Description Usage Arguments Details Author(s) Examples
A symbolic wrapper to indicate a graph term in a formula
call to either
the s4pm
, jtharm
, agraph
, or a call to the spa
from
the spa package.
The dG
stands for a dissimilarity graph matrix, sG
stands for
a similarity graph matrix, and aG
stands for an ‘anchor’ graph
object.
1 2 3 |
x |
a symbolic representation depending on the context of call. For |
k |
the k-NN graph parameter for the |
metric |
the metric used to compute distances. |
nok |
a parameter to treat the graph input as the final adjacency matrix, i.e., no k-NN graph is computed. This bypasses the k parameter. |
The y~. ‘formula’ case automatically accounts for graph terms based on their respective function calls, but there are cases where one must specify the graph terms directly.
In a ‘formula’ call with direct graph input (i.e., not y~.), the graph must be specified based on the original function call and the type of graph desired. There are three cases.
1) For the anchor graph, agraph
, the aG
function must be invoked
and the graph must be of class ‘anchor’. The only way to create this object
is to use the AnchorGraph
function. Refer to AnchorGraph
for an example.
2) The dG
function passes or creates a dissimilarity graph (i.e., edges
correspond to dissimilarity with ‘0’ as close and ‘Inf’ as far).
3) The sG
passes a similarity graph (i.e., edges corresponding to dissimilarity
with ‘1’ (typically) as close and ‘0’ as far).
Examples of each case are provided below.
These commands are designed to work in the ‘formula’ instance of the following S4 generics:
agraph
, s4pm
, jtharm
, and also the spa
from the
spa package.
Mark Vere Culp
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## Equivalent uses of the formula and default s4pm call.
#######
## Set up Sonar data with 20% labeled
library(mlbench)
data(Sonar)
n=dim(Sonar)[1]
p=dim(Sonar)[2]
nu=0.2
set.seed(100)
L=sort(sample(1:n,ceiling(nu*n)))
U=setdiff(1:n,L)
y.true<-Sonar$Class
Sonar$Class[U]=NA
control=SemiSupervised.control(stability=0.0) ## turn off adjustment parameters for comparison
(g.s4pm<-s4pm(Class~.,data=Sonar,control=control)) ### Fit s4pm to Sonar
##The following give equivalent output to the g.s4pm<-s4pm(Class~.,data=Sonar) call.
D11=as.matrix(cosineDist(x.scaleL(Sonar[,-p],L)))
(g.s4pm1<-s4pm(Class~.+dG(D11),data=Sonar,control=control))
#######
## Equivalent uses of the formula, Class ~ ., and default jtharm call.
#######
control=SemiSupervised.control(stability=0.0)
(g.jtharm1<-jtharm(Class~.,data=Sonar,control=control))
(g.jtharm2<-jtharm(Class~dG(D11),data=Sonar,control=control))
|
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