Move backward

Move the turtles backward of their headings' directions.

bk(turtles, dist, world, torus = FALSE, out = TRUE)

# S4 method for agentMatrix,numeric
bk(turtles, dist, world, torus = FALSE, out = TRUE)

Arguments

turtles

AgentMatrix object representing the moving agents.

dist

Numeric. Vector of distances to move. Must be of length 1 or of length turtles.

world

WorldMatrix or worldArray object.

torus

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

out

Logical. Determine if a turtle should move when torus = FALSE and its ending position will be outside of the world's extent. Default is out = TRUE.

Value

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

and prevY.

Details

If torus = FALSE and out = TRUE, world does not need to be provided.

     If a distance to move leads a `turtle` outside of the `world`'s extent

     and `torus = TRUE`, the `turtle` is

     relocated on the other side of the `world`, inside its extent; if

     `torus = FALSE` and `out = TRUE`, the `turtle` moves past the

     `world`'s extent; if `torus = FALSE` and `out = FALSE`, the

     `turtle` does not move at all. In the event that a `turtle` does not move,

     its previous coordinates are still updated with its position before

     running `bk()` (i.e., its current position).



     If a given `dist` value is negative, then the `turtle` moves

     forward.



     The `turtles`' headings are not affected by the function (i.e., the

     `turtles` do not face backward).

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#back

     <https://ccl.northwestern.edu/netlogo/docs/dictionary.html#jump>

Author

Sarah Bauduin

Examples

w1 <- createWorld(
  minPxcor = 0, maxPxcor = 4, minPycor = 0, maxPycor = 4,
  data = runif(25)
)
t1 <- createOTurtles(n = 10, world = w1)
plot(w1)
points(t1, col = of(agents = t1, var = "color"), pch = 16)

t1 <- fd(turtles = t1, dist = 2)
points(t1, col = of(agents = t1, var = "color"), pch = 16)
t1 <- bk(turtles = t1, dist = 1)
points(t1, col = of(agents = t1, var = "color"), pch = 16)
t1 <- fd(turtles = t1, dist = 0.5)
points(t1, col = of(agents = t1, var = "color"), pch = 16)