join_node {cat.dt} R Documentation

## Node joiner

### Description

Given all the nodes from one level, join_node evaluates all possible pairs one by one and decides whether or not to join them based on the similarity between the estimated ability levels and the density functions. If a pair of nodes is joined, the density function of the resulting node is the mean of the density functions of the joined nodes and the confluencies are summed.

### Usage

join_node(nodes, level, limit, tol, inters)


### Arguments

 nodes list of node lists. Every node list must contain the ID of the node, the vector of density function values of the evaluated abiity levels, the vector of previous items, the estimated ability level and the node confluency level level of the CAT decision tree limit maximum number of level nodes tol minimum distance between estimated ability levels to join two nodes inters minimum common area between density functions in the nodes of the evaluated pair in order to join them

### Value

A list of node lists. This list is the input list updated with the joined nodes