Utilities#

Graph Indexing#

See the Coordinates Conversion subsection on instantiating the needed lattice size and setting correct domain and range for coordinates in a QPU working graph. For the iterator versions of these functions, see the code.

Chimera#

`chimera_coordinates.chimera_to_linear`(q)	Converts a 4-term Chimera coordinate to a linear index.
`chimera_coordinates.graph_to_chimera`(g)	Returns a copy of the graph `g` relabeled to have Chimera coordinates.
`chimera_coordinates.graph_to_linear`(g)	Returns a copy of the graph `g` relabeled to have linear indices.
`chimera_coordinates.linear_to_chimera`(r)	Converts a linear index to a 4-term Chimera coordinate.
`chimera_sublattice_mappings`(source, target)	Yields mappings from a Chimera graph into a larger Chimera graph.
`find_chimera_indices`(G)	Determines the Chimera indices of the nodes in graph `G`.

Pegasus#

`pegasus_coordinates.graph_to_linear`(g)	Returns a copy of the graph `g` relabeled to have linear indices.
`pegasus_coordinates.graph_to_nice`(g)	Returns a copy of the graph `g` relabeled to have nice coordinates.
`pegasus_coordinates.graph_to_pegasus`(g)	Returns a copy of the graph `g` relabeled to have Pegasus coordinates.
`pegasus_coordinates.linear_to_nice`(r)	Converts a linear index into a 5-term nice coordinate.
`pegasus_coordinates.linear_to_pegasus`(r)	Converts a linear index into a 4-term Pegasus coordinate.
`pegasus_coordinates.nice_to_linear`(n)	Converts a 5-term nice coordinate into a linear index.
`pegasus_coordinates.nice_to_pegasus`(n)	Converts a 5-term nice coordinate into a 4-term Pegasus coordinate.
`pegasus_coordinates.pegasus_to_linear`(q)	Converts a 4-term Pegasus coordinate into a linear index.
`pegasus_coordinates.pegasus_to_nice`(p)	Converts a 4-term Pegasus coordinate to a 5-term nice coordinate.
`pegasus_sublattice_mappings`(source, target)	Yields mappings from a Chimera or Pegasus graph into a Pegasus graph.

Zephyr#

`zephyr_coordinates.graph_to_linear`(g)	Returns a copy of the graph g relabeled to have linear indices.
`zephyr_coordinates.graph_to_zephyr`(g)	Returns a copy of the graph g relabeled to have Zephyr coordinates.
`zephyr_coordinates.linear_to_zephyr`(r)	Converts a linear index into a 5-term Zephyr coordinate.
`zephyr_coordinates.zephyr_to_linear`(q)	Converts a 5-term Zephyr coordinate into a linear index.
`zephyr_sublattice_mappings`(source, target[, ...])	Yields mappings from a Chimera or Zephyr graph into a Zephyr graph.

Coordinates Conversion#

class chimera_coordinates(m: int, n: int | None = None, t: int | None = None)[source]#

Provides coordinate converters for the chimera indexing scheme.

Parameters:

m – The number of rows in the Chimera lattice.
n – The number of columns in the Chimera lattice.
t – The size of the shore within each Chimera tile.

Examples

Convert between Chimera coordinates and linear indices directly

>>> coords = dwave.graphs.chimera_coordinates(16, 16, 4)
>>> coords.chimera_to_linear((0, 2, 0, 1))
17
>>> coords.linear_to_chimera(17)
(0, 2, 0, 1)

Construct a new graph with the coordinate labels

>>> C16 = dwave.graphs.chimera_graph(16)
>>> coords = dwave.graphs.chimera_coordinates(16)
>>> G = nx.Graph()
>>> G.add_nodes_from(coords.iter_linear_to_chimera(C16.nodes))
>>> G.add_edges_from(coords.iter_linear_to_chimera_pairs(C16.edges))

See also: chimera_graph() describes the various conventions.

class pegasus_coordinates(m: int)[source]#

Provides coordinate converters for the Pegasus indexing schemes.

Parameters:: m – Size parameter for the Pegasus lattice.

See also: pegasus_graph() describes the various coordinate conventions.

class zephyr_coordinates(m: int, t: int = 4)[source]#

Provides coordinate converters for the Zephyr indexing schemes.

Parameters:

m – Grid parameter for the Zephyr lattice.
t – Tile parameter for the Zephyr lattice; must be even.

See also zephyr_graph() for descriptions the various coordinate conventions.

Exceptions#

Base exceptions and errors for dwave-graphs.

DWaveGraphsError

Base exception for dwave-graphs errors.