# foldchange: Compute fold-change or convert between log-ratio and... In gtools: Various R Programming Tools

 foldchange R Documentation

## Compute fold-change or convert between log-ratio and fold-change.

### Description

foldchange computes the fold change for two sets of values. logratio2foldchange converts values from log-ratios to fold changes. foldchange2logratio does the reverse.

### Usage

foldchange(num, denom)

logratio2foldchange(logratio, base = 2)

foldchange2logratio(foldchange, base = 2)


### Arguments

 num, denom vector/matrix of numeric values logratio vector/matrix of log-ratio values base Exponential base for the log-ratio. foldchange vector/matrix of fold-change values

### Details

Fold changes are commonly used in the biological sciences as a mechanism for comparing the relative size of two measurements. They are computed as: \frac{num}{denom} if num>denom, and as \frac{-denom}{num} otherwise.

Fold-changes have the advantage of ease of interpretation and symmetry about num=denom, but suffer from a discontinuity between -1 and 1, which can cause significant problems when performing data analysis. Consequently statisticians prefer to use log-ratios.

### Value

A vector or matrix of the same dimensions as the input containing the converted values.

### Functions

• foldchange(): Compute fold-change.

• logratio2foldchange(): Compute foldchange from log-ratio values.

• foldchange2logratio(): Compute log-ratio from fold-change values.

### Author(s)

Gregory R. Warnes greg@warnes.net

### Examples



a <- 1:21
b <- 21:1

f <- foldchange(a, b)

cbind(a, b, f)


gtools documentation built on Nov. 20, 2023, 5:07 p.m.