plot_direction_Dopt {SLSEdesign}

Verify the optimality condition for the D-optimal design

Description

Verify the optimality condition for the D-optimal design

Usage

plot_direction_Dopt(u, design, tt, FUN, theta)

Arguments

u

The discretized design points.

design

The D-optimal design that contains the design points and the associated weights.

tt

The level of skewness.

FUN

The function to calculate the derivative of the given model.

theta

The parameter value of the model.

Details

This function produces the figure for the negative value of the directional derivative of the given D-optimal design of the compact supports. According to the general equivalence theorem, for an optimal design, all the directional derivative should be below zero line.

Value

The plot of the negative value of the directional derivative of a D-optimal design

Examples

poly3 <- function(xi, theta){
    matrix(c(1, xi, xi^2, xi^3), ncol = 1)
}
design = data.frame(location = c(-1, -0.447, 0.447, 1),
 weight = rep(0.25, 4))
u = seq(-1, 1, length.out = 201)
plot_direction_Dopt(u, design, tt=0, FUN = poly3,
  theta = rep(0, 4))