flip4image: Flip a matrix to be passed to 'image'.

In tsieger/tsiMisc: Miscelaneous utility functions, mostly related to exploratory statistical analysis

Flip a matrix to be passed to image.

Description

Flip a matrix such that it will appear ‘as is’ when plotted by image. Note that image shows the rows of the matrix on the x axis and the columns of the matrix on the y axis (with column 1 at the bottom), such that the matrix gets displayed rotated 90 degree clockwise. ‘flip4image’ therefore rotates the matrix 90 degree coutner-clockwise, such that the rotation made by image results in the desired form of the matrix.

Usage

flip4image(x)

Arguments

x

a matrix

Value

The matrix x prepared to be displyed by image.

Author(s)

Tomas Sieger

Examples

# plot a toy matrix
m<-rbind(1:10,c(1:3,14:20),20*sin(seq(0,4*pi,length=10)))
m
image(flip4image(m),col=gray.colors(20))
# with labels
image(x=1:10,y=1:3,z=flip4image(m),col=gray.colors(20),yaxt='n')
axis(2,at=1:3,labels=rev(1:3))

# plot a covariance matrix
m<-cov(matrix(rnorm(100),10,10))
image(flip4image(m),col=gray.colors(20))
# plot the Cholsky decomposition of the a covariance matrix (an upper triangular matrix)
image(flip4image(chol(cov(m))),col=gray.colors(20))

tsieger/tsiMisc documentation built on Oct. 10, 2023, 10:24 p.m.