mqt.predictor.rl.parsing

Helper methods necessary for parsing between circuit formats.

Module Contents

class PreProcessTKETRoutingAfterQiskitLayout

Pre-processing step to route a circuit with TKET after a Qiskit Layout pass has been applied.

The reason why we can apply the trivial layout here is that the circuit already got assigned a layout by qiskit. Implicitly, Qiskit is reordering its qubits in a sequential manner, i.e., the qubit with the lowest physical qubit first.

Assuming, the layouted circuit is given by

┌───┐ ░ ┌─┐

q_2 -> 0 ┤ H ├──■────────░───────┤M├

└───┘┌─┴─┐ ░ ┌─┐└╥┘

q_1 -> 1 ─────┤ X ├──■───░────┤M├─╫─

└───┘┌─┴─┐ ░ ┌─┐└╥┘ ║

q_0 -> 2 ──────────┤ X ├─░─┤M├─╫──╫─

└───┘ ░ └╥┘ ║ ║

ancilla_0 -> 3 ───────────────────╫──╫──╫─

║ ║ ║

ancilla_1 -> 4 ───────────────────╫──╫──╫─

║ ║ ║

meas: 3/═══════════════════╩══╩══╩═

0 1 2

Applying the trivial layout, we get the same qubit order as in the original circuit and can be respectively routed. This results in:

┌───┐ ░ ┌─┐

q_0: ┤ H ├──■────────░───────┤M├

└───┘┌─┴─┐ ░ ┌─┐└╥┘

q_1: ─────┤ X ├──■───░────┤M├─╫─

└───┘┌─┴─┐ ░ ┌─┐└╥┘ ║

q_2: ──────────┤ X ├─░─┤M├─╫──╫─

└───┘ ░ └╥┘ ║ ║

q_3: ───────────────────╫──╫──╫─

║ ║ ║

q_4: ───────────────────╫──╫──╫─

║ ║ ║

meas: 3/═══════════════════╩══╩══╩═

0 1 2

If we would not apply the trivial layout, no layout would be considered resulting, e.g., in the following circuit:

┌───┐ ░ ┌─┐

q_0: ─────┤ X ├─────■───░────┤M├───

┌───┐└─┬─┘ ┌─┴─┐ ░ ┌─┐└╥┘

q_1: ┤ H ├──■───X─┤ X ├─░─┤M├─╫────

└───┘ │ └───┘ ░ └╥┘ ║ ┌─┐

q_2: ───────────X───────░──╫──╫─┤M├

░ ║ ║ └╥┘

q_3: ──────────────────────╫──╫──╫─

║ ║ ║

q_4: ──────────────────────╫──╫──╫─

║ ║ ║

meas: 3/══════════════════════╩══╩══╩═

0 1 2

apply(circuit: pytket.Circuit) → None

Applies the pre-processing step to route a circuit with tket after a Qiskit Layout pass has been applied.

get_bqskit_native_gates(device: Target) → list[Gate]

Returns the native gates of the given device.

Parameters:

device – The device for which the native gates are returned.

Returns:

The native gates of the given device as BQSKit gates.

Raises:

ValueError – If a gate in the device is not supported in BQSKit.

bqskit_to_qiskit(circuit: Circuit) → QuantumCircuit

Convert a BQSKit Circuit to Qiskit’s QuantumCircuit.

This function extends BQSKit’s built-in conversion by adding support for IQM’s native ‘r’ gate. BQSKit represents this as U1qGate, which is converted to Qiskit’s RGate by rewriting the OpenQASM 2 output.

Parameters:

circuit – The BQSKit circuit to convert.

Returns:

The equivalent Qiskit QuantumCircuit with ‘r’ gates properly mapped.

final_layout_pytket_to_qiskit(pytket_circuit: pytket.Circuit, qiskit_circuit: QuantumCircuit) → Layout

Converts a final layout from pytket to qiskit.

final_layout_bqskit_to_qiskit(bqskit_initial_layout: tuple[int, Ellipsis], bqskit_final_layout: tuple[int, Ellipsis], compiled_qc: QuantumCircuit, initial_qc: QuantumCircuit) → TranspileLayout

Converts a final layout from bqskit to qiskit.

BQSKit provides an initial layout as a list[int] where each virtual qubit is mapped to a physical qubit similarly, it provides a final layout as a list[int] representing where each virtual qubit is mapped to at the end of the circuit.

postprocess_vf2postlayout(qc: QuantumCircuit, post_layout: Layout, layout_before: TranspileLayout) → tuple[QuantumCircuit, ApplyLayout]

Postprocess a quantum circuit after VF2 layout assignment.

Parameters:

• qc – The quantum circuit to transform.

• post_layout – The layout computed after routing.

• layout_before – The layout before post-routing adjustment.

Returns:

A tuple of the transformed circuit and the ApplyLayout used.