0

Background:

I'm trying to come up with a coding scheme such that any of my 14 players (separately; each player is shown as numbered circles below) on the center thick line of my soccer field independently moves to left by .1 (in x-axis value unit) if the result of outcome = sample(x = c(1, 2), size = 1) is 1 and if the result of outcome = sample(x = c(1, 2), size = 1) is 2, the player moves to right by .1 (in x-axis value unit).

Thus, the goal is that each player can independently move to the left or right based on the result of the outcome.

Coding Question (R code is provided below):

Do I need to write outcome[i] = sample(x = c(1, 2), size = 1) 16 times for each player and then construct something like:

outcome1 = sample(x = c(1, 2), size = 1)
outcome2 = sample(x = c(1, 2), size = 1)
#.
#.
#.

and then change the x of that player based on his outcome:

if(outcome1 == 1) {  points(x - .1, y, cex = 4.5, lwd = 3, pch = 21, bg = 0)  
  } else { points(x + .1, y, cex = 4.5, lwd = 3, pch = 21, bg = 0)  }

Or there is a better way?

enter image description here

enter image description here

Here is my R code:

plot(1, ty = "n", ann = F, cex = 3)

par = par('usr')
rect(par[1], par[3], par[2], par[4], col = 'darkseagreen1' )

points( 1, 1, cex = 5, pch =20, col = 0)
points( 1, 1, cex = 33, lwd = 5, col = 0)
abline(v = 1, lwd = 10, col = 0)

rect(.6, .6, 1.4, 1.4, lwd = 5, border = 0)
rect(0, .85, .65, 1.15, lwd = 5, col = 'darkseagreen1', border = 0)
rect(1.35, .85, 1.45, 1.15, lwd = 5, col = 'darkseagreen1', border = 0)
box()

x = rep(1, 14); y = seq(.6, 1.4, len = 14)
points(x, y, cex = 4.5, lwd = 3, pch = 21, bg = 0)
text(x, y, 1:14, font = 2)
Community
  • 1
  • 1
rnorouzian
  • 7,397
  • 5
  • 27
  • 72
  • How about `xoffsetVec <- sample(c(-0.1, 0.1), 14, replace = TRUE)` and then updating `x <- x + xoffsetVec` in each iteration? – ikop May 03 '17 at 05:48

1 Answers1

1

You could first sample all the moves for each player and store that in a matrix (rows are the players, columns are the time steps):

nSteps <- 16
nPlayers <- 14

## Sample movement of players:
xStepsMx <- matrix(sample(c(-1,1)*0.1, nPlayers*nSteps, replace = TRUE),
        nrow = nPlayers, ncol = nSteps)

You can then evaluate the position of each player at each time step:

## Position of players:
xPosMx <- t(sapply(1:nrow(xStepsMx), function(ii) cumsum(xStepsMx[ii,]))) + x

For each time step timeStep in 1,2,...,16 you can then e.g. plot your players' position using

timeStep <- 5    
points(xPosMx[,timeStep], y, cex = 4.5, lwd = 3, pch = 21, bg = "white")
text(xPosMx[,timeStep], y, 1:14, font = 2)
ikop
  • 1,760
  • 1
  • 12
  • 24
  • @parvinkarimi if you just want the x-position of each player at each time step then, yes, you can increase the value of `nPlayers`. You will just have to adapt the initial vector `x` as well (i.e., `x <- rep(1, nPlayers)`) – ikop May 03 '17 at 06:23
  • The matrix `xPosMx` stores the positions of all players for each time step. So if you want to know the position of player `i` at time `t`, you find that as `xPosMx[i,t]`. The initial position (that would be at time step 0) is not stored in the matrix, but given in your vector `x`. Time step `t = 1` (the first column in `xPosMx`) is the time after the first movement of your players. – ikop May 04 '17 at 04:25
  • Here, `nSteps` is the total number of times each player tosses the coin. After each coin toss he moves either left or right according to the result of the toss. If you just want to know where each player landed after 16 tosses you can find that in the last column of `xPosMx`. – ikop May 04 '17 at 04:34
  • Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/143341/discussion-between-ikop-and-parvin-karimi). – ikop May 04 '17 at 04:59
  • Dear iKop, could you possibly let me know when you get a chance? – rnorouzian May 06 '17 at 17:51