R/estimate_time_diploid.R

In junctions: The Breakdown of Genomic Ancestry Blocks in Hybrid Lineages

#' estimates the time since admixture, given diploid ancestry data.
#' @description Calculates the time since admixture, given unphased
#' ancestry data.
#' @param ancestry_information a matrix with five columns: column 1) indicator
#' of individual, column 2) indicator of chromosome, 3) location of marker in
#' Morgan, 4) ancestry at chromosome 5) ancestry at chromosome 2.
#' @param analysis_type how should the data be broken down? there are multiple
#' options: "individuals" - time is inferred for each individual separately,
#' grouping all chromosomes together that belong to the same individual.
#' "chromosomes" - time is inferred for each chromosome separately, grouping
#' chromosomes together belonging from separate individuals. "separate" - time
#' is inferred for each chromosome from each individual separately, "all" - time
#' is inferred jointly for all chromosomes and individuals, grouping all
#' chromosomes and individuals together.
#' @param phased is the data phased?
#' @param pop_size population size
#' @param freq_ancestor_1 Frequency of ancestor 1 at t = 0
#' @param lower_lim lower limit of the optimization algorithm. Increase
#' if the expected admixture time is relatively ancient
#' @param upper_lim upper limit of hte optimization algorithm. If set too
#' large, recent admixture events can be overlooked - best to set as low
#' as possible.
#' @param num_threads num_threads, default is all threads. 5 threads is
#' recommended.
#' @param verbose display intermediate output? Default = FALSE
#' @export
estimate_time_diploid <- function(ancestry_information,
                                  analysis_type = "individuals",
                                  phased = FALSE,
                                  pop_size = 1000,
                                  freq_ancestor_1 = 0.5,
                                  lower_lim = 2,
                                  upper_lim = 2000,
                                  num_threads = 1,
                                  verbose = FALSE) {

  if (!(analysis_type %in% c("all", "individuals", "chromosomes", "separate"))) {
    stop("analysis type not known,
         did you perhaps spell individual instead of individuals?")
  }

  if (!is.matrix(ancestry_information)) {
    ancestry_information <- as.matrix(ancestry_information)
  }

  time_estimates <- c()
  if (analysis_type == "separate") {
    time_estimates <- estimate_time_separate(ancestry_information,
                                        pop_size,
                                        freq_ancestor_1,
                                        lower_lim,
                                        upper_lim,
                                        verbose,
                                        phased,
                                        num_threads)
  }
  if (analysis_type == "individuals") {
    time_estimates <- estimate_time_individuals(ancestry_information,
                                                pop_size,
                                                freq_ancestor_1,
                                                lower_lim,
                                                upper_lim,
                                                verbose,
                                                phased,
                                                num_threads)
  }
  if (analysis_type == "chromosomes") {
    time_estimates <- estimate_time_chromosomes(ancestry_information,
                                                pop_size,
                                                freq_ancestor_1,
                                                lower_lim,
                                                upper_lim,
                                                verbose,
                                                phased,
                                                num_threads)
  }
  if (analysis_type == "all") {
    time_estimates <- estimate_time_all(ancestry_information,
                                        pop_size,
                                        freq_ancestor_1,
                                        lower_lim,
                                        upper_lim,
                                        verbose,
                                        phased,
                                        num_threads)
  }


  output <- tibble::as_tibble(time_estimates)
  return(output)
}

#' @keywords internal
estimate_time_individuals <- function(ancestry_information,
                                      pop_size,
                                      freq_ancestor_1,
                                      lower_lim,
                                      upper_lim,
                                      verbose,
                                      phased,
                                      num_threads) {
  time_estimates <- c()
  for (indiv in unique(ancestry_information[, 1])) {
    local_anc_data <- subset(ancestry_information,
                             ancestry_information[, 1] == indiv)

    result <- estimate_time_cpp(local_anc_matrix =
                                  as.matrix(local_anc_data[, c(2, 4, 5)]),
                                locations = local_anc_data[, 3],
                                pop_size = pop_size,
                                freq_ancestor_1 = freq_ancestor_1,
                                lower_lim = lower_lim,
                                upper_lim = upper_lim,
                                verbose = verbose,
                                phased = phased,
                                num_threads = num_threads)
    time_estimates <- rbind(time_estimates, c(indiv,
                                              result$time, result$likelihood))
  }
  colnames(time_estimates) <- c("individual", "time", "loglikelihood")
  return(time_estimates)
}


#' @keywords internal
estimate_time_chromosomes <- function(ancestry_information,
                                      pop_size,
                                      freq_ancestor_1,
                                      lower_lim,
                                      upper_lim,
                                      verbose,
                                      phased,
                                      num_threads) {
  time_estimates <- c()
  for (chrom in unique(ancestry_information[, 2])) {
    local_anc_data <- subset(ancestry_information,
                             ancestry_information[, 2] == chrom)

    result <- estimate_time_cpp(local_anc_matrix =
                                  as.matrix(local_anc_data[, c(1, 4, 5)]),
                                locations = local_anc_data[, 3],
                                pop_size = pop_size,
                                freq_ancestor_1 = freq_ancestor_1,
                                lower_lim = lower_lim,
                                upper_lim = upper_lim,
                                verbose = verbose,
                                phased = phased,
                                num_threads = num_threads)
    time_estimates <- rbind(time_estimates, c(chrom,
                                              result$time, result$likelihood))
  }
  colnames(time_estimates) <- c("chromosome", "time", "loglikelihood")
  return(time_estimates)
}


#' @keywords internal
estimate_time_separate <- function(ancestry_information,
                              pop_size,
                              freq_ancestor_1,
                              lower_lim,
                              upper_lim,
                              verbose,
                              phased,
                              num_threads) {
  time_estimates <- c()
  for (indiv in unique(ancestry_information[, 1])) {
    focal_anc_data <- subset(ancestry_information,
                             ancestry_information[, 1] == indiv)
    for (chrom in unique(focal_anc_data[, 2])) {
      local_anc_data <- subset(focal_anc_data,
                               focal_anc_data[, 2] == chrom)

      # could still be empty.
      if (length(local_anc_data[, 1]) > 0) {

        result <- estimate_time_cpp(local_anc_matrix =
                                      as.matrix(local_anc_data[, c(2, 4, 5)]),
                                    locations = local_anc_data[, 3],
                                    pop_size = pop_size,
                                    freq_ancestor_1 = freq_ancestor_1,
                                    lower_lim = lower_lim,
                                    upper_lim = upper_lim,
                                    verbose = verbose,
                                    phased = phased,
                                    num_threads = num_threads)
        time_estimates <- rbind(time_estimates, c(indiv, chrom,
                                                  result$time,
                                                  result$likelihood))
      }
    }
  }
  colnames(time_estimates) <- c("individual", "chromosome",
                                "time", "loglikelihood")
  return(time_estimates)
}

#' @keywords internal
estimate_time_all <- function(ancestry_information,
                              pop_size,
                              freq_ancestor_1,
                              lower_lim,
                              upper_lim,
                              verbose,
                              phased,
                              num_threads) {
  time_estimates <- c()

  # indiv, chrom, pos, anc1, anc2

  cnt <- max(unique(ancestry_information[, 2])) + 1
  for (indiv in unique(ancestry_information[, 1])) {
    indices <- which(ancestry_information[, 1] == indiv)
    b <- ancestry_information[indices, ]
    chroms <- unique(b[, 2])
    chroms2 <- cnt + chroms
    cnt <- cnt + length(chroms2)
    for (i in 1:length(chroms)) {
      local_indices <- which(ancestry_information[indices, 2] == chroms[i])
      ancestry_information[local_indices, 2] <- chroms2[i]
    }
  }


  result <- estimate_time_cpp(local_anc_matrix =
                                as.matrix(ancestry_information[, c(2, 4, 5)]),
                              locations = ancestry_information[, 3],
                              pop_size = pop_size,
                              freq_ancestor_1 = freq_ancestor_1,
                              lower_lim = lower_lim,
                              upper_lim = upper_lim,
                              verbose = verbose,
                              phased = phased,
                              num_threads = num_threads)
  time_estimates <- rbind(time_estimates, c(indiv,
                                            result$time, result$likelihood))
  colnames(time_estimates) <- c("individual", "time", "loglikelihood")
  return(time_estimates)
}