Class that manages the mapping from logical to physical qubits.
cirq.MappingManager(
device_graph: nx.Graph, initial_mapping: Dict['cirq.Qid', 'cirq.Qid']
) -> None
For efficiency, the mapping manager maps all logical and physical qubits to integers, and
maintains a mapping from logical qubit integers to physical qubit integers. This speedup is
important to avoid qubit hashing in hot-paths like querying distance of two logical qubits
on the device (via dist_on_device method).
All public methods of this class expect logical qubits (or corresponding integers that the
logical qubits are mapped to, via self.logical_qid_to_int map).
Args |
|---|
device_graph
|
connectivity graph of qubits in the hardware device.
|
initial_mapping
|
the initial mapping of logical (keys) to physical qubits (values).
|
Attributes |
|---|
induced_subgraph_int
|
Induced subgraph on physical qubit integers present in self.logical_to_physical.
|
int_to_logical_qid
|
Inverse mapping of unique integers to corresponding physical qubits.
self.logical_qid_to_int[self.int_to_logical_qid[i]] == i for each i.
|
int_to_physical_qid
|
Inverse mapping of unique integers to corresponding physical qubits.
self.physical_qid_to_int[self.int_to_physical_qid[i]] == i for each i.
|
logical_qid_to_int
|
Mapping of logical qubits, that were part of the initial mapping, to unique integers.
|
logical_to_physical
|
The mapping of logical qubit integers to physical qubit integers.
Let lq: cirq.Qid be a logical qubit. Then the corresponding physical qubit that it
maps to can be obtained by:
self.int_to_physical_qid[self.logical_to_physical[self.logical_qid_to_int[lq]]]
|
physical_qid_to_int
|
Mapping of physical qubits, that were part of the initial mapping, to unique integers.
|
physical_to_logical
|
The mapping of physical qubits integers to logical qubits integers.
Let pq: cirq.Qid be a physical qubit. Then the corresponding logical qubit that it
maps to can be obtained by:
self.int_to_logical_qid[self.physical_to_logical[self.physical_qid_to_int[pq]]]
|
Methods
apply_swap
View source
apply_swap(
lq1: int, lq2: int
) -> None
Updates the mapping to simulate inserting a swap operation between lq1 and lq2.
| Args |
|---|
lq1
|
integer corresponding to the first logical qubit.
|
lq2
|
integer corresponding to the second logical qubit.
|
| Raises |
|---|
ValueError
|
whenever lq1 and lq2 are not adjacent on the device.
|
dist_on_device
View source
dist_on_device(
lq1: int, lq2: int
) -> int
Finds distance between logical qubits 'lq1' and 'lq2' on the device.
| Args |
|---|
lq1
|
integer corresponding to the first logical qubit.
|
lq2
|
integer corresponding to the second logical qubit.
|
| Returns |
|---|
|
The shortest path distance.
|
is_adjacent
View source
is_adjacent(
lq1: int, lq2: int
) -> bool
Finds whether logical qubits lq1 and lq2 are adjacent on the device.
| Args |
|---|
lq1
|
integer corresponding to the first logical qubit.
|
lq2
|
integer corresponding to the second logical qubit.
|
| Returns |
|---|
True, if physical qubits corresponding to lq1 and lq2 are adjacent on
the device.
|
mapped_op
View source
mapped_op(
op: 'cirq.Operation'
) -> 'cirq.Operation'
Transforms the given logical operation to act on corresponding physical qubits.
| Args |
|---|
op
|
logical operation acting on logical qubits.
|
| Returns |
|---|
|
The same operation acting on corresponding physical qubits.
|
shortest_path
View source
shortest_path(
lq1: int, lq2: int
) -> Sequence[int]
Find the shortest path between two logical qubits on the device, given their mapping.
| Args |
|---|
lq1
|
integer corresponding to the first logical qubit.
|
lq2
|
integer corresponding to the second logical qubit.
|
| Returns |
|---|
A sequence of logical qubit integers on the shortest path from lq1 to lq2.
|
View source on GitHub