All notable changes to this project will be documented in this file.
The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.
- Additionally allow using strings or sympy expressions in
PointGroupElement
for the rotation part gitlab issue #7. - Avoid a numerical instability in symmetry finder gitlab issue #49.
- Fix compatibility with latest sympy v1.12.
- integration test: run the tests for Kwant's qsymm module against the current version of qsymm.
- Avoided using deprecated functionality in latest scipy, numpy, and sympy
- Fix syntax for python 3.9
- Support of python < 3.7, numpy < 1.16, scipy < 1.1, sympy < 1.3 (similar to the upcoming Kwant release)
- Downgraded scipy version requirement to 0.19, to maintain compatibility with Kwant
- Correctly set model format when reshaping models with sparse values
- Added basic reference documentation
- Added citation instructions in CITING.md
- Added a tutorial with downloadable Python files and Jupyter notebooks
- Allow 'display_family' to work when IPython is not installed
- Bug when multiplying a model by a sympy expression (undefined variable)
- Bug when multiplying BlochCoeff with sympy expression (sympy multiplication was being used, when BlochCoeff multiplication should have been used)
- Remove copying of Sympy symbols (the hash values for the original and copy is different in some cases (probably a bug in Sympy)), which broke comparison between Models.
- Remove 'real' assumption from Sympy symbols in 'hamiltonian_from_family'; this makes all Sympy symbols in Qsymm consistently have no assumptions.
- Minor clarifications to various docstrings
- Removed the notebooks from the source repository
- Set correct content-type on long description metadata
- Add long description to package metadata
- Adding zero to a model is now idempotent
- Add CHANGELOG.md
- Restore compatibility with Python 3.5
- Factory functions for discrete symmetries:
time_reversal
,particle_hole
,chiral
,inversion
,rotation
,mirror
. - Better representation of
PointGroupElement
s andContinuousGroupGenerator
, using_repr_pretty_
and_repr_latex_
. Removeprint_PG_elements
and update example notebooks. - Implemented new functionality in
Model
:
- Implement
__matmul__
(@
). - Support of sparse matrices and
LinearOperator
as values. - Consistent support of scalar valued
Model
s. - Add
keep
to only keep track of certain symbolic coefficients. - More options and more transparent initialization, allow string keys which are automatically symmpified by default.
- Several new utility functions, such as
trace
,reshape
,allclose
etc.
- Slight change to the internal representation of
PointGroupElements
, allow mixing integer tinyarray with either sympy matrix or floating point tinyarray in the rotation part, but do not allow mixing the latter two representations. This removes the need to have two different representations for simple operators. Optimize multiplication by caching. - Changes in the API of
Model
: - Add
format
attribute to keep track of the type of data entries (i.e scalar, dense or sparse array). - Change the behaviour of
*
forModel
objects, matrix multiplication only works with@
from now on. This breaks backward compatibility, a few uses in the qsymm code base were fixed. - Stop supporting a sequence of ints as
momenta
, instead string keys (e.g.'k_x'
) orsympy
expressions can be used. Certain other, rarely used ways to initializeModel
don't work anymore, some tests were changed accordingly. - Stop rounding and removing small entries from
Model
objects. This means that testing that theModel
is empty is not a good test anymore to see if it is approximately zero. UseModel.allclose
instead. - Optimizations in
Model
:
- Remove unnecessary deep copying, which was slow.
- Optimize the implementation of arithmetic operations to minimize number of loops and function calls.
- Fast initialization by making restructuring optional when initialized with a dict.
- Clean up the code of
BlochModel
to utilize improvements inModel
. - Update symmetry finder to work with sparse models.
- Deprecate initializing empty
Model
without providingshape
andformat
.
Many of these changes were made in anticipation of integrating qsymm
with kwant
,
allowing conversion between the Hamiltonian formats used.
BlochModel
as a subclass ofModel
in order to store Bloch Hamiltonians with floating point hopping vectors.bravais_point_group
to find the point group of a Bravais lattice using the translation vectors only. This is intended for generating candidades forsymmetries
.
- Change the way equality of
Model
s is tested, the current implementation treats tolerances more consistently, this fixes some bugs in symmetry finding. - Allow using floating point rotation matrices in
PointGroupElement
.
- Several bugs and internal code restructuring.