CouplingMap

class CouplingMap(couplinglist=None, description=None)

Bases: object

Directed graph specifying fixed coupling.

Nodes correspond to physical qubits (integers) and directed edges correspond to permitted CNOT gates

Create coupling graph. By default, the generated coupling has no nodes.

Parameters

• couplinglist (list or None) – An initial coupling graph, specified as an adjacency list containing couplings, e.g. [[0,1], [0,2], [1,2]]. It is required that nodes are contiguously indexed starting at 0. Missed nodes will be added as isolated nodes in the coupling map.

• description (str) – A string to describe the coupling map.

Methods

add_edge	Add directed edge to coupling graph.
add_physical_qubit	Add a physical qubit to the coupling graph as a node.
compute_distance_matrix	Compute the full distance matrix on pairs of nodes.
distance	Returns the undirected distance between physical_qubit1 and physical_qubit2.
draw	Draws the coupling map.
from_full	Return a fully connected coupling map on n qubits.
from_grid	Return a coupling map of qubits connected on a grid of num_rows x num_columns.
from_heavy_hex	Return a heavy hexagon graph coupling map.
from_heavy_square	Return a heavy square graph coupling map.
from_hexagonal_lattice	Return a hexagonal lattice graph coupling map.
from_line	Return a coupling map of n qubits connected in a line.
from_ring	Return a coupling map of n qubits connected to each of their neighbors in a ring.
get_edges	Gets the list of edges in the coupling graph.
is_connected	Test if the graph is connected.
largest_connected_component	Return a set of qubits in the largest connected component.
make_symmetric	Convert uni-directional edges into bi-directional.
neighbors	Return the nearest neighbors of a physical qubit.
reduce	Returns a reduced coupling map that corresponds to the subgraph of qubits selected in the mapping.
shortest_undirected_path	Returns the shortest undirected path between physical_qubit1 and physical_qubit2.
size	Return the number of physical qubits in this graph.
subgraph	Return a CouplingMap object for a subgraph of self.

Attributes

description

graph

distance_matrix

Return the distance matrix for the coupling map.

is_symmetric

Test if the graph is symmetric.

Return True if symmetric, False otherwise

physical_qubits

Returns a sorted list of physical_qubits