Node connectivity {cheddar} R Documentation

## Node connectivity

### Description

Functions that report the connectivity of nodes in a food web.

### Usage

```IsBasalNode(community)
IsTopLevelNode(community)
IsIntermediateNode(community)
IsIsolatedNode(community)
IsConnectedNode(community)
IsNonBasalNode(community)
IsNonTopLevelNode(community)

BasalNodes(community)
TopLevelNodes(community)
IntermediateNodes(community)
IsolatedNodes(community)
ConnectedNodes(community)
NonTopLevelNodes(community)
NonBasalNodes(community)

FractionBasalNodes(community)
FractionIntermediateNodes(community)
FractionTopLevelNodes(community)
FractionIsolatedNodes(community)
FractionNonBasalNodes(community)
FractionConnectedNodes(community)
FractionNonTopLevelNodes(community)
```

### Arguments

 `community` an object of class `Community`.

### Details

Each node in a community is defined as:

 isolated No resources or consumers, other than possibly itself basal No resources and one or more consumers top-level One or more resources and no consumers, other than possibly itself intermediate Nodes not fitting any of the above categories

These definitions allow the following additional definitions:

 connected basal, intermediate or top-level non-basal isolated, intermediate or top-level non-top-level isolated, basal or intermediate

For each of the above seven definitions, ‘X’, there are three functions: `IsX`, `X` and `FractionX`. The first returns a vector of `logical` of length `NumberOfNodes`; values are `TRUE` for nodes that fit the definition of ‘X’. The second returns the names of nodes for which `IsX` returns `TRUE`. The third returns the proportion of nodes in the community that fit the definition of ‘X’.

### Value

Either a `logical` vector of length `NumberOfNodes` or a vector of names.

### Author(s)

Lawrence Hudson

`NumberOfNodes`, `Cannibals`, `IsCannibal`, `NumberOfTrophicLinks`, `PredationMatrix`, `Degree`, `InDegree`, `OutDegree`, `ResourcesByNode`, `ConsumersByNode`, `ResourcesOfNodes`, `ConsumersOfNodes`

### Examples

```data(TL84)

# Assemble a table of node connectivity. Only one of each of the following
# four properties is TRUE for each node.
connectivity <- NPS(TL84, c('IsBasalNode', 'IsIsolatedNode',
'IsIntermediateNode', 'IsTopLevelNode'))
connectivity

# Each row sums to 1, confirming that exactly one of the columns in each row
# is TRUE.
all(1==rowSums(connectivity))

# These summations are 1
sum(FractionBasalNodes(TL84),
FractionIntermediateNodes(TL84),
FractionTopLevelNodes(TL84),
FractionIsolatedNodes(TL84))

sum(FractionConnectedNodes(TL84),
FractionIsolatedNodes(TL84))

sum(FractionBasalNodes(TL84),
FractionNonBasalNodes(TL84))

sum(FractionTopLevelNodes(TL84),
FractionNonTopLevelNodes(TL84))
```

[Package cheddar version 0.1-636 Index]