dgridplot function

Image and/or Contour plots of spectral densities in trivariate extreme value models

Plots contours or gray-scale level sets of a spectral density on the two-dimensional simplex.

dgridplot(
  density = matrix(5 * sin(1/73 * (1:(40 * 40)))^2, ncol = 40, nrow = 40),
  eps = 10^(-3),
  equi = TRUE,
  add = FALSE,
  breaks = seq(-0.01, 5.1, length.out = 1000),
  levels = seq(0, 6, length.out = 13),
  col.lines = "black",
  labcex = 0.8,
  background = FALSE,
  col.polygon = gray(0.5),
  lab1 = "w1",
  lab2 = "w2",
  lab3 = "w3",
  ...
)

Arguments

• density: A npoints*npoints matrix containing the density's values scattered on the discretization grid defined by npoints, equi, eps (see discretize).
• eps: Positive number: minimum distance from any node inside the simplex to the simplex boundary
• equi: logical. Is the simplex represented as an equilateral triangle (if TRUE) or a right triangle (if FALSE) ?
• add: Logical. Should the contours be added to a currently active plot ?
• breaks: Set of breakpoints for the gray scale colors. See image
• levels: Levels to which plot the contour lines. See contour
• col.lines: The color to be used for the contour lines.
• labcex: cex for contour labeling. See contour.
• background: Logical. Should a the background be filled inside the simplex via a call to image ?
• col.polygon: The background color outside the simplex.
• lab1: Character string: label for first component.
• lab2: Character string: label for second component.
• lab3: Character string: label for third component.
• ...: Additional graphical parameters and arguments to be passed to contour and image.

Details

The function interprets the density matrix as contour does, i.e. as a table of f(X[i], Y[j]) values, with column 1 at the bottom, where X and Y are returned by discretize and f is the density function.

Examples

wrapper <- function(x, y, my.fun,...) 
      {
       sapply(seq_along(x), FUN = function(i) my.fun(x[i], y[i],...))
      }

grid <- discretize(npoints=40,eps=1e-3,equi=FALSE)

Density <- outer(grid$X,grid$Y,FUN=wrapper,
                my.fun=function(x,y){10*((x/2)^2+y^2)*((x+y)<1)})

dgridplot(density= Density,npoints=40, equi=FALSE)