R/rPopulationIndependenceM.R

In dbmss: Distance-Based Measures of Spatial Structures

rPopulationIndependenceM <- function(
    X,
    ReferenceType,
    CheckArguments = TRUE) {

  if (CheckArguments) {
    CheckdbmssArguments()
  }

  if (inherits(X, "Dtable")) {
    # Dtable case
    ReferencePoints <- (marks(X)$PointType == ReferenceType)
    # Index vector
    Index <- seq_along(marks(X)$PointType)
    # Randomize the other points
    RandomizedOthers <- sample(Index[!ReferencePoints])
    # Replace randomized elements in the index
    i <- o <- 1
    while (i <= length(marks(X)$PointType)) {
      if (!ReferencePoints[i]) {
        Index[i] <- RandomizedOthers[o]
        o <- o + 1
      }
      i <- i + 1
    }
    # Apply the randomization to PointType and PointWeight
    marks(X)$PointType <- marks(X)$PointType[Index]
    marks(X)$PointWeight <- marks(X)$PointWeight[Index]
    return(X)
  } else {
    # wmppp case
    ReferencePP <- (X[marks(X)$PointType == ReferenceType])
    OtherPointsPP <- (X[marks(X)$PointType != ReferenceType])
    RandomizedX <- superimpose(ReferencePP, rlabel(OtherPointsPP))
    class(RandomizedX) <- c("wmppp", "ppp")
    return(RandomizedX)
  }
}