PWMEnrich (version 4.8.2)

makePWMLognBackground: Make a lognormal background distribution

Description

Construct a lognormal background distribution for a set of sequences. Sequences concatenated are binned in 'bg.len' chunks and lognormal distribution fitted to them.

Usage

makePWMLognBackground(bg.seq, motifs, bg.pseudo.count = 1, bg.len = 250, bg.len.sizes = 2^(0:4), bg.source = "", verbose = TRUE, algorithm = "default")

Arguments

bg.seq

a set of background sequences, either a list of DNAString object or DNAStringSet object

motifs

a set of motifs, either a list of frequency matrices, or a list of PWM objects. If frequency matrices are given, the background distribution is fitted from bg.seq.

bg.pseudo.count

the pseudo count which is shared between nucleotides when frequency matrices are given

bg.len

background sequences will be split into tiles of this length (default: 250bp)

bg.len.sizes

background tiles will be joined into bigger tiles containing this much smaller tiles. The default is 2^(0:4), which with bg.len translates into 250bp, 500bp, 1000bp, 1500bp, 2000bp, 4000bp. Note this is only used in the "human" algorithm.

bg.source

a free-form textual description of how the background was generated

verbose

if to produce verbose output

algorithm

type of algorithm to use, valid values are: "default" and "human".

Examples

## Not run: 
# if(require("PWMEnrich.Dmelanogaster.background")){
#    data(MotifDb.Dmel.PFM)
# 
#    # make background for MotifDb motifs using 2kb promoters of all D. melanogaster transcripts
# 	  if(require("BSgenome.Dmelanogaster.UCSC.dm3"))
#      makePWMLognBackground(Dmelanogaster$upstream2000, MotifDb.Dmel.PFM)
# }
# ## End(Not run)