couple is used to link class-probability estimates produced by
pairwise coupling in multi-class classification problems.
Usage
couple(probin, coupler = "minpair")
Arguments
probin
The pairwise coupled class-probability estimates
coupler
The type of coupler to use. Currently minpar and
pkpd and vote are supported (see reference for more
details).
If vote is selected the returned value is a primitive estimate
passed on given votes.
Value
A matrix with the resulting probability estimates.
Details
As binary classification problems are much easier to solve many
techniques exist to decompose multi-class classification problems into
many binary classification problems (voting, error codes,
etc.). Pairwise coupling (one against one) constructs a rule for
discriminating between every pair of classes and then selecting the
class
with the most winning two-class decisions.
By using Platt's probabilities output for SVM one can get a class
probability for each of the $k(k-1)/2$ models created in the pairwise
classification. The couple method implements various techniques to combine
these probabilities.