simIRT <- function(NBOBS=2000,DIM,MU,COV,COVM,DIS,DIF,PMI,PMAX,ACC,CLEAR,STORE,REP,PREF,DRAW,
                    DRAWALL,ICC,GR=0,RAND,DEL=0,RSM1,RSM2,THR,TIT,PCM,ID,GENP,GENI) {

if (GR < 0 | GR > 1) {
  stop('Error 198: The GR option defines a probability. The values defined by this option must be greater (or equal) to 0 and lesser (or equal) to 1.')
}

if ( is.null(CLEAR) & is.null(STORE) ) {
  stop('Error 198: You must use at least one of these two options: clear and/or store.')
}

if (!is.null(DIM)) {
  nbdim <- length(DIM)
  if (nbdim > 2 & is.null(COVM)) {
      stop('Error 198: You can simulate data with one or two dimensions, and you have indicated more dimensions in the DIM option. Please correct it.')
  }

  if (!is.null(COVM)) {
      nbrowcovm <- nrow(COVM)
      if (nbdim != nbrowcovm) {
        stop('Error 198: DIM and COVM dimension mismatch. Please correct.')
      }
  }

  nbitems <- sum(DIM)

  if (!is.null(DIF)) {
    nbdiff <- length(DIF)
    tmp <- DIF[1]
    if (tmp=='gauss' | tmp=='uniform') {
      typediff <- tmp
    }
    else if (nbdiff != nbitems) {
      stop('Error 198: "You have indicated a number of difficulty parameters (DIF option) different of the number of items to simulate (DIM option). Please correct these options.')
    }
  }

  else if (is.null(DIF)) {
    DIF <- vector(mode='list', length=DIM)
    for (d in seq(1,DIM)) {
        DIF[[d]] <- c('gauss',0,1)
    }
    typediff <- 'gauss'
    nbdiff <- length(DIF)*3
  }





}













}