Struct PartialContractionSpec 

pub struct PartialContractionSpec<I: IndexLike> {
    pub contract_pairs: Vec<(I, I)>,
    pub diagonal_pairs: Vec<(I, I)>,
    pub output_order: Option<Vec<I>>,
}

Specification for partial site contraction between two TreeTNs.

• contract_pairs: Site index pairs to sum over and remove from the result.
• diagonal_pairs: Site index pairs to identify through diagonal/copy structure while keeping the left-hand site leg in the result.
• Remaining (unmentioned) site indices pass through as external legs.

Uses Index objects directly (not raw IDs), following Julia ITensor-style conventions.

Examples

use tensor4all_core::DynIndex;
use tensor4all_treetn::PartialContractionSpec;

let idx_a = DynIndex::new_dyn(4);
let idx_b = DynIndex::new_dyn(4);
let idx_c = DynIndex::new_dyn(3);
let idx_d = DynIndex::new_dyn(3);

let spec = PartialContractionSpec {
    contract_pairs: vec![(idx_a.clone(), idx_b.clone())],
    diagonal_pairs: vec![(idx_c.clone(), idx_d.clone())],
    output_order: None,
};

assert_eq!(spec.contract_pairs.len(), 1);
assert_eq!(spec.diagonal_pairs.len(), 1);

Fields

contract_pairs: Vec<(I, I)>

Site index pairs to contract (summed over, removed from result).

diagonal_pairs: Vec<(I, I)>

Site index pairs to link through diagonal/copy structure while keeping the left-hand site index in the result.

output_order: Option<Vec<I>>

Optional order for the surviving external site indices in the result.

The indices must refer to the final result indices after applying contract_pairs and diagonal_pairs. When provided, the result is post-processed so that these indices appear in the requested order.

Current implementation requires that each surviving site index occupies a distinct node in the result.

Trait Implementations

impl<I: Clone + IndexLike> Clone for PartialContractionSpec<I>

fn clone(&self) -> PartialContractionSpec<I>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<I: Debug + IndexLike> Debug for PartialContractionSpec<I>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.