Code graph functions
Functions to access and manipulate the CodeGraph associated with a TensorNetworkCode.
Introductory notes
- Node labels are of type
Intwith negative and positive integers representing virtual nodes and physical qubits, respectively. - Edge labels are of type
Set{Int}and contain two elements corresponding to the labels of the nodes that the edge links. - Node coordinates are of type
Vector{<:Real}and contain two elements corresponding to 2-dimensional Cartesian coordinates. - Node types are of type
Stringand can take the values: "physical" for physical qubits or else they take the name of a seed code for virtual nodes, e.g., "Five qubit code". - Edge types are of type
Stringand can take the values: "physical" for an edge between a virtual node and physical (i.e., qubit) node or "bond" for an edge between two virtual nodes, e.g., as occurs after contracting a "Five qubit code" and a "Steane code". - Edge indices are of type
Vector{ITensors.Index{Int64}}}. These are lists of the indices necessary for tensor-network contraction (e.g., for decoding). - Node indices are also of type
Vector{ITensors.Index{Int64}}}. These indices match the indices on the incident edges to that node. This is necessary for, e.g., tensor-network decoding: when a tensor is created at a node, the first index in the list of node indices corresponds to the first qubit of the seed code, and so on.
Specialized functions
TensorNetworkCodes.edges — Functionedges(code) -> Vector{Set{Int}}Returns a list of edge labels for the code, corresponding to edges between nodes.
TensorNetworkCodes.new_indices — Functionnew_indices(code::TensorNetworkCode) -> TensorNetworkCodeDeepcopies the code but changes all ITensor indices.
TensorNetworkCodes.nodes — Functionnodes(code::TensorNetworkCode) -> Vector{Int}Returns an ordered list of node labels for the code, corresponding to the qubits and virtual nodes.
TensorNetworkCodes.num_nodes — Functionnum_nodes(code::TensorNetworkCode) -> IntReturns the number of nodes in the code, which is the sum of the number of qubits and the number of virtual nodes.
TensorNetworkCodes.physical_neighbours — Functionphysical_neighbours(code::TensorNetworkCode, node::Int) -> Set{Int}Returns the node labels of physical qubits connected by an edge to the given node.
TensorNetworkCodes.set_coords! — Methodset_coords!(
code::TensorNetworkCode,
new_coords::AbstractVector{<:AbstractVector{<:Real}}
)Assign new coordinates to all (physical and virtual) nodes of the code, where the order of the coordinates matches that of the nodes returned by nodes, i.e. in ascending order.
TensorNetworkCodes.shift_coords! — Methodshift_coords!(code::TensorNetworkCode, shift::AbstractVector{<:Real})Shift the coordinates of all (physical and virtual) nodes of the code by the given shift.
Generic getters / setters
TensorNetworkCodes.coords — Functioncoords(code::TensorNetworkCode)Return coords field of the code's CodeGraph.
coords(code::TensorNetworkCode, label::Int)Return coords[label] for the node from the code's CodeGraph.
TensorNetworkCodes.set_coords! — Methodset_coords!(code::TensorNetworkCode, label::Int, new_data)Set coords[label] for the node from the code's CodeGraph.
TensorNetworkCodes.edge_indices — Functionedge_indices(code::TensorNetworkCode)Return edge_indices field of the code's CodeGraph.
edge_indices(code::TensorNetworkCode, label::Set{Int})Return edge_indices[label] for the edge from the code's CodeGraph.
TensorNetworkCodes.set_edge_indices! — Functionset_edge_indices!(code::TensorNetworkCode, label::Set{Int}, new_data)Set edge_indices[label] for the edge from the code's CodeGraph.
TensorNetworkCodes.edge_types — Functionedge_types(code::TensorNetworkCode)Return edge_types field of the code's CodeGraph.
edge_types(code::TensorNetworkCode, label::Set{Int})Return edge_types[label] for the edge from the code's CodeGraph.
TensorNetworkCodes.set_edge_types! — Functionset_edge_types!(code::TensorNetworkCode, label::Set{Int}, new_data)Set edge_types[label] for the edge from the code's CodeGraph.
TensorNetworkCodes.node_indices — Functionnode_indices(code::TensorNetworkCode)Return node_indices field of the code's CodeGraph.
node_indices(code::TensorNetworkCode, label::Int)Return node_indices[label] for the node from the code's CodeGraph.
TensorNetworkCodes.set_node_indices! — Functionset_node_indices!(code::TensorNetworkCode, label::Int, new_data)Set node_indices[label] for the node from the code's CodeGraph.
TensorNetworkCodes.node_types — Functionnode_types(code::TensorNetworkCode)Return node_types field of the code's CodeGraph.
node_types(code::TensorNetworkCode, label::Int)Return node_types[label] for the node from the code's CodeGraph.
TensorNetworkCodes.set_node_types! — Functionset_node_types!(code::TensorNetworkCode, label::Int, new_data)Set node_types[label] for the node from the code's CodeGraph.