ITensor / ITensor/ITensorMPS.jl

[ITensors] [ENHANCEMENT] DMRG with nonzero primes on MPO link indices

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enhancement
Dominant language
Julia
Stars
85
Forks
27
Avg merge
22m
Merged PRs (30d)
1

Description

dmrg doesn't work with MPOs where the link indices have nonzero prime levels, see https://itensor.discourse.group/t/dmrg-for-non-hermitian-mpo/1287. Would be good to fix that so it "just works".

This is likely already fixed in the new solver/DMRG code in ITensorNetworks.jl since that design is more generic but it's good to fix here as well.

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start at the dmrg implementation in ITensorMPS.jl and reproduce the failure with an MPO whose link indices have nonzero prime levels, using the linked Discourse report for context. Compare the behavior with the newer solver/DMRG code in ITensorNetworks.jl; done means dmrg works with these MPOs without special handling by callers.

Written by the indexing model from the issue text.

Assessment

Tech stack
julia
Domain
hpc
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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