Variables representation
In this type of graphical display, the variables X and Y are represented through their projections onto the plane defined either by X-variates or Y-variates. The variables X and Y being assumed to be of unit variance, their projections are inside a circle of radius 1 centered at the origin called correlation circle. Strongly associated (or correlated) variables are projected in the same direction from the origin. The greater the distance from the origin the stronger the association. Two circumferences of radius 1 and 0.5 are plotted to reveal the correlation structure of the variables.
Note that this function also works for the case when there is a single data set (using a (s)PCA or a (s)PLS-DA result).
Usage in mixOmics
Variables 2D plots can be obtained in mixOmics via the function plotVar as displayed below:
## We consider that we have the results of a sPLS computation ## on liver.toxicity in a 'result' variable plotVar(result, comp = 1:2, Y.label = TRUE)
R script: 
You should have the following image:
