使用While循環重寫用戶定義的函數

Question

我正在寫下面的函數，它應該計算seed.times處強度函數的值。

Intensity=function(params, eval.times, event.times) { 
# This function computes the value of the intensity function. 
# It takes as seed a vector of values/times at which to compute the 
# the value of the function and a vector with the occurrence times 
# of the events. 

# Input: eval.times, event.times and values of parameters 
# Output: values of intensity function 

s<-sort(eval.times) 
t<-sort(event.times) 
par1<-params[1] 
par2<-params[2] 
par3<-params[3] 

values <- rep(par1,length(s)) 
for (i in 1:length(values)) { 
    j<-1 
    while (t[j] < s[i]) 
    { 
      values[i] <- values[i] + par2*exp(-par3*(s[i]-t[j])) 
      j <- j+1 
     } 
    } 

return(values) 
} 

然而，當我R中運行它，我得到以下錯誤：Error in while (t[j] < s[i]) { : missing value where TRUE/FALSE needed。這是什麼意思？上述功能實際上是我試圖提高自己的寫作

Intensity=function(params, eval.times, event.times) { 
# This function computes the value of the intensity function. 
# It takes as seed a vector of values/times at which to compute the 
# the value of the function and a vector with the occurence times 
# of the events. 

# Input: eval.times, event.times and values of parameters 
# Output: values of intensity function 

s<-sort(eval.times) 
t<-sort(event.times) 
par1<-params[1] 
par2<-params[2] 
par3<-params[3] 

values<-foreach(i=seq_along(s), .combine=c) %do% {par1+sum(par2*exp(-par3*(s[i]-t[which(t<s[i])])))} 


return(values) 

原有功能}

中，我想用一個while循環來替代sum和which因爲我的數組是有序的時間，並能得到相當長。有什麼建議麼？

至於建議，讓我後產生錯誤的數據：如果您檢查T [J]和s的值

event1<-c(3580.794 3583.079 3583.714 3583.998 3584.116 3585.042 3586.264) seed.times1<-seq(3580, 3590, by=0.001)

hintensity1<-Intensity(c(0.1,5,17), seed.times1, event1)

Error in while (t[j] < s[i]) { : missing value where TRUE/FALSE needed

Answer 1

[j]在發生錯誤的地方，我懷疑你會發現其中一個是NA。更具體地說，我認爲這是t [j]。這是因爲你允許索引j無邊界增長，所以在某些時候你會超過你的t向量中的元素數量。嘗試在你的where（）控件中包含一個附加條件。當t的所有元素都是詳盡的時，我不知道你想要發生什麼，但類似這樣的事情可能會發生：

event1<-c(3580.794, 3583.079, 3583.714, 3583.998, 3584.116, 3585.042, 3586.264) 
seed.times1<-seq(3580, 3590, by=0.001) 

Intensity=function(params, eval.times, event.times) { 
# This function computes the value of the intensity function. 
# It takes as seed a vector of values/times at which to compute the 
# the value of the function and a vector with the occurrence times 
# of the events. 

# Input: eval.times, event.times and values of parameters 
# Output: values of intensity function 

s<-sort(eval.times) 
t<-sort(event.times) 
par1<-params[1] 
par2<-params[2] 
par3<-params[3] 

values <- rep(par1,length(s)) 
for (i in 1:length(values)) { 
    j<-1 
    while (!is.na(t[j]) && t[j] < s[i]) 
    { 
     values[i] <- values[i] + par2*exp(-par3*(s[i]-t[j])) 
     j <- j+1 
     } 
    } 

return(values) 
} 

hintensity1<-Intensity(c(0.1,5,17), seed.times1, event1)