plot3logit (version 2.2.0)

effect: Draw a change in the probability distribution on an existing plot

Description

Given the first two probabilities of a trinomial distribution before and after a change, effect() adds an arrow to an existing ternary plot. If the probability distribution does not change, a point (instead of an arrow) is added to the plot.

Usage

effect(x, y, ..., length = 0.05)

Arguments

x, y

numeric vectors of the first two probabilities. If the probability distribution is unchanged, x and y should have length one.

...

other graphical parameters such as xpd and the line characteristics lend, ljoin and lmitre. See graphics::par().

length

length of the edges of the arrow head (in inches).

Warning

Only when effect() is passed to Ternary::AddToTernary() as the first argument, arrows and points are drawn consistently with ternary coordinate system, otherwise effect draws both arrows and points according to a Cartesian coorinate system centered on \((0,0.5,0.5)\).

Examples

# NOT RUN {
TernaryPlot()

# Arrow
plot3logit:::effect(c(0.1, 0.2), c(0.3, 0.2))

# Point
plot3logit:::effect(0.3, 0.2)

# Compare the two coordinate systems
plot3logit:::effect(0.1, 0.2, pch = 19, col = 'red')
AddToTernary(plot3logit:::effect, list(c(0.1, 0.2, 0.7)), pch = 19, col = 'blue')

# The origin of Cartesian coordinate systems
plot3logit:::effect(0, 0, pch = 19, col = 'red')
AddToTernary(plot3logit:::effect, list(c(0, 0.5, 0.5)), pch = '+', col = 'white')

# }