.. _plotting:

==================
Plotting
==================
Py4mulas enables two types of plotting.

Plotting band stractures
------------------------

We start with some model such as defined in :ref:`transport`

To plot the band structure along a path

.. code-block:: python

    from py4mulas.plotters import plot_bands
    import numpy as np

    path = [(0, 0), (np.pi, 0)]
    labels = [r'$\Gamma$', r'$X$']
    plot_bands(kmodel, path=path, path_labels=labels)

One might want to plot the bands with some operator expectation values. For instance spin density

.. code-block:: python

    from py4mulas.operators import SpinDensity
    operator = SpinDensity(kmodel, pauli=sigma_z)
    plot_bands(kmodel, path=path, path_labels=labels, operator=operator, cmap='siesmic')

It is important to note that when band structures are to be plotted 
the model should be provided in the cartesian momentum representaton. See ``py4mulas/examples/kagomeAFM.py``


Plotting k-resolved quantities
------------------------------

One can plot the transport response of any Py4mulas formula 

.. code-block:: python

    from py4mulas.plotters import kplot
    quantity = some_formula(mu=0, temperature=0, eta=0, k_resolved=True)
    kplot(kmodel, quantity, cmap='siesmic')

Generally operators are matrices, so they cannot be plotted directly.
However, one can plot them when band resolved.  

.. code-block:: python

    quantity = operator.band_resolved(n=0)
    kplot(kmodel, quantity, cmap='siesmic')

The band resolved feature is only impemented for spin operators. See. :class:`~py4mulas.operators.SpinOperator`.
This should be generalized for all operators.