spectralcluster 0.2.22
Spectral Clustering

# Spectral Clustering
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## Overview

This is a Python re-implementation of the spectral clustering algorithms
presented in these papers:

| Algorithm                       | Paper       |
| ------------------------------- | ----------- |
| Refined Laplacian matrix        | [Speaker Diarization with LSTM](https://google.github.io/speaker-id/publications/LstmDiarization/) |
| Constrained spectral clustering | [Turn-to-Diarize: Online Speaker Diarization Constrained by Transformer Transducer Speaker Turn Detection](https://arxiv.org/abs/2109.11641) |
| Multi-stage clustering          | [Highly Efficient Real-Time Streaming and Fully On-Device Speaker Diarization with Multi-Stage Clustering](https://arxiv.org/abs/2210.13690)

![refinement](https://raw.githubusercontent.com/wq2012/SpectralCluster/master/resources/refinement.png)

## Notice

We recently added new functionalities to this library to include
 algorithms in a [new paper](https://arxiv.org/abs/2109.11641). We updated the APIs as well.

If you depend on our old API, please use an **older version** of this library:
```
pip3 install spectralcluster==0.1.0
```

## Disclaimer

**This is not a Google product.**

**This is not the original C++ implementation used by the papers.**

Please consider this repo as a "demonstration" of the algorithms,
instead of a "reproduction" of what we use at Google. Some features
might be missing or incomplete.

## Installation

Install the [package](https://pypi.org/project/spectralcluster/) by:

```bash
pip3 install spectralcluster
```

or

```bash
python3 -m pip install spectralcluster
```

## Tutorial

Simply use the `predict()` method of class `SpectralClusterer` to perform
spectral clustering. The example below should be closest to the original C++
implemention used by our
[ICASSP 2018 paper](https://google.github.io/speaker-id/publications/LstmDiarization/).

```python
from spectralcluster import configs

labels = configs.icassp2018_clusterer.predict(X)
```

The input `X` is a numpy array of shape `(n_samples, n_features)`,
and the returned `labels` is a numpy array of shape `(n_samples,)`.

You can also create your own clusterer like this:

```
from spectralcluster import SpectralClusterer

clusterer = SpectralClusterer(
    min_clusters=2,
    max_clusters=7,
    autotune=None,
    laplacian_type=None,
    refinement_options=None,
    custom_dist="cosine")

labels = clusterer.predict(X)
```

For the complete list of parameters of `SpectralClusterer`, see
`spectralcluster/spectral_clusterer.py`.

[![youtube_screenshot_icassp2018](https://raw.githubusercontent.com/wq2012/SpectralCluster/master/resources/youtube_screenshot_icassp2018.jpg)](https://youtu.be/pjxGPZQeeO4)
[![youtube_screenshot_icassp2022](https://raw.githubusercontent.com/wq2012/SpectralCluster/master/resources/youtube_screenshot_icassp2022.png)](https://youtu.be/U79Aw1ky7ag)

## Advanced features

### Refinement operations

In our [ICASSP 2018 paper](https://google.github.io/speaker-id/publications/LstmDiarization/), we apply a sequence of refinment operations on the affinity matrix, which is critical to the performance on the speaker diarization results.

You can specify your refinement operations like this:

```
from spectralcluster import RefinementOptions
from spectralcluster import ThresholdType
from spectralcluster import ICASSP2018_REFINEMENT_SEQUENCE

refinement_options = RefinementOptions(
    gaussian_blur_sigma=1,
    p_percentile=0.95,
    thresholding_soft_multiplier=0.01,
    thresholding_type=ThresholdType.RowMax,
    refinement_sequence=ICASSP2018_REFINEMENT_SEQUENCE)
```

Then you can pass the `refinement_options` as an argument when initializing your
`SpectralClusterer` object.

For the complete list of `RefinementOptions`, see
`spectralcluster/refinement.py`.

### Laplacian matrix

In our [ICASSP 2018 paper](https://google.github.io/speaker-id/publications/LstmDiarization/),
we apply a refinement operation `CropDiagonal` on the affinity matrix, which replaces each diagonal element of the affinity matrix by the max non-diagonal value of the row. After this operation, the matrix has similar properties to a standard Laplacian matrix, and it is also less sensitive (thus more robust) to the Gaussian blur operation than a standard Laplacian matrix.

In the new version of this library, we support different types of Laplacian matrix now, including:

* None Laplacian (affinity matrix): `W`
* Unnormalized Laplacian: `L = D - W`
* Graph cut Laplacian: `L' = D^{-1/2} * L * D^{-1/2}`
* Random walk Laplacian: `L' = D^{-1} * L`

You can specify the Laplacian matrix type with the `laplacian_type` argument of the `SpectralClusterer` class.

Note: Refinement operations are applied to the affinity matrix **before** computing the Laplacian matrix.

### Distance for K-Means

In our [ICASSP 2018 paper](https://google.github.io/speaker-id/publications/LstmDiarization/),
the K-Means is based on Cosine distance.

You can set `custom_dist="cosine"` when initializing your `SpectralClusterer` object.

You can also use other distances supported by [scipy.spatial.distance](https://docs.scipy.org/doc/scipy/reference/spatial.distance.html), such as `"euclidean"` or `"mahalanobis"`.

### Affinity matrix

In our [ICASSP 2018 paper](https://google.github.io/speaker-id/publications/LstmDiarization/),
the affinity between two embeddings is defined as `(cos(x,y)+1)/2`.

You can also use other affinity functions by setting `affinity_function` when initializing your `SpectralClusterer` object.

### Auto-tune

We also support auto-tuning the `p_percentile` parameter of the `RowWiseThreshold` refinement operation, which was original proposed in [this paper](https://arxiv.org/abs/2003.02405).

You can enable this by passing in an `AutoTune` object to the `autotune` argument when initializing your `SpectralClusterer` object.

Example:

```python
from spectralcluster import AutoTune, AutoTuneProxy

autotune = AutoTune(
    p_percentile_min=0.60,
    p_percentile_max=0.95,
    init_search_step=0.01,
    search_level=3,
    proxy=AutoTuneProxy.PercentileSqrtOverNME)
```

For the complete list of parameters of `AutoTune`, see
`spectralcluster/autotune.py`.

### Fallback clusterer

Spectral clustering exploits the global structure of the data. But there are
cases where spectral clustering does not work as well as some other simpler
clustering methods, such as when the number of embeddings is too small.

When initializing the `SpectralClusterer` object, you can pass in a `FallbackOptions` object to the `fallback_options` argument, to use a fallback clusterer under certain conditions.

Also, spectral clustering and eigen-gap may not work well at making single-vs-multi cluster decisions. When `min_clusters=1`, we can also specify `FallbackOptions.single_cluster_condition` and `FallbackOptions.single_cluster_affinity_threshold` to help determine single cluster cases by thresdholding the affinity matrix.

For the complete list of parameters of `FallbackOptions`, see `spectralcluster/fallback_clusterer.py`.

### Speed up the clustering

Spectral clustering can become slow when the number of input embeddings is large. This is due to the high costs of steps such as computing the Laplacian matrix, and eigen decomposition of the Laplacian matrix. One trick to speed up the spectral clustering when the input size is large is to use hierarchical clustering as a pre-clustering step.

To use this feature, you can specify the `max_spectral_size` argument when constructing the `SpectralClusterer` object. For example, if you set `max_spectral_size=200`, then the Laplacian matrix can be at most `200 * 200`.

But please note that setting `max_spectral_size` may cause degradations of the final clustering quality. So please use this feature wisely.

### Constrained spectral clustering

![turn-to-diarize-diagram](https://raw.githubusercontent.com/wq2012/SpectralCluster/master/resources/turn-to-diarize.png)

In the [Turn-to-Diarize paper](https://arxiv.org/abs/2109.11641),
the spectral clustering is constrained by speaker turns.
We implemented two constrained spectral clustering methods:

* Affinity integration.
* Constraint propagation (see paper [[1](https://link.springer.com/chapter/10.1007/978-3-642-15567-3_1)] and [[2](https://arxiv.org/abs/1109.4684)]).

If you pass in a `ConstraintOptions` object when initializing your `SpectralClusterer` object, you can call the `predict` function with a `constraint_matrix`.

Example usage:

```python
from spectralcluster import constraint

ConstraintName = constraint.ConstraintName

constraint_options = constraint.ConstraintOptions(
    constraint_name=ConstraintName.ConstraintPropagation,
    apply_before_refinement=True,
    constraint_propagation_alpha=0.6)

clusterer = spectral_clusterer.SpectralClusterer(
    max_clusters=2,
    refinement_options=refinement_options,
    constraint_options=constraint_options,
    laplacian_type=LaplacianType.GraphCut,
    row_wise_renorm=True)

labels = clusterer.predict(matrix, constraint_matrix)
```

The constraint matrix can be constructed from a `speaker_turn_scores` list:

```python
from spectralcluster import constraint

constraint_matrix = constraint.ConstraintMatrix(
    speaker_turn_scores, threshold=1).compute_diagonals()
```

### Multi-stage clustering

![multi-stage-clustering-diagram](https://raw.githubusercontent.com/wq2012/SpectralCluster/master/resources/multi-stage-clustering.png)


In the [multi-stage clustering paper](https://arxiv.org/abs/2210.13690),
we introduced a highly efficient **streaming** clustering approach. This is
implemented as the `MultiStageClusterer` class in
`spectralcluster/multi_stage_clusterer.py`.

> Note: We did NOT implement speaker turn detection in this open source library.
We only implemented fallback, main, pre-clusterer and dynamic compression here.

The `MultiStageClusterer` class has a method named `streaming_predict`.
In streaming clustering, every time we feed a **single** new embedding to the
`streaming_predict` function, it will return the sequence of cluster labels
for **all** inputs, including corrections for the predictions on previous
embeddings.

Example usage:

```python
from spectralcluster import Deflicker
from spectralcluster import MultiStageClusterer
from spectralcluster import SpectralClusterer

main_clusterer = SpectralClusterer()

multi_stage = MultiStageClusterer(
    main_clusterer=main_clusterer,
    fallback_threshold=0.5,
    L=50,
    U1=200,
    U2=400,
    deflicker=Deflicker.Hungarian)

for embedding in embeddings:
    labels = multi_stage.streaming_predict(embedding)
```

## Citations

Our papers are cited as:

```
@inproceedings{wang2018speaker,
  title={{Speaker Diarization with LSTM}},
  author={Wang, Quan and Downey, Carlton and Wan, Li and Mansfield, Philip Andrew and Moreno, Ignacio Lopz},
  booktitle={2018 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)},
  pages={5239--5243},
  year={2018},
  organization={IEEE}
}

@inproceedings{xia2022turn,
  title={{Turn-to-Diarize: Online Speaker Diarization Constrained by Transformer Transducer Speaker Turn Detection}},
  author={Wei Xia and Han Lu and Quan Wang and Anshuman Tripathi and Yiling Huang and Ignacio Lopez Moreno and Hasim Sak},
  booktitle={2022 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)},
  pages={8077--8081},
  year={2022},
  organization={IEEE}
}

@article{wang2022highly,
  title={Highly Efficient Real-Time Streaming and Fully On-Device Speaker Diarization with Multi-Stage Clustering},
  author={Quan Wang and Yiling Huang and Han Lu and Guanlong Zhao and Ignacio Lopez Moreno},
  journal={arXiv:2210.13690},
  year={2022}
}
```

## Star History

[![Star History Chart](https://api.star-history.com/svg?repos=wq2012/SpectralCluster&type=Date)](https://star-history.com/#wq2012/SpectralCluster&Date)

## Misc

We also have fully supervised speaker diarization systems, powered by
[uis-rnn](https://github.com/google/uis-rnn).
Check this [Google AI Blog](https://ai.googleblog.com/2018/11/accurate-online-speaker-diarization.html).

Also check out our recent work on [DiarizationLM](https://arxiv.org/abs/2401.03506).

To learn more about speaker diarization, you can check out:
* A curated list of resources:
[awesome-diarization](https://github.com/wq2012/awesome-diarization)
* An online course on Udemy: [A Tutorial on Speaker Diarization](https://www.udemy.com/course/diarization/?referralCode=21D7CC0AEABB7FE3680F)