Layout

Adds a map element between bit and physical_bit. If physical_bit is not defined, bit will be mapped to a new physical bit.

Parameters

• virtual_bit (tuple(opens in a new tab)) – A (qu)bit. For example, (QuantumRegister(3, ‘qr’), 2).
• physical_bit (int(opens in a new tab)) – A physical bit. For example, 3.

Adds at the end physical_qubits that map each bit in reg.

Parameters

reg (Register) – A (qu)bit Register. For example, QuantumRegister(3, ‘qr’).

Combines self and another_layout into an “edge map”.

For example:

   self       another_layout  resulting edge map
qr_1 -> 0        0 <- q_2         qr_1 -> q_2
qr_2 -> 2        2 <- q_1         qr_2 -> q_1
qr_3 -> 3        3 <- q_0         qr_3 -> q_0

The edge map is used to compose dags via, for example, compose.

Parameters

another_layout (Layout) – The other layout to combine.

Returns

A “edge map”.

Return type

dict(opens in a new tab)

Raises

LayoutError – another_layout can be bigger than self, but not smaller. Otherwise, raises.

Returns a copy of a Layout instance.

Populates a Layout from a dictionary.

The dictionary must be a bijective mapping between virtual qubits (tuple) and physical qubits (int).

Parameters

input_dict (dict(opens in a new tab)) –

e.g.:

{(QuantumRegister(3, 'qr'), 0): 0,
 (QuantumRegister(3, 'qr'), 1): 1,
 (QuantumRegister(3, 'qr'), 2): 2}
 
Can be written more concisely as follows:
 
* virtual to physical::
 
    {qr[0]: 0,
     qr[1]: 1,
     qr[2]: 2}
 
* physical to virtual::
 
    {0: qr[0],
     1: qr[1],
     2: qr[2]}

Converts a list of integers to a Layout mapping virtual qubits (index of the list) to physical qubits (the list values).

Parameters

• int_list (list(opens in a new tab)) – A list of integers.
• *qregs (QuantumRegisters) – The quantum registers to apply the layout to.

Returns

The corresponding Layout object.

Return type

Layout

Raises

LayoutError – Invalid input layout.

Populates a Layout from a list containing virtual qubits, Qubit or None.

Parameters

• qubit_list (list(opens in a new tab)) – e.g.: [qr[0], None, qr[2], qr[3]]
• *qregs (QuantumRegisters) – The quantum registers to apply the layout to.

Returns

the corresponding Layout object

Return type

Layout

Raises

LayoutError – If the elements are not Qubit or None

Creates a trivial (“one-to-one”) Layout with the registers and qubits in regs.

Parameters

*regs (Registers, Qubits) – registers and qubits to include in the layout.

Returns

A layout with all the regs in the given order.

Return type

Layout

Returns the dictionary where the keys are physical (qu)bits and the values are virtual (qu)bits.

Returns the registers in the layout [QuantumRegister(2, ‘qr0’), QuantumRegister(3, ‘qr1’)] :returns: A set of Registers in the layout :rtype: Set

Returns the dictionary where the keys are virtual (qu)bits and the values are physical (qu)bits.

decides which one is physical/virtual based on the type. Returns (virtual, physical)

Given an ordered list of bits, reorder them according to this layout.

The list of bits must exactly match the virtual bits in this layout.

Parameters

bits (list(opens in a new tab)[Bit]) – the bits to reorder.

Returns

ordered bits.

Return type

List

Swaps the map between left and right.

Parameters

• left (tuple(opens in a new tab) orint(opens in a new tab)) – Item to swap with right.
• right (tuple(opens in a new tab) orint(opens in a new tab)) – Item to swap with left.

Raises

LayoutError – If left and right have not the same type.