.. SPDX-FileCopyrightText: © 2022 the SimWeights contributors
..
.. SPDX-License-Identifier: BSD-2-Clause

How to Calculate Effective Areas
================================

SimWeights objects have a method :py:func:`simweights.Weighter.effective_area` for calculating effective
areas. Some example usage is shown below.

The first example will calculate effective area in 4 different zenith bins and 25 energy bins
and plot each zenith bin separately.

.. literalinclude :: ../examples/effective_area.py
    :start-after: start-example1
    :end-before: end-example1

.. figure :: effective_area_zenith.svg

This example demonstrates the use of the mask parameter.
Effective areas are calculated separately for both NuMu and NuMuBar primaries.
Only a single zenith bin is used.
The third call to ``effective_area()`` has both NuMu and NuMuBar and so the output
is averaged over primary type.

.. literalinclude :: ../examples/effective_area.py
    :start-after: start-example2
    :end-before: end-example2

.. figure :: effective_area_type.svg

The final example shows a different use of the mask parameter.
Three different filters are used as masks creating three different curves.
Again only a single zenith bin is used.

.. literalinclude :: ../examples/effective_area.py
    :start-after: start-example3
    :end-before: end-example3

.. figure :: effective_area_filters.svg