We are happy to announce the initial release of the ITensorMPS.jl package. This package will be the future home of all of the MPS and MPO functionality currently living in ITensors.jl and ITensorTDVP.jl.
For the time being, to make the upgrade path for current users of ITensors.jl and ITensorTDVP.jl easier, it simply re-exports the MPS and MPO functionality of ITensors.jl and ITensorTDVP.jl. To get started with ITensorMPS.jl, install it as usual with using Pkg; Pkg.add("ITensorMPS") and load it with using ITensorMPS, which gives you access to the same MPS and MPO functionality as the latest version of ITensors.jl, such as the MPS and MPO types, OpSum, dmrg, apply, expect, etc., along with the functionality of ITensorTDVP.jl, such as tdvp, dmrg_x, linsolve, etc.
We strongly encourage all users to switch over to using ITensorMPS.jl as soon as possible if you are using any MPS and MPO functionality currently in ITensors.jl and ITensorTDVP.jl. The upgrade is simple, just install ITensorMPS.jl and change scripts that load ITensors.jl with using ITensors to using ITensors, ITensorMPS (to make sure you get access to both basic ITensor functionality along with MPS and MPO functionality). If you are using ITensorTDVP.jl, simply change using ITensorTDVP to using ITensorMPS. Eventually (probably by fall of 2024) we will require users to do this since we will remove the MPS and MPO functionality from ITensors.jl, deprecate ITensorTDVP.jl, and move the MPS and MPO functionality of those packages to ITensorMPS.jl.
See the ITensorMPS.jl README for more information.