R/allpart.R

In obreschkow/simstar: Reading, processing and visualising astrophysical N-body simulation data

#' Concatenate identical properties of different Gadget particle species
#' 
#' @description Concatenate identical properties of different particle species in a Gadget snapshot
#'
#' @param dat list containing the particle data of a single Gadget snapshot, e.g. read via \code{\link{readgadget}}.
#' @param field character specifying particle property to concatenate.
#' @param species vector of particle species to be incluced.
#' 
#' @return Returns N-vector or N-by-3 matrix representing the property "field" of all the particle species given in \code{species} (0-indexed).
#' 
#' @author Danail Obreschkow
#'
#' @export

allpart = function(dat, field = 'Coordinates', species = seq(0,5)) {
  x = list()
  k = 0
  for (i in species) {
    group = sprintf('PartType%d',i)
    if (!is.null(dat[[group]])) {
      if (!is.null(dat[[group]][[field]])) {
        k = k+1
        x[[k]] = t(dat[[group]][[field]])
      } else {
        stop(sprintf('Field %s does not exist for species %d.\n',field,i))
      }
    }
  }
  if (k==0) stop(sprintf('Field %s not found in considered species.\n',field))
  if (length(dim(x[[1]]))!=2) stop('unknown data format')
  if (dim(x[[1]])[1]==3) {
    x = unlist(x)
    if (length(x)%%3!=0) stop('length of field inconsistent with N-by-3 matrix')
    N = length(x)/3
    x = t(array(x,c(3,N)))
  } else if (dim(x[[1]])[1]==1) {
    x = unlist(x)
  } else {
    stop('unknown data format')
  }
  return(x)
}