Node connectivity | R Documentation |
Functions that report the connectivity of nodes in a food web.
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)
community |
an object of class |
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’.
Either a logical
vector of length NumberOfNodes
or a
vector of names.
Lawrence Hudson
NumberOfNodes
,
Cannibals
,
IsCannibal
,
NumberOfTrophicLinks
,
PredationMatrix
,
Degree
,
InDegree
,
OutDegree
,
ResourcesByNode
,
ConsumersByNode
,
ResourcesOfNodes
,
ConsumersOfNodes
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))
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