Move downhill

Move the turtles to their neighboring patch with the lowest value.

downhill(world, pVar, turtles, nNeighbors, torus = FALSE)

# S4 method for worldMatrix,missing,agentMatrix,numeric
downhill(world, turtles, nNeighbors, torus)

# S4 method for worldArray,character,agentMatrix,numeric
downhill(world, pVar, turtles, nNeighbors, torus = FALSE)

Arguments

world

WorldMatrix or worldArray object.

pVar

Character. If the world is a worldArray object, pVar is the name of the layer to use to define the patches values. pVar must not be provided if the world is a worldMatrix object.

turtles

AgentMatrix object representing the moving agents.

nNeighbors

Integer: 4 or 8. Represents the number of neighbor patches considered.

torus

Logical to determine if the world is wrapped. Default is torus = FALSE.

Value

AgentMatrix representing the turtles with updated coordinates and updated data for their heading values and previous coordinates prevX

and prevY.

Details

If no neighboring patch has a smaller value than the patch where the turtle is currently located on, the turtle stays on this patch. It still moves to the patch center if it was not already on it.

     If there are multiple neighboring `patches` with the same lowest value,

     the `turtle` chooses one `patch` randomly.



     If a `turtle` is located on a `patch` on the edge

     of the `world` and `torus = FALSE`, it has fewer

     neighboring `patches` as options to move than `nNeighbors`; if

     `torus = TRUE`, the `turtle` can move on the other side of the `world` to

     move downhill and its choice of neighboring `patches` is always equals to

     `nNeighbors`.

References

Wilensky, U. 1999. NetLogo. http://ccl.northwestern.edu/netlogo/. Center for Connected Learning and Computer-Based Modeling, Northwestern University. Evanston, IL.

See also

https://ccl.northwestern.edu/netlogo/docs/dictionary.html#downhill

Author

Sarah Bauduin

Examples

w1 <- createWorld(
  minPxcor = 1, maxPxcor = 10, minPycor = 1, maxPycor = 10,
  data = runif(100)
)
t1 <- createTurtles(n = 10, coords = randomXYcor(w1, n = 10))
plot(w1)
points(t1, col = of(agents = t1, var = "color"), pch = 16)

if (requireNamespace("SpaDES.tools", quietly = TRUE)) {
  t1 <- downhill(world = w1, turtles = t1, nNeighbors = 8)
  points(t1, col = of(agents = t1, var = "color"), pch = 16)
}