Silhouette¶
Group (Subgroup)¶
DREAM3D Review (Clustering)
Description¶
This Filter computes the silhouette for a clustered Attribute Array. The user must select both the original array that has been clustered and the array of cluster Ids. The silhouette represents a measure for the quality of a clustering. Specifically, the silhouette provides a measure for how strongly a given point belongs to its own cluster compared to all other clusters. The silhouette is computed as follows:
\f[ s_{i} = \frac{b_{i} - a_{i}}{\max{a_{i},b_{i}}} \f]
where \f$ a \f$ is the average distance between point \f$ i \f$ and all other points in the cluster point \f$ i \f$ belongs to, \f$ b \f$ is the next closest average distance among all other clusters, and \f$ s \f$ is the silhouette value. Using this definition, \f$ s \f$ exists on the interval \f$ [-1, 1] \f$, where 1 indicates that the point strongly belongs to its current cluster and -1 indicates that the point does not belong well to its current cluster. The user may select from a variety of options to use as the distance metric. Additionally, the user may opt to use a mask array to ignore points in the silhouette; these points will contain a silhouette value of 0.
The silhouette can be used to determine how well a particular clustering has performed, such as k means or k medoids.
Parameters¶
| Name | Type | Description |
|---|---|---|
| Distance Metric | Enumeration | The metric used to determine the distances between points |
| Use Mask | bool | Whether to use a boolean mask array to ignore certain points flagged as false from the algorithm |
Required Geometry¶
None
Required Objects¶
| Kind | Default Name | Type | Component Dimensions | Description |
|---|---|---|---|---|
| Any Attribute Array | None | Any | Any | The Attribute Array to silhouette |
| Attribute Array | ClusterIds | int32_t | (1) | Specifies to which cluster each point belongs |
| Attribute Array | Mask | bool | (1) | Specifies if the point is to be counted in the algorithm, if Use Mask is checked |
Created Objects¶
| Kind | Default Name | Type | Component Dimensions | Description |
|---|---|---|---|---|
| Attribute Array | Silhouette | double | (1) | Silhouette value for each point |
Example Pipelines¶
License & Copyright¶
Please see the description file distributed with this plugin.
DREAM3D Mailing Lists¶
If you need more help with a filter, please consider asking your question on the DREAM3D Users mailing list: https://groups.google.com/forum/?hl=en#!forum/dream3d-users