Expands the spatial population range by a specified distance in a given time-window

expand_range(
  pop,
  by,
  end,
  start,
  overlap = 0.8,
  snapshots = NULL,
  polygon = NULL,
  lock = FALSE,
  verbose = TRUE
)

Arguments

pop

Object of the class slendr_pop

by

How many units of distance to expand by?

start, end

When does the expansion start/end?

overlap

Minimum overlap between subsequent spatial boundaries

snapshots

The number of intermediate snapshots (overrides the overlap parameter)

polygon

Geographic region to restrict the expansion to

lock

Maintain the same density of individuals. If FALSE (the default), the number of individuals in the population will not change. If TRUE, the number of individuals simulated will be changed (increased or decreased) appropriately, to match the new population range area.

verbose

Report on the progress of generating intermediate spatial boundaries?

Value

Object of the class slendr_pop

Examples

# spatial definitions -----------------------------------------------------

# create a blank abstract world 1000x1000 distance units in size
map <- world(xrange = c(0, 1000), yrange = c(0, 1000), landscape = "blank")

# all spatial slendr objects can be visualised with a function plot_map()
plot_map(map)

# create a circular population with the center of a population boundary at
# [200, 800] and a radius of 100 distance units, 1000 individuals at time 1
# occupying a map just specified
pop1 <- population("pop1", N = 1000, time = 1,
                   map = map, center = c(200, 800), radius = 100)

# printing a population object to a console shows a brief summary
pop1

# create another population occupying a polygon range, splitting from pop1
# at a given time point (note that specifying a map is not necessary because
# it is "inherited" from the parent)
pop2 <- population("pop2", N = 100, time = 50, parent = pop1,
                        polygon = list(c(100, 100), c(320, 30), c(500, 200),
                                  c(500, 400), c(300, 450), c(100, 400)))

pop3 <- population("pop3", N = 200, time = 80, parent = pop2,
                   center = c(800, 800), radius = 200)

# move "pop1" to another location along a specified trajectory and saved the
# resulting object to the same variable (the number of intermediate spatial
# snapshots can be also determined automatically by leaving out the
# `snapshots = ` argument)
pop1_moved <- move(pop1, start = 100, end = 200, snapshots = 10,
                   trajectory = list(c(600, 820), c(800, 400), c(800, 150)))
pop1_moved

# many slendr functions are pipe-friendly, making it possible to construct
# pipelines which construct entire history of a population
pop1 <- population("pop1", N = 1000, time = 1,
                   map = map, center = c(200, 800), radius = 100) %>%
  move(start = 100, end = 200, snapshots = 10,
       trajectory = list(c(400, 800), c(600, 700), c(800, 400), c(800, 150)))

# a population boundary at a given time can be "manually" created by calling
# the function set_range() -- here we extend the pipeline from the previous
# command to set the final spatial map of pop1 to another polygon
pop1 <-
  population(
    "pop1", N = 1000, time = 1,
    map = map, center = c(200, 800), radius = 100
  ) %>%
  move(
    start = 100, end = 200, snapshots = 10,
    trajectory = list(c(400, 800), c(600, 700), c(800, 400), c(800, 150))
  ) %>%
  set_range(time = 300, polygon = list(
    c(400, 0), c(1000, 0), c(1000, 600), c(900, 400), c(800, 250),
    c(600, 100), c(500, 50))
  )

# spatial boundaries can be plotted with a function plot_map()
plot_map(pop1)

# population ranges can expand by a given distance in all directions
pop2 <- expand_range(pop2, by = 200, start = 50, end = 150, snapshots = 10)

# we can check the positions of all populations interactively by plotting their
# ranges together on a single map
plot_map(pop1, pop2, pop3)

# gene flow events --------------------------------------------------------

# individual gene flow events can be saved to a list
gf <- list(
  gene_flow(from = pop1, to = pop3, start = 150, end = 200, rate = 0.15),
  gene_flow(from = pop1, to = pop2, start = 300, end = 330, rate = 0.25)
)

# compilation -------------------------------------------------------------

# location where to save slendr model configuration files
model_dir <- paste0(tempdir(), "_slendr_model")

# compile model components in a serialized form to dist, returning a single
# slendr model object (in practice, the resolution should be smaller)
model <- compile_model(
  populations = list(pop1, pop2, pop3), generation_time = 1,
  path = model_dir, overwrite = TRUE,
  resolution = 10, sim_length = 500,
  competition = 5, mating = 5, dispersal = 1
)

# serialized models can be read from disk to their R representation again
loaded_model <- read_model(model_dir)

# clean up the model temporary directory
unlink(model_dir, recursive = TRUE, force = TRUE)