Quimb

**Breaking Changes**

- Quantum circuit RZZ definition corrected (angle changed by -1/2 to match qiskit).

**Enhancements:**

- add OpenQASM 2.0 parsing support: :meth:`Circuit.from_openqasm2_file`
- :class:`Circuit`: add RXX, RYY, CRX, CRY, CRZ, toffoli, fredkin, givens gates
- truncate TN pretty html reprentation to 100 tensors for performance
- add :meth:`Tensor.sum_reduce` and :meth:`Tensor.vector_reduce`
- :meth:`contract_compressed`, default to 'virtual-tree' gauge
- add :func:`TN_rand_tree`
- `experimental.operatorbuilder`: fix parallel and heisenberg builder
- make parametrized gate generation even more robost (ensure matching types so e.g. tensorflow can be used)

**Bug fixes:**

- fix gauge size check for some backends

**Full Changelog**: https://github.com/jcmgray/quimb/compare/v1.5.1...v1.6.0

- add various MPO-MPS gate methods, including zip-up and density matrix, in the experimental submodule
- some PTensor refactoring
- Circuit: more robust parametrized gate generation
- various new contraction convenience interfaces (incld. array_contract)
- add `Tensor.check()` and `TensorNetwork.check()` for diagnostics
- add `TensorNetwork.isconnected()`, `TensorNetwork.istree()`

**Full Changelog**: https://github.com/jcmgray/quimb/compare/v1.5.0...v1.5.1

**Enhancements**

- refactor 'isometrize' methods including new "cayley", "householder" and
"torch_householder" methods. See :func:`quimb.tensor.decomp.isometrize`.
- add :meth:`~quimb.tensor.tensor_core.TensorNetwork.compute_reduced_factor`
and :meth:`~quimb.tensor.tensor_core.TensorNetwork.insert_compressor_between_regions`
methos, for some RG style algorithms.
- add the ``mode="projector"`` option for 2D tensor network contractions
- add HOTRG style coarse graining and contraction in 2D and 3D. See
:meth:`~quimb.tensor.tensor_2d.TensorNetwork2D.coarse_grain_hotrg`,
:meth:`~quimb.tensor.tensor_2d.TensorNetwork2D.contract_hotrg`,
:meth:`~quimb.tensor.tensor_3d.TensorNetwork3D.coarse_grain_hotrg`, and
:meth:`~quimb.tensor.tensor_3d.TensorNetwork3D.contract_hotrg`,
- add CTMRG style contraction for 2D tensor networks:
:meth:`~quimb.tensor.tensor_2d.TensorNetwork2D.contract_ctmrg`
- add 2D tensor network 'corner double line' (CDL) builders:
:func:`~quimb.tensor.tensor_builder.TN2D_corner_double_line`
- update the docs to use the `furo <https://pradyunsg.me/furo/>`_ theme,
`myst_nb <https://myst-nb.readthedocs.io/en/latest/>`_ for notebooks, and
several other `sphinx` extensions.
- add the `'adabelief'` optimizer to
:class:`~quimb.tensor.optimize.TNOptimizer` as well as a quick plotter:
:meth:`~quimb.tensor.optimize.TNOptimizer.plot`
- add initial 3D plotting methods for tensors networks (
``TensorNetwork.draw(dim=3, backend='matplotlib3d')`` or
``TensorNetwork.draw(dim=3, backend='plotly')``
). The new ``backend='plotly'`` can also be used for 2D interactive plots.
- Update :func:`~quimb.tensor.tensor_builder.HTN_from_cnf` to handle more
weighted model counting formats.
- Add :func:`~quimb.tensor.tensor_builder.cnf_file_parse`
- Add :func:`~quimb.tensor.tensor_builder.random_ksat_instance`
- Add :func:`~quimb.tensor.tensor_builder.TN_from_strings`
- Add :func:`~quimb.tensor.tensor_builder.convert_to_2d`
- Add :func:`~quimb.tensor.tensor_builder.TN2D_rand_hidden_loop`
- Add :func:`~quimb.tensor.tensor_builder.convert_to_3d`
- Add :func:`~quimb.tensor.tensor_builder.TN3D_corner_double_line`
- Add :func:`~quimb.tensor.tensor_builder.TN3D_rand_hidden_loop`
- various optimizations for minimizing computational graph size and
construction time.
- add ``'lu'``, ``'polar_left'`` and ``'polar_right'`` methods to
:func:`~quimb.tensor.tensor_core.tensor_split`.
- add experimental arbitrary hamilotonian MPO building
- :class:`~quimb.tensor.tensor_core.TensorNetwork`: allow empty constructor
(i.e. no tensors representing simply the scalar 1)
- :meth:`~quimb.tensor.tensor_core.TensorNetwork.drop_tags`: allow all tags to
be dropped
- tweaks to compressed contraction and gauging
- add jax, flax and optax example
- add 3D and interactive plotting of tensors networks with via plotly.
- add pygraphiviz layout options
- add :meth:`~quimb.tensor.tensor_core.TensorNetwork.combine` for unified
handling of combining
tensor networks potentially with structure
- add HTML colored pretty printing of tensor networks for notebooks
- add `quimb.experimental.cluster_update.py`


**Bug fixes:**

- fix :func:`~quimb.tensor.decomp.qr_stabilized` bug for strictly upper
triangular R factors.

**Full Changelog**: https://github.com/jcmgray/quimb/compare/1.4.2...v1.5.0

Add automatic building and publishing of `quimb` to `pypi`.

**Enhancements**

- unify much functionality from 1D, 2D and 3D into general arbitrary geometry
class :class:`quimb.tensor.tensor_arbgeom.TensorNetworkGen`
- refactor contraction, allowing using cotengra directly
- add :meth:`~quimb.tensor.tensor_core.Tensor.visualize` for visualizing the
actual data entries of an arbitrarily high dimensional tensor
- add :class:`~quimb.tensor.circuit.Gate` class for more robust tracking and
manipulation of gates in quantum :class:`~quimb.tensor.circuit.Circuit`
simulation
- tweak TN drawing style and layout
- tweak default gauging options of compressed contraction
- add :meth:`~quimb.tensor.tensor_core.TensorNetwork.compute_hierarchical_grouping`
- add :meth:`~quimb.tensor.tensor_core.Tensor.as_network`
- add :meth:`~quimb.tensor.tensor_core.TensorNetwork.inds_size`
- add :meth:`~quimb.tensor.tensor_core.TensorNetwork.get_hyperinds`
- add :meth:`~quimb.tensor.tensor_core.TensorNetwork.outer_size`
- improve :meth:`~quimb.tensor.tensor_core.TensorNetwork.group_inds`
- refactor tensor decompositiona and 'isometrization' methods
- begin supporting pytree specifications in `TNOptimizer`, e.g. for constants
- add `experimental` submodule for new sharing features
- register tensor and tensor network objects with `jax` pytree interface
(:pull:`150`)
- update CI infrastructure

**Bug fixes:**

- fix force atlas 2 and `weight_attr` bug (:issue:`126`)
- allow unpickling of `PTensor` objects (:issue:`128`, :pull:`131`)

**Enhancements**

- Add 2D tensor network support and algorithms
- Add 3D tensor network infrastructure
- Add arbitrary geometry quantum state infrastructure
- Many changes to :class:`TNOptimizer`
- Many changes to TN drawing
- Many changes to :class:`Circuit` simulation
- Many improvements to TN simplification
- Make all tag and index operations deterministic
- Add :func:`~quimb.tensor.tensor_core.tensor_network_sum`,
:func:`~quimb.tensor.tensor_core.tensor_network_distance` and
:meth:`~quimb.tensor.tensor_core.TensorNetwork.fit`
- Various memory and performance improvements
- Various graph generators and TN builders