.. _usersguide_troubleshoot:

====================
Troubleshooting NDPP
====================

-------------------------
Problems with Compilation
-------------------------

If you are experiencing problems trying to compile NDPP, first check if the
error you are receiving is among the following options.

Fatal Error: File 'xml_data_settings_t.mod' opened at (1) is not a GFORTRAN module file
***************************************************************************************

When NDPP compiles, the first thing it needs to do is compile source in the
xml-fortran subdirectory. If you compiled everything with a compiler other than
gfortran, performed a :program:`make clean`, and then tried to :program:`make`
with gfortran, the xml-fortran modules would have been compiled with a different
compiler. To fix this, try clearing out all modules and object files with
:program:`make distclean` and then recompiling.

gfortran: unrecognized option '-cpp'
************************************

You are probably using a version of the gfortran compiler that is too
old. Download and install the latest version of gfortran_.

f951: error: unrecognized command line option "-fbacktrace"
***********************************************************

You are probably using a version of the gfortran compiler that is too
old. Download and install the latest version of gfortran_.


make[1]: ifort: Command not found
*********************************

You tried compiling with the Intel Fortran compiler and it was not found on your
:envvar:`PATH`. If you have the Intel compiler installed, make sure the shell
can locate it (this can be tested with :program:`which ifort`).

----------------------------
Problems with NDPP Execution
----------------------------

Segmentation Fault
******************

A segmentation fault occurs when the program tries to access a variable in
memory that was outside the memory allocated for the program. The best way to
debug a segmentation fault is to re-compile NDPP with debug options turned
on. First go to your ``ndpp/src`` directory where NDPP was compiled and type
the following commands:

.. code-block:: sh

    make distclean
    make DEBUG=yes

Now when you re-run your problem, it should report exactly where the program
failed. If after reading the debug output, you are still unsure why the program
failed, send inquiries to the NDPP Users Group_.

ERROR: No cross_sections.xml file was specified in ndpp.xml or in the CROSS_SECTIONS environment variable.
**********************************************************************************************************

NDPP needs to know where to find cross section data for each nuclide. This
information is provided by the `cross_sections.xml` file. You need to tell
NDPP where to find the `cross_sections.xml` file either with the
`cross_sections` element in ndpp.xml or with the :envvar:`CROSS_SECTIONS`
environment variable. It is recommended to add a line in your ``.profile``,
``.bash_profile``, ``.bashrc`` (or equivalent)
setting the :envvar:`CROSS_SECTIONS` environment variable.


.. _gfortran: http://gcc.gnu.org/wiki/GFortran
.. _Group: TODO