Dimod

New Features

- Add `SampleSet.from_samples_cqm()` method.

Bug Fixes

- `ExactCQMSolver.sample_cqm` now uses `SampleSet.from_samples_cqm`. This corrects a small error in the calculation of constraint satisfaction.

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- `dimod.generators.random_knapsack()` and `dimod.generators.random_bin_packing()` no longer use a fixed seed by default.

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- `ConstrainedQuadraticModel.add_discrete()`, `ConstrainedQuadraticModel.add_constraint_from_iterable()`, and `ConstrainedQuadraticModel.add_discrete_from_model()` now correctly raise an error when given a binary variable that overlaps with an existing discrete constraint. See [1149](https://github.com/dwavesystems/dimod/issues/1149).

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- `SampleSet.from_samples_bqm` now handles empty list input correctly.

Deprecation Notes

- Deprecate `cls` parameter in `dimod.serialization.coo.load()` and `dimod.serialization.coo.loads()`.

Bug Fixes

- Fix energy calculations for quadratic models with squared terms. See [1136](https://github.com/dwavesystems/dimod/issues/1136).

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- `dimod.serialization.fileview.load()` now correctly propagates `KeyError` from the loading function.

New Features

- Add `Polynomial` to `dimod.typing`.

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- Add `Comparison.to_polystring()` method.

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- Printing `Comparison` objects now returns an equation representation of the comparison as a string.

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- Add `ConstrainedQuadraticModel.relabel_constraints()` method. See [1066](https://github.com/dwavesystems/dimod/issues/1066).

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- Add `ConstrainedQuadraticModel.remove_constraint()` method. See [1104](https://github.com/dwavesystems/dimod/issues/1104).

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- Add methods to report memory usage of quadratic models:

- Add `QuadraticModel.nbytes()` method.
- Add `BinaryQuadraticModel.nbytes()` method.
- Add `QuadraticModel::nbytes()` method to C++ the code.
- Add `BinaryQuadraticModel::nbytes()` method to C++ the code.

See [668](https://github.com/dwavesystems/dimod/issues/668)

Deprecation Notes

- Deprecate `cls` parameter in `dimod.generators.random.gnm_random_bqm()`, `dimod.generators.random.gnp_random_bqm()`, `dimod.generators.random.uniform()`, `dimod.generators.random.ran_r()`, `dimod.generators.random.randint()`, and `dimod.generators.random.doped()`.

Bug Fixes

- `Comparison.__repr__()` now correctly returns a representation that can be passed to `eval()`.

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- Fix `dimod.typing.Bias` to correctly exclude `numpy.complexfloating`.

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- Attempting to relabel two model variables to the same target will now correctly raise a `ValueError`. See [1110](https://github.com/dwavesystems/dimod/issues/1110).

New Features

- Add `ConstrainedQuadraticModel.add_discrete_from_comparison()` method.

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- Add `ConstrainedQuadraticModel.add_discrete_from_iterable()` method.

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- Add `ConstrainedQuadraticModel.add_discrete_from_model()` method.

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- `ConstrainedQuadraticModel.add_discrete()` now supports additional argument types.

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- Add `QuadraticModel.flip_variable()` method.

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- Add `ConstrainedQuadraticModel.flip_variable()` method.

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- Support iterator inputs to `as_samples()`. See [543](https://github.com/dwavesystems/dimod/issues/543).

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- Add `SamplesLike` and `SampleLike` to `dimod.typing`. See [1008](https://github.com/dwavesystems/dimod/issues/1008).

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- Add `dimod::vartype_limits` to C++ code for compile-time information about variable types.

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- Add `dimod::vartype_info` to C++ code for runtime information about variable types.

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- Add `vartype_info()` function.

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- `BinaryQuadraticModel.resize()` now returns the difference in the number of variables between the current and previous binary quadratic model. Previously it always returned 0. See [1091](https://github.com/dwavesystems/dimod/issues/1091)

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- Add `BinaryQuadraticModel.maximum_energy_delta()` method.

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- Add `ConstrainedQuadraticModel.set_lower_bound()` method. See [1105](https://github.com/dwavesystems/dimod/issues/1105).

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- Add `ConstrainedQuadraticModel.set_upper_bound()` method. See [1105](https://github.com/dwavesystems/dimod/issues/1105).

Upgrade Notes

- `as_samples()` no longer always casts input sample values to integers.

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- `QuadraticModel.energies()` and `BinaryQuadraticModel.energies()` now return a NumPy array with dtype `np.float64` be default. Previously they defaulted to match the dtype of the model.

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- Bounds for integer variables are no longer rounded to the nearest int in `QuadraticModel` and `ConstrainedQuadraticModel`.

Deprecation Notes

- Deprecate support for a 2-tuple of `(dict, list)` as a samples-like. E.g. `({'a': 1, 'b': 0}, ['a', 'b'])` is no longer supported. `(array_like, labels)` is still supported, as is a dictionary. Support will be removed in dimod 0.12.0.

Bug Fixes

- `QuadraticModel.energies()` and `BinaryQuadraticModel.energies()` will return the correct energy when given samples with non-integer values.

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- It is no longer possible to add an integer variables to a quadratic model with bounds that do not include at least one integer between them. E.g. `qm.add_variable('INTEGER', 'v', lower_bound=1.2, upper_bound=1.5)` will now raise a `ValueError`.

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- `ConstrainedQuadraticModel.add_variable()` now correctly raises an error when a variable is added twice with inconsistent bounds.

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- `ConstrainedQuadraticModel.add_variable()` now correctly returns the variable label when a variable is added twice.

New Features

- Add `cascade` keyword argument to `ConstrainedQuadraticModel.fix_variable()` and `ConstrainedQuadraticModel.fix_variables()`. These methods also now return any variables fixed using the <span class="title-ref">cascade</span> keyword argument.

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- Add `QuadraticModel::swap_variables()` and `BinaryQuadraticModel::swap_variables()` methods to the C++ code.

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- Reintroduce `BinaryQuadraticModel.to_serializable()` and `BinaryQuadraticModel.from_serializable()` methods that were previously removed in dimod 0.10.0, see [847](https://github.com/dwavesystems/dimod/pull/847).

Upgrade Notes

- `ConstrainedQuadraticModel.fix_variable()` and `ConstrainedQuadraticModel.fix_variables()` now raise a `ValueError` if given a variable not in the model.

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- Make `use_bytes` and `bytes_type` keyword-only arguments in `BinaryQuadraticModel.to_serializable()`. Note that `BinaryQuadraticModel.to_serializable()` was removed in 0.10.0 but restored in 0.10.12.

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- The `bias_dtype` keyword-only argument in `BinaryQuadraticModel.to_serializable()` now does nothing. Note that `BinaryQuadraticModel.to_serializable()` was removed in 0.10.0 but restored in 0.10.12.

Bug Fixes

- Fix `QuadraticModel.fix_variable()` to correctly update the vartypes and bounds of of variables that are not fixed.

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- Fix `QuadraticModel.fix_variable()` when fixing the last variable in the quadratic model. Previously it would incorrectly raise an `AttributeError`.

New Features

- Add `.fix_variable()` and `.fix_variables()` methods to `ConstrainedQuadraticModel`.

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- Add `.fix_variable()` and `.fix_variables()` methods to `QuadraticModel`.

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- Add `QuadraticModel::resize()` method in C++ code.

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- Speed up printing sample sets with a large number of variables. See [1068](https://github.com/dwavesystems/dimod/issues/1068).

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- Add ability to pass a slice to `Variables.__getitem__`. This allows for syntax like `variables[:5]` which will return a new `Variables` object. See [1069](https://github.com/dwavesystems/dimod/issues/1069).

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- Add `BinaryQuadraticModel.iter_linear()` method.

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- Add `BinaryQuadraticModel.to_polystring()` method.

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- Add `QuadraticModel.iter_linear()` method.

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- Add `QuadraticModel.to_polystring()` method.

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- Introduces variable array methods `dimod.BinaryArray`, `dimod.SpinArray`, and `dimod.IntegerArray`. These methods build numpy object arrays from their respective generator methods `dimod.Binaries`, `dimod.Spins` and `dimod.Integers`.

Upgrade Notes

- `QuadraticViewsMixin` now has `.add_linear()` as an abstract method.

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- `BinaryQuadraticModel.fix_variable()` no longer raises a `ValueError` when given a value that does not match the variable type.

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- Python 3.6 is no longer supported.

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- NumPy 1.17 and 1.18 are no longer supported.

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- `dimod.views.quadratic.QuadraticModelMixin` now has an abstract property `.offset`.

Bug Fixes

- Fix setting linear and quadratic biases on vartype views when the relevant variable or interaction does not already exist.

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- `multiplcation_circuit` now adds the carry from the most significant column in a row into the most significant column of the next row.