Extracting contexts in a PST satisfying user defined criterion
1 2 
object 
A probabilistic suffix tree, i.e., an object of class 
l 
length of the context to search for. 
pmin 
numeric. Minimal probability for selecting the (sub)sequence. 
pmax 
numeric. Maximal probability for selecting the (sub)sequence. 
state 
character. One or several states of the alphabet for which the (cumulated) probability is greater than 
as.tree 
logical. If 
delete 
Logical. If 
If as.tree=TRUE
a PST, that is an object of class PSTf
which can be printed and plotted; if as.tree=FALSE
a list of contexts with their associated next symbol probability distribution, that is an object of class cprobd.list
for which a plot
method is available. Subscripts can be used to select subsets of the contexts, see examples.
The cmine
function searches in the tree for nodes fulfilling certain characteristics, for example contexts that are highly likely to be followed by a given state (see example 1). One can also mine for contexts corresponding to a minimum or maximum probability for several states together (see example 2). For more details, see Gabadinho 2016.
Alexis Gabadinho
Gabadinho, A. & Ritschard, G. (2016). Analyzing State Sequences with Probabilistic Suffix Trees: The PST R Package. Journal of Statistical Software, 72(3), pp. 139.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15  ## Loading the SRH.seq sequence object
data(SRH)
## Learning the model
SRH.pst < pstree(SRH.seq, nmin=30, ymin=0.001)
## Example 1: searching for all contexts yielding a probability of the
## state G1 (very good health) of at least pmin=0.5
cm1 < cmine(SRH.pst, pmin=0.5, state="G1")
cm1[1:10]
## Example 2: contexts associated with a high probability of
## medium or lower self rated health
cm2 < cmine(SRH.pst, pmin=0.5, state=c("B1", "B2", "M"))
plot(cm2, tlim=0, main="(a) p(B1,B2,M)>0.5")

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