cost-surface-rayshader

library(colorspace)
library(rayshader)
library(tidyverse)

mse <- function(x, y, a, b) {
  pred <- a + b*x
  resid2 <- (y - pred)^2
  1/length(y)*sum(resid2)
}

set.seed(8675309)
n <- 1000
x <- rnorm(n)

a <- 5
b <- 1.3
e <- 4

y <- a + b*x + rnorm(n, sd = e)

sim_d <- tibble(x = x, y = y)

grid <- expand.grid(a = seq(-5, 10, 0.1), b = seq(-5, 5, 0.1))

surface <- grid %>% 
  mutate(cost = map2_dbl(a, b, ~mse(x, y, .x, .y))) %>% 
  ggplot(aes(a, b)) +
  geom_raster(aes(fill = cost)) +
  scale_fill_continuous_sequential(palette = "Terrain")

plot_gg(surface, multicore = TRUE)