check.associations {SIAMCAT} | R Documentation

## Check and visualize associations between features and classes

### Description

This function computes different measures of association between features and the label and visualizes the results

### Usage

    check.associations(siamcat, fn.plot=NULL, color.scheme = "RdYlBu",
        alpha =0.05, mult.corr = "fdr", sort.by = "fc",
        detect.lim = 1e-06, pr.cutoff = 1e-6, max.show = 50,
        plot.type = "quantile.box",
        panels = c("fc","auroc"), prompt = TRUE,
        feature.type = 'filtered', verbose = 1)

### Arguments

`siamcat` | object of class siamcat-class
`fn.plot` | string, filename for the pdf-plot. If `fn.plot` is `NULL`, the plot will be produced in the active graphics device.
`color.scheme` | valid R color scheme or vector of valid R colors (must be of the same length as the number of classes), defaults to `'RdYlBu'`
`alpha` | float, significance level, defaults to `0.05`
`mult.corr` | string, multiple hypothesis correction method, see `p.adjust`, defaults to `"fdr"`
`sort.by` | string, sort features by p-value (`"p.val"`), by fold change (`"fc"`) or by prevalence shift (`"pr.shift"`), defaults to `"fc"`
`detect.lim` | float, pseudocount to be added before log-transformation of the data, defaults to `1e-06`. Will be ignored if `feature.type` is `"normalized"`.
`pr.cutoff` | float, cutoff for the prevalence computation, defaults to `1e-06`
`max.show` | integer, how many associated features should be shown, defaults to `50`
`plot.type` | string, specify how the abundance should be plotted, must be one of these: `c("bean", "box", "quantile.box", "quantile.rect")`, defaults to `"quantile.box"`
`panels` | vector, name of the panels to be plotted next to the abundances, possible entries are `c("fc", "auroc", "prevalence")`, defaults to `c("fc", "auroc")`
`prompt` | boolean, turn on/off prompting user input when not plotting into a pdf-file, defaults to TRUE
`feature.type` | string, on which type of features should the function work? Can be either `c()"original", "filtered", or "normalized")`. Please only change this paramter if you know what you are doing! If `feature.type` is `"normalized"`, the normalized abundances will not be log10-transformed.
`verbose` | integer, control output: `0` for no output at all, `1` for only information about progress and success, `2` for normal level of information and `3` for full debug information, defaults to `1`

### Details

For each feature, this function calculates different measures of association between the feature and the label. In detail, these associations are:

- Significance as computed by a Wilcoxon test followed by multiple hypothesis testing correction.

- AUROC (Area Under the Receiver Operating Characteristics Curve) as a non-parameteric measure of enrichment (corresponds to the effect size of the Wilcoxon test).

- The generalized Fold Change (gFC) is a pseudo fold change which is calculated as geometric mean of the differences between the quantiles for the different classes found in the label.

- The prevalence shift between the two different classes found in the label.

Finally, the function produces a plot of the top `max.show` associated features at a user-specified significance level `alpha`, showing the distribution of the log10-transformed abundances for both classes, and user-selected panels for the effect (AU-ROC, Prevalence Shift, and Fold Change).

### Value

object of class siamcat-class with the slot `associations` filled

### Examples

    # Example data
    data(siamcat_example)

    # Simple example
    siamcat_example <- check.associations(siamcat_example,
        fn.plot='./assoc_plot.pdf')

    # Plot associations as box plot
    siamcat_example <- check.associations(siamcat_example,
        fn.plot='./assoc_plot_box.pdf', plot.type='box')

    # Additionally, sort by p-value instead of by fold change
    siamcat_example <- check.associations(siamcat_example,
        fn.plot='./assoc_plot_fc.pdf', plot.type='box', sort.by='p.val')

    # Custom colors
    siamcat_example <- check.associations(siamcat_example,
        fn.plot='./assoc_plot_blue_yellow.pdf', plot.type='box',
        color.scheme=c('cornflowerblue', '#ffc125'))

[Package SIAMCAT version 1.4.0 Index]