flows (version 1.1.1)

firstflowsg: Flow Selection Based on Global Criteria

Description

Flow selection based on global criteria.

Usage

firstflowsg(mat, method = "nfirst", k, ties.method = "first")

Arguments

mat

A square matrix of flows.

method

A method of flow selection, one of "nfirst", "xfirst" or "xsumfirst":

• nfirst selects the k first flows of the matrix,
• xfirst selects flows greater than k,
• xsumfirst selects as many flows as necessary so that their sum is at least equal to k.

k

Selection threshold.

ties.method

In case of equality with "nfirst" method, use "random" or "first" (see rank).

Value

A boolean matrix of selected flows.

Details

As the output is a boolean matrix, use element-wise multiplication to get flows intensity.

See Also

firstflows, domflows

Examples

# Import data
data(nav)
myflows <- prepflows(mat = nav, i = "i", j = "j", fij = "fij")

# Remove the matrix diagonal
diag(myflows) <- 0

# Select the 50 first flows of the matrix
flowSel <- firstflowsg(mat = myflows, method = "nfirst", ties.method = "first",
                       k = 50)
statmat(mat = myflows * flowSel, output = "none")

# Select all flows greater than 2000
flowSel <- firstflowsg(myflows, method = "xfirst", k= 2000)
statmat(mat = myflows * flowSel, output = "none")

# Select flows that represent at least 50% of the matrix flows
k50 <- sum(myflows)/2
flowSel <- firstflowsg(mat = myflows, method = "xsumfirst", k = 150000)
statmat(mat = myflows * flowSel, output = "none")