Module contract 

Multi-tensor contraction with optimal contraction order.

This module provides functions to contract multiple tensors efficiently using einsum optimization via the tensorbackend (tenferro-backed implementation).

This module works with concrete types (DynIndex, TensorDynLen) only.

Main Functions

• contract_multi: Contracts tensors, handling disconnected components via outer product
• contract_connected: Contracts tensors that must form a connected graph

Diag Tensor Handling

Diagonal tensors are materialized as dense native operands for contraction, so numeric einsum labels must keep uncontracted logical axes distinct. Diagonal/structured equality metadata is propagated separately onto the result when the contraction leaves equal axes behind.

Structs

AxisUnionFind

Union-Find data structure for grouping axis IDs.

ContractionOptions

Options for multi-tensor contraction.

Functions

build_diag_union

Build a union-find structure from a collection of tensors.

collect_sizes

Collect dimension sizes for remapped IDs.

contract_connected

Contract multiple tensors that form a connected graph.

contract_connected_with_options

Contract a connected tensor network with additional options.

contract_multi

Contract multiple tensors into a single tensor, handling disconnected components.

contract_multi_owned

Contract multiple owned tensors into a single tensor.

contract_multi_with_options

Contract multiple tensors into a single tensor with additional options.

print_and_reset_contract_profile

Print and clear the aggregated multi-tensor contraction profile.

remap_output_ids

Remap output IDs using the union-find structure.

remap_tensor_ids

Remap tensor indices using the union-find structure.

reset_contract_profile

Reset the aggregated multi-tensor contraction profile.