downhill: Move downhill

In NetLogoR: Build and Run Spatially Explicit Agent-Based Models

Move downhill

Description

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

Usage

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

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

## S4 method for signature '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.

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`.

Value

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

Author(s)

Sarah Bauduin

References

Wilensky, U. 1999. NetLogo. https://www.netlogo.org. Center for Connected Learning and Computer-Based Modeling, Northwestern University. Evanston, IL.

See Also

https://docs.netlogo.org/dictionary.html#downhill

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)
}

NetLogoR documentation built on Sept. 9, 2025, 5:27 p.m.