18/11/11 11:07:30.56 RT24eksu.net
seqNp <- function(N=100,K=5,p=0.5){
if(p==0) return(0)
if(N==K) return(p^K)
q=1-p
a=numeric(N) # a(n)=P0(n)/p^n , P0(n)=a(n)*p^n
for(i in 1:K) a[i]=q/p^i # P0(i)=q
for(i in K:(N-1)){ # recursive formula
a[i+1]=0
for(j in 0:(K-1)){
a[i+1]=(a[i+1]+a[i-j])
}
a[i+1]=q/p*a[i+1]
}
P0=numeric(N)
for(i in 1:N) P0[i]=a[i]*p^i # P0(n)=a(n)*p^n
MP=matrix(rep(NA,N*K),ncol=K)
colnames(MP)=paste0('P',0:(K-1))
MP[,'P0']=P0
head(MP);tail(MP)
MP[1,'P1']=p
for(i in (K-2):K) MP[1,i]=0
for(k in 2:K){
for(i in 1:(N-1)) MP[i+1,k]=p*MP[i,k-1]
} # Pk(n+1)=p*P(k-1)(n)
ret=1-apply(MP,1,sum)
ret[N]
}
seqNpJ <- function(N,K,p) seqNp(N,K,p) - seqNp(N,K+1,p)