### Description

`dNetInduce`

is supposed to produce a subgraph induced by given
vertices and its k nearest neighbors. The input is a graph of "igraph"
or "graphNET" object, a list of the vertices of the graph, and a k
value for finding k nearest neighbors for these vertices. The output is
a subgraph induced by given vertices plus their k neighbours. The
resultant subgraph inherits the class from the input one. The induced
subgraph contains exactly the vertices of interest, and all the edges
between them.

### Usage

dNetInduce(g, nodes_query, knn = 0, remove.loops = F, largest.comp = T, min.comp.size = 1)

### Arguments

- g
- an object of class "igraph" or "graphNEL"
- nodes_query
- the vertices for which the calculation is performed
- knn
- an integeter specifying how many k steps are used to find
the nearest neighbours of the given vertices. By default, knn is set to
zero; it means no neighbors will be considered. When knn is 1, the
immediate neighbors of the given vertices will be also considered for
inducing the subgraph. The same is true when knn is 2, etc
- remove.loops
- logical to indicate whether the loop edges are to
be removed. By default, it sets to false
- largest.comp
- logical to indicate whether the largest component
is only retained. By default, it sets to true for the largest component
being left
- min.comp.size
- an integer specifying the minimum size of
component that will be retained. This parameter only works when setting
the false to keep the largest component. By default, it sets to 1
meaning all nodes will be retained

### Value

`subg`

: an induced subgraph, an object of class "igraph" or
"graphNEL"

### Note

The given vertices plus their k nearest neighbors will be used to
induce the subgraph.

### Examples

# 1) generate a random graph according to the ER model
g <- erdos.renyi.game(100, 1/100)
# 2) select the first 10 vertices as the query nodes
nodes_query <- V(g)[1:10]
# 3) produce the induced subgraph only based on the nodes in query
subg <- dNetInduce(g, nodes_query, knn=0)
# 4) produce the induced subgraph based on the nodes in query ane their immediate neighbours
subg <- dNetInduce(g, nodes_query, knn=1)