Effective measures (or roles) suite: weighted measures for networks

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Description

Calculates effective connectivity, effective flows, effective nodes and effective roles of a network.

Usage

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EffInd(Flow = NULL, Tij = t(Flow), 
       Import = NULL, Export = NULL)

Arguments

Flow

network matrix with Flow[i,j] the flow from i (row) to j (column); component positions in rows and columns must be the same; if present, rownames or columnnames denote the compartment names.

Tij

network matrix where connectance is from column j to row i; component positions in rows and columns must be the same ; if present, rownames or columnnames denote the compartment names.

Import

vector with either the *indices* or the *names* of external compartmens from where flow enters the network; the indices point to the column positions in Tij (and the row positions in Flow).

Export

vector with either the *indices* or the *names* of external compartmens to where flow leaves the network; the indices point to the row positions in Tij (and the column positions in Flow).

Details

The mathematical formulation of these indices can be found in the package vignette - vignette("NetIndices").

The PDF can be found in the subdirectory ‘doc’ of the NetIndices package.

Value

a list with the following items:

CZ

Effective connectance

FZ

Effective Flows

NZ

Effective nodes

RZ

Effective roles

Author(s)

Karline Soetaert <karline.soetaert@nioz.nl>, Julius Kipyegon Kones<jkones@uonbi.ac.ke>

References

Latham LG. 2006. Network flow analysis algorithms. Ecological Modelling 192: 586-600.

Zorach and Ulanowicz, 2003. Quantifying the complexity of flow networks: how many roles are there?. Complexity 8,68-76.

Kones, J.K., Soetaert, K., van Oevelen, D. and J.Owino (2009). Are network indices robust indicators of food web functioning? a Monte Carlo approach. Ecological Modelling, 220, 370-382.

Examples

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# The takapoto atoll network
EffInd(Takapoto, Import = "CO2",
       Export = c("CO2", "Sedimentation", "Grazing"))

# Conesprings is the example set 1a from Latham 2006.
as.data.frame(
  EffInd(Tij = Conesprings, Import = "Inflows",
         Export = c("Export", "Dissipation"))
)