first commit of ellipse, added from the mixtools package (which is be…

…ing decommissioned).
drammock · Mar 25, 2013 · 60e3e7f · 60e3e7f
1 parent beb5dc7
commit 60e3e7f
Showing 1 changed file with 17 additions and 0 deletions.
diff --git a/phonR/R/ellipse.R b/phonR/R/ellipse.R
@@ -0,0 +1,17 @@
+ellipse <- function(mu, sigma, alpha=.05, npoints=250,
+                    newplot=FALSE, draw=TRUE, ...) {
+  es <- eigen(sigma)
+  e1 <- es$vec%*%diag(sqrt(es$val))
+  r1 <- sqrt(qchisq(1-alpha,2))
+  theta <- seq(0,2*pi,len=npoints)
+  v1 <- cbind(r1*cos(theta),r1*sin(theta))
+  pts=t(mu-(e1%*%t(v1)))
+  if (newplot && draw) {
+    plot(pts, ...)
+  } else if (!newplot && draw) {
+    lines(pts, ...)
+  }
+  invisible(pts)
+}
+
+