Visualization of frfast objects with the base graphics

Useful for drawing the estimated regression function, first and second derivative (for each factor's level). Additionally, with the diffwith argument it is possible to draw the differences between two factor's levels.

Usage

# S3 method for frfast
plot(
  x = model,
  y,
  fac = NULL,
  der = NULL,
  diffwith = NULL,
  points = TRUE,
  xlab = model$name[2],
  ylab = model$name[1],
  ylim = NULL,
  main = NULL,
  col = "black",
  CIcol = "black",
  pcol = "grey80",
  ablinecol = "red",
  abline = TRUE,
  type = "l",
  CItype = "l",
  lwd = 2,
  CIlwd = 1,
  lty = 1,
  CIlty = 2,
  cex = 0.6,
  ...
)

Arguments

x: frfast object.
y: NULL.
fac: Vector which determines the level to take into account in the plot. By default is NULL.
der: Number or vector which determines any inference process. By default der is NULL. If this term is 0, the plot shows the initial estimate. If it is 1 or 2, it is designed for the first or second derivative, respectively.
diffwith: Factor's level used for drawing the differences respect to the level specified in the fac argument. By default, NULL. The differences are computed for the r-th derivative speciefied in the der argument.
points: Draw the original data into the plot. By default it is TRUE.
xlab: A title for the x axis.
ylab: A title for the y axis.
ylim: The y limits of the plot.
main: An overall title for the plot.
col: A specification for the default plotting color.
CIcol: A specification for the default confidence intervals plotting color.
pcol: A specification for the points color.
ablinecol: The color to be used for abline.
abline: Draw an horizontal line into the plot of the second derivative of the model.
type: What type of plot should be drawn. Possible types are, p for points, l for lines, o for overplotted, etc. See details in par.
CItype: What type of plot should be drawn for confidence intervals. Possible types are, p for points, l for lines, o for overplotted.
lwd: The line width, a positive number, defaulting to 1. See details in par.
CIlwd: The line width for confidence intervals, a positive number, defaulting to 1.
lty: The line type. Line types can either be specified as an integer (0 = blank, 1 = solid (default), 2 = dashed, 3 = dotted, 4 = dotdash, 5 = longdash, 6 = twodash). See details in par.
CIlty: The line type for confidence intervals. Line types can either be specified as an integer (0 = blank, 1 = solid (default), 2 = dashed, 3 = dotted, 4 = dotdash, 5 = longdash, 6 = twodash).
cex: A numerical value giving the amount by which plotting symbols should be magnified relative to the default. See details in par.
...: Other options.

Value

Simply produce a plot.

Author

Marta Sestelo, Nora M. Villanueva and Javier Roca-Pardinas.

Examples

library(npregfast)
data(barnacle)

# Nonparametric regression without interactions
fit <- frfast(DW ~ RC, data = barnacle, nboot = 100) 
plot(fit)

plot(fit, der = 0)

plot(fit, der = 0, points = FALSE)

plot(fit, der = 1, col = "red", CIcol = "blue")


# Nonparametric regression with interactions
fit2 <- frfast(DW ~ RC : F, data = barnacle, nboot = 100) 
plot(fit2)

plot(fit2, der = 0, fac = "lens")

plot(fit2, der = 1, col = "grey", CIcol = "red")

plot(fit2, der = c(0,1), fac = c("barca","lens"))


# Visualization of the differences between two factor's levels
plot(fit2, fac = "barca", diffwith = "lens")

plot(fit2, fac = "barca", diffwith = "lens", der = 1)