Plaquette

class tqec.plaquette.Plaquette(name, qubits, circuit, mergeable_instructions=<factory>, debug_information=<factory>)

Bases: object

Represents a QEC plaquette.

This class stores qubits in the plaquette local coordinate system and a scheduled circuit that should be applied on those qubits to perform the QEC experiment.

By convention, the local plaquette coordinate system is composed of a X-axis pointing to the right and a Y-axis pointing down.

name

a unique name for the plaquette. This field is used to compare plaquettes efficiently (two Plaquette instances are considered equal if and only if their names are the same) as well as computing a hash value for any plaquette instance. Finally, the name is used to represent a Plaquette instance as a string.

Type:

str

qubits

qubits used by the plaquette circuit, given in the local plaquette coordinate system.

Type:

tqec.plaquette.qubit.PlaquetteQubits

circuit

scheduled quantum circuit implementing the computation that the plaquette should represent.

Type:

tqec.circuit.schedule.circuit.ScheduledCircuit

mergeable_instructions

a set of instructions that can be merged. This is useful when merging several plaquettes’ circuits together to remove duplicate instructions.

Type:

frozenset[str]

Raises:

TQECException – if the provided circuit uses qubits not listed in qubits.

Parameters:

• name (str)

• qubits (PlaquetteQubits)

• circuit (ScheduledCircuit)

• mergeable_instructions (frozenset[str])

• debug_information (PlaquetteDebugInformation)

Methods

__init__(name, qubits, circuit[, ...])
from_dict(data)	Return a plaquette from its dictionary representation.
is_empty()	Check if the plaquette is empty.
project_on_boundary(projected_orientation)	Project the plaquette on boundary and return a new plaquette with the remaining qubits and circuit.
project_on_data_qubit_indices(...)	Project the plaquette on the provided qubits and return a new plaquette with the remaining qubits and circuit.
project_on_data_qubits(data_qubits)	Project the plaquette on the provided qubits and return a new plaquette with the remaining qubits and circuit.
reliable_hash()	Return a hash of self that is replicable across OSes and Python runs.
to_dict()	Return a dictionary representation of the plaquette.
with_debug_information(debug_information)	Create a copy of self with its debug information replaced by the provided debug_information.

Attributes

num_measurements	Return the number of measurements performed in the circuit representing self.
num_moments	Return the number of moments in the circuit representing self.
origin	Return the plaquette origin.
name
qubits
circuit
mergeable_instructions
debug_information

Detailed methods

__init__(name, qubits, circuit, mergeable_instructions=<factory>, debug_information=<factory>)

Parameters:

• name (str)

• qubits (PlaquetteQubits)

• circuit (ScheduledCircuit)

• mergeable_instructions (frozenset[str])

• debug_information (PlaquetteDebugInformation)

Return type:

None

static from_dict(data)

Return a plaquette from its dictionary representation.

Parameters:

data (dict[str, Any]) – dictionary with the keys name, qubits, circuit, mergeable_instructions and debug_information.

Returns:

a new instance of Plaquette with the provided name, qubits, circuit, mergeable_instructions and debug_information.

Return type:

Plaquette

is_empty()

Check if the plaquette is empty.

An empty plaquette is a plaquette that contain empty scheduled circuit.

Return type:

bool

project_on_boundary(projected_orientation)

Project the plaquette on boundary and return a new plaquette with the remaining qubits and circuit.

This method is useful for deriving a boundary plaquette from a integral plaquette.

Parameters:

projected_orientation (PlaquetteOrientation) – the orientation of the plaquette after the projection.

Returns:

A new plaquette with projected qubits and circuit. The qubits are updated to only keep the qubits on the side complementary to the provided orientation. The circuit is also updated to only use the kept qubits and empty moments with the corresponding schedules are removed.

Return type:

Plaquette

project_on_data_qubit_indices(data_qubits_indices)

Project the plaquette on the provided qubits and return a new plaquette with the remaining qubits and circuit.

This method is useful for deriving a boundary plaquette from a integral plaquette.

Parameters:

• data_qubits – data-qubit indices that will be kept in the returned plaquette.

• data_qubits_indices (list[int])

Returns:

A new plaquette with projected qubits and circuit. The qubits are updated to only keep the provided data_qubits_indices. The circuit is also updated to only use the kept qubits and empty moments with the corresponding schedules are removed.

Return type:

Plaquette

project_on_data_qubits(data_qubits)

Project the plaquette on the provided qubits and return a new plaquette with the remaining qubits and circuit.

This method is useful for deriving a boundary plaquette from a integral plaquette.

Parameters:

data_qubits (list[GridQubit]) – qubits that will be kept in the returned plaquette.

Returns:

A new plaquette with projected qubits and circuit. The qubits are updated to only keep the provided data_qubits. The circuit is also updated to only use the kept qubits and empty moments with the corresponding schedules are removed.

Return type:

Plaquette

reliable_hash()

Return a hash of self that is replicable across OSes and Python runs.

The default hash function from Python is not guaranteed to always give the same value from the same input. In particular, with CPython, str instances are hashed with an additional salt that is randomly picked at each call to the Python executable.

This is an issue when trying to store a dictionary involving a plaquette as key and re-use it in subsequent runs or on other machines / OSes.

Return type:

int

to_dict()

Return a dictionary representation of the plaquette.

The dictionary is intended to be used as a JSON object.

Return type:

dict[str, Any]

with_debug_information(debug_information)

Create a copy of self with its debug information replaced by the provided debug_information.

Parameters:

debug_information (PlaquetteDebugInformation)

Return type:

Plaquette