pennylane

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Add `has_decomposition` and `has_adjoint` attributes

2

Here we add the `Operator` attributes `has_decomposition` and `has_adjoint` in analogy to `has_matrix`. They allow faster decisions of whether a decomposition/adjoint is available than calling `decomposition/adjoint` and catching exceptions. Similar...

dwierichs

Hessian diagonal via adjoint method

2

### Before submitting Please complete the following checklist when submitting a PR: - [x] All new features must include a unit test. If you've fixed a bug or added code...

dwierichs

[Op. Arithm.] Improve performance #4 (Matrix Caching)

3

**Context:** When composing operations, sums and products of operators can get very big (lots of summands and factors). Computing the matrix of such composite operators will be very time consuming....

Jaybsoni

Support qml.equal with op. arithmetic

3

1. Compare the `op.hash` when using `qml.equal` with operator arithmetic. 2. Take into account the `op.name` when sorting summands. 3. Add `op.hash` to some arithmetic operators. 4. Use `qml.equal` in...

AlbertMitjans

Add qchem basis rotation function

2

**Context:** This PR adds a function for basis rotation grouping of a molecular Hamiltonian. **Description of the Change:** The function `basis_rotation` is added to qchem.factorization module. **Benefits:** **Possible Drawbacks:** **Related...

soranjh

[BUG] Returning non-commuting observables and probabilities from a QNode raises an error

1

### Expected behavior The below code should print out the quantities: ```python def debug(): dev = qml.device("default.qubit", wires=2) @qml.qnode(dev) def circuit(x): qml.RY(x, wires=0) qml.CNOT(wires=[0, 1]) return qml.expval(qml.PauliX(0) @ qml.PauliZ(1)), qml.expval(qml.PauliZ(0)...

eddddddy

[Prototype] Pauli Arithmetic Integration v1

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**Context:** We want to take advantage of the known rules for obtaining the products of Pauli operators to enhance the speed of operator arithmetic. This is one prototype which uses...

Jaybsoni

Performance: use in-place matrix operations

1

For manipulations involving large matrices, we want to cut down on memory allocation whenever possible. One way to do that is by using in-place manipulations instead. ```pycon >>> mat1 +=...

albi3ro

Iteratively unwrap nested parameters

3

Currently, unwrapping operator arithmetic data can cause a multitude of `VisibleDeprecationWarnings` from ragged arrays: ``` import warnings warnings.simplefilter("error") with qml.tape.QuantumTape() as tape: obs = qml.op_sum(qml.s_prod(torch.tensor(1.2), qml.PauliX(0)), qml.PauliZ(0)) qml.expval(obs) with qml.tape.Unwrap(tape):...

albi3ro

Simplify multiple operators in a QNode

1

Added a small modification in the `qml.simplify` function to simplify (and group) multiple operators in a QNode. Example: ```python dev = qml.device("default.qubit", wires=2) @qml.qnode(dev) def circuit(x): qml.RX(x, 0) qml.RX(1, 0)...

AlbertMitjans