qubiter.device_specific.QbitPlanarLattice module

class qubiter.device_specific.QbitPlanarLattice.QbitPlanarLattice(ascii_pic)

Bases: object

This class translates between int and int pair coordinates for qubits on a planar lattice. From a rectangular ascii picture of the planar chip ( for instance, device_specific.chip_couplings_google._BRISTLECONE_GRID), the class finds neighbors of each qubit. Two qubits are neighbors iff they are adjacent and have the same column or row. Two qubits are neighbors also iff a CNOT is physically allowed with either one of the qubits as target and the other as control.

Variables:

• num_qbits (int) –
• qbit_2d_coords (list[tuple[int, int]]) – List of 2d coords for each qubit

References

1. cirq/google/xmon_device.py
2. cirq/devices/grid_qubit.py
3. cirq/google/known_devices.py

__init__(ascii_pic)

Constructor

Parameters:ascii_pic (str) – rectangular ascii picture of planar chip. For instance, device_specific.chip_couplings_google._BRISTLECONE_GRID

are_neighbors(ind1, ind2)

Returns True iff qubits with int coords ind1 and ind2 are neighbors.

Parameters:

• ind1 (int) –
• ind2 (int) –

Returns:

Return type:

bool

get_c_to_tars()

Returns a dictionary mapping each qubit j to a list of all physically allowed target qubits, assuming j is a control of a CNOT. All qubits are specified by their int coords.

Returns: Return type:dict[int, list[int]]

is_empty(pair)

True iff pair=(row, col) position on grid has no qubit.

Parameters:pair (tuple[int, int]) – Returns: Return type:bool

neighbors_of(ind)

Returns list of ints that are int coords of qubits that are neighbors of qubit with int coord ind.

Parameters:ind (int) – Returns: Return type:list[int]

one2two(index)

Translates from int coord to int pair coords.

Parameters:index (int) – Returns: Return type:tuple[int, int]

two2one(pair)

Translates from int pair coords to int coord.

Parameters:pair (tuple[int, int]) – Returns: Return type:int