triplot {broman}

Plot Holmans triangle

Description

Plot Holmans triangle (an equilateral triangle used to depict trinomial distributions).

Usage

triplot(
  labels = c("(1,0,0)", "(0,1,0)", "(0,0,1)"),
  col = "black",
  lwd = 2,
  bgcolor = "gray90",
  gridlines = 0,
  grid_col = "white",
  grid_lty = 1,
  grid_lwd = 1,
  ...
)

Arguments

labels

Labels for the three corners (lower-right, top, lower-left).

col

Color of edges of triangle

lwd

Line width for edges of triangle

bgcolor

Background color for triangle

gridlines

Number of grid lines (if 0, no grid lines will be plotted)

grid_col

Color of grid lines

grid_lty

Line type of grid lines

grid_lwd

Line width of grid lines

...

Passed to plot().

Details

Plot of an equilateral triangle, in order to depict trinomial distributions. A trinomial distribution (that is, a trio of non-negative numbers that add to 1) is equated to a point in the triangle through the distances to the three sides. This makes use of the fact that for any point in an equilateral triangle, the sum of the distances to the three sides is constant. The triplot function creates an empty triangle for use with the related functions tripoints(), trilines(), triarrow().

Value

The (x,y) coordinates of the points plotted, if any.

See Also

tripoints(), trilines(), triarrow(), tritext()

Examples

triplot()
x <- cbind(c(0.9, 0.05, 0.05), c(0.8, 0.1, 0.1), c(0.1, 0.9, 0), c(0, 0.9, 0.1))
tripoints(x, lwd=2, col=c("black","blue","red","green"), pch=16)
trilines(x, lwd=2, col="orange")
y <- cbind(c(0.05, 0.05, 0.9), c(0.25, 0.25, 0.5))
triarrow(y, col="blue", lwd=2, len=0.1)