---
name: "mlpack_kmeans_RefinedStart"
section: "3"
platform: "linux"
package: "mlpack-doc"
version: "1.0.10-1"
release: "Debian 8 (Jessie)"
platforms: ["linux"]
url: "https://new.carta.tech/mlpack_kmeans_RefinedStart"
---

# mlpack\_kmeans\_RefinedStart(3)

A refined approach for choosing initial points for k-means clustering.

## NAME

mlpack::kmeans::RefinedStart -

A refined approach for choosing initial points for k-means clustering.

## SYNOPSIS

### Public Member Functions

**RefinedStart** (const size\_t **samplings**=100, const double **percentage**=0.02)\
 *Create the* **RefinedStart** *object, optionally specifying parameters for the number of samplings to perform and the percentage of the dataset to use in each sampling.*  template\<typename MatType \> void **Cluster** (const MatType &data, const size\_t clusters, arma::Col\< size\_t \> &assignments) const \
 *Partition the given dataset into the given number of clusters according to the random sampling scheme outlined in Bradley and Fayyad's paper.*  double **Percentage** () const \
 *Get the percentage of the data used by each subsampling.*  double & **Percentage** ()\
 *Modify the percentage of the data used by each subsampling.*  size\_t **Samplings** () const \
 *Get the number of samplings that will be performed.*  size\_t & **Samplings** ()\
 *Modify the number of samplings that will be performed.*

### Private Attributes

double **percentage**\
 *The percentage of the data to use for each subsampling.*  size\_t **samplings**\
 *The number of samplings to perform.*

## Detailed Description

A refined approach for choosing initial points for k-means clustering.

This approach runs k-means several times on random subsets of the data, and then clusters those solutions to select refined initial cluster assignments. It is an implementation of the following paper:

{bradley1998refining, title={Refining initial points for k-means clustering}, author={Bradley, Paul S and Fayyad, Usama M}, booktitle={Proceedings of the Fifteenth International Conference on Machine Learning (ICML 1998)}, volume={66}, year={1998} }

Definition at line 47 of file refined\_start.hpp.

## Constructor & Destructor Documentation

### mlpack::kmeans::RefinedStart::RefinedStart (const size\_tsamplings = `100`, const doublepercentage = `0.02`)` [inline]`

Create the **RefinedStart** object, optionally specifying parameters for the number of samplings to perform and the percentage of the dataset to use in each sampling.

Definition at line 55 of file refined\_start.hpp.

## Member Function Documentation

### template\<typename MatType \> void mlpack::kmeans::RefinedStart::Cluster (const MatType &data, const size\_tclusters, arma::Col\< size\_t \> &assignments) const

Partition the given dataset into the given number of clusters according to the random sampling scheme outlined in Bradley and Fayyad's paper.

**Template Parameters:**

*MatType* Type of data (arma::mat or arma::sp\_mat).

**Parameters:**

*data* Dataset to partition. \
 *clusters* Number of clusters to split dataset into. \
 *assignments* Vector to store cluster assignments into. Values will be between 0 and (clusters - 1).

### double mlpack::kmeans::RefinedStart::Percentage () const` [inline]`

Get the percentage of the data used by each subsampling.

Definition at line 80 of file refined\_start.hpp.

References percentage.

### double& mlpack::kmeans::RefinedStart::Percentage ()` [inline]`

Modify the percentage of the data used by each subsampling.

Definition at line 82 of file refined\_start.hpp.

References percentage.

### size\_t mlpack::kmeans::RefinedStart::Samplings () const` [inline]`

Get the number of samplings that will be performed.

Definition at line 75 of file refined\_start.hpp.

References samplings.

### size\_t& mlpack::kmeans::RefinedStart::Samplings ()` [inline]`

Modify the number of samplings that will be performed.

Definition at line 77 of file refined\_start.hpp.

References samplings.

## Member Data Documentation

### double mlpack::kmeans::RefinedStart::percentage` [private]`

The percentage of the data to use for each subsampling.

Definition at line 88 of file refined\_start.hpp.

Referenced by Percentage().

### size\_t mlpack::kmeans::RefinedStart::samplings` [private]`

The number of samplings to perform.

Definition at line 86 of file refined\_start.hpp.

Referenced by Samplings().

## Author

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