Pepsy Library

pepsy is a Python package for boundary-MPS based PEPS norm contraction and related DMRG fitting workflows.

Current package version: 0.0.1 (from pepsy/VERSION).

Package Layout

• pepsy/: installable library code
  • boundary_states.py: boundary state initialization (BdyMPS)
  • boundary_sweeps.py: sweep/contraction runner (CompBdy)
  • boundary_norm.py: input preparation + contraction (prepare_boundary_inputs, ContractBoundary)
  • dmrg_fit.py, core.py, linalg_registrations.py
• example/: example notebooks
• docs/: Sphinx documentation source
• tests/: package tests

Install

python -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
pip install -e .
# Optional backends:
# pip install -e .[torch]
# pip install -e .[jax]

Quick Usage

import pepsy
from pepsy import BdyMPS, CompBdy, ContractBoundary, prepare_boundary_inputs

print(pepsy.__version__)

Documentation

Build docs locally:

pip install -e .[docs]
sphinx-build -W -b html docs docs/_build/html

Main docs sections:

• getting_started
• tutorials/
• howto/
• api/

Guided notebook example:

• example/norm.ipynb

Notes

• .gitattributes marks notebooks as binary to avoid noisy diffs.
• .gitignore excludes checkpoints, caches, cash/, and nohup.out.