Convert an object to an mpoly

Description

mpoly is the most basic function used to create objects of class mpoly.

Usage

as.mpoly(x, ...)

Arguments

Value

the object formated as a mpoly object.

Author(s)

David Kahle david.kahle@gmail.com

See Also

mp

Examples

library(plyr)

n <- 101
s <- seq(-5, 5, length.out = n)

# one dimensional case
df <- data.frame(x = s)
df <- mutate(df, y = -x^2 + 2*x - 3 + rnorm(n, 0, 2))
with(df, plot(x, y))
mod <- lm(y ~ x + I(x^2), data = df)
(p <- as.mpoly(mod))
f <- as.function(p)
lines(s, f(s), col = "red")



# one dimensional case with ggplot2
library(ggplot2); theme_set(theme_bw())

qplot(x, y, data = df) 
qplot(x, y, data = df) +
  stat_function(fun = f, colour = "red")


# two dimensional case with ggplot2

df <- expand.grid(x = s, y = s)
df <- mutate(df, z = x^2 - y^2 + 2 * x*y + rnorm(n^2, 0, 3))
qplot(x, y, data = df, geom = "raster", fill = z)
mod <- lm(z ~ x + y + I(x^2) + I(y^2) + I(x*y), data = df)
p <- as.mpoly(mod)
f <- as.function(p)
df$fit <- apply(df[,c("x","y")], 1, f)
qplot(x, y, data = df, geom = "raster", fill = fit)
qplot(x, y, data = df, geom = "raster", fill = z - fit) # residuals

Results