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