问模拟马尔可夫链的概率数不正确

EN

             BP          IP             SP 


BPBP     0.4586757     0.3772354     0.1640889

IPBP     0.3489484     0.4746654     0.1763862

SPBP     0.3756522     0.4162319     0.2081159

BPIP     0.3646061     0.4640000     0.1713939

IPIP     0.2666122     0.5654956     0.1678922

SPIP     0.3054187     0.4860427     0.2085386

BPSP     0.4125561     0.3974215     0.1900224

IPSP     0.2974337     0.5069415     0.1956247

SPSP     0.3576642     0.4333942     0.2089416

  function(trans,initprob,N)
  {
  BrokerPosition <- c("BP", "IP", "SP")
  mysequence<-character()
  firstposition <- sample(BrokerPosition, 1, rep=TRUE, prob=initprob)
  mysequence[1]   <- firstposition
  for (i in 2:N){
   prevposition <- mysequence[i-1]
   probabilities  <- trans[,prevposition]
   BPosition<- sample(BrokerPosition, 1, rep=TRUE, prob=probabilities)
   mysequence[i]  <- BPosition
                }
  return(mysequence)
  }