PythTB

https://pythtb.readthedocs.io/en/latest/
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PythTB is a Python library for constructing and analyzing tight-binding models with a focus on...
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### Install from Source

Source: https://pythtb.readthedocs.io/en/latest/install.html

Commands to install the package from the local source directory, including editable mode.

```bash
pip install .  # or pip install .[$GROUP] for optional dependencies
```

```bash
pip install -e .
```

--------------------------------

### Check Installed Package Details

Source: https://pythtb.readthedocs.io/en/latest/install.html

Display information about the installed PythTB package.

```bash
pip show pythtb
```

--------------------------------

### Verify Installation via Python Script

Source: https://pythtb.readthedocs.io/en/latest/install.html

Import the package in a Python script to verify it is correctly installed.

```python
import pythtb
print(pythtb.__version__)
```

--------------------------------

### Install PythTB in editable mode

Source: https://pythtb.readthedocs.io/en/latest/contributing/installation.html

Steps to clone the repository and install the package such that local code changes are immediately reflected.

```bash
# Clone the repository
git clone https://github.com/pythtb/pythtb.git
cd pythtb

# Install in editable/development mode
pip install -e .
```

--------------------------------

### Install PythTB via Package Managers

Source: https://pythtb.readthedocs.io/en/latest/install.html

Standard installation commands for PythTB using pip or conda.

```bash
# Using pip
pip install pythtb --upgrade

# Using conda
conda install -c conda-forge pythtb
```

--------------------------------

### Verify PythTB Installation

Source: https://pythtb.readthedocs.io/en/latest/install.html

Commands to check the installed version of the PythTB package.

```bash
python -c "import pythtb; print(pythtb.__version__)"
```

--------------------------------

### Verify PythTB installation

Source: https://pythtb.readthedocs.io/en/latest/contributing/installation.html

Commands to confirm the package is correctly installed and view the current environment's package list.

```python
import pythtb
print(pythtb.__version__)
```

```bash
conda list
```

--------------------------------

### Install Python via System Package Manager

Source: https://pythtb.readthedocs.io/en/latest/install.html

Commands to install Python on Ubuntu/Debian or macOS.

```bash
# Ubuntu / Debian
sudo apt-get install python3

# macOS (via Homebrew)
brew install python
```

--------------------------------

### Install Specific Versions

Source: https://pythtb.readthedocs.io/en/latest/install.html

Commands to install a specific version of PythTB using conda or pip.

```bash
conda install -c conda-forge pythtb=X.Y.Z
```

```bash
pip install pythtb==X.Y.Z
```

--------------------------------

### Install PythTB in Editable Mode

Source: https://pythtb.readthedocs.io/en/latest/contributing/installation.html

Install the package using `pip` with the `-e` flag for editable mode. This ensures that changes made to the source code are immediately reflected without needing to reinstall.

```bash
pip install -e .

```

--------------------------------

### Set Up Development Environment

Source: https://pythtb.readthedocs.io/en/latest/install.html

Commands to create a conda environment and clone the PythTB repository for source installation.

```bash
conda create -n pythtb-dev python=3.12
conda activate pythtb-dev
```

```bash
git clone https://github.com/pythtb/pythtb.git
cd pythtb
```

--------------------------------

### Initialize W90 interface

Source: https://pythtb.readthedocs.io/en/latest/generated/pythtb.W90.html

Example of initializing the W90 class by specifying the directory path and file prefix.

```python
>>> silicon = w90("example_a", "silicon")
```

--------------------------------

### GET /get_trial_wfs

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/wannier.html

Builds a normalized trial-wavefunction array from specifications.

```APIDOC
## GET /get_trial_wfs

### Description
Builds a normalized trial-wavefunction array from tuple specifications.

### Method
GET

### Parameters
#### Query Parameters
- **twf_list** (list) - Optional - List of list of tuples defining the trial wavefunctions.
```

--------------------------------

### Module imports and setup for pythtb.tbmodel

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/tbmodel.html

Initializes the module with necessary dependencies, logging, and public API exports.

```python
from collections.abc import Mapping
import copy
from functools import lru_cache
import logging
import warnings
import numpy as np
import inspect
from typing import Callable
from .visualization import plot_bands, plot_tbmodel, plot_tbmodel_3d
from .utils import (
    _offdiag_approximation_warning_and_stop,
    is_Hermitian,
    deprecated,
    copydoc,
    finite_difference,
    levi_civita,
)
from .lattice import Lattice
from .hoptable import HoppingTable

# set up logging
logger = logging.getLogger(__name__)

# what is exported when "from pythtb import *" is used
__all__ = ["TBModel", "tb_model"]
```

--------------------------------

### Check Python Version

Source: https://pythtb.readthedocs.io/en/latest/install.html

Verify the current Python version installed in the environment.

```bash
python -V
```

--------------------------------

### Solve Hamiltonian at k-points

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/tbmodel.html

Examples of solving for eigenvalues and eigenvectors using the solve_ham method.

```python
>>> k_pts = [[0.0, 0.0], [0.5, 0.0], [0.5, 0.5]]
>>> eval = tb.solve_ham(k_pts)
```

```python
>>> eval, evec = tb.solve_ham(k_pts, return_eigvecs=True)
```

```python
>>> eval, evec = tb.solve_ham(k_pts, return_eigvecs=True, t1=[0.0, 1.0, 2.0])
```

--------------------------------

### Evaluate Hamiltonian with Parameters

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/tbmodel.html

Examples of evaluating the Hamiltonian using specific parameter values.

```python
>>> H = tb.hamiltonian(k_pts, t1=0.5, t2=1.0)
>>> H = tb.hamiltonian(k_pts, t1=np.linspace(0,1,5), t2=1.0)
```

--------------------------------

### Define Trial Wavefunctions

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/wannier.html

Example of defining two trial wavefunctions for a spinless system with 4 orbitals.

```python
>>> twf_list = [[(0, 1.0), (2, 1.0)], [(1, 1.0), (3, -1.0)]]
>>> wan.set_trial_wfs(twf_list)
```

--------------------------------

### Build documentation locally

Source: https://pythtb.readthedocs.io/en/latest/contributing/documentation.html

Commands to navigate to the documentation directory and initiate a local build of the HTML files.

```bash
cd docs
make html
```

```bash
cd docs/
```

```bash
make html
```

```bash
sphinx-build -b html . _build/html
```

--------------------------------

### Initialize and Populate WFArray

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/wfarray.html

Demonstrates creating a mesh, initializing a WFArray, and solving a TBModel to populate it with eigenstates.

```python
>>> mesh = Mesh(['k', 'k'])
>>> mesh.build_grid(shape=(20, 20), gamma_centered=True)
>>> wfa = WFArray(lattice, mesh, spinful=True, nstates=4)
>>> wfa.shape
(20, 20, ...)

>>> wfa.filled
False

>>> wfa.solve_model(tb_model)
>>> wfa.energies.shape
(20, 20, ...)

>>> curv = wfa.berry_curvature(non_abelian=False)
```

--------------------------------

### Run tests and build documentation

Source: https://pythtb.readthedocs.io/en/latest/contributing/packaging.html

Commands to verify the project state before a release.

```bash
pytest -n auto
```

```bash
sphinx-build docs/source docs/build/html
```

--------------------------------

### View documentation in browser

Source: https://pythtb.readthedocs.io/en/latest/contributing/documentation.html

Utility script to launch the locally built documentation in the default web browser.

```bash
./see
```

```bash
./see --html # or
./see --dirhtml
```

--------------------------------

### WFArray Usage Examples

Source: https://pythtb.readthedocs.io/en/latest/generated/pythtb.WFArray.html

Demonstrates how to create, populate, and use the WFArray for various calculations, including solving a TBModel and computing physical quantities.

```APIDOC
## WFArray Usage Examples

### Populating a Mesh and WFArray

```python
# Populate Mesh with a uniform Monkhorst-Pack grid of k-points
mesh = Mesh(['k', 'k'])
mesh.build_grid(shape=(20, 20), gamma_centered=True)
wfa = WFArray(lattice, mesh, spinful=True, nstates=4)
print(wfa.shape) # Output: (20, 20, ...)
print(wfa.filled) # Output: False
```

### Solving a Model and Computing Berry Curvature

```python
# Solve a `TBModel` on the mesh and store the eigenstates
wfa.solve_model(tb_model)
print(wfa.energies.shape) # Output: (20, 20, ...)

# Compute the Berry curvature on the grid
curv = wfa.berry_curvature(non_abelian=False)
```

### Using WFArray with Parameter Sweeps

```python
# Store states from a finite model on a parameter sweep (no k-axes)
mesh = Mesh(['l'])
mesh.build_grid(shape=(101,), lambda_start=0.0, lambda_stop=2*np.pi)

# If the parameter points in the mesh are adiabatic cycles, ensure the boundary conditions are set correctly
mesh.loop(axis_idx=0, loop_idx=0)
wfa = WFArray(lattice, mesh)
wfa.set_states(eigenvectors_lambda, is_cell_periodic=False)
print(np.allclose(wfa[0], wfa[-1])) # Output: True (states at the endpoints match due to adiabatic cycle)
```

### Manual State Assignment and Periodic Boundary Conditions

```python
# Even if we set the states manually with the indexer, periodic boundary conditions are still enforced automatically
wfa[-1] = eigvecs  # shape (nstates, norb[, nspin])
print(np.allclose(wfa[0], wfa[-1])) # Output: True (states at the endpoints still match due to adiabatic cycle)
```
```

--------------------------------

### GET /plot_density

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/wannier.html

Visualizes the density distribution of a Wannier function.

```APIDOC
## GET /plot_density

### Description
Plots the density distribution of a Wannier function with options to mark the home cell, center, and lattice.

### Method
GET

### Parameters
#### Query Parameters
- **wan_idx** (int) - Required - Index of the Wannier function.
- **mark_home_cell** (bool) - Optional - Whether to mark the home cell.
- **mark_center** (bool) - Optional - Whether to mark the center.
- **show_lattice** (bool) - Optional - Whether to show the lattice.
- **dens_size** (int) - Optional - Size of the density markers.
- **lat_size** (int) - Optional - Size of the lattice markers.
- **show** (bool) - Optional - Whether to display the plot.
- **fig** (object) - Optional - Figure object.
- **ax** (object) - Optional - Axis object.
- **cbar** (bool) - Optional - Whether to show the colorbar.
```

--------------------------------

### GET /plot_decay

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/wannier.html

Visualizes the decay of a specific Wannier function.

```APIDOC
## GET /plot_decay

### Description
Generates a plot showing the decay of a Wannier function indexed by wan_idx.

### Method
GET

### Parameters
#### Query Parameters
- **wan_idx** (int) - Required - Index of the Wannier function.
- **fig** (object) - Optional - Figure object.
- **ax** (object) - Optional - Axis object.
- **show** (bool) - Optional - Whether to display the plot.
```

--------------------------------

### Build distribution artifacts

Source: https://pythtb.readthedocs.io/en/latest/contributing/packaging.html

Manual steps to create source distributions and wheels using the build module.

```bash
pip install build
python -m build
```

--------------------------------

### GET pythtb.TBModel.chern_number

Source: https://pythtb.readthedocs.io/en/latest/generated/pythtb.TBModel.html

Compute the Chern number on a specified plane.

```APIDOC
## GET pythtb.TBModel.chern_number

### Description
Compute the Chern number on the specified plane.

### Method
GET

### Endpoint
pythtb.TBModel.chern_number
```

--------------------------------

### Clone PythTB Repository

Source: https://pythtb.readthedocs.io/en/latest/development.html

Clone the PythTB project to your local machine to begin development. This is the first step for new contributors.

```bash
git clone https://github.com/your-username/pythtb.git

```

--------------------------------

### GET /model/info

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/tbmodel.html

Generates a textual report describing the model configuration.

```APIDOC
## GET /model/info

### Description
Prints or returns a textual report describing the model, including lattice vectors, orbital positions, and hopping information.

### Method
GET

### Parameters
#### Query Parameters
- **show** (bool) - Optional - If True, prints to stdout and returns None. Default is True.
- **short** (bool) - Optional - If True, includes only a lattice summary. Default is False.

### Response
#### Success Response (200)
- **report** (str or None) - The report string if show is False, otherwise None.
```

--------------------------------

### GET /model/hoppings

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/tbmodel.html

Retrieves the list of hopping terms defined in the model.

```APIDOC
## GET /model/hoppings

### Description
Returns a list of dictionaries representing the hopping terms in the model.

### Response
#### Success Response (200)
- **hoppings** (list[dict]) - List of hopping terms containing:
  - **amplitude** (complex/np.ndarray) - Hopping amplitude.
  - **from_orbital** (int) - Index of starting orbital.
  - **to_orbital** (int) - Index of ending orbital.
  - **lattice_vector** (list[int]) - Lattice vector displacement.
```

--------------------------------

### GET /info

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/wannier.html

Prints a formatted report of Wannier centers and spreads.

```APIDOC
## GET /info

### Description
Prints a formatted report of Wannier centers and spreads to the console.

### Method
GET

### Parameters
#### Query Parameters
- **precision** (int) - Optional - Number of decimal places in printed values. Defaults to 8.
```

--------------------------------

### WFArray Initialization

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/wfarray.html

Initializes a new WFArray object with a lattice and mesh configuration.

```APIDOC
## __init__

### Description
Initializes the WFArray object, validating the lattice and mesh dimensions and setting up the internal wavefunction storage.

### Parameters
- **lattice** (Lattice) - Required - The lattice object associated with the model.
- **mesh** (Mesh) - Required - The mesh object defining the grid.
- **nstates** (int) - Optional - Number of states to store. Defaults to total number of bands.
- **spinful** (bool) - Optional - Whether the model is spinful. Defaults to False.
```

--------------------------------

### Troubleshoot Environment Issues

Source: https://pythtb.readthedocs.io/en/latest/install.html

Commands to activate environments, list packages, or uninstall conflicting versions.

```bash
conda activate your-env-name
```

```bash
conda list | grep pythtb
```

```bash
pip uninstall pythtb
conda remove pythtb
```

```bash
pip install -e .
```

--------------------------------

### Create Environment via Miniconda

Source: https://pythtb.readthedocs.io/en/latest/install.html

Create and activate a dedicated environment for PythTB.

```bash
conda create -n pythtb-env python=3.12
conda activate pythtb-env
```

--------------------------------

### GET /model/nhops

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/tbmodel.html

Retrieves the total number of hopping terms defined in the model.

```APIDOC
## GET /model/nhops

### Description
Returns the number of hoppings defined in the model.

### Method
GET

### Response
#### Success Response (200)
- **nhops** (int) - Number of hoppings defined in the model.
```

--------------------------------

### Get Number of Hoppings

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/tbmodel.html

Returns the total number of hoppings defined in the model.

```python
return len(self._hoptable)
```

--------------------------------

### W90 Class Initialization

Source: https://pythtb.readthedocs.io/en/latest/generated/pythtb.W90.html

Initializes the W90 class by specifying the path to Wannier90 output files and the prefix used in the Wannier90 calculation.

```APIDOC
## W90 Class

### Description
Interface to Wannier90. This class imports tight-binding model parameters from a Wannier90 calculation and makes them available in PythTB. Upon construction, it reads the relevant Wannier90 output files from the specified directory.

### Parameters
*   **path** (str) - Relative path to the folder that contains Wannier90 files (`prefix.win`, `prefix_hr.dat`, `prefix_centres.xyz`, and optionally `prefix_band.kpt` and `prefix_band.dat`).
*   **prefix** (str) - The prefix used by the Wannier90 code (e.g., the input file name is typically `prefix.win`).

### Notes
*   Units used throughout this interface with Wannier90 are electron-volts (eV) and Angstroms.
*   This class has been tested on Wannier90 v3.1.0. Compatibility with other versions is not guaranteed.
*   The user needs to ensure that the Wannier functions computed using Wannier90 code are well localized for accurate band structure interpolation.
*   The interpolation is only exact within the frozen energy window of the disentanglement procedure.
*   PythTB assumes the position operator is diagonal in the tight-binding basis, which may affect calculations of Berry-like objects involving the position operator.

### References
[1] "Wannier90 as a community code: new features and applications", G. Pizzi et al., J. Phys. Cond. Matt. 32, 165902 (2020).

### Request Example
```python
>>> from pythtb import W90
>>> silicon = W90("example_a", "silicon")
```
```

--------------------------------

### GET /model/properties

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/tbmodel.html

Retrieves various structural and physical properties of the tight-binding model.

```APIDOC
## GET /model/properties

### Description
Retrieves properties such as dimensionality, spin configuration, and lattice geometry.

### Response
#### Success Response (200)
- **dim_k** (int) - Number of periodic directions.
- **nspin** (int) - Number of spin components.
- **spinful** (bool) - Whether the model includes spin degrees of freedom.
- **periodic_dirs** (list[int]) - Indices of periodic directions.
- **norb** (int) - Number of tight-binding orbitals per unit cell.
- **nstate** (int) - Total number of electronic states.
- **orb_vecs** (np.ndarray) - Orbital positions in reduced coordinates.
- **lat_vecs** (np.ndarray) - Lattice vectors in Cartesian coordinates.
- **recip_lat_vecs** (np.ndarray) - Reciprocal lattice vectors.
- **recip_volume** (float) - Volume of the reciprocal unit cell.
- **cell_volume** (float) - Volume of the real-space unit cell.
- **onsite** (np.ndarray) - On-site energies for each orbital.
```

--------------------------------

### GET /projectors

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/wfarray.html

Computes and returns the band projectors associated with the states in the WFArray.

```APIDOC
## GET /projectors

### Description
Returns the band projectors defined as the outer product of the wavefunctions. Optionally returns the complement projector Q.

### Method
GET

### Endpoint
/projectors

### Parameters
#### Query Parameters
- **state_idx** (int or array-like) - Optional - Index or indices of the states to include in the projector calculation.
- **return_Q** (bool) - Optional - If True, returns both the projector P and its complement Q = I - P.

### Response
#### Success Response (200)
- **P** (np.ndarray) - The band projectors.
- **Q** (np.ndarray, optional) - The complement projectors, returned only if return_Q is True.
```

--------------------------------

### POST /project

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/wannier.html

Initializes or updates Bloch-like states by projecting them onto trial wavefunctions using SVD alignment.

```APIDOC
## POST /project

### Description
Performs a single-shot projection step for Wannierization. It builds the overlap matrix between selected states and trial wavefunctions, computes the SVD, and applies the optimal unitary alignment to produce projected states.

### Method
POST

### Endpoint
/project

### Parameters
#### Request Body
- **tf_list** (list) - Optional - Trial-wavefunction specification.
- **band_idxs** (list) - Optional - State indices to include from the Bloch states.
- **use_tilde** (boolean) - Optional - Flag to determine if tilde states are used.
```

--------------------------------

### GET /compute_Amn

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/wannier.html

Computes the overlap matrix between Bloch states and trial wavefunctions.

```APIDOC
## GET /compute_Amn

### Description
Calculates the overlap matrix A_{k, n, j} = <psi_{n,k} | t_j> between reference Bloch states and trial wavefunctions.

### Method
GET

### Endpoint
/compute_Amn

### Parameters
#### Query Parameters
- **psi_nk** (np.ndarray) - Optional - States used for overlaps. If None, uses internal Bloch eigenstates.
- **twfs** (np.ndarray) - Required - Trial wavefunctions with shape (n_trial, n_orb[, n_spin]).
- **band_idxs** (sequence) - Required - State indices to include from psi_nk.

### Response
#### Success Response (200)
- **A_k** (np.ndarray) - Overlap matrix with shape (*shape_mesh, n_selected, n_trial).
```

--------------------------------

### Set Trial Wavefunctions and Project

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/wannier.html

Sets trial wavefunctions and projects them onto either Bloch energy eigenstates or tilde states. Handles default band indices for half-filling or all current tilde states.

```python
if tf_list is None:
            if self.trial_wfs is None:
                raise ValueError(
                    "Trial wavefunctions must be set before Wannierization."
                )
        else:
            self.set_trial_wfs(tf_list)

        twfs = self.trial_wfs

        if use_tilde:
            # projecting back onto tilde states
            if band_idxs is None:  # assume we are projecting onto all tilde states
                band_idxs = list(range(self.tilde_states.nstates))

            psi_til = self.tilde_states.states(flatten_spin_axis=True, return_psi=True)[
                1
            ]
            psi_til_til = self._single_shot_project(psi_til, twfs, state_idx=band_idxs)
            self.set_tilde_states(
                psi_til_til, is_cell_periodic=False, is_spin_axis_flat=True
            )

        else:
            # projecting onto Bloch energy eigenstates
            if band_idxs is None:  # assume we are Wannierizing occupied bands
                n_occ = int(self.bloch_states.nstates / 2)  # assuming half filled
                band_idxs = list(range(0, n_occ))

            psi_nk = self.bloch_states.states(flatten_spin_axis=True, return_psi=True)[
                1
            ]

            # shape: (*nks, states, orbs*n_spin])
            psi_tilde = self._single_shot_project(psi_nk, twfs, state_idx=band_idxs)
            self.set_tilde_states(
                psi_tilde, is_cell_periodic=False, is_spin_axis_flat=True
            )
```

--------------------------------

### GET /get_centers

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/wannier.html

Retrieves Wannier centers in either Cartesian or fractional coordinates.

```APIDOC
## GET /get_centers

### Description
Returns Wannier centers computed from the phases of diagonal overlap matrices.

### Method
GET

### Parameters
#### Query Parameters
- **cartesian** (bool) - Optional - If True, returns Cartesian coordinates. If False, returns fractional coordinates in the lattice basis.
```

--------------------------------

### Build a Grid Mesh in 3D k-space with a parameter

Source: https://pythtb.readthedocs.io/en/latest/generated/pythtb.Mesh.html

Initializes a Mesh object for 3D k-space and an additional parameter dimension, then builds a grid. The shape parameter defines the number of points along each axis.

```python
mesh = Mesh(axis_types=['k', 'k', 'k', 'l'])
mesh.build_grid(shape=(10, 10, 10, 100), gamma_centered=True)
mesh.grid.shape
```

--------------------------------

### GET bands_w90

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/w90.html

Reads interpolated band structure from Wannier90 output files.

```APIDOC
## GET bands_w90

### Description
Reads the band structure interpolated by Wannier90 to compare with PythTB interpolation. Requires prefix_band.kpt and prefix_band.dat files.

### Parameters
#### Query Parameters
- **return_k_cart** (bool) - Optional - If True, returns k-points in Cartesian coordinates.
- **return_k_dist** (bool) - Optional - If True, returns cumulative k-path distance.
- **return_k_nodes** (bool) - Optional - If True, returns k-point nodes and labels.

### Returns
- **kpts** (array) - k-points in reduced coordinates used in the interpolation.
```

--------------------------------

### Configure Wannier90 input file

Source: https://pythtb.readthedocs.io/en/latest/generated/pythtb.W90.html

Required flags in the prefix.win file to ensure necessary output files are generated for the PythTB interface.

```text
write_hr = True
write_xyz = True
translate_home_cell = False
```

--------------------------------

### GET shells

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/w90.html

Retrieves all unique shells of distances between Wannier function centers.

```APIDOC
## GET shells

### Description
Calculates and returns all unique distances between all Wannier function centers, rounded to a specified number of digits.

### Parameters
#### Query Parameters
- **num_digits** (int) - Optional - Distances will be rounded to these many digits. Default is 2.

### Returns
- **shells** (list) - Sorted list of unique distances in Angstroms.
```

--------------------------------

### GET dist_hop

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/w90.html

Retrieves distances and hopping terms of the Hamiltonian in the Wannier basis.

```APIDOC
## GET dist_hop

### Description
Returns all hopping terms (from orbital i to j+R) and the distances between the i and j+R orbitals. Useful for analyzing the decay of hopping terms.

### Returns
- **dist** (np.ndarray) - Distances between Wannier function centers in Angstroms.
- **ham** (np.ndarray) - Corresponding hopping terms in eV.
```

--------------------------------

### GET /model/parameters

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/tbmodel.html

Retrieves a list of parameter providers registered on on-site and hopping terms.

```APIDOC
## GET /model/parameters

### Description
Returns a list of dictionaries describing parameter providers for on-site and hopping terms.

### Method
GET

### Response
#### Success Response (200)
- **parameters** (list[dict]) - List of providers containing fields: kind, orbitals, R (for hopping), names, source (optional), and function (optional).
```

--------------------------------

### Manage WFArray Instances

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/wfarray.html

Methods for creating new instances or copies of a WFArray.

```python
[docs]
def empty_like(self, nstates: int = None) -> "WFArray":
    r"""Create a new :class:`WFArray` object with the same :class:`Lattice` and :class:`Mesh`.

    Parameters
    ----------
    nstates : int, optional
        Number of states for the new :class:`WFArray`.
        If None, uses the current number of states (default).

        .. versionchanged:: 2.0.0
            Renamed from ``nsta_arr`` for consistency with initialization.

    Returns
    -------
    WFArray
        A new :class:`WFArray` object with the same :class:`Lattice` and :class:`Mesh`.
    """
    # make a full copy of the WFArray
    wf_new = WFArray(self.lattice, self.mesh, nstates=nstates, spinful=self.spinful)
    return wf_new
```

```python
[docs]
def copy(self) -> "WFArray":
    r"""Create a copy of the current :class:`WFArray` object.

    .. versionadded:: 2.0.0

    Returns
    -------
    WFArray
        A copy of the current :class:`WFArray` object.
    """
    return copy.deepcopy(self)
```

--------------------------------

### GET /berry_flux

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/wfarray.html

Calculates the Berry flux tensor using the Fukui-Hatsugai-Suzuki plaquette method.

```APIDOC
## GET /berry_flux

### Description
Evaluates the Berry flux tensor on a reduced mesh point by forming the ordered product of parallel-transport link unitaries around an elementary plaquette.

### Parameters
#### Query Parameters
- **plane** (array_like) - Optional - Array or tuple of two mesh-axis indices over which the flux is computed.
- **state_idx** (int or array_like) - Optional - Indices of the states spanning the subspace.
- **non_abelian** (bool) - Optional - If True, return the matrix-valued non-Abelian flux. Default is False.
- **use_tensorflow** (bool) - Optional - If True, use TensorFlow for speedup. Default is False.

### Response
#### Success Response (200)
- **flux** (ndarray) - The Berry flux tensor array with shape dependent on non_abelian and plane parameters.
```

--------------------------------

### GET pythtb.TBModel.berry_curvature

Source: https://pythtb.readthedocs.io/en/latest/generated/pythtb.TBModel.html

Compute the Berry curvature in the energy eigenbasis using the Kubo formula.

```APIDOC
## GET pythtb.TBModel.berry_curvature

### Description
Compute the Berry curvature in energy eigenbasis via Kubo formula.

### Method
GET

### Endpoint
pythtb.TBModel.berry_curvature
```

--------------------------------

### WFArray Methods

Source: https://pythtb.readthedocs.io/en/latest/_modules/pythtb/wfarray.html

Methods for manipulating and initializing WFArray objects.

```APIDOC
## Methods

### empty_like
- **Description**: Create a new WFArray object with the same Lattice and Mesh.
- **Parameters**:
  - **nstates** (int) - Optional - Number of states for the new WFArray.
- **Returns**: WFArray

### copy
- **Description**: Create a copy of the current WFArray object.
- **Returns**: WFArray

### set_states
- **Description**: Populate the wavefunction array.
- **Parameters**:
  - **wfs** (np.ndarray) - Required - The wavefunctions to store.
  - **is_cell_periodic** (bool) - Optional - Whether input is cell-periodic.
  - **is_spin_axis_flat** (bool) - Optional - Whether the spin axis is flat.
```
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