# Changelog

## Version 4.0.0

This is the first public release of ModEST, the Modular Electronic Structure
Toolkit. ModEST is the electronic-structure extension pack to TRIQS, providing
the building blocks for generic quantum-embedding (DMFT and beyond)
calculations in connection with electronic-structure methods such as DFT and
many-body perturbation theory.

This release requires a TRIQS installation of the same major and minor version
(4.0) and is built on the latest app4triqs skeleton, with Python bindings
generated by the clair + c2py framework.

We thank all contributors: Jennifer Coulter, Thomas Hahn, Alexander Hampel, Harrison LaBollita, Jae-Mo Lihm, Henri Menke, Olivier Parcollet, Dylan Simon, Nils Wentzell

The main features of this release are:

### One-body elements and tight-binding
* `one_body_elements` (OBE) types describing the one-body part of an embedding
  problem, both on a fixed k-grid and as a tight-binding model (`obe_tb`)
* Adaptive Brillouin-zone integration for tight-binding models, with a
  user-specified target accuracy
* Construction of `obe_tb` directly from a `tb_hamiltonian`, and from GW input
* MPI broadcast and equality operators for the one-body-element types

### Embedding
* `embedding` class describing the correlated subspace and its mapping to
  impurities, with `embed` / `extract` operations dispatched on array rank
* Support for constructing a two-particle embedding from a one-particle one,
  and for embedding/extraction of CoQui-type (GW+EDMFT) objects
* `split_block`, `make_embedding` (incl. from HDF5 and atomic decomposition),
  spinless embeddings, and rotation of embedded self-energies for sign-problem
  optimization
* Automatic detection of unconnected impurities and degenerate-block analysis

### Local Green's function and charge self-consistency
* Local Green's function `gloc` with a Woodbury-based inversion that scales
  linearly rather than cubically in the number of bands
* `charge_density_correction` for charge self-consistent DFT+DMFT
* Hybrid OpenMP/MPI parallelism in the density routines

### Double counting and interaction Hamiltonians
* `dc_solver` supporting spin-polarized and non-polarized double counting
* Interaction-Hamiltonian factories (`hamiltonians`), including
  density-density interactions

### DFT interfaces
* Generic DFT driver and DFT-code-specific support (VASP, Quantum ESPRESSO,
  Wien2k), organized under `dft_tools/`
* Loaders for `HkConverter` and GW input

### Post-processing and I/O
* Spectral-function and Green's-function post-processing utilities
* HDF5 checkpointing of calculations
* `symmetrize` for block-matrix and Green's-function types, and exposure of
  `ibz_symmetry_ops` to Python

### Python bindings and documentation
* Python bindings split into per-component submodules, generated with
  clair + c2py and compiled with hidden symbol visibility
* Documentation built with Doxygen and Sphinx, including a charge
  self-consistent VASP+DMFT tutorial for SrVO3 and theory notes

### Build, install and CI
* Dependencies managed via CPM
* Optional Git LFS test data (`Enable_LFS_Tests`) for large multi-orbital tests
* GitHub Actions and TRIQS Jenkins CI for Linux (clang/gcc) and macOS