.. api_reference:

CDI analysis using a command-line script
========================================
The simplest way to analyse a CDI dataset using PyNX is to use a
command-line script.

*Note regarding command-line arguments*:

* previous versions of PyNX (<2024) used e.g. ``pynx-ptycho-cxi data=data.cxi``
* now command-line arguments all start with ``--`` to use standard parsing libarries
  and make it easier to documentation
* you can use equivalently ``pynx-ptycho-cxi --data=data.cxi`` or
  ``pynx-ptycho-cxi --data data.cxi``, with the exception of options where
  the supplied value begins with ``--``, e.g. it is mandatory to use
  ``--support_post_expand=-2,2``, as using ``--support_post_expand -2 2``
  will try to interpret ``-2`` as a new command-line argument

There are two main scripts which can be currently used:
``pynx-cdi-id01`` and ``pynx-cdi-id10``, which differ only by
a few default options (HIO vs RAAR algorithm, and for id10: ``--positivity``
and ``--mask=zero`` options).

A simple data analysis can be done, when reading a CXI file, using:

``pynx-id01cdi.py data=data.cxi``

This will simply run the analysis with default parameter. The initial
support will be determined using auto-correlation (which is usually
fine for Bragg CDI where no beamstop is used), no positivity...

A more detailed example using a Vaterite dataset (`Cherkas et al.,
Crystal Growth & Design 17, 4183–4188 (2017)
<http://dx.doi.org/10.1021/acs.cgd.7b00476>`_):

.. code-block:: bash

  # If necessary, activate your python environment with PyNX
  source /path/to/my/python/environment/bin activate

  # Download the example dataset
  curl -O http://ftp.esrf.fr/pub/scisoft/PyNX/data/T25_60_3D.cxi

  # View the CXI file using the silx viewer:
  silx view T25_60_3D.cxi

  # Run the PyNX analysis script
  pynx-cdi-id10 --data T25_60_3D.cxi --support circle --support_size 70\
                --nb_raar 800 --nb_hio 0 --nb_er 200 --verbose 50\
                --support_smooth_width_begin 3 --support_smooth_width_end 1\
                --positivity --support_threshold 0.2 --max_size 512\
                --support_threshold_method max --liveplot

  # View the result from the output CXI file using the silx viewer
  silx view latest.cxi

  # Note that you can see all the parameters used for the optimisation
  # in entry_last/image_1/process_1/

  # You can tune the threshold if you want to improve the solution,
  # or try HIO instead of RAAR (``--nb_hio 800 --nb_raar 0``)


To perform a more complete analysis, it is advised to use multiple runs,
select the best from the free log-likelihood, and combine them:

.. code-block:: bash

  # Perform 10 runs and combine the 5 best ones (takes a little longer,
  # 30s per run on a V100 GPU, liveplot is disabled)
  # Note --support_threshold 0.1 0.2 means threshold is randomly chosen
  # between 0.1 and 0.2 for each run

  rm -f *LLK*.cxi  # remove previous results

  pynx-cdi-id10 --data T25_60_3D.cxi --support circle --support_size 70\
                --nb_raar 800 --nb_hio 0 --nb_er 200 --verbose 50\
                --support_smooth_width_begin 3 --support_smooth_width_end 1\
                --positivity support_threshold 0.1 0.2 --max_size 512\
                --support_threshold_method max --nb_run 10 --nb_run_keep 5

  # Perform a modes analysis and produce a movie (requires ffmpeg)
  pynx-cdi-analysis.py *LLK*.cxi modes movie

  # Look at modes analysis
  silx view modes.h5

  # See movie of slices from modes analysis
  vlc cdi-3d-slices.mp4

More information
----------------

The full documentation for the command-line scripts can be obtained by using
the ``--help`` command-line option, e.g.:

``pynx-cdi-id10 --help``

For more information, please read the
:ref:`online documentation on CDI scripts <cdi_scripts>`