popdemo (version 0.1-2)

projection.distance: Calculate projection distance

Description

Calculate projection distance for a given population projection matrix (PPM) model.

Usage

projection.distance(A, vector)

Arguments

A

a square, irreducible, non-negative numeric matrix of any dimension.

vector

a specified initial age/stage distribution of class vector or class matrix.

Value

• Projection distance.

Details

projection.distance (Haridas & Tuljapurkar 2007) is the difference between the reproductive value of a population with demographic distribution given by vector and the reproductive value of a population in stable state. projection.distance will not work for reducible matrices and returns a warning for imprimitive matrices (although will not function for imprimitive matrices with nonzero imaginary components in the dominant eigenpair).

References

Haridas & Tuljapurkar (2007) Ecol. Lett., 10, 1143-1153. Stott et al. (2011) Ecol. Lett., 14, 959-970.

Examples

# Create a 3x3 PPM
    A <- matrix(c(0,1,2,0.5,0.1,0,0,0.6,0.6), byrow=TRUE, ncol=3)
    A

    # Create an initial stage structure
    initial <- c(1,3,2)
    initial

    # Calculate projection distance
    projection.distance(A, vector=initial)