HexagonalLattice#

class HexagonalLattice(rows, cols, edge_parameter=1.0, onsite_parameter=0.0)[source]#

Bases: Lattice

Hexagonal lattice.

Parameters:
  • rows (int) – Number of hexagons in the x direction.

  • cols (int) – Number of hexagons in the y direction.

  • edge_parameter (complex) – Weight on all the edges, specified as a single value. Defaults to 1.0.

  • onsite_parameter (complex) – Weight on the self-loops, which are edges connecting a node to itself. Defaults to 0.0.

Attributes

edge_parameter#

Weights on all edges.

Returns:

the parameter for the edges.

graph#

Return a copy of the input graph.

node_indexes#

Return the node indexes.

num_nodes#

Return the number of nodes.

onsite_parameter#

Weight on the self-loops (edges connecting a node to itself).

Returns:

the parameter for the self-loops.

weighted_edge_list#

Return a list of weighted edges.

Methods

copy()#

Return a copy of the lattice.

Return type:

Lattice

draw(*, self_loop=False, style=None)#

Draw the lattice.

Parameters:
classmethod from_adjacency_matrix(interaction_matrix)#

Constructs a new lattice from a 2-dimensional adjacency matrix.

This method is equivalent to PyGraph.from_adjacency_matrix() or its complex counterpart when given a complex-valued matrix.

Parameters:

interaction_matrix (ndarray) – the adjacency matrix from which to build out the lattice.

Raises:

ValueError – if the provided adjacency matrix is not a 2-D square matrix.

Returns:

A new lattice based on the provided adjacency matrix.

Return type:

Lattice

classmethod from_nodes_and_edges(num_nodes, weighted_edges)#

Return an instance of Lattice from the number of nodes and the list of edges.

Parameters:
  • num_nodes (int) – The number of nodes.

  • weighted_edges (List[Tuple[int, int, complex]]) – A list of tuples consisting of two nodes and the weight between them.

Returns:

Lattice generated from lists of nodes and edges.

Return type:

Lattice

to_adjacency_matrix(weighted=False)#

Return its adjacency matrix from weighted edges. The weighted edge list is interpreted as the upper triangular matrix. Defaults to False.

Parameters:

weighted (bool) – The matrix elements are 0 or 1 when it is False. Otherwise, the weights on edges are returned as the matrix elements.

Returns:

The adjacency matrix of the input graph.

Return type:

ndarray

uniform_parameters(uniform_interaction, uniform_onsite_potential)#

Returns a new lattice with uniform parameters but otherwise identical structure.

Parameters:
  • uniform_interaction (complex) – the value to use for all edge weights.

  • uniform_onsite_potential (complex) – the value to use for all single-vertex loop weights.

Returns:

A new lattice with identical structure but uniform parameters.

Return type:

Lattice