geva.hcluster {geva} | R Documentation

## GEVA Hierarchical Clustering

### Description

Performs a hierarchical cluster analysis from summarized data.

### Usage

    geva.hcluster(
      sv,
      resolution = 0.3,
      hc.method = options.hc.method,
      hc.metric = options.hc.metric,
      cl.score.method = options.cl.score.method,
      ...,
      include.raw.results = FALSE
    )

    options.hc.metric
    # c("euclidean", "maximum", "manhattan", "canberra",
    #   "binary", "minkowski")

    options.hc.method
    # c("centroid", "median", "ward", "single")

### Arguments

`sv` | a `numeric` `SVTable` object (usually `GEVASummary`)
`resolution` | `numeric` (`0` to `1`), used as a "zoom" parameter for cluster detection. A zero value returns the minimum number of clusters that can detected, while `1` returns the maximum amount of detectable clusters
`hc.method` | `character`, the agglomeration method to be used. Used as the `method` argument for `fastcluster::hclust.vector()`
`hc.metric` | `character`, the distance measure to be used. Used as the `metric` argument for `fastcluster::hclust.vector()`
`cl.score.method` | `character`, method used to calculate the cluster scores for each point. If `"auto"`, the `"hclust.height"` method is selected
`...` | additional arguments: `mink.p` : `numeric`, parameter for the Minkowsky metric. Used as the `p` argument for `fastcluster::hclust.vector()` `verbose` : `logical`, whether to print the current progress (default is `TRUE`)
`include.raw.results` | `logical`, whether to attach intermediate results to the returned object

### Details

This function performs a hierarchical cluster analysis with the aid of implemented methods from the `fastcluster::fastcluster` package, particularly the `fastcluster::hclust.vector()` function. The available methods for the `hc.method` and `hc.metric` are described in the function's documentation page (see `fastcluster::hclust.vector()`).

The `resolution` value is an accessible way to define the cluster separation threshold used in hierarchical clustering. The algorithm produces a dendrogram-like hierarchy in which each level/node is separated by a distance (sometimes called "height") to the next level/node, and the `resolution` translates a value between `0` and `1` to a propotional value within the total hierarchy height. This allows defining the rate of clusters from `0` to `1`, which results in the least number of possible clusters (usually two) for `0`, and the highest number (approximately one cluster per point) for `1`.

If `include.raw.results` is `TRUE`, some aditional data will be attached to the `info` slot of the returned `GEVACluster` objects, including the kNN tree generated during the intermediate steps.

### Value

A `GEVACluster` object

### Note

In hierarchical clustering, all points are clustered. Therefore, setting `resolution` to `1` will result into one cluster per point, where the cluster analysis may become pointless (no pun intended).

### See Also

Other geva.cluster: `geva.cluster()`, `geva.dcluster()`, `geva.quantiles()`

### Examples

    ## Hierarchical clustering from a randomly generated input

    # Preparing the data
    ginput <- geva.ideal.example()      # Generates a random input example
    gsummary <- geva.summarize(ginput)  # Summarizes with the default parameters

    # Hierarchical clustering
    gclust <- geva.hcluster(gsummary)
    plot(gclust)

    # Hierarchical clustering with slightly more resolution
    gclust <- geva.hcluster(gsummary,
                           resolution=0.35)
    plot(gclust)

[Package geva version 1.2.0 Index]