Commit 68d49654 authored by Christoph Groth's avatar Christoph Groth

reorder 1.4 whatsnew by decreasing importance

parent 141688ec
...@@ -6,48 +6,6 @@ See also the `full list of changes up to the most recent bugfix ...@@ -6,48 +6,6 @@ See also the `full list of changes up to the most recent bugfix
release of the 1.4 series release of the 1.4 series
<https://gitlab.kwant-project.org/kwant/kwant/compare/v1.4.0...latest-1.4>`_. <https://gitlab.kwant-project.org/kwant/kwant/compare/v1.4.0...latest-1.4>`_.
Configurable maximum velocity in stream plots
---------------------------------------------
The function `~kwant.plotter.streamplot` has got a new option ``vmax``. Note
that this option is not available in `~kwant.plotter.current`. In order to use
it, one has to call ``streamplot`` directly as shown in the docstring of
``current``.
Improved heuristic for colorscale limits in `kwant.plotter.map`
---------------------------------------------------------------
Previously `~kwant.plotter.map` would set the limits for the color scale
to the extrema of the data being plotted when ``vmin`` and ``vmax`` were
not provided. This is the behaviour of ``matplotlib.imshow``. When the data
to be plotted has very sharp and high peaks this would mean that most of the
data would appear near the bottom of the color scale, and all of the features
would be washed out by the presence of the peak. Now `~kwant.plotter.map`
employs a heuristic for setting the colorscale when there are outliers,
and will emit a warning when this is detected.
System parameter substitution
-----------------------------
After the introduction of ``Builder.fill`` it has become possible to construct
Kwant systems by first creating a "model" system with high symmetry and then
filling a lower symmetry system with this model. Often, however, one wants
to use different parameter values in different parts of a system. In
previous versions of Kwant this was difficult to achieve.
Builders now have a method ``substitute`` that makes it easy to substitute
different names for parameters. For example if a builder ``model``
has a parameter ``V``, and one wishes to have different values for ``V`` in
the scattering region and leads, one could do the following::
syst = kwant.Builder()
syst.fill(model.substitute(V='V_dot', ...))
lead = kwant.Builder()
lead.fill(model.substitute(V='V_lead'), ...)
syst.attach_lead(lead)
fsyst = syst.finalized()
kwant.smatrix(syst, params=dict(V_dot=0, V_lead=1))
Value functions no longer accept default values for parameters Value functions no longer accept default values for parameters
-------------------------------------------------------------- --------------------------------------------------------------
Using value functions with default values for parameters can be Using value functions with default values for parameters can be
...@@ -77,6 +35,30 @@ Concretely, the above means that the following no longer works:: ...@@ -77,6 +35,30 @@ Concretely, the above means that the following no longer works::
# Raises ValueError # Raises ValueError
syst = syst.finalized() syst = syst.finalized()
System parameter substitution
-----------------------------
After the introduction of ``Builder.fill`` it has become possible to construct
Kwant systems by first creating a "model" system with high symmetry and then
filling a lower symmetry system with this model. Often, however, one wants
to use different parameter values in different parts of a system. In
previous versions of Kwant this was difficult to achieve.
Builders now have a method ``substitute`` that makes it easy to substitute
different names for parameters. For example if a builder ``model``
has a parameter ``V``, and one wishes to have different values for ``V`` in
the scattering region and leads, one could do the following::
syst = kwant.Builder()
syst.fill(model.substitute(V='V_dot', ...))
lead = kwant.Builder()
lead.fill(model.substitute(V='V_lead'), ...)
syst.attach_lead(lead)
fsyst = syst.finalized()
kwant.smatrix(syst, params=dict(V_dot=0, V_lead=1))
Interpolated density plots Interpolated density plots
-------------------------- --------------------------
A new function `~kwant.plotter.density` has been added that can be used to A new function `~kwant.plotter.density` has been added that can be used to
...@@ -86,6 +68,13 @@ in realspace. The output of `~kwant.plotter.density` can be more informative ...@@ -86,6 +68,13 @@ in realspace. The output of `~kwant.plotter.density` can be more informative
that `~kwant.plotter.map` when plotting systems with many sites, where it is that `~kwant.plotter.map` when plotting systems with many sites, where it is
not important to see the individual contribution from each site. not important to see the individual contribution from each site.
Configurable maximum velocity in stream plots
---------------------------------------------
The function `~kwant.plotter.streamplot` has got a new option ``vmax``. Note
that this option is not available in `~kwant.plotter.current`. In order to use
it, one has to call ``streamplot`` directly as shown in the docstring of
``current``.
kwant.continuum.discretize can be used with rectangular lattices kwant.continuum.discretize can be used with rectangular lattices
---------------------------------------------------------------- ----------------------------------------------------------------
Previously the discretizer could only be used with lattices with the same Previously the discretizer could only be used with lattices with the same
...@@ -99,3 +88,14 @@ lattices to the discretizer:: ...@@ -99,3 +88,14 @@ lattices to the discretizer::
This is useful when you need a finer discretization step in some spatial This is useful when you need a finer discretization step in some spatial
directions, and a coarser one in others. directions, and a coarser one in others.
Improved heuristic for colorscale limits in `kwant.plotter.map`
---------------------------------------------------------------
Previously `~kwant.plotter.map` would set the limits for the color scale
to the extrema of the data being plotted when ``vmin`` and ``vmax`` were
not provided. This is the behaviour of ``matplotlib.imshow``. When the data
to be plotted has very sharp and high peaks this would mean that most of the
data would appear near the bottom of the color scale, and all of the features
would be washed out by the presence of the peak. Now `~kwant.plotter.map`
employs a heuristic for setting the colorscale when there are outliers,
and will emit a warning when this is detected.
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