Santiago Barreda
Assistant Professor, Department of Linguistics, UC Davis

Main Research Vignettes CV phonTools Statistics Links

 


sdellipse [phonTools]

 This function may be used in 2 diffierent ways:   1) To draw standard deviation ellipses around a set of observations (if 'means' is not specified)   2) To draw ellipses/circles on plots (if 'means' is specified).

 

 

 

 

Code used to generate examples:


## alternatively, a covariance matrix may be specified directly. par (mfrow = c(2,2), mar = c(4,4,1,1)) ## draw random points draws = rmvtnorm (n = 1000, k = 2, sigma = .3) plot (draws) ## draw standard deviation ellipses sdellipse (draws, stdev = 3, lwd = 3, col = 2) ## draw random points draws = rmvtnorm (n = 1000, k = 2, sigma = -.3) plot (draws) ## draw standard deviation ellipses sdellipse (draws, stdev = 3, lwd = 3, col = 2) ## draw an ellipse sdellipse (matrix(c(1,.5,.5,1),2,2), means = c(5,-3), add = FALSE, stdev = 1) ## draw a circle sdellipse (matrix(c(4,0,0,4),2,2), means = c(-100,17), add = FALSE, stdev = 1)