* Regular lat-lon grid dimensions:

  - ``NLON`` longitude dimension. By default 144.
  
  - ``NLAT`` longitude dimension. By default 143.
  
* Icosahedral grid dimensions:

  - ``NBP`` nbp number. By default 80.