Dimod

New Features

- Add `dimod.generators.magic_square()` which allows for the generation of a constrained quadratic model whose feasible solutions are normal magic squares. The function also generates magic squares of squares when passed `power=2` as a keyword argument.
- Implement version 2.0 of constrained quadratic model serialization. See `ConstrainedQuadraticModel.to_file()` for details.
- Improve LP file reading by wrapping [HiGHS](https://github.com/ERGO-Code/HiGHS) LP file parser.
- Add C++ ``ConstrainedQuadraticModel::remove_constraints_if()`` method.

Upgrade Notes

- Remove the `ObjectView.to_file()` method.
- Remove the `ConstraintView.to_file()` method.
- Remove `dimod::lp` C++ namespace.
- Drop support for Python 3.7.

Bug Fixes
- Fix `ConstrainedQuadraticModel.from_discrete_quadratic_model()` incorrectly formulating the discrete constraints. This bug was
introduced in version 0.12.7.
- Fix `dimod.generators.frustrated_loop()` to correctly handle graphs with tuple labels. See [\1342](https://github.com/dwavesystems/dimod/issues/1342).

Bug Fixes

- Fix loading constrained quadratic models that are serialized with CQM serialization version 2.0 and that have tuple labels.
- Support serializing constraints that need more than 2GB to save.

Fixes
- Fix `ConstrainedQuadraticModel.from_discrete_quadratic_model()` incorrectly formulating the discrete constraints. This bug was introduced in version 0.12.7.

New Features

- Implement version 2.0 of constrained quadratic model serialization. See `ConstrainedQuadraticModel.to_file()` for details.

Upgrade Notes

- Remove the `ObjectView.to_file()` method.
- Remove the `ConstraintView.to_file()` method.

New Features

- Implement `CaseLabelDQM.to_file()` when the keyword argument `ignore_labels` is true. Also make the error message clearer in the case that `ignore_labels` is false.
- Improve the performance of `ConstrainedQuadraticModel.from_discrete_quadratic_model()`.

Upgrade Notes

- Make the arguments of `DiscreteQuadraticModel.to_file()` keyword-only.

New Features

- Add `dimod::Constraint::clear()` C++ method.