Contraction
Contraction path optimization and execution is delegated to the EinExprs library. A EinExpr is a lower-level form of a Tensor Network, in which the contraction path has been laid out as a tree. It is similar to a symbolic expression (i.e. Expr) but in which every node represents an Einstein summation expression (aka einsum).
EinExprs.einexpr — Methodeinexpr(tn::TensorNetwork; optimizer = EinExprs.Greedy, output = inds(tn, :open), kwargs...)Search a contraction path for the given TensorNetwork and return it as a EinExpr.
Keyword Arguments
optimizerContraction path optimizer. CheckEinExprsdocumentation for more info.outputsIndices that won't be contracted. Defaults to open indices.kwargsOptions to be passed to the optimizer.
See also: contract.
Tenet.contract — Methodcontract(tn::TensorNetwork; kwargs...)Contract a TensorNetwork. The contraction order will be first computed by einexpr.
The kwargs will be passed down to the einexpr function.
Tenet.contract! — Functioncontract!(tn::TensorNetwork, index)In-place contraction of tensors connected to index.
See also: contract.
Tenet.contract!(tn::Chain, ::Val{:between}, site1::Site, site2::Site; direction::Symbol = :left, delete_Λ = true)For a given Chain tensor network, contracts the singular values Λ between two sites site1 and site2. The direction keyword argument specifies the direction of the contraction, and the delete_Λ keyword argument specifies whether to delete the singular values tensor after the contraction.