diagnoseColRow {biclust} R Documentation

## Bootstrap Procedure for Bicluster Diagnostics

### Description

Calculate the significance of the discovered patter in the data based on the bootstrapping procedure.

### Usage

diagnoseColRow(x, bicResult, number, nResamplings, replace = TRUE)


### Arguments

 x data matrix, which biclust function was applied to bicResult object of class biclust, containing result of a biclustering algorithm number number of bicluster from the output for the diagnostics nResamplings number of bootstrap replicates replace logical flag for bootstrap (TRUE), or sampling without replacement (FALSE)

### Details

The function computes observed F statistics for row and column effect based on two-way ANOVA model. Bootstrap procedure is used to evaluate the significance of discovered bicluster. Based on nResamplings replicates, the disribution of F statistics for row and column effects are obtained. The p-value is computed as

 P(A) = \frac{ \# \left \{ F^{*}(A)_{b} > F(A)^{obs} \right \} } {nResamplings+1} 

Low p-values denote non-random selection of columns for a given bicluster. Large p-values show that in other columns for a given set of genes in the bicluster structure is similar. Hence, bicluster columns were just randomly picked by an algorithm for a set of co-regulated genes.

### Value

 bootstrapFstats matrix with two columns, containing values of bootstrap F-statistics. The first column corresponds to row, the second column corresponds to column. observedFstatRow observed F-statistics for the row effect observedFstatCol observed F-statistics for the column effect bootstrapPvalueRow bootstrap p value for row effect bootstrapPvalueCol bootstrap p value for column effect

### Author(s)

Tatsiana KHAMIAKOVA tatsiana.khamiakova@uhasselt.be

diagnosticTest, diagnosticPlot2, diagnosticPlot, computeObservedFstat, ChiaKaruturi

### Examples

#---simulate dataset with 1 bicluster ---#
xmat<-matrix(rnorm(50*50,0,0.25),50,50) # background noise only
rowSize <- 20 #number of rows in a bicluster
colSize <- 10 #number of columns in a bicluster
a1<-rnorm(rowSize,1,0.1) #sample row effect from N(0,0.1) #adding a coherent values bicluster:
b1<-rnorm((colSize),2,0.25)  #sample column effect from N(0,0.05)
mu<-0.01 #constant value signal
for ( i in 1 : rowSize){
for(j in 1: (colSize)){
xmat[i,j] <- xmat[i,j] + mu + a1[i] + b1[j]
}
}
#--obtain a bicluster by running an algorithm---#
plaidmab <- biclust(x=xmat, method=BCPlaid(), cluster="b", fit.model = y ~ m + a+ b,
background = TRUE, row.release = 0.6, col.release = 0.7, shuffle = 50, back.fit = 5,
max.layers = 1, iter.startup = 100, iter.layer = 100, verbose = TRUE)

#Run boosotrap procedure:
Bootstrap <- diagnoseColRow(x=xmat, bicResult = plaidmab, number = 1, nResamplings = 999,
replace = TRUE)
diagnosticPlot(bootstrapOutput = Bootstrap) 	# plotting distribution of bootstrap replicates



[Package biclust version 2.0.3.1 Index]