qat.core.Topology

class qat.core.Topology(is_directed=False, nbqbits=None, **kwargs)

Simple higher-level wrapper for the serializable Topology class.

Parameters

  • topology (ThriftTopology, optional) – serializable object describing the topology

  • is_directed (bool, optional) – set the topology directed or undirected (used if your topology is Custom). If your topology is undirected, any qubit of a pair is either a control or a target qubit, otherwise, only one qubit of the pair is the control qubit. The topology is, by default, undirected

  • type (TopologyType, optional) – type of the topology (All to All, LNN or Custom)

  • graph (dict<int, list<int>>, optional) – graph describing the topology (required iff the topology is Custom). Any key of this dictionary corresponds to the index of a control qubit and each linked value corresponds to indexes of qubits which can be target of this control qubit

  • nbqbits (int, optional) – number of qubits

add_edge(qb1, qb2)

Update connectivity between qubits. The topology will be set to CUSTOM (if needed). Use this method if a two qubits gate can be applied between qubits of indexes qb1 and qb2

Note

If your topology is directed, the first argument is the control qubit.

Parameters

  • qb1 (int) – index of the first qubit

  • qb2 (int) – index of the second qubit

dump(fname)

Dumps the Toplogy inside a file in binary format.

Parameters

fname (str) – the file name

classmethod from_bytes(data: bytes)

Builds a topology from raw bytes object

static from_nx(nx_graph, vmap=None)

Builds a Topology object from a networkx Graph

Parameters

  • nx_graph (networkx.Graph) – a networkx Graph

  • vmap (optional, dict) – if set, the dictionary is update with a map that maps graph nodes to qubit indexes

classmethod from_thrift(tobject, init_none=False)

Builds a Topology object from a thrift topology object

static load(fname)

Loads a Topology from a file.

Parameters

fname (str) – the file name

Returns

Topology

property nbqbits

Getter of nbqbits of a topology object

set_nbqbits()

A helper method that set the nbqbits of a custom topology, used by the HardwareSpecs to fix the number of qubits of a custom topology

to_nx(nqbits=None)

Cast the Topology object into a networkx graph.

Parameters

nqbits (optional, int) – if specified, the number of qubits

Returns

a networkx graph

Return type

nx.Graph