Add parallel computing support to antibiogram() and wisca() (#281) (#282)

* Add parallel computing support to antibiogram() and wisca() (#281) For WISCA: simulations are distributed across (group, chunk) job pairs via future.apply::future_lapply(), keeping all workers active even when the regimen count is smaller than nbrOfWorkers(). Sequential fallback with progress ticker is preserved when parallel = FALSE or workers = 1. For grouped antibiograms: each group is processed by a separate worker, mirroring the row-batch approach in as.sir(). Same gate pattern as as.sir() (PR #280): requires a non-sequential future::plan() to be active; auto-upgrades to parallel = TRUE when a parallel plan is detected; throws an informative error otherwise. https://claude.ai/code/session_01FC43syPbzhGmKgrrVNHjnF * Fix version to 3.0.1.9055 and update CLAUDE.md version formula Uses origin/${defaultbranch} (with a fetch) instead of the local branch ref so the commit count is never stale after a merge. https://claude.ai/code/session_01FC43syPbzhGmKgrrVNHjnF * Fix non-ASCII characters in antibiogram.R Replace en/em dashes and non-breaking spaces with ASCII equivalents to satisfy R CMD check portability requirement. https://claude.ai/code/session_01FC43syPbzhGmKgrrVNHjnF * Update auto-generated Rd files after documentation rebuild https://claude.ai/code/session_01FC43syPbzhGmKgrrVNHjnF * Move parallel gate to top of antibiogram.default() like sir.R The gate was inside the wisca==TRUE block, so parallel=TRUE with a sequential plan was silently ignored for non-WISCA antibiograms. Now the gate runs unconditionally at the top of the function, identical to the as.sir() pattern: error on explicit parallel=TRUE with sequential plan, auto-upgrade when a non-sequential plan is already active. https://claude.ai/code/session_01FC43syPbzhGmKgrrVNHjnF * Fix parallel WISCA returning all NA; strengthen tests; add sequential hint Bug: lapply() over a factor yields length-1 factor elements (integer codes), while for() over a factor yields character strings. The job list stored j\$group as a factor integer, but the reassembly loop compared it with identical(j\$group, g) where g was character -- always FALSE, so no simulation chunks were ever assembled and coverage stayed NA throughout. Fix: convert unique_groups to character before building jobs so both the job list and the reassembly loop use the same type. Tests: replaced na.rm = TRUE guards with explicit anyNA() checks so the test suite would have caught the all-NA result immediately. Also adds a sequential-mode performance hint (analogous to sir.R lines 1116-1127) when simulations >= 500 and >= 3 regimens. https://claude.ai/code/session_01FC43syPbzhGmKgrrVNHjnF --------- Co-authored-by: Claude <noreply@anthropic.com>
2026-05-14 01:10:45 +02:00 · 2026-04-30 18:41:56 +01:00
parent 23beebc6c3
commit f7e9294bea
8 changed files with 279 additions and 79 deletions
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -167,7 +167,8 @@ Then run the following from the repo root to determine the version string to use
 currenttag=$(git describe --tags --abbrev=0 | sed 's/v//')
 currenttagfull=$(git describe --tags --abbrev=0)
 defaultbranch=$(git branch | cut -c 3- | grep -E '^master$|^main$')
-currentcommit=$(git rev-list --count ${currenttagfull}..${defaultbranch})
+git fetch origin ${defaultbranch} --quiet
+currentcommit=$(git rev-list --count ${currenttagfull}..origin/${defaultbranch})
 currentversion="${currenttag}.$((currentcommit + 9001 + 1))"
 echo "$currentversion"
 ```
--- a/4
+++ b/4
@@ -1,6 +1,6 @@
 Package: AMR
-Version: 3.0.1.9053
-Date: 2026-04-27
+Version: 3.0.1.9055
+Date: 2026-04-30
 Title: Antimicrobial Resistance Data Analysis
 Description: Functions to simplify and standardise antimicrobial resistance (AMR)
  data analysis and to work with microbial and antimicrobial properties by
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,4 +1,4 @@
-# AMR 3.0.1.9053
+# AMR 3.0.1.9055

 This will become release v3.1.0, intended for launch end of May.

@@ -7,6 +7,7 @@ This will become release v3.1.0, intended for launch end of May.
 * Support for the [`future`](https://future.futureverse.org) package and its framework, as the previous implementation of parallel computing was slow
  - **Breaking change**: `as.sir()` with `parallel = TRUE` now requires a non-sequential `future::plan()` to be active before the call — e.g., `future::plan(future::multisession)` — and throws an informative error if none is set.
  - New all-core usage setup: when the number of AB columns is smaller than the number of available cores, rows are now split into batches so all cores stay active (row-batch mode). Previously, a 6-column dataset on a 16-core machine would only use 6 cores; now all 16 are used, with each worker processing a smaller row slice (lower per-worker memory pressure and processing time)
+  - `antibiogram()` and `wisca()` gained a `parallel` argument using the same `future`/`future.apply` pattern: for WISCA, Monte Carlo simulations are split into `(group, chunk)` job pairs distributed across workers; for grouped antibiograms, each group is processed by a separate worker (#281)
 * Integration with the *tidymodels* framework to allow seamless use of SIR, MIC and disk data in modelling pipelines via `recipes`
  - `step_mic_log2()` to transform `<mic>` columns with log2, and `step_sir_numeric()` to convert `<sir>` columns to numeric
  - New `tidyselect` helpers:
--- a/R/antibiogram.R
+++ b/R/antibiogram.R
@@ -54,7 +54,7 @@
 #' @param add_total_n *(deprecated in favour of `formatting_type`)* A [logical] to indicate whether `n_tested` available numbers per pathogen should be added to the table (default is `TRUE`). This will add the lowest and highest number of available isolates per antimicrobial (e.g, if for *E. coli* 200 isolates are available for ciprofloxacin and 150 for amoxicillin, the returned number will be "150-200"). This option is unavailable when `wisca = TRUE`; in that case, use [retrieve_wisca_parameters()] to get the parameters used for WISCA.
 #' @param only_all_tested (for combination antibiograms): a [logical] to indicate that isolates must be tested for all antimicrobials, see *Details*.
 #' @param digits Number of digits to use for rounding the antimicrobial coverage, defaults to 1 for WISCA and 0 otherwise.
-#' @param formatting_type Numeric value (1–22 for WISCA, 1-12 for non-WISCA) indicating how the 'cells' of the antibiogram table should be formatted. See *Details* > *Formatting Type* for a list of options.
+#' @param formatting_type Numeric value (1-22 for WISCA, 1-12 for non-WISCA) indicating how the 'cells' of the antibiogram table should be formatted. See *Details* > *Formatting Type* for a list of options.
 #' @param col_mo Column name of the names or codes of the microorganisms (see [as.mo()]) - the default is the first column of class [`mo`]. Values will be coerced using [as.mo()].
 #' @param language Language to translate text, which defaults to the system language (see [get_AMR_locale()]).
 #' @param minimum The minimum allowed number of available (tested) isolates. Any isolate count lower than `minimum` will return `NA` with a warning. The default number of `30` isolates is advised by the Clinical and Laboratory Standards Institute (CLSI) as best practice, see *Source*.
@@ -65,6 +65,7 @@
 #' @param simulations (for WISCA) a numerical value to set the number of Monte Carlo simulations.
 #' @param conf_interval A numerical value to set confidence interval (default is `0.95`).
 #' @param interval_side The side of the confidence interval, either `"two-tailed"` (default), `"left"` or `"right"`.
+#' @param parallel A [logical] to indicate if parallel computing must be used, defaults to `FALSE`. Requires the [`future.apply`][future.apply::future_lapply()] package. For WISCA, Monte Carlo simulations are distributed across workers; for grouped antibiograms, each group is processed by a separate worker. **A non-sequential [future::plan()] must already be active before setting `parallel = TRUE`** -- for example, `future::plan(future::multisession)`. An error is thrown if `parallel = TRUE` is used without a plan set by the user.
 #' @param info A [logical] to indicate info should be printed - the default is `TRUE` only in interactive mode.
 #' @param object An [antibiogram()] object.
 #' @param ... When used in [R Markdown or Quarto][knitr::kable()]: arguments passed on to [knitr::kable()] (otherwise, has no use).
@@ -413,6 +414,7 @@ antibiogram <- function(x,
                        conf_interval = 0.95,
                        interval_side = "two-tailed",
                        info = interactive(),
+                        parallel = FALSE,
                        ...) {
  UseMethod("antibiogram")
 }
@@ -439,6 +441,7 @@ antibiogram.default <- function(x,
                                conf_interval = 0.95,
                                interval_side = "two-tailed",
                                info = interactive(),
+                                parallel = FALSE,
                                ...) {
  meet_criteria(x, allow_class = "data.frame")
  x <- ascertain_sir_classes(x, "x")
@@ -478,6 +481,35 @@ antibiogram.default <- function(x,
  meet_criteria(conf_interval, allow_class = c("numeric", "integer"), has_length = 1, is_finite = TRUE, is_positive = TRUE)
  meet_criteria(interval_side, allow_class = "character", has_length = 1, is_in = c("two-tailed", "left", "right"))
  meet_criteria(info, allow_class = "logical", has_length = 1)
+  meet_criteria(parallel, allow_class = "logical", has_length = 1)
+
+  # parallel gate - identical pattern to as.sir()
+  if (requireNamespace("future.apply", quietly = TRUE) && !inherits(future::plan(), "sequential")) {
+    if (isFALSE(parallel)) {
+      message_("Assuming {.code parallel = TRUE} since parallel computing has been set up using the {.pkg future} package before. Set {.help [{.fun plan}](future::plan)} to sequential to prevent this.")
+    }
+    parallel <- TRUE
+  }
+  if (isTRUE(parallel)) {
+    stop_ifnot(
+      requireNamespace("future.apply", quietly = TRUE),
+      "Setting {.code parallel = TRUE} requires the {.pkg future.apply} package.\n",
+      "Install it with {.code install.packages(\"future.apply\")}."
+    )
+    stop_if(inherits(future::plan(), "sequential"),
+      "Setting {.code parallel = TRUE} requires a non-sequential {.help [{.fun future::plan}](future::plan)} to be active.\n",
+      "For your system, you could first run: {.code library(future); ",
+      ifelse(.Platform$OS.type == "windows" || in_rstudio(),
+        "plan(multisession)",
+        "plan(multicore)"
+      ),
+      "}",
+      call = FALSE
+    )
+    n_workers <- future::nbrOfWorkers()
+  } else {
+    n_workers <- 1L
+  }

  # try to find columns based on type
  if (is.null(col_mo)) {
@@ -705,52 +737,96 @@ antibiogram.default <- function(x,

    wisca_parameters <- out

-    progress <- progress_ticker(
-      n = length(unique(wisca_parameters$group)) * simulations,
-      n_min = 25,
-      print = info,
-      title = paste("Calculating WISCA for", length(unique(wisca_parameters$group)), "regimens")
-    )
-    on.exit(close(progress))
-
-    # run WISCA per group
-    for (group in unique(wisca_parameters$group)) {
-      params_current <- wisca_parameters[wisca_parameters$group == group, , drop = FALSE]
-      if (sum(params_current$n_tested, na.rm = TRUE) == 0) {
-        next
-      }
-
-      # prepare priors
-      priors_current <- create_wisca_priors(params_current)
-
-      # Monte Carlo simulations
-      coverage_simulations <- vapply(
-        FUN.VALUE = double(1),
-        seq_len(simulations), function(i) {
-          progress$tick()
-          simulate_coverage(priors_current)
-        }
-      )
-
-      # summarise results
-      coverage_mean <- mean(coverage_simulations)
-
-      if (interval_side == "two-tailed") {
-        probs <- c((1 - conf_interval) / 2, 1 - (1 - conf_interval) / 2)
-      } else if (interval_side == "left") {
-        probs <- c(0, conf_interval)
-      } else if (interval_side == "right") {
-        probs <- c(1 - conf_interval, 1)
-      }
-
-      coverage_ci <- unname(stats::quantile(coverage_simulations, probs = probs))
-
-      out_wisca$coverage[out_wisca$group == group] <- coverage_mean
-      out_wisca$lower_ci[out_wisca$group == group] <- coverage_ci[1]
-      out_wisca$upper_ci[out_wisca$group == group] <- coverage_ci[2]
+    # quantile probabilities are constant across all groups
+    probs <- if (interval_side == "two-tailed") {
+      c((1 - conf_interval) / 2, 1 - (1 - conf_interval) / 2)
+    } else if (interval_side == "left") {
+      c(0, conf_interval)
+    } else {
+      c(1 - conf_interval, 1)
    }

-    close(progress)
+    unique_groups <- as.character(unique(wisca_parameters$group))
+
+    use_parallel_wisca <- isTRUE(parallel) && n_workers > 1L && length(unique_groups) > 0L
+
+    if (use_parallel_wisca) {
+      if (isTRUE(info)) {
+        message_("Running WISCA in parallel mode using ", n_workers, " workers...", as_note = FALSE, appendLF = FALSE)
+      }
+      # chunks_per_group gives ~n_workers total jobs so all workers stay busy
+      # even when the number of regimens is smaller than n_workers
+      chunks_per_group <- max(1L, ceiling(n_workers / length(unique_groups)))
+      chunk_sizes <- diff(c(0L, round(seq_len(chunks_per_group) * simulations / chunks_per_group)))
+
+      # precompute priors per group and build (group, chunk) job list
+      jobs <- unlist(lapply(unique_groups, function(g) {
+        params_g <- wisca_parameters[wisca_parameters$group == g, , drop = FALSE]
+        if (sum(params_g$n_tested, na.rm = TRUE) == 0L) return(NULL)
+        priors_g <- create_wisca_priors(params_g)
+        lapply(seq_along(chunk_sizes), function(ch) {
+          list(group = g, priors = priors_g, n_sims = chunk_sizes[ch])
+        })
+      }), recursive = FALSE)
+      jobs <- Filter(Negate(is.null), jobs)
+
+      flat <- future.apply::future_lapply(jobs, function(job) {
+        vapply(FUN.VALUE = double(1), seq_len(job$n_sims), function(i) {
+          simulate_coverage(job$priors)
+        })
+      }, future.seed = TRUE)
+
+      # reassemble per group: concatenate chunks, then summarise
+      for (g in unique_groups) {
+        g_idx <- vapply(jobs, function(j) identical(j$group, g), logical(1))
+        if (!any(g_idx)) next
+        sims <- unlist(flat[g_idx], use.names = FALSE)
+        out_wisca$coverage[out_wisca$group == g] <- mean(sims)
+        ci_vals <- unname(stats::quantile(sims, probs = probs))
+        out_wisca$lower_ci[out_wisca$group == g] <- ci_vals[1]
+        out_wisca$upper_ci[out_wisca$group == g] <- ci_vals[2]
+      }
+
+      if (isTRUE(info)) message_(font_green_bg(" DONE "), as_note = FALSE)
+
+    } else {
+      progress <- progress_ticker(
+        n = length(unique_groups) * simulations,
+        n_min = 25,
+        print = info,
+        title = paste("Calculating WISCA for", length(unique_groups), "regimens")
+      )
+      on.exit(close(progress), add = TRUE)
+
+      for (group in unique_groups) {
+        params_current <- wisca_parameters[wisca_parameters$group == group, , drop = FALSE]
+        if (sum(params_current$n_tested, na.rm = TRUE) == 0) next
+        priors_current <- create_wisca_priors(params_current)
+        coverage_simulations <- vapply(
+          FUN.VALUE = double(1),
+          seq_len(simulations), function(i) {
+            progress$tick()
+            simulate_coverage(priors_current)
+          }
+        )
+        out_wisca$coverage[out_wisca$group == group] <- mean(coverage_simulations)
+        ci_vals <- unname(stats::quantile(coverage_simulations, probs = probs))
+        out_wisca$lower_ci[out_wisca$group == group] <- ci_vals[1]
+        out_wisca$upper_ci[out_wisca$group == group] <- ci_vals[2]
+      }
+      close(progress)
+      if (isTRUE(info) && simulations >= 500 && length(unique_groups) >= 3) {
+        suggest <- ifelse(.Platform$OS.type == "windows" || in_rstudio(),
+          "plan(multisession)",
+          "plan(multicore)"
+        )
+        if (requireNamespace("future.apply", quietly = TRUE)) {
+          message_("Running in sequential mode. To speed up WISCA, set a parallel {.help [{.fun future::plan}](future::plan)} such as {.code ", suggest, "} and use {.code parallel = TRUE}.")
+        } else {
+          message_("Running in sequential mode. To speed up WISCA, install the {.pkg future.apply} package and then set {.code parallel = TRUE}.")
+        }
+      }
+    }

    # final output preparation
    out <- out_wisca
@@ -997,30 +1073,50 @@ antibiogram.grouped_df <- function(x,
                                   conf_interval = 0.95,
                                   interval_side = "two-tailed",
                                   info = interactive(),
+                                   parallel = FALSE,
                                   ...) {
  stop_ifnot(is.null(mo_transform), "{.arg mo_transform} must not be set if creating an antibiogram using a grouped tibble. The groups will become the variables over which the antimicrobials are calculated, which could include the pathogen information (though not necessary). Nonetheless, this makes {.arg mo_transform} redundant.", call = FALSE)
  stop_ifnot(is.null(syndromic_group), "{.arg syndromic_group} must not be set if creating an antibiogram using a grouped tibble. The groups will become the variables over which the antimicrobials are calculated, making {.arg syndromic_group} redundant.", call = FALSE)
+  meet_criteria(parallel, allow_class = "logical", has_length = 1)
+
  groups <- attributes(x)$groups
  n_groups <- NROW(groups)
-  progress <- progress_ticker(
-    n = n_groups,
-    n_min = 5,
-    print = info,
-    title = paste("Calculating AMR for", n_groups, "groups")
-  )
-  on.exit(close(progress))

-  out <- NULL
-  wisca_parameters <- NULL
-  long_numeric <- NULL
-
-  for (i in seq_len(n_groups)) {
-    progress$tick()
-    rows <- unlist(groups[i, ]$.rows)
-    if (length(rows) == 0) {
-      next
+  # parallel gate - identical pattern to as.sir()
+  if (requireNamespace("future.apply", quietly = TRUE) && !inherits(future::plan(), "sequential")) {
+    if (isFALSE(parallel)) {
+      message_("Assuming {.code parallel = TRUE} since parallel computing has been set up using the {.pkg future} package before. Set {.help [{.fun plan}](future::plan)} to sequential to prevent this.")
    }
-    new_out <- antibiogram(as.data.frame(x)[rows, , drop = FALSE],
+    parallel <- TRUE
+  }
+  if (isTRUE(parallel)) {
+    stop_ifnot(
+      requireNamespace("future.apply", quietly = TRUE),
+      "Setting {.code parallel = TRUE} requires the {.pkg future.apply} package.\n",
+      "Install it with {.code install.packages(\"future.apply\")}."
+    )
+    stop_if(inherits(future::plan(), "sequential"),
+      "Setting {.code parallel = TRUE} requires a non-sequential {.help [{.fun future::plan}](future::plan)} to be active.\n",
+      "For your system, you could first run: {.code library(future); ",
+      ifelse(.Platform$OS.type == "windows" || in_rstudio(),
+        "plan(multisession)",
+        "plan(multicore)"
+      ),
+      "}",
+      call = FALSE
+    )
+    n_workers <- future::nbrOfWorkers()
+  } else {
+    n_workers <- 1L
+  }
+
+  use_parallel <- isTRUE(parallel) && n_workers > 1L && n_groups > 1L
+
+  x_df <- as.data.frame(x)
+  run_group <- function(i) {
+    rows <- unlist(groups[i, ]$.rows)
+    if (length(rows) == 0L) return(NULL)
+    antibiogram(x_df[rows, , drop = FALSE],
      antimicrobials = antimicrobials,
      mo_transform = NULL,
      ab_transform = ab_transform,
@@ -1040,12 +1136,42 @@ antibiogram.grouped_df <- function(x,
      conf_interval = conf_interval,
      interval_side = interval_side,
      info = FALSE,
-      ...
+      parallel = FALSE  # never nest parallelism in workers
    )
+  }
+
+  if (use_parallel) {
+    if (isTRUE(info)) {
+      message_("Running antibiogram for ", n_groups, " groups in parallel using ", n_workers, " workers...", as_note = FALSE, appendLF = FALSE)
+    }
+    results_raw <- future.apply::future_lapply(seq_len(n_groups), run_group, future.seed = TRUE)
+    if (isTRUE(info)) message_(font_green_bg(" DONE "), as_note = FALSE)
+  } else {
+    progress <- progress_ticker(
+      n = n_groups,
+      n_min = 5,
+      print = info,
+      title = paste("Calculating AMR for", n_groups, "groups")
+    )
+    on.exit(close(progress), add = TRUE)
+    results_raw <- vector("list", n_groups)
+    for (i in seq_len(n_groups)) {
+      progress$tick()
+      results_raw[[i]] <- run_group(i)
+    }
+    close(progress)
+  }
+
+  out <- NULL
+  wisca_parameters <- NULL
+  long_numeric <- NULL
+
+  for (i in seq_len(n_groups)) {
+    new_out <- results_raw[[i]]
    new_wisca_parameters <- attributes(new_out)$wisca_parameters
    new_long_numeric <- attributes(new_out)$long_numeric

-    if (NROW(new_out) == 0) {
+    if (is.null(new_out) || NROW(new_out) == 0) {
      next
    }

@@ -1071,8 +1197,7 @@ antibiogram.grouped_df <- function(x,
      new_long_numeric <- new_long_numeric[, c(col_name, setdiff(names(new_long_numeric), col_name))] # set place to 1st col
    }

-    if (i == 1) {
-      # the first go
+    if (is.null(out)) {
      out <- new_out
      wisca_parameters <- new_wisca_parameters
      long_numeric <- new_long_numeric
@@ -1083,8 +1208,6 @@ antibiogram.grouped_df <- function(x,
    }
  }

-  close(progress)
-
  out <- structure(as_original_data_class(out, class(x), extra_class = "antibiogram"),
    has_syndromic_group = FALSE,
    combine_SI = isTRUE(combine_SI),
@@ -1116,6 +1239,7 @@ wisca <- function(x,
                  conf_interval = 0.95,
                  interval_side = "two-tailed",
                  info = interactive(),
+                  parallel = FALSE,
                  ...) {
  antibiogram(
    x = x,
@@ -1137,6 +1261,7 @@ wisca <- function(x,
    conf_interval = conf_interval,
    interval_side = interval_side,
    info = info,
+    parallel = parallel,
    ...
  )
 }
--- a/man/antibiogram.Rd
+++ b/man/antibiogram.Rd
@@ -25,7 +25,8 @@ antibiogram(x, antimicrobials = where(is.sir), mo_transform = "shortname",
  ifelse(wisca, 14, 18)), col_mo = NULL, language = get_AMR_locale(),
  minimum = 30, combine_SI = TRUE, sep = " + ", sort_columns = TRUE,
  wisca = FALSE, simulations = 1000, conf_interval = 0.95,
-  interval_side = "two-tailed", info = interactive(), ...)
+  interval_side = "two-tailed", info = interactive(), parallel = FALSE,
+  ...)

 wisca(x, antimicrobials = where(is.sir), ab_transform = "name",
  syndromic_group = NULL, only_all_tested = FALSE, digits = 1,
@@ -33,7 +34,7 @@ wisca(x, antimicrobials = where(is.sir), ab_transform = "name",
  col_mo = NULL, language = get_AMR_locale(), combine_SI = TRUE,
  sep = " + ", sort_columns = TRUE, simulations = 1000,
  conf_interval = 0.95, interval_side = "two-tailed",
-  info = interactive(), ...)
+  info = interactive(), parallel = FALSE, ...)

 retrieve_wisca_parameters(wisca_model, ...)

@@ -80,7 +81,7 @@ retrieve_wisca_parameters(wisca_model, ...)

 \item{digits}{Number of digits to use for rounding the antimicrobial coverage, defaults to 1 for WISCA and 0 otherwise.}

-\item{formatting_type}{Numeric value (1–22 for WISCA, 1-12 for non-WISCA) indicating how the 'cells' of the antibiogram table should be formatted. See \emph{Details} > \emph{Formatting Type} for a list of options.}
+\item{formatting_type}{Numeric value (1-22 for WISCA, 1-12 for non-WISCA) indicating how the 'cells' of the antibiogram table should be formatted. See \emph{Details} > \emph{Formatting Type} for a list of options.}

 \item{col_mo}{Column name of the names or codes of the microorganisms (see \code{\link[=as.mo]{as.mo()}}) - the default is the first column of class \code{\link{mo}}. Values will be coerced using \code{\link[=as.mo]{as.mo()}}.}

@@ -104,6 +105,8 @@ retrieve_wisca_parameters(wisca_model, ...)

 \item{info}{A \link{logical} to indicate info should be printed - the default is \code{TRUE} only in interactive mode.}

+\item{parallel}{A \link{logical} to indicate if parallel computing must be used, defaults to \code{FALSE}. Requires the \code{\link[future.apply:future_lapply]{future.apply}} package. For WISCA, Monte Carlo simulations are distributed across workers; for grouped antibiograms, each group is processed by a separate worker. \strong{A non-sequential \code{\link[future:plan]{future::plan()}} must already be active before setting \code{parallel = TRUE}} -- for example, \code{future::plan(future::multisession)}. An error is thrown if \code{parallel = TRUE} is used without a plan set by the user.}
+
 \item{...}{When used in \link[knitr:kable]{R Markdown or Quarto}: arguments passed on to \code{\link[knitr:kable]{knitr::kable()}} (otherwise, has no use).}

 \item{wisca_model}{The outcome of \code{\link[=wisca]{wisca()}} or \code{\link[=antibiogram]{antibiogram(..., wisca = TRUE)}}.}
--- a/man/g.test.Rd
+++ b/man/g.test.Rd
@@ -45,9 +45,8 @@ A list with class \code{"htest"} containing the following
  \item{residuals}{the Pearson residuals,
    \code{(observed - expected) / sqrt(expected)}.}
  \item{stdres}{standardized residuals,
-    \code{(observed - expected) / sqrt(V)}, where \code{V} is the
-    residual cell variance (Agresti, 2007, section 2.4.5
-    for the case where \code{x} is a matrix, \code{n * p * (1 - p)} otherwise).}
+    \code{(observed - expected) / sqrt(V)}, where \code{V} is the residual cell variance (Agresti, 2007,
+    section 2.4.5 for the case where \code{x} is a matrix, \code{n * p * (1 - p)} otherwise).}
 }
 \description{
 \code{\link[=g.test]{g.test()}} performs chi-squared contingency table tests and goodness-of-fit tests, just like \code{\link[=chisq.test]{chisq.test()}} but is more reliable (1). A \emph{G}-test can be used to see whether the number of observations in each category fits a theoretical expectation (called a \strong{\emph{G}-test of goodness-of-fit}), or to see whether the proportions of one variable are different for different values of the other variable (called a \strong{\emph{G}-test of independence}).
--- a/man/pca.Rd
+++ b/man/pca.Rd
@@ -32,7 +32,7 @@ pca(x, ..., retx = TRUE, center = TRUE, scale. = TRUE, tol = NULL,
    standard deviations are less than or equal to \code{tol} times the
    standard deviation of the first component.)  With the default null
    setting, no components are omitted (unless \code{rank.} is specified
-    less than \code{min(dim(x))}.).  Other settings for \code{tol} could be
+    less than \code{min(dim(x))}.).  Other settings for tol could be
    \code{tol = 0} or \code{tol = sqrt(.Machine$double.eps)}, which
    would omit essentially constant components.}

--- a/tests/testthat/test-antibiogram.R
+++ b/tests/testthat/test-antibiogram.R
@@ -130,6 +130,77 @@ test_that("test-antibiogram.R", {
    expect_equal(colnames(ab9), c("ward", "gender", "Piperacillin/tazobactam", "Piperacillin/tazobactam + Gentamicin", "Piperacillin/tazobactam + Tobramycin"))
  }

+  # Parallel computing ----------------------------------------------------
+  # Tests must pass even when only 1 core is available; parallel = TRUE then
+  # silently falls back to sequential, but results must still be correct.
+
+  if (AMR:::pkg_is_available("future.apply")) {
+    set.seed(42)
+
+    # sequential reference for WISCA
+    wisca_seq <- suppressWarnings(suppressMessages(
+      wisca(example_isolates, antimicrobials = c("TZP", "TZP+TOB", "TZP+GEN"), simulations = 100, info = FALSE)
+    ))
+
+    future::plan(future::multicore)
+
+    # 1. parallel = TRUE produces the same antibiogram structure as sequential
+    wisca_par <- suppressWarnings(suppressMessages(
+      wisca(example_isolates, antimicrobials = c("TZP", "TZP+TOB", "TZP+GEN"), simulations = 100, parallel = TRUE, info = FALSE)
+    ))
+    expect_inherits(wisca_par, "antibiogram")
+    expect_equal(colnames(wisca_par), colnames(wisca_seq))
+    expect_true(isTRUE(attributes(wisca_par)$wisca))
+
+    # 2. coverage values are non-NA and fall within [0, 1]
+    ln <- attributes(wisca_par)$long_numeric
+    expect_false(anyNA(ln$coverage))
+    expect_false(anyNA(ln$lower_ci))
+    expect_false(anyNA(ln$upper_ci))
+    expect_true(all(ln$coverage >= 0 & ln$coverage <= 1))
+    expect_true(all(ln$lower_ci <= ln$coverage))
+    expect_true(all(ln$upper_ci >= ln$coverage))
+
+    # 3. a second parallel run gives the same column names
+    wisca_par2 <- suppressWarnings(suppressMessages(
+      wisca(example_isolates, antimicrobials = c("TZP", "TZP+TOB", "TZP+GEN"), simulations = 100, parallel = TRUE, info = FALSE)
+    ))
+    expect_equal(colnames(wisca_par), colnames(wisca_par2))
+
+    # 4. parallel with workers = 1 gives same structure as sequential
+    future::plan(future::multicore, workers = 1)
+    wisca_par1 <- suppressWarnings(suppressMessages(
+      wisca(example_isolates, antimicrobials = c("TZP", "TZP+TOB", "TZP+GEN"), simulations = 100, parallel = TRUE, info = FALSE)
+    ))
+    expect_equal(colnames(wisca_seq), colnames(wisca_par1))
+
+    # 5. grouped antibiogram in parallel yields identical structure to sequential
+    if (AMR:::pkg_is_available("dplyr", min_version = "1.0.0", also_load = TRUE)) {
+      future::plan(future::sequential)
+      ab_grp_seq <- suppressWarnings(suppressMessages(
+        example_isolates %>%
+          group_by(ward) %>%
+          wisca(antimicrobials = c("TZP", "TZP+TOB"), simulations = 50, info = FALSE)
+      ))
+      future::plan(future::multicore)
+      ab_grp_par <- suppressWarnings(suppressMessages(
+        example_isolates %>%
+          group_by(ward) %>%
+          wisca(antimicrobials = c("TZP", "TZP+TOB"), simulations = 50, parallel = TRUE, info = FALSE)
+      ))
+      expect_equal(colnames(ab_grp_seq), colnames(ab_grp_par))
+      expect_equal(nrow(ab_grp_seq), nrow(ab_grp_par))
+    }
+
+    # 6. parallel = TRUE without a plan raises an informative error
+    future::plan(future::sequential)
+    expect_error(
+      suppressWarnings(wisca(example_isolates, antimicrobials = "TZP", parallel = TRUE, info = FALSE)),
+      "non-sequential"
+    )
+
+    future::plan(future::sequential)
+  }

  # Generate plots with ggplot2 or base R --------------------------------