pool {methylKit} | R Documentation

## Pool replicates within groups to a single sample per group

### Description

The function sums up coverage, numCs and numTs values within each group so one representative sample for each group will be created in a new methylBase object

### Usage

    pool(obj, sample.ids, chunk.size = 1e+06, save.db = FALSE, ...)

    ## S4 method for signature 'methylBase'
    pool(obj, sample.ids, chunk.size = 1e+06, save.db = FALSE, ...)

    ## S4 method for signature 'methylBaseDB'
    pool(obj, sample.ids, chunk.size = 1e+06, save.db = TRUE, ...)

### Arguments

`obj` | methylBase or methylBaseDB object with two groups or more and each group should have multiple samples
`sample.ids` | a character vector of new sample.ids ex:c("test","control"), should follow the same order as unique treatment vector, and should be equal to the length of the unique treatment vector
`chunk.size` | Number of rows to be taken as a chunk for processing the `methylRawListDB` objects, default: 1e6
`save.db` | A Logical to decide whether the resulting object should be saved as flat file database or not, default: explained in Details sections
`...` | optional Arguments used when save.db is TRUE `suffix` A character string to append to the name of the output flat file database, only used if save.db is true, default actions: The default suffix is a 13-character random string appended to the fixed prefix “methylBase”, e.g. “methylBase_16d3047c1a254.txt.bgz”. `dbdir` The directory where flat file database(s) should be stored, defaults to getwd(), working directory for newly stored databases and to same directory for already existing database `dbtype` The type of the flat file database, currently only option is "tabix" (only used for newly stored databases)

### Value

a methylBase or methylBaseDB object depending on class of input object

### Details

The parameter `chunk.size` is only used when working with `methylBaseDB` objects, as they are read in chunk by chunk to enable processing large-sized objects which are stored as flat file database. Per default the chunk.size is set to 1M rows, which should work for most systems. If you encounter memory problems or have a high amount of memory available feel free to adjust the `chunk.size`.

The parameter `save.db` is per default TRUE for methylDB objects as `methylBaseDB`, while being per default FALSE for `methylBase`. If you wish to save the result of an in-memory-calculation as flat file database or if the size of the database allows the calculation in-memory, then you might want to change the value of this parameter.

### Author(s)

Altuna Akalin

### Examples

    data(methylKit)

    # methylBase.obj has two groups, each group has two samples,
    # the following function will pool the samples in each group
    # so that each group will be represented by one pooled sample
    pooled.methylBase=pool(methylBase.obj,sample.ids=c("test","control"))

[Package methylKit version 1.18.0 Index]