BalancedSampling (version 1.4)

lcubeflightphase: Flight phase for the local cube method

Description

Flight phase for the local cube method. To have a fixed sample size, include the inclusion probabilities as a balancing variable in Xbal and make sure the inclusion probabilities sum to a positive integer. This is a simplified (optimized for speed) implementation of the flight phase of the local cube method (doubly balanced sampling). Euclidean distance is used in the Xspread space.

Usage

lcubeflightphase(prob,Xspread,Xbal)

Arguments

prob

vector of length N with inclusion probabilities

Xspread

matrix of (standardized) auxiliary variables of N rows and q columns

Xbal

matrix of balancing auxiliary variables of N rows and r columns

Value

• Returns a vector of length N with new probabilities, where at most r are non-integer.

References

Grafström, A. and Tillé, Y. (2013). Doubly balanced spatial sampling with spreading and restitution of auxiliary totals. Environmetrics, 24(2), 120-131.

Examples

# Example 1
# Select sample
set.seed(12345);
N = 100; # population size
n = 10; # sample size
p = rep(n/N,N); # inclusion probabilities
X = cbind(runif(N),runif(N)); # matrix of auxiliary variables
pflight = lcubeflightphase(p,X,cbind(p,X)); 
# check balance
colSums(X)
colSums(X/p*pflight)