`plotmatrix`

Matrix of scatter plots of the columns of a data matrix against each other.

Syntax

plotmatrix(X)

Plots every column of X against every other, with histograms on the diagonal.

plotmatrix(X, Y)

Plots the columns of X against the columns of Y.

[h, ax, bigax] = plotmatrix(___)

Also returns the point handles, the small axes and the large axes that surrounds them.

Description

For p variables the plot is a p-by-p grid. Cell (i,j) shows variable j on the horizontal axis against variable i on the vertical axis. It reveals pairwise relations, clusters and outliers at a glance.

Input arguments

X: Matrix with observations in rows and variables in columns.
Y: Second matrix with the same number of rows.

Output arguments

h: Matrix of handles of the scatter lines.
ax: Matrix of handles of the small axes.
bigax: Handle of the invisible axes that holds the whole grid.

Example

Three random variables

rng(1)
X = rand(30, 3);
X(:,3) = X(:,1) + 0.2*X(:,3);
plotmatrix(X)

In the app, the figure is drawn below the code.

plotmatrix