# How to use the tensornetwork.network_operations.get_subgraph_dangling function in tensornetwork

## To help you get started, we’ve selected a few tensornetwork examples, based on popular ways it is used in public projects.

Secure your code as it's written. Use Snyk Code to scan source code in minutes - no build needed - and fix issues immediately. google / TensorNetwork / tensornetwork / contractors / opt_einsum_paths / utils.py View on Github def _get_path_nodes(nodes: Iterable[BaseNode], algorithm: Algorithm
) -> Tuple[List[Tuple[int, int]], List[BaseNode]]:
"""Calculates the contraction paths using opt_einsum methods.

Args:
nodes: An iterable of nodes.
algorithm: opt_einsum method to use for calculating the contraction path.

Returns:
The optimal contraction path as returned by opt_einsum.
"""
sorted_nodes = sorted(nodes, key=lambda n: n.signature)

input_sets = [set(node.edges) for node in sorted_nodes]
output_set = get_subgraph_dangling(nodes)
size_dict = {edge: edge.dimension for edge in get_all_edges(nodes)}

return algorithm(input_sets, output_set, size_dict), sorted_nodes google / TensorNetwork / tensornetwork / contractors / opt_einsum_paths / path_contractors.py View on Github if final node has more than one edge,
output_edge_order must be pronvided.
ignore_edge_order: An option to ignore the output edge
order.

Returns:
Final node after full contraction.
"""
nodes_set = set(nodes)
edges = get_all_edges(nodes_set)
#output edge order has to be determinded before any contraction
#(edges are refreshed after contractions)

if not ignore_edge_order:
if output_edge_order is None:
output_edge_order = list(get_subgraph_dangling(nodes))
if len(output_edge_order) > 1:
raise ValueError("The final node after contraction has more than "
"one remaining edge. In this case output_edge_order "
"has to be provided.")

if set(output_edge_order) != get_subgraph_dangling(nodes):
raise ValueError(
"output edges are not equal to the remaining "
"non-contracted edges of the final node."
)

for edge in edges:
if not edge.is_disabled:  #if its disabled we already contracted it
if edge.is_trace():
nodes_set.remove(edge.node1)
nodes_set.add(contract_parallel(edge)) google / TensorNetwork / tensornetwork / contractors / opt_einsum_paths / path_contractors.py View on Github Final node after full contraction.
"""
nodes_set = set(nodes)
edges = get_all_edges(nodes_set)
#output edge order has to be determinded before any contraction
#(edges are refreshed after contractions)

if not ignore_edge_order:
if output_edge_order is None:
output_edge_order = list(get_subgraph_dangling(nodes))
if len(output_edge_order) > 1:
raise ValueError("The final node after contraction has more than "
"one remaining edge. In this case output_edge_order "
"has to be provided.")

if set(output_edge_order) != get_subgraph_dangling(nodes):
raise ValueError(
"output edges are not equal to the remaining "
"non-contracted edges of the final node."
)

for edge in edges:
if not edge.is_disabled:  #if its disabled we already contracted it
if edge.is_trace():
nodes_set.remove(edge.node1)

if len(nodes_set) == 1:
# There's nothing to contract.
if ignore_edge_order:
return list(nodes_set)
return list(nodes_set).reorder_edges(output_edge_order)

## tensornetwork

A high level tensor network API for accelerated tensor network calculations. GitHub Apache-2.0 Latest version published 2 years ago

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