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Python read-only implementation of the EventIO file format

Project description

pyeventio |Build Status|

A Python (read-only) implementation of the EventIO data format invented
by Konrad Bernloehr as used for example by the IACT extension for

Reading the data of the following Objects is currently supported:

| Code | Description |
| 1200 | CORSIKA Run Header |
| 1201 | CORSIKA Telescope Positions |
| 1202 | CORSIKA Event Header |
| 1203 | CORSIKA Array Offsets |
| 1204 | CORSIKA Telescope Data |
| 1205 | IACT Photons |
| 1209 | CORSIKA Event End Block |
| 1210 | CORSIKA Run End Block |
| 1211 | CORSIKA Longitudinal Block |
| 1212 | CORSIKA Input Card |

The following blocks are known, but reading their data is not (yet)

| Code | Description |
| 1206 | IACT Layout |
| 1207 | IACT Trigger Time |
| 1208 | IACT PhotoElectrons |

install with


pip install eventio

Open a file produced by the IACT CORSIKA extension

First Example

One may iterate over an instance of ``IACTFile`` class in order to
retrieve events. Events have a small number of fields. The most
important one is the ``photon_bunches`` field, which is dictionary
mapping telescope ids to a simple structured ``np.array``, containing
the typical parameters Cherekov photons bunches in Corsika have, like:

- ``x``, ``y`` coordinate in the observation plane (in cm)
- direction cosine ``cx``, ``cy`` in x and y direction of the incident
angle of the photon
- wavelength ``lambda`` of the photon (in nm)
- number of ``photons`` associated with this bunch
- the ``time`` since the first interaction (in ns, I believe)
- the production height of the photon bunch (called ``zem``)
- a bool flag, whether the photon was scattered in the atmosphere

An event has the following attributes: \* ``header``: a dictionary
containing the Corsika Event Header data \* ``end_block``: a numpy array
containing the Corsika Event End data \* ``time_offset``, ``x_offset``,
``y_offsett``, the offset of the array

This prints the number of photons for the first telescope in every

.. code:: {python}

import eventio

with eventio.IACTFile('data/telescope.dat') as f:
for event in f:

Second Example

If you like to plot the origin of the Cherenkov photons of the first
event in file ``data/telescope.dat`` for the first telescope, have a
look into `this
example <>`__

It might look similar to this picture:

.. figure::
:alt: an example shower

an example shower

Low level access

For more low level access to the items of an ``EventIO`` file (or to
implement a higher level abstraction like ``IACTFile``) one can use the
``EventIOFile`` class which gives access to the ``Objects`` and
``subitems`` in ``EventIO`` files.

This is how our test file looks like in the low level view:


In [1]: import eventio

In [2]: eventio.EventIOFile('eventio/resources/one_shower.dat')
EventIOFile(path=eventio/resources/one_shower.dat, objects=[
CorsikaRunHeader(first=0, length=1096)
CorsikaInputCard(first=1112, length=448)
CorsikaTelescopeDefinition(first=1576, length=20)
CorsikaEventHeader(first=1612, length=1096)
CorsikaArrayOffsets(first=2724, length=16)
CorsikaTelescopeData(first=2756, length=6136, subitems=1)
CorsikaEventEndBlock(first=8908, length=1096)
CorsikaRunEndBlock(first=10020, length=16)

And this is how a ``sim_telarray`` file looks like (sim\_telarray
objects are not implemted yet):


In [3]: eventio.EventIOFile('gamma_test.simtel')
EventIOFile(path=../../CTA/ctapipe/ctapipe-extra/datasets/gamma_test.simtel, objects=[
UnknownObject[70](first=0, length=11960, subitems=131)
UnknownObject[70](first=11976, length=1744732, subitems=21526)
UnknownObject[70](first=1756724, length=838000, subitems=11186)
UnknownObject[2000](first=2594740, length=1876)
UnknownObject[2010](first=50007852, length=1782080, subitems=19)
UnknownObject[2021](first=51789948, length=12)
UnknownObject[2026](first=51789976, length=3536)
UnknownObject[2010](first=51793528, length=1560656, subitems=9)

.. |Build Status| image::

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