manual_layout#

manual_layout(qubit_mapping: list[int]) → Callable[[QuantumCircuit], QuantumCircuit][source]#

Create a pass that applies a manual qubit layout to the circuit.

Parameters:

qubit_mappinglist[int]

A list of physical qubit indices. The i-th logical qubit in the circuit is mapped to physical qubit qubit_mapping[i].

For example, [2, 0, 1] means:

Logical qubit 0 → Physical qubit 2
Logical qubit 1 → Physical qubit 0
Logical qubit 2 → Physical qubit 1

Returns:

Callable[[QuantumCircuit], QuantumCircuit]: A pass function that transforms the circuit.

Raises:

ValueError: If the mapping length does not match the circuit qubit count, if any index is negative, or if there are duplicate indices.

Examples

>>> from qrisp import QuantumCircuit, PassManager
>>> from qrisp import manual_layout
>>> qc = QuantumCircuit(3)
>>> qc.h(0)
>>> qc.cx(1, 2)
>>> print(qc)
      ┌───┐
qb_0: ┤ H ├
      └───┘
qb_1: ──■──
      ┌─┴─┐
qb_2: ┤ X ├
      └───┘

>>> pm = PassManager()
>>> pm += manual_layout([2, 0, 1])  # Logical 0→2, 1→0, 2→1
>>> new_layout_qc = pm.run(qc)
>>> print(new_layout_qc)

qb_1: ──■──
      ┌─┴─┐
qb_2: ┤ X ├
      ├───┤
qb_0: ┤ H ├
      └───┘