R PST何时从左到右和从右到左显示上下文？

PST

包是否总是从右向左显示上下文

在

query（）

函数中，我们使用字符串来表示上下文。如果我假设上下文是从右到左指定的（就像在

print（）

和

cmine（）

函数中一样），并且我对序列

A->B->C

感兴趣，那么我应该查询：

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

?

此外，在

predict（）

函数中，我们使用

seqdef（）

定义要预测的序列。这是否意味着我应该像TraMineR通常那样从左到右指定它们

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

---

x在概率后缀树（PST）中，当我们从根开始读取时，分支从右向左定义后缀。在第一级，您有后缀的最后一个元素，在第二级，您有最后一个元素之前的元素，等等。打印的树显示在左侧，根从左向右展开。然而，打印结果节点中显示的后缀应该从左到右自然读取。例如，一个节点
a-b-c
表示一个后缀，其末尾带有
c
。通过在左侧添加
a
，从节点
b-c
获得这样的节点

cmine
的结果也是如此。对于每个找到的上下文，例如
a-b-c
，
cmine
给出了在上下文之后立即获得每个可能状态的概率，即示例中的
c
之后

总之，序列和上下文总是从左到右显示，即使上下文是从右到左构建的

因此，如果您想查询序列
A->B->C
，只需使用
query（S1.p1，“A-B-C”）
。同样，要使用
predict
预测特定序列，请从左到右自然定义序列
 序列应从左到右读取。以下代码对此进行了验证：

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)

库（PST）
data.seq