セルオートマトン

nCell=201;nGen=100;
res=matrix(0,nrow=nGen,ncol=nCell)
res[1,ceiling(nCell/2)]=1;
for (i_gen in 2:nGen) {
  temp.vec=c(res[i_gen-1,nCell],res[i_gen-1,],res[i_gen-1,1])
  res[i_gen,]=(temp.vec[1:nCell]+temp.vec[2:(nCell+1)]+temp.vec[3:(nCell+2)])%%2;
}
# その1R（直感的に理解しやすい例）
for (i_gen in 2:nGen) {
  for (i_cell in 2:(nCell-1)) {
    res[i_gen,i_cell]=sum(res[i_gen-1,(i_cell-1):(i_cell+1)])%%2;
  }
  res[i_gen,1]=(res[i_gen-1,nCell]+res[i_gen-1,1]+res[i_gen-1,2])%%2;
  res[i_gen,nCell]=(res[i_gen-1,(nCell-1)]+res[i_gen-1,nCell]+res[i_gen-1,1])%%2;
}

解答例その2 256のルールに対応

dec2bin<-function(num, digits=8) {
  bin=c()
  if (num==0){
    bin=0
  } else {
    while(num!=0){
      rem=num%%2
　　   num=num%/%2
      bin=c(rem,bin)
    }
  }
  if (length(bin) < digits){
    res=matrix(0,nrow=1,ncol=digits)
    res[(digits-length(bin)+1):digits]=bin
  } else {res=bin}
  return(res)
}

transFUN<-function(st,ruleID){
  output=dec2bin(ruleID,8);
  a=matrix(c(1,1,1,1,1,0,1,0,1,1,0,0,0,1,1,0,1,0,0,0,1,0,0,0),nrow=8,byrow=T)
  newSt=output[which(apply(a,1,function(x) {all(x==st)}))]
  return(newSt)
}
ECA<-function(nCell, nGen,ruleID){
  res=matrix(0,nrow=nGen,ncol=nCell)
  res[1,ceiling(nCell/2)]=1;
  for (i_gen in 2:nGen) {
    for (i_cell in 2:(nCell-1)) {
      res[i_gen,i_cell]=transFUN(res[i_gen-1,(i_cell-1):(i_cell+1)],ruleID)
     }
   res[i_gen,1]=transFUN(c(res[i_gen-1,nCell],
                          res[i_gen-1,1],
                          res[i_gen-1,2]),ruleID)
   res[i_gen,nCell]=transFUN(c(res[i_gen-1,(nCell-1)],
                               res[i_gen-1,nCell],
                               res[i_gen-1,1]),ruleID)
  }
  return(res)
}
# その2R （計算時間の改善はほぼなし）　
ECA2<-function(nCell, nGen,ruleID){
  res=matrix(0,nrow=nGen,ncol=nCell)
  res[1,ceiling(nCell/2)]=1;
  for (i_gen in 2:nGen) {
    temp.mat=cbind(c(res[i_gen-1,nCell],res[i_gen-1,1:(nCell-1)]),res[i_gen-1,],
      c(res[i_gen-1,2:nCell],res[i_gen-1,1]))
    res[i_gen,]=apply(temp.mat,1,transFUN,ruleID)
  }
  return(res)
}