You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 

131 lines
3.1 KiB

library(reshape)
library(tidyverse)
library(ggforce)
normalize_landscape <- function(landscape) {
min_val <- min(landscape)
max_val <- max(landscape)
range_val <- max_val - min_val
return((landscape - min_val) / range_val)
}
plot_landscape <- function(landscape) {
p <- ggplot(data=melt(landscape), aes(x=X1, y=X2, z=value)) +
geom_contour_filled()
return(p)
}
init_population <- function(landscape, n) {
population <- list()
dims <- length(dim(landscape))
for(i in 1:n) {
coords <- round(runif(dims, 0, 1) * dim(landscape))
sigmas <- rnorm(dims)
population[[i]] <- matrix(c(coords, sigmas), ncol=2)
}
return(population)
}
next_generation <- function(landscape, population) {
return(map(population, function(indiv) {
return(select_indiv(landscape, list(indiv, create_child(indiv))))
}))
}
select_indiv <- function(landscape, indivs) {
return(reduce(indivs, function(a, b) {
if(eval_indiv(landscape, a) >= eval_indiv(landscape, b)) {
return(a)
}
return(b)
}))
}
eval_indiv <- function(landscape, indiv) {
dims <- dim(landscape)
x <- indiv[1,1]
y <- indiv[2, 1]
if(x > dims[1] || y > dims[2] || x < 1 || y < 1) {
return(-1)
}
return(landscape[indiv[1,1], indiv[2,1]])
}
create_child <- function(parent) {
new_sigmas <- mutate_sigmas(parent[,2])
new_coords <- mutate_coords(parent[,1], new_sigmas)
return(matrix(c(new_coords, new_sigmas), ncol=2))
}
mutate_sigmas <- function(sigmas) {
global_rate <- 1 / sqrt(2 * length(sigmas))
local_rate <- 1 / (2 * sqrt(length(sigmas)))
global_step <- global_rate * rnorm(1)
return(map_dbl(sigmas, function(s) s * exp(global_step + local_rate * rnorm(1))))
}
mutate_coords <- function(coords, sigmas) {
return(imap_dbl(coords, function(x, i) x + sigmas[i] * rnorm(1)))
}
experiment <- function(landscape, population, gens) {
df <- population_to_df(landscape, population, 0)
for(g in 1:gens) {
population <- next_generation(landscape, population)
df <- rbind(df, population_to_df(landscape, population, g))
}
return(df)
}
population_to_df <- function(landscape, population, gen) {
df <- reduce(imap(population, function(indv, i) indiv_to_df(landscape, indv, i)), rbind)
df["generation"] <- gen
return(df)
}
indiv_to_df <- function(landscape, indiv, index) {
return(data.frame(x=indiv[1,1], y=indiv[2,1],
sx=indiv[1, 2], sy=indiv[2,2],
individual=index, value=eval_indiv(landscape, indiv)))
}
plot_generation <- function(landscape, df) {
p <-ggplot(data=df) +
geom_contour_filled(data=melt(landscape), aes(x=X1, y=X2, z=value)) +
geom_point(aes(x=x, y=y)) +
geom_ellipse(aes(x0=x, y0=y, a=sx, b=sy, angle=0))
return(p)
}
plot_experiment <- function(landscape, df, filename) {
pdf(file=filename, onefile=TRUE)
for(g in unique(df$generation)) {
tmp_df <- df[df$generation == g,]
p <- plot <- plot_generation(landscape, tmp_df)
print(p)
}
dev.off()
}