R/WheresCroc.R

In ejames917/AI-Lab2_Where_is_Croc: What the package does (short line)

#' @export
randomWC=function(moveInfo,readings,positions,edges,probs) {
  moveInfo$moves=c(sample(getOptions(positions[3],edges),1),0) 
  print(moveInfo)
  print(readings)
  print(positions)
  return(moveInfo)
}

#' @export
manualWC=function(moveInfo,readings,positions,edges,probs) {
  options=getOptions(positions[3],edges)
  print("Move 1 options (plus 0 for search):")
  print(options)
  # print(probs)
  # print(readings)
  # print(edges)
  mv1=readline("Move 1: ")
  if (mv1=="q") {stop()}
  if (!mv1 %in% options && mv1 != 0) {
    warning ("Invalid move. Search ('0') specified.")
    mv1=0
  }
  if (mv1!=0) {
    options=getOptions(mv1,edges)
  }
  print("Move 2 options (plus 0 for search):")
  print(options)
  mv2=readline("Move 2: ")    
  if (mv2=="q") {stop()}
  if (!mv1 %in% options && mv1 != 0) {
    warning ("Invalid move. Search ('0') specified.")
    mv2=0
  }
  moveInfo$moves=c(mv1,mv2)
  return(moveInfo)
}

#' Run Where's Croc
#' 
#' Runs the Where's Croc game. In this game, you are a ranger in an Australian national park. 
#' This park consists of a number of waterholes, some of which are connected to each other.
#' There is a crocodile in the park called 'Croc'. Croc has been fitted with sensors that record 
#' the salinity, phosphate and nitrogen levels in the water where he is swimming. He was also 
#' fitted with a sensor that records his position, but that has broken.
#' Your task is to find Croc using the available information. To aid in this you have information
#' about the probability distributions for different salinity, phosphate and nitrogen levels in 
#' different waterholes.
#' There are also two tourists in the park. Both the tourists and Croc walk randomly, each turn
#' moving to one of the neighboring waterholes from where they are or staying still. All moves
#' are equally likely.
#' If Croc and a tourist end up on the same waterhole, Croc will eat the tourist. If you search
#' the waterhole you are on when Croc is there, you have found Croc and win the game. 
#' Your score is the number of turns it takes to find Croc.
#' To play manually pass manualWC
#' as the makeMoves function and enter the appropriate numbers to make moves.
#' @param makeMoves Your function that takes five arguments: (1) A list of information for the move.
#' This has two fiels. The first is a vector of numbers called 'moves', where you will enter 
#' the moves you want to make. You should
#' enter two moves (so you can move to a neighboring waterhole and search). Valid moves are the 
#' numbers of a neighboring or current waterhole or '0' which means you will search your current
#' waterhole for Croc. The second field is a list called
#' 'mem' that you can use to store information you want to remember from turn to turn. (2) A 
#' vector giving the salinity, phosphate and nitrogen reading from Croc sensors at his current 
#' location. (3) A vector giving the positions of the two tourists and yourself. If a tourist
#' has just been eaten by Croc that turn, the position will be multiplied by -1. If a tourist 
#' was eaten by Croc in a previous turn, then the position will be NA. (4) a matrix giving the 
#' edges paths between waterholes (edges) present. (5) a list of three matrices giving the mean
#' and standard deviation of readings for salinity, phosphate and nitrogen respectively
#' at each waterhole.
#' Your function should return the first argument passed with an updated moves vector 
#' and any changes to the 'mem' field you wish to access later on.
#' @param showCroc A Boolean value specifying whether you want Croc to be shown on the gameboard.
#' Note that you are not permitted to use this visual information when you are scored.
#' @param pause The pause period between moves. Ignore this.
#' @return A string describing the outcome of the game.
#' @export
runWheresCroc=function(makeMoves=markovWC,showCroc=T,pause=1) {
  positions=sample(1:40,4) # Croc, BP1, BP2, Player
  ##### DIAGNOSTICS SO BP GETS EATEN RIGHT AWAY #####
  #positions=c(1,1,6,40)

  points=getPoints()
  edges=getEdges()
  probs=getProbs()
  move=0
  moveInfo=list(moves=c(),mem=list())
  while (!is.na(positions[1])) {
    move=move+1
    positions[1]=sample(getOptions(positions[1],edges),1)
    if (!is.na(positions[2])&&positions[2]>0) {
      positions[2]=sample(getOptions(positions[2],edges),1)
    } else if (!is.na(positions[2]) && positions[2]<0) {
      positions[2]=NA
    }
    if (!is.na(positions[3])&&positions[3]>0) {
      positions[3]=sample(getOptions(positions[3],edges),1)
    } else if (!is.na(positions[3]) && positions[3]<0) {
      positions[3]=NA
    }
    if (!is.na(positions[2]) && positions[2]==positions[1]) {
      positions[2]=-positions[2]
    }
    if (!is.na(positions[3]) && positions[3]==positions[1]) {
      positions[3]=-positions[3]
    }
    plotGameboard(points,edges,move,positions,showCroc)
    
    Sys.sleep(pause)
    
    readings=getReadings(positions[1],probs)
    moveInfo=makeMoves(moveInfo,readings,positions[2:4],edges,probs)
    if (length(moveInfo$moves)!=2) {
      stop("Error! Passed makeMoves function should return a vector of two elements.")
    }
    for (m in moveInfo$moves) {
      if (m==0) {
        if (positions[1]==positions[4]) {
          print(paste("Congratualations! You got croc at move ",move,".",sep=""))
          return (move)
        }
      } else {
        if (m%in%getOptions(positions[4],edges)) {
          positions[4]=m
        } else {
          warning("Invalid move.")
        }
      }      
    }
  }
}
#' @export
getPoints=function() {
  points=matrix(c(1,1),ncol=2)
  points=rbind(points,c(1,7))
  points=rbind(points,c(1,17))
  points=rbind(points,c(2,3))
  points=rbind(points,c(2,12))
  points=rbind(points,c(3,2))
  points=rbind(points,c(3,19))
  points=rbind(points,c(4,7))
  points=rbind(points,c(4,11))
  points=rbind(points,c(5,5))
  points=rbind(points,c(5,15))
  points=rbind(points,c(6,1))
  points=rbind(points,c(6,20))
  points=rbind(points,c(7,6))
  points=rbind(points,c(7,11))
  points=rbind(points,c(8,2))
  points=rbind(points,c(8,14))
  points=rbind(points,c(8,18))
  points=rbind(points,c(9,6))
  points=rbind(points,c(10,10))
  points=rbind(points,c(10,18))
  points=rbind(points,c(11,1))
  points=rbind(points,c(11,12))
  points=rbind(points,c(12,6))
  points=rbind(points,c(12,12))
  points=rbind(points,c(13,16))
  points=rbind(points,c(14,4))
  points=rbind(points,c(14,12))
  points=rbind(points,c(14,20))
  points=rbind(points,c(15,3))
  points=rbind(points,c(15,8))
  points=rbind(points,c(15,17))
  points=rbind(points,c(16,14))
  points=rbind(points,c(17,3))
  points=rbind(points,c(17,18))
  points=rbind(points,c(18,10))
  points=rbind(points,c(19,13))
  points=rbind(points,c(20,2))
  points=rbind(points,c(20,6))
  points=rbind(points,c(20,19))
  return (points)
}

#' @export
getEdges=function() {
  edges=matrix(c(1,2),ncol=2)
  edges=rbind(edges,c(1,4))
  edges=rbind(edges,c(1,6))
  edges=rbind(edges,c(2,4))
  edges=rbind(edges,c(2,5))
  edges=rbind(edges,c(3,5))
  edges=rbind(edges,c(3,7))
  edges=rbind(edges,c(4,6))
  edges=rbind(edges,c(4,8))
  edges=rbind(edges,c(5,7))
  edges=rbind(edges,c(5,9))
  edges=rbind(edges,c(6,12))
  edges=rbind(edges,c(7,11))
  edges=rbind(edges,c(7,13))
  edges=rbind(edges,c(8,9))
  edges=rbind(edges,c(8,10))
  edges=rbind(edges,c(9,11))
  edges=rbind(edges,c(10,12))
  edges=rbind(edges,c(10,14))
  edges=rbind(edges,c(11,13))
  edges=rbind(edges,c(11,15))
  edges=rbind(edges,c(12,16))
  edges=rbind(edges,c(13,18))
  edges=rbind(edges,c(14,15))
  edges=rbind(edges,c(14,16))
  edges=rbind(edges,c(15,17))
  edges=rbind(edges,c(16,19))
  edges=rbind(edges,c(16,22))
  edges=rbind(edges,c(17,18))
  edges=rbind(edges,c(17,19))
  edges=rbind(edges,c(17,20))
  edges=rbind(edges,c(18,21))
  edges=rbind(edges,c(19,20))
  edges=rbind(edges,c(19,22))
  edges=rbind(edges,c(20,23))
  edges=rbind(edges,c(21,23))
  edges=rbind(edges,c(21,29))
  edges=rbind(edges,c(22,24))
  edges=rbind(edges,c(22,27))
  edges=rbind(edges,c(23,24))
  edges=rbind(edges,c(23,25))
  edges=rbind(edges,c(24,25))
  edges=rbind(edges,c(24,27))
  edges=rbind(edges,c(25,26))
  edges=rbind(edges,c(25,27))
  edges=rbind(edges,c(25,28))
  edges=rbind(edges,c(26,28))
  edges=rbind(edges,c(26,29))
  edges=rbind(edges,c(27,30))
  edges=rbind(edges,c(27,31))
  edges=rbind(edges,c(28,31))
  edges=rbind(edges,c(28,32))
  edges=rbind(edges,c(29,32))
  edges=rbind(edges,c(29,35))
  edges=rbind(edges,c(30,31))
  edges=rbind(edges,c(30,34))
  edges=rbind(edges,c(31,33))
  edges=rbind(edges,c(31,34))
  edges=rbind(edges,c(32,33))
  edges=rbind(edges,c(32,35))
  edges=rbind(edges,c(33,35))
  edges=rbind(edges,c(33,36))
  edges=rbind(edges,c(33,37))
  edges=rbind(edges,c(34,36))
  edges=rbind(edges,c(34,38))
  edges=rbind(edges,c(35,40))
  edges=rbind(edges,c(36,37))
  edges=rbind(edges,c(36,39))
  edges=rbind(edges,c(37,39))
  edges=rbind(edges,c(37,40))
  edges=rbind(edges,c(38,39))
  
  return (edges)
}

#' @export
getProbs=function(){
  salinity=cbind(runif(40,100,200),runif(40,5,30))
  phosphate=cbind(runif(40,100,200),runif(40,5,30))
  nitrogen=cbind(runif(40,100,200),runif(40,5,30))
  list(salinity=salinity,phosphate=phosphate,nitrogen=nitrogen)
}

#' @export
getReadings=function(point,probs){
  c(
    rnorm(1,probs$salinity[as.numeric(point),1],probs$salinity[as.numeric(point),2]),
    rnorm(1,probs$phosphate[as.numeric(point),1],probs$phosphate[as.numeric(point),2]),
    rnorm(1,probs$nitrogen[as.numeric(point),1],probs$nitrogen[as.numeric(point),2])
  )
}


#' @export
plotGameboard=function(points,edges,move,positions,showCroc) {
  plot(points,pch=18,col="blue",cex=2,xlab="X",ylab="Y",main=paste("Where's Croc - Move",move))
  xFrom=points[edges[,1],1]
  yFrom=points[edges[,1],2]
  xTo=points[edges[,2],1]
  yTo=points[edges[,2],2]
  segments(xFrom,yFrom,xTo,yTo)
  for (bp in 2:3)
    if (!is.na(positions[bp])) {
      if (positions[bp]>0) {
        points(points[as.numeric(positions[bp]),1],points[as.numeric(positions[bp]),2],col="orange",pch=17,cex=4)
      } else {
        points(points[-as.numeric(positions[bp]),1],points[-as.numeric(positions[bp]),2],col="red",pch=17,cex=4)
      }
    }
  points(points[as.numeric(positions[4]),1],points[as.numeric(positions[4]),2],col="green",pch=15,cex=4)
  if (showCroc) {
    points(points[as.numeric(positions[1]),1],points[as.numeric(positions[1]),2],col="red",pch=15,cex=4)      
  }
  text(points[,1]+.4, points[,2], labels=as.character(1:40))
}

#' @export
getOptions=function(point,edges) {
  c(edges[which(edges[,1]==point),2],edges[which(edges[,2]==point),1],point)
}

########################################################
############### Our functions start here ###############
########################################################

#Finds the probability using the dnorm function
normDistProb <- function(value, mean, std) {
  #play with the interval to see if it gives better results
  interval = 20.0
  lowcut = value - interval
  highcut = value + interval
  
  return(pnorm(highcut, mean = mean, sd = std) - pnorm(lowcut, mean = mean, sd = std))
}

forward=function(waterhole, obs, prevProbs, probs, neighbors) {
  #Returns proportional probability of croc being at any given waterhole
  #waterhole = number of waterhole
  #neighbors = list of neighbors for each node in the network (including itself)
  
  #Computes the emission probabilty from the set of obs
  emission = normDistProb(obs[1], probs$salinity[waterhole,1], probs$salinity[waterhole,2])
  emission = emission * normDistProb(obs[2], probs$phosphate[waterhole,1], probs$phosphate[waterhole,2])
  emission = emission * normDistProb(obs[3], probs$nitrogen[waterhole,1], probs$nitrogen[waterhole,2])
  
  #Figure the probability of the croc reaching a given waterhole, considering previous state
  moving = 0
  for(n in 1:length(neighbors[[waterhole]])) {
    neighbor = neighbors[[waterhole]][n]
    moving = moving + (1.0/length(neighbors[[neighbor]])) * prevProbs[neighbor]
  }
  
  return(emission*moving)
}

computeProbs=function(obs, prevProbs, probs, neighbors) {
  #Return vector of probabilities that croc is in each waterhole
  #This returns probs for EVERY watering hole, forward returns prob for SINGLE watering hole

  #If this is the first turn
  if(sum(prevProbs) == 0 || is.nan(sum(prevProbs))) {
    prevProbs = vector(mode="double", length=40)
    possibleWaterholes = 0
    for(waterhole in 1:40) {
      if(!is.nan(obs[[4]]) && !is.nan(obs[[5]])) {
        if(obs[[4]] == waterhole || obs[[5]] == waterhole) {
          prevProbs[waterhole] = 0 #If tourist is there, croc isn't
          next()
        }
      }
      prevProbs[waterhole] = 1 
      possibleWaterholes = possibleWaterholes + 1
    }
    #probabilites is equal to 1/waterholes without a tourist
    prevProbs = sapply(prevProbs, function(x) x/possibleWaterholes)
  }
  
  holeProbs = vector(mode="double", length=40)
  #check if tourist was eaten this turn
  if((!is.na(obs[[4]])) && (obs[[4]] < 0)) {
    croc = -obs[[4]]
    for(hole in 1:40) {
      holeProbs[hole] = 0
    }
    holeProbs[croc] = 1
  }
  else if((!is.na(obs[[5]])) && (obs[[5]] < 0)) {
    croc = -obs[[5]]
    for(hole in 1:40) {
      holeProbs[hole] = 0
    }
    holeProbs[croc] = 1
  }
  #else tourist wasn't
  else {
    for(hole in 1:40) {
      #Compute proportional probabilites
      holeProbs[hole] = forward(hole, obs, prevProbs, probs, neighbors)
    }
  }
  
  totalProbs = sum(holeProbs)
  holeProbs = sapply(holeProbs, function(x) x/totalProbs)
  return(holeProbs)
}

#BFS based implementation of movement
BFSmove=function(crocProbs, positions, edges) {
  #Find the max prob value
  crocPos = 1
  maxProb = 0
  for(i in 1:40) {
    if(!is.nan(crocProbs[i]) && maxProb < crocProbs[i]) {
      crocPos = i
      maxProb = crocProbs[i]
    }
  }
  #browser()
  graph = igraph::graph_from_edgelist(edges, directed=FALSE)
  #results = bfs(graph, positions[3], order=TRUE, dist=TRUE, father=TRUE)
  shortest = igraph::shortest_paths(graph, positions[3], crocPos, weights=NULL, predecessors=TRUE)
  move = c()
  if(length(shortest$vpath[[1]])==1) {
    move[1] = 0
    move[2] = 0
  } else if(length(shortest$vpath[[1]])==2) {
    move[1] = shortest$vpath[[1]][2]
    move[2] = 0
  } else {
    move[1] = shortest$vpath[[1]][2]
    move[2] = shortest$vpath[[1]][3]
  }
  return(move)
}

markovWC=function(moveInfo, readings, positions, edges, probs) {
  #neighbors is a list of lists containing the neighbors of each waterhole
  neighbors = list()
  #Each waterhole is it's own neighbor
  for(i in 1:40) {
    neighbors[i] = list(i)
  }
  for(edge in 1:nrow(edges)) {
    from = edges[edge, 1]
    to = edges[edge, 2]
    neighbors[[from]][length(neighbors[[from]])+1] = to
    neighbors[[to]][length(neighbors[[to]])+1] = from
  }
  
  #Put the different observations into one vector
  observations = vector(mode="double", length=6)
  for(i in 1:3) {
    observations[i] = readings[[i]]
    observations[i+3] = positions[[i]]
  }
  
  #Get previous probs from memory
  if(length(moveInfo$mem) == 0) {
    moveInfo$mem[["prevProbs"]] = vector(mode="double", length=40)
  }
  prevProbs = moveInfo$mem[["prevProbs"]]
  
  #compute probabilities of croc being at each waterhole
  newProbs = computeProbs(observations, prevProbs, probs, neighbors)

  #Placeholder to return random move so this can run
  #moveInfo$moves=c(sample(getOptions(positions[3],edges),1),0) 
  
  #Use BFS search to find best moves
  moveInfo$moves = BFSmove(newProbs, positions, edges)
  
  moveInfo$mem[["prevProbs"]] = newProbs 
  return(moveInfo)
}