NodeConnectivity: Node connectivity

Description Usage Arguments Details Value Author(s) See Also Examples

Description

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

Usage

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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

See Also

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

Examples

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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))

quicklizard99/cheddar documentation built on June 10, 2018, 12:15 p.m.