pickHardThreshold: Analysis of scale free topology for hard-thresholding.

Description

Analysis of scale free topology for multiple hard thresholds. The aim is to help the user pick an appropriate threshold for network construction.

Usage

pickHardThreshold(
  data, 
  dataIsExpr,
  RsquaredCut = 0.85, 
  cutVector = seq(0.1, 0.9, by = 0.05), 
  moreNetworkConcepts = FALSE,
  removeFirst = FALSE, nBreaks = 10, 
  corFnc = "cor", corOptions = "use = 'p'")

pickHardThreshold.fromSimilarity(
    similarity,
    RsquaredCut = 0.85, 
    cutVector = seq(0.1, 0.9, by = 0.05),
    moreNetworkConcepts=FALSE, 
    removeFirst = FALSE, nBreaks = 10)

Arguments

data

expression data in a matrix or data frame. Rows correspond to samples and columns to genes.

dataIsExpr

logical: should the data be interpreted as expression (or other numeric) data, or as a similarity matrix of network nodes?

similarity

similarity matrix: a symmetric matrix with entries between -1 and 1 and unit diagonal.

RsquaredCut

desired minimum scale free topology fitting index $R^2$.

cutVector

a vector of hard threshold cuts for which the scale free topology fit indices are to be calculated.

moreNetworkConcepts

logical: should additional network concepts be calculated? If TRUE, the function will calculate how the network density, the network heterogeneity, and the network centralization depend on the power. For the definition of these additional n

removeFirst

should the first bin be removed from the connectivity histogram?

nBreaks

number of bins in connectivity histograms

corFnc

a character string giving the correlation function to be used in adjacency calculation.

corOptions

further options to the correlation function specified in corFnc.

Value

A list with the following components:
cutEstimateestimate of an appropriate hard-thresholding cut: the lowest cut for which the scale free topology fit $R^2$ exceeds RsquaredCut. If $R^2$ is below RsquaredCut for all cuts, NA is returned.
fitIndicesa data frame containing the fit indices for scale free topology. The columns contain the hard threshold, adjusted $R^2$ for the linear fit, the linear coefficient, adjusted $R^2$ for a more complicated fit models, mean connectivity, median connectivity and maximum connectivity. If input moreNetworkConcepts is TRUE, 3 additional columns containing network density, centralization, and heterogeneity.

Details

The function calculates unsigned networks by thresholding the correlation matrix using thresholds given in cutVector. For each power the scale free topology fit index is calculated and returned along with other information on connectivity.

References