Function contract_pair 

pub fn contract_pair(
    lhs: &IdxTensor,
    rhs: &IdxTensor,
) -> Result<IdxTensor, IdxTensorError>

Contract two tensors with the default pairwise semantics.

This is the concrete IdxTensor entry point for binary contraction. It contracts all common indices and preserves the pairwise structured fast paths used by crate::TensorContractionLike::contract_pair.

Errors

Returns IdxTensorError::Operation when the pair has incompatible indices or when the backend contraction fails.