CSC 120, Assignment #3, Script to run the requested simulations.

> source("a3funs.r")

Define a function to produce three plots of amount of grass over time, cow row position over time, and cow column position over time, from the results of a simulation.

> plot_grass_pos <- function (r) {
+ 
+     par(mfrow=c(3,1))
+ 
+     plot(r$grass,pch=20,xlab="Time",ylab="")
+     title("Amount of grass")
+ 
+     plot(r$pos[,1],xlab="Time",ylab="",ylim=c(1,nr),pch=20)
+     title("Cow row position")
+ 
+     plot(r$pos[,2],xlab="Time",ylab="",ylim=c(1,nc),pch=20)
+     title("Cow column position")
+ }

Set the random number seed so results will be reproducible. Note that the seed is supposed to be set to your student ID number.

> set.seed(999999999)

Do the first simulation.

> nr <- 10         # Number of rows
> nc <- 15         # Number of columns
> steps <- 400     # Time steps to simulate for
> pr <- 0.004      # Probability of grass growing
> 
> par(mfrow=c(2,2))
> r <- simulate (nr, nc, pr, steps, plot=c(100,200,300,400))

> plot_grass_pos(r)

Do the second simulation.

> nr <- 10         # Number of rows
> nc <- 15         # Number of columns
> steps <- 400     # Time steps to simulate for
> pr <- 0.007      # Probability of grass growing
> 
> par(mfrow=c(2,2))
> r <- simulate (nr, nc, pr, steps, plot=c(100,200,300,400))

> plot_grass_pos(r)

Do the third simulation.

> nr <- 20         # Number of rows
> nc <- 20         # Number of columns
> steps <- 1000    # Time steps to simulate for
> pr <- 0.002      # Probability of grass growing
> 
> par(mfrow=c(2,2))
> r <- simulate (nr, nc, pr, steps, plot=c(100,200,500,1000))

> plot_grass_pos(r)