## scores.PyODScore


Uncertainty scores based on detectors supplied by PyOD.


Usage

``` python
scores.PyODScore(
    detector,
    pca=None,
)
```


Computes outlier scores using PyOD detectors where low scores indicate samples similar to the training distribution (low uncertainty) and high scores indicate samples deviating from the training distribution (high uncertainty).


## Parameters


`detector: pyod.models.base.BaseDetector`  
A fitted or unfitted PyOD detector instance. Any detector from the `pyod` library that implements [fit](scores.PCAScore.md#seapig.scores.PCAScore.fit) and `decision_function` is supported (e.g., `pyod.models.knn.KNN`).

`pca: TensorPCA or None = None`  
Optional PCA for dimensionality reduction prior to scoring.


## Notes

Requires the optional `pyod` dependency. Install with:

    pip install pyod


## See Also

[scores.EmbeddingScore](scores.EmbeddingScore.md#seapig.scores.EmbeddingScore)  


## Methods

| Name | Description |
|----|----|
| [fit()](#fit) | Train an uncertainty score based on sample embeddings. |
| [score()](#score) | Compute uncertainty scores for query samples. |
| [select()](#select) | Select samples for prediction based on their uncertainty score. |
| [set_threshold()](#set_threshold) | Set a threshold based on a quantile of the available uncertainty scores. |
| [get_threshold()](#get_threshold) | Get the current threshold value. |
| [plot()](#plot) | Plot densities for uncertainty scores. |
| [plot_embs()](#plot_embs) | Visualize training, validation, and query embeddings in 2D. |

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


#### fit()


Train an uncertainty score based on sample embeddings.


Usage

``` python
fit(
    X=None,
    Y=None,
    model=None,
    loaders=None,
    outdir=None,
    prefix=None,
    q=False
)
```


This method supports two usage modes:

1.  **Precomputed embeddings**: Supply training embeddings via `X` and optional calibration embeddings via `Y`.
2.  **On-the-fly extraction**: Supply a `model` with an `.embed()` method and a dictionary of `DataLoaders` to extract embeddings automatically.

You must use either embeddings (X/Y) OR model+loaders, but not both.

``` python
# Mode 1: Precomputed embeddings
from pyod.models.knn import KNN
from seapig.scores.pyod import PyODScore
my_score = PyODScore(detector=KNN(n_neighbors=5))
my_score.fit(X=train_embs, Y=val_embs)

# Mode 2: On-the-fly extraction
my_score = PyODScore(detector=KNN(n_neighbors=5))
my_score.fit(model=model, loaders={"train": train_loader, "val": val_loader})
```


##### Parameters


`X: torch.Tensor | None = None`  
A `torch.Tensor` with training sample embeddings. Required when not using `model` and `loaders`.

`Y: torch.Tensor | None = None`  
A `torch.Tensor` with calibration sample embeddings. Optional.

`model: torch.nn.Module | None = None`  
A `torch.nn.Module` with an `.embed()` method. Required when not using `X`.

`loaders: dict[str, DataLoader[torch.Tensor | dict[str, torch.Tensor]]] | None = None`  
A `dict` with `DataLoader` objects. Required keys: `["train"]`. Optional key: `["val"]`. Required when using `model`.

`outdir: Path | None = None`  
A `pathlib.Path` pointing to a directory for saving/loading embeddings. Only used with `model` and `loaders`.

`prefix: str | None = None`  
A `str` used as filename prefix for saved embeddings. Only used with `model` and `loaders`.

`q: bool | float = ``False`  
A `float` or `bool` indicating if outliers from the training distribution should be filtered before fitting. Defaults to `False`.


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


#### score()


Compute uncertainty scores for query samples.


Usage

``` python
score(X=None, model=None, loader=None, outdir=None, prefix=None)
```


This method supports two usage modes:

1.  **Precomputed embeddings**: Supply query embeddings via `X`.
2.  **On-the-fly extraction**: Supply a `model` with an `.embed()` method and a `DataLoader` to extract embeddings automatically.

You must use either embeddings (X) OR model+loader, but not both.

``` python
# Mode 1: Precomputed embeddings
from seapig.scores import EuclideanScore
my_score = EuclideanScore()
scores = my_score.score(X=test_embeddings)

# Mode 2: On-the-fly extraction
my_score = EuclideanScore()
scores = my_score.score(model=model, loader=test_dl)
```


##### Parameters


`X: torch.Tensor | None = None`  
A `torch.Tensor` with query embeddings of shape `(N, D)`. Required when not using `model` and `loader`.

`model: torch.nn.Module | None = None`  
A `torch.nn.Module` with an `.embed()` method. Required when not using `X`.

`loader: DataLoader[torch.Tensor | dict[str, torch.Tensor]] | None = None`  
A `torch.utils.data.DataLoader` returning `torch.Tensor`s or dicts with the `"image"` key. Required when using `model`.

`outdir: Path | None = None`  
A `pathlib.Path` pointing to a directory for saving/loading embeddings. Only used with `model` and `loader`.

`prefix: str | None = None`  
A `str` used as filename prefix for saved embeddings. Only used with `model` and `loader`.


##### Returns


`torch.Tensor`  
1-D tensor of shape `(N,)` with uncertainty scores. Low values indicate likely inliers, high values indicate likely outliers.


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


#### select()


Select samples for prediction based on their uncertainty score.


Usage

``` python
select(X=None, model=None, loader=None, outdir=None, prefix=None)
```


This method supports two usage modes:

1.  **Precomputed embeddings**: Supply query embeddings via `X`.
2.  **On-the-fly extraction**: Supply a `model` with an `.embed()` method and a `DataLoader` to extract embeddings automatically.

You must use either embeddings (X) OR model+loader, but not both.

Samples are selected based on their uncertainty score relative to a threshold. Samples with scores lower than the threshold are selected, while samples with scores higher than the threshold are excluded. The threshold should be calibrated beforehand (e.g., on validation samples).

``` python
# Mode 1: Precomputed embeddings
from seapig.scores import EuclideanScore
my_score = EuclideanScore()
my_score.fit(X=train_data, Y=val_data)
result = my_score.select(X=test_data)

# Mode 2: On-the-fly extraction
my_score = EuclideanScore()
my_score.fit(X=train_data, Y=val_data)
result = my_score.select(model=model, loader=test_loader)
```


##### Parameters


`X: torch.Tensor | None = None`  
A `torch.Tensor` with query sample embeddings of shape `(N, D)`. Required when not using `model` and `loader`.

`model: torch.nn.Module | None = None`  
A `torch.nn.Module` with an `.embed()` method. Required when not using `X`.

`loader: DataLoader[torch.Tensor | dict[str, torch.Tensor]] | None = None`  
A `torch.utils.data.DataLoader` returning `torch.Tensor`s or dicts with the `"image"` key. Required when using `model`.

`outdir: Path | None = None`  
A `pathlib.Path` pointing to a directory for saving/loading embeddings. Only used with `model` and `loader`.

`prefix: str | None = None`  
A `str` used as filename prefix for saved embeddings. Only used with `model` and `loader`.


##### Returns


`dict[str, torch.Tensor]`  
A dict with keys `'score'` (uncertainty scores) and `'selected'` (boolean mask where `True` means the sample is selected).


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


#### set_threshold()


Set a threshold based on a quantile of the available uncertainty scores.


Usage

``` python
set_threshold(q=0.99)
```


Samples with scores higher than the threshold are excluded from prediction. If calibration embeddings were provided during [fit](scores.PCAScore.md#seapig.scores.PCAScore.fit), the threshold is computed from their scores; otherwise the training sample scores are used.


##### Parameters


`q: float = ``0.99`  
Quantile in `(0, 1)` used to determine the threshold. Defaults to `0.99` (i.e., 1% of samples are rejected as outliers).


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


#### get_threshold()


Get the current threshold value.


Usage

``` python
get_threshold()
```


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


#### plot()


Plot densities for uncertainty scores.


Usage

``` python
plot(query_scores=None, bins=100)
```


By default, this method plots densities for the uncertainty scores. Optionally, it can also plot densities for `query_scores`.


##### Parameters


`query_scores: torch.Tensor | None = None`  
A `torch.Tensor` representing query scores to include in the plot. Defaults to `None`.

`bins: int = ``100`  
An `int` indicating the number of bins to use for density estimation. Defaults to `100`.


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


#### plot_embs()


Visualize training, validation, and query embeddings in 2D.


Usage

``` python
plot_embs(query_embeddings, method="tsne", method_args=None)
```


##### Parameters


`query_embeddings: torch.Tensor | None`  
Embeddings of query samples to visualize.

`method: (tsne, umap) = ``"tsne"`  
Dimensionality reduction method, by default "tsne".

`method_args: dict[str, Any] | None = None`  
A dictionary of arguments to pass to the dimensionality reduction method, by default None.
