.. _fortran:

***************
Fortran version
***************


Much of the Clawpack 4.3 documentation still applies:

  * `Original 4.3 documentation <http://www.amath.washington.edu/~claw/doc.html>`_


New in 4.4
----------

Input parameters are generally specified in a Python script :file:`setrun.py`
and then::

   $ make .data

creates the :file:`*.data` files that the Fortran code requires.  These have nearly
the same form as in Clawpack 4.3, except:

* :file:`clawNez.data` is now :file:`claw.data`

* The first line of the file now contains ``ndim``, the number of space dimensions.

The output files :file:`fort.*` have nearly the same form as in Clawpack 4.3
except:

* The :file:`fort.t*` files now contain ``ndim``.

Makefiles
---------

Most example directories contain a :file:`Makefile` that offers several
options.  Type::

  $ make help

for a list.
Often::

  $ make .plots

is all you need to type to create the data files,
compile the code, run it, and produce plots as png and html files.

Or, if you just want to run the code and produce output without making
all the plots (and then do the plotting interactively, for example)::

  $ make .output

Note: There is a dot before ``plots`` and ``output`` in the above
commands.  

The directory where output and plots are stored is specified in the Makefile.

The Makefile in most directories includes a common Makefile found at
`$CLAW/util/Makefile.common <claw/util/Makefile.common>`_ that does most
of the work.  

More tips
---------

* The "make .output"
  command runs the code and stores the name of the output directory in the
  file ``.output`` and it is the modification time of this file that is checked
  relative to the dependencies. (Note: the unix command ls generally does
  not display files that start with a dot so this file may be invisible
  unless you use "ls -a".)

  If you want to re-run the code and encounter::

    $ make .output
    $ make: `.output' is up to date.

  you can remove the file ``.output`` to force the code to be run again.  

* Similarly, remove the file ``.plots`` to force the plots to be recreated.
  

* If you change the compiler flags FFLAGS in the Makefile then you should
  make sure that all files used are recompiled with the new flags.  The
  Makefiles as written do not catch this dependency and will not recompile
  all the .o files when the Makefile changes.  To force recompilation,
  use::

     $ make new