cirq.MutablePauliString | Cirq | Google Quantum AI (original) (raw)

Mutable version of cirq.PauliString, used mainly for efficiently mutating pauli strings.

cirq.MutablePauliString(
    *contents,
    coefficient: 'cirq.TParamValComplex' = 1,
    pauli_int_dict: Optional[Dict[TKey, int]] = None
)

cirq.MutablePauliString is a mutable version of cirq.PauliString, which is often useful for mutating pauli strings efficiently instead of always creating a copy. Note that, unlike cirq.PauliString, MutablePauliString is not a cirq.Operation.

It exists mainly to help mutate pauli strings efficiently and then convert back to a frozen cirq.PauliString representation, which can then be used as operators or observables.

Args
*contents	A value or values to convert into a pauli string. This can be a number, a pauli operation, a dictionary from qubit to pauli/identity gates, or collections thereof. If a list of values is given, they are each individually converted and then multiplied from left to right in order.
coefficient	Initial scalar coefficient or symbol. Defaults to 1.
pauli_int_dict	Initial dictionary mapping qubits to integers corresponding to pauli operations. Defaults to the empty dictionary. Note that, unlike dictionaries passed to contents, this dictionary must not contain values corresponding to identity gates; i.e. all integer values must be between [1, 3]. Further note that this argument specifies values that are logically_before_ factors specified in contents; contents are right multiplied onto the values in this dictionary.

Raises
ValueError	If the pauli_int_dict has integer values v not satisfying 1 <= v <= 3.

Methods

`frozen`

frozen() -> 'cirq.PauliString'

Returns a cirq.PauliString with the same contents.

For example, this is useful because cirq.PauliString is an operation whereas cirq.MutablePauliString is not.

`get`

get(
    key: TKey, default=None
) -> Union['cirq.Pauli', TDefault, None]

Returns the cirq.Pauli operation acting on qubit key or default if none exists.

`inplace_after`

inplace_after(
    ops: 'cirq.OP_TREE'
) -> 'cirq.MutablePauliString'

Propagates the pauli string from before to after a Clifford effect.

If the old value of the MutablePauliString is \(P\) and the Clifford operation is \(C\), then the new value of the MutablePauliString is \(C P C^\dagger\).

Args
ops	A stabilizer operation or nested collection of stabilizer operations.

Returns
The mutable pauli string that was mutated.

Raises
NotImplementedError	If any ops decompose into an unsupported Clifford gate.

`inplace_before`

inplace_before(
    ops: 'cirq.OP_TREE'
) -> 'cirq.MutablePauliString'

Propagates the pauli string from after to before a Clifford effect.

If the old value of the MutablePauliString is \(P\) and the Clifford operation is \(C\), then the new value of the MutablePauliString is \(C^\dagger P C\).

Args
ops	A stabilizer operation or nested collection of stabilizer operations.

Returns
The mutable pauli string that was mutated.

`inplace_left_multiply_by`

inplace_left_multiply_by(
    other: 'cirq.PAULI_STRING_LIKE'
) -> 'cirq.MutablePauliString'

Left-multiplies a pauli string into this pauli string.

Args
other	A pauli string or cirq.PAULI_STRING_LIKE to left-multiply into self.

Returns
The self mutable pauli string that was mutated.

Raises
TypeError	other was not a cirq.PAULI_STRING_LIKE. selfwas not mutated.

`inplace_right_multiply_by`

inplace_right_multiply_by(
    other: 'cirq.PAULI_STRING_LIKE'
) -> 'cirq.MutablePauliString'

Right-multiplies a pauli string into this pauli string.

Args
other	A pauli string or cirq.PAULI_STRING_LIKE to right-multiply into self.

Returns
The self mutable pauli string that was mutated.

Raises
TypeError	other was not a cirq.PAULI_STRING_LIKE. selfwas not mutated.

`items`

items() -> Iterator[Tuple[TKey, 'cirq.Pauli']]

Returns (cirq.Qid, cirq.Pauli) pairs representing 1-qubit operations of pauli string.

`keys`

keys() -> AbstractSet[TKey]

Returns the sequence of qubits on which this pauli string acts.

`mutable_copy`

mutable_copy() -> 'cirq.MutablePauliString'

Returns a new cirq.MutablePauliString with the same contents.

`transform_qubits`

transform_qubits(
    func: Callable[[TKey], TKeyNew], *, inplace: bool = False
) -> 'cirq.MutablePauliString[TKeyNew]'

Returns a MutablePauliString with transformed qubits.

Args
func	The qubit transformation to apply.
inplace	If false (the default), creates a new mutable pauli string to store the result. If true, overwrites this mutable pauli string's contents. Defaults to false for consistency withcirq.PauliString.transform_qubits in situations where the pauli string being used may or may not be mutable.

Returns
A transformed MutablePauliString. If inplace=True, returns self. If inplace=False, returns a new instance.

`values`

values() -> Iterator['cirq.Pauli']

Ordered sequence of cirq.Pauli gates acting on self.keys().

`bool`

__bool__() -> bool

`contains`

__contains__(
    item: Any
) -> bool

`eq`

__eq__(
    other: _SupportsValueEquality
) -> bool

`getitem`

__getitem__(
    item: Any
) -> 'cirq.Pauli'

`iter`

__iter__() -> Iterator[TKey]

`len`

__len__() -> int

`mul`

__mul__(
    other: 'cirq.PAULI_STRING_LIKE'
) -> 'cirq.PauliString'

Multiplies two pauli-string-likes together.

The result is not mutable.

`ne`

__ne__(
    other: _SupportsValueEquality
) -> bool

`neg`

__neg__() -> 'cirq.MutablePauliString'

`pos`

__pos__() -> 'cirq.MutablePauliString'

`rmul`

__rmul__(
    other: 'cirq.PAULI_STRING_LIKE'
) -> 'cirq.PauliString'

Multiplies two pauli-string-likes together.

The result is not mutable.