Reading Output
==============

XGC outputs ADIOS2 files (\*.bp), which can be read by XGC itself, e.g., for restarting or analyzed with C/C++/Fortran/Python/Matlab. 

In a terminal, users can quickly check the contents of variables written inside a ADIOS2 file with ``bpls`` utility. An example output is as follows:

.. code-block:: bash

   $ bpls -lva xgc.mesh.bp
   File info:
   of variables:  23
   of attributes: 7
   statistics:    Min / Max 

   string   /XP_CLASS                       attr   = "Mesh"
   string   /cell_set[0]/cell_name          attr   = "Tri"
   int32_t  /cell_set[0]/ncells             attr   = 2762126
   int32_t  /cell_set[0]/node_connect_list  {2762126, 3} = 0 / 1383674
   int32_t  /cell_set[0]/nodes_per_elem     attr   = 3
   double   /coordinates/values             {1383675, 2} = -4.5643 / 8.3938
   int32_t  /ncell_sets                     attr   = 1
   int32_t  /nnodes                         attr   = 1383675
   int32_t  /nspace                         attr   = 2
   double   epsilon                         {400} = 0 / 0.361958
   int32_t  grid_nwall                      scalar = 5222
   int32_t  grid_wall_nodes                 {5222} = 1375857 / 1381078
   double   mapping                         {2762126, 3, 2} = -51864.7 / 85140.1
   int32_t  n_geo                           scalar = 400
   int32_t  n_n                             scalar = 1383675
   int32_t  n_t                             scalar = 2762126
   int32_t  nd_connect_list                 {2762126, 3} = 0 / 1383674
   int32_t  nextnode                        {1383675} = 0 / 1383674
   double   node_vol                        {1383675} = 1.677e-08 / 0.00252515
   double   node_vol_ff0                    {1383675} = 9.97916e-09 / 0.00126423
   double   node_vol_ff1                    {1383675} = 7.83344e-09 / 0.00126383
   double   node_vol_nearest                {1383675} = 1.75853e-08 / 0.00252601
   double   one_per_dx                      {2, 1383675} = 0.774202 / 1.71111
   double   psi                             {1383675} = 0 / 11.2365
   double   qsafety                         {400} = 1.13299 / 15.025
   double   rmaj                            {400} = 6.11042 / 6.55989
   double   rmin                            {400} = 0 / 2.21546
   double   rz                              {1383675, 2} = -4.5643 / 8.3938
   double   tr_area                         {2762126} = 1.2808e-08 / 0.000922785
   double   trapped                         {400} = 0.210179 / 0.644313


To run ``bpls``, ADIOS2's ``bin`` directory should be in PATH env. Most systems (Summit, Cori, Theta) have installed ADIOS2 by default and users can use by ``module`` command:

.. code-block:: bash

   $ module load adios2

For more details, please refer to `Adios2 user manual`_.

.. _Adios2 user manual: https://adios2.readthedocs.io/en/latest/


.. toctree::
   :maxdepth: 1