cluster {chromswitch} | R Documentation

## cluster

### Description

Given a sample-by-feature matrix and sample-associated metadata including their biological condition groupings, cluster samples hierarchically and use external cluster validity measures (Adjusted Rand Index, Normalized Mutual Information, and V measure) to assess the agreement between the inferred clusters and the biological conditions. Optionally, produce a heatmap reflecting the hierarchical clustering result.

### Usage

    cluster(ft_mat, metadata, query, heatmap = FALSE, title = NULL,
      outdir = NULL, optimal_clusters = TRUE, n_features = FALSE,
      estimate_state = FALSE, method = NULL, test_condition = NULL,
      signal_col = NULL, mark = NULL)

### Arguments

`ft_mat` | matrix where columns are features and rows are samples as returned by `summarizePeaks` or `binarizePeaks`
`metadata` | A dataframe with a column "Sample" which stores the sample identifiers, and a column "Condition", which stores the biological condition labels of the samples
`query` | GRanges object specifying the query region
`heatmap` | (Optional) Logical value indicating whether to plot the heatmap for hierarchical clustering. Default: FALSE
`title` | (Optional) If `heatmap` is TRUE, specify the title of the plot, which will also be used for the output file name in PDF format
`outdir` | (Optional) String specifying the name of the directory where PDF of heatmaps should be saved
`optimal_clusters` | (Optional) Logical value indicate whether to cluster samples into two groups, or to find the optimal clustering solution by choosing the set of clusters which maximizes the Average Silhouette width. Default: TRUE
`n_features` | (Optional) Logical value indicating whether to include a column "n_features" in the output storing the number of features in the feature matrix constructed for the region, which may be useful for understanding the behaviour of the binary strategy for constructing feature matrices. Default: FALSE
`estimate_state` | (Optional) Logical value indicating whether to include a column "state" in the output specifying the estimated chromatin state of a test condition. The state will be on of "ON", "OFF", or NA, where the latter results if a binary switch between the conditions is unclear. Default: FALSE.
`method` | (Optional) If `estimate_state` is TRUE, one of "summary" or "binary", specifying which method was used to construct the feature matrix in `ft_mat`
`test_condition` | (Optional) If `estimate_state` is TRUE, string specifying one of the two biological condtions in `metadata$Condition` for which to estimate chromatin state.
`signal_col` | (Optional) If `estimate_state` is TRUE, and `method` is "summary", string specifying the name of the column in the original peak files which corresponds to the level of enrichment in the region, e.g. fold change
`mark` | (Optional) If `estimate_state` is TRUE, and `method` is "summary",string specifying the name of the mark for which `ft_mat` was constructed

### Value

A dataframe with the region, the number of clusters inferred, the cluster validity statistics, and the cluster assignments for each sample

### Examples

    samples <- c("E068", "E071", "E074", "E101", "E102", "E110")
    bedfiles <- system.file("extdata", paste0(samples, ".H3K4me3.bed"),
    package = "chromswitch")
    Conditions <- c(rep("Brain", 3), rep("Other", 3))

    metadata <- data.frame(Sample = samples,
        H3K4me3 = bedfiles,
        Condition = Conditions,
        stringsAsFactors = FALSE)

    region <- GRanges(seqnames = "chr19",
        ranges = IRanges(start = 54924104, end = 54929104))

    lpk <- retrievePeaks(H3K4me3,
        metadata = metadata,
        region = region)

    ft_mat <- summarizePeaks(lpk, mark = "H3K4me3",
    cols = c("qValue", "signalValue"))

    cluster(ft_mat, metadata, region)

    # Estimate the state of the test condition, "Brain"
    cluster(ft_mat, metadata, region,
        estimate_state = TRUE,
        method = "summary",
        signal_col = "signalValue",
        mark = "H3K4me3",
        test_condition = "Brain")

[Package chromswitch version 1.2.1 Index]