PST何時從左到右和從右到左顯示上下文？

在query()函數中，我們使用字符串來表示上下文。如果我假設的背景下從右到左（因爲它似乎是在print()和cmine()功能）指定的，我很感興趣的序列A->B->C中，那麼我應該查詢：

query(S1.p1, "C-B-A")

？

此外，在predict()函數中，我們使用seqdef()來定義要預測的序列。這是否意味着我應該從左到右指定它們，正如TraMineR通常那樣？

x <- seqdef("A-B-C) 
predict(S1.p1, x)

？

來源

2017-03-03 histelheim

在概率性後綴樹（PST）中，當我們從根開始讀取分支時，分支定義從右到左的後綴。在第一級，你有後綴的最後一個元素，在第二級你有元素在最後一個元素之前，等等。打印的樹顯示在左邊的根，並且從左到右展開。儘管如此，在打印結果的節點中顯示的後綴應該從左到右自然地閱讀。例如，節點a-b-c表示末尾帶有c的後綴。通過在左側添加a從節點b-c獲得這樣的節點。

對於cmine的結果也是如此。對於每個發現的情況，例如a-b-c,cmine給出了在上下文之後立即獲得每個可能狀態的概率，即在示例中的c之後。

總之，序列和上下文總是從左到右顯示，即使上下文是從右到左構建的。

所以，如果你想查詢序列A->B->C，只需使用query(S1.p1, "A-B-C")。同樣，要預測具有predict的特定序列，請自然地從左到右定義序列。

來源

2017-03-06 10:27:50 Gilbert

序列應該從左到右讀取。下面的代碼提供了此驗證：

library(PST) 
data.seq <- seqdef("A-B-C-D-E-F") 
S1.test <- pstree(data.seq, ymin = 0.001, lik = FALSE, with.missing = FALSE) 
print(S1.test) 

--(e)-[ p=(0.2,0.2,0.2,0.2,0.2,0.2) - n=6 ] 
    `--(A)-[ p=(0.001,0.995,0.001,0.001,0.001,0.001) - n=1 ]--| 
    `--(B)-[ p=(0.001,0.001,0.995,0.001,0.001,0.001) - n=1 ] 
    `--(A-B)-[ p=(0.001,0.001,0.995,0.001,0.001,0.001) - n=1 ]--| 
    `--(C)-[ p=(0.001,0.001,0.001,0.995,0.001,0.001) - n=1 ] 
    `--(B-C)-[ p=(0.001,0.001,0.001,0.995,0.001,0.001) - n=1 ] 
     `--(A-B-C)-[ p=(0.001,0.001,0.001,0.995,0.001,0.001) - n=1 ]--| 
    `--(D)-[ p=(0.001,0.001,0.001,0.001,0.995,0.001) - n=1 ] 
    `--(C-D)-[ p=(0.001,0.001,0.001,0.001,0.995,0.001) - n=1 ] 
     `--(B-C-D)-[ p=(0.001,0.001,0.001,0.001,0.995,0.001) - n=1 ] 
      `--(A-B-C-D)-[ p=(0.001,0.001,0.001,0.001,0.995,0.001) - n=1 ]--| 
    `--(E)-[ p=(0.001,0.001,0.001,0.001,0.001,0.995) - n=1 ] 
    `--(D-E)-[ p=(0.001,0.001,0.001,0.001,0.001,0.995) - n=1 ] 
     `--(C-D-E)-[ p=(0.001,0.001,0.001,0.001,0.001,0.995) - n=1 ] 
      `--(B-C-D-E)-[ p=(0.001,0.001,0.001,0.001,0.001,0.995) - n=1 ] 
       `--(A-B-C-D-E)-[ p=(0.001,0.001,0.001,0.001,0.001,0.995) - n=1 ]--| 


plot(S1.test)

這也表明，所繪製的樹應該從底部讀到頂部。

來源

2017-03-06 14:23:15 histelheim

PST何時從左到右和從右到左顯示上下文？

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