R function to calculate elasticity of the dual Lorenz curve

EmpiricalDualElasticity.R

EmpiricalDualElasticity <- function(dataset){
  # ###########################################################################
  # R function to calculate elasticity of the dual Lorenz curve
  # ---------------------------------------------------------
  # 
  # Authors: Berihuete, A.; Ramos, C.D; Sordo, M.A. and Ramos, H.
  #
  # input: a dataset formatted with rtip package (https://cran.r-project.org/web/packages/rtip/)
  #
  # output: abscissas and ordinates of the elasticiy of the dual Lorenz curve.
  #
  # example: Estonia (EE). You will need EU-SILC 2010 csv files.
  # 
  # library(rtip)
  # dataset10 <- loadEUSILC("UDB_c10D.csv", "UDB_c10H.csv")
  # dataEE <- setupDataset(dataset = dataset10, country = "EE")
  # delas <- EmpiricalDualElasticity(dataEE)
  # plot(delas)
  #
  #############################################################################
  
  dataset_aux <- dataset[order(dataset[,'ipuc']),]
  
  dataset_aux <- subset(dataset_aux, ipuc > 0)
  
  dataset_aux$cum1_w <- cum1_w <- cumsum(dataset_aux$wHX040)
  
  dataset_aux$p <- dataset_aux$cum1_w/dataset_aux$cum1_w[length(dataset_aux$cum1_w)]
  
  dataset_aux$invp <- 1-dataset_aux$p
  
  dataset_aux <- dataset_aux[order(dataset_aux[,'invp']),]
  
  dataset_aux$cum2_w <- cumsum(dataset_aux$wHX040)

  dataset_aux$cum3_w <- cumsum(dataset_aux$wHX040*dataset_aux$ipuc)
  
  delas <- c()
  
  for(i in 1:(dim(dataset_aux)[1]-1)){
    index <- which(dataset_aux$cum2_w > cum1_w[i])[1]
    if(index == 1){
      delas[i] <- 1
    }else{
      num.delas <- dataset_aux$ipuc[index]
      dem.delas <- (dataset_aux$cum3_w[index-1] + dataset_aux$ipuc[index]*(cum1_w[i]-dataset_aux$cum2_w[index-1]))/cum1_w[i]
      delas[i] <- num.delas/dem.delas
    }
  }
  
  p <- cum1_w/cum1_w[length(cum1_w)]
  p <- p[-length(p)]
  results <- data.frame(p = p, delas = delas)
  return(results)
}