Adding genCrossed and documentation (#253)

* Adding genCrossed and documentation

* Update CITATION.cff

---------

Co-authored-by: kgoldfeld <kgoldfeld@users.noreply.github.com>

Author: kgoldfeld

CITATION.cff

@@ -8,7 +8,7 @@ message: 'To cite package "simstudy" in publications use:'
 type: software
 license: GPL-3.0-only
 title: 'simstudy: Simulation of Study Data'
-version: 0.9.2
+version: 0.9.2.9000
 doi: 10.21105/joss.02763
 identifiers:
 - type: doi
@@ -73,10 +73,13 @@ references:
   url: https://www.R-project.org/
   authors:
   - name: R Core Team
+    website: https://ror.org/02zz1nj61
   institution:
     name: R Foundation for Statistical Computing
+    website: https://ror.org/05qewa988
     address: Vienna, Austria
   year: '2026'
+  doi: 10.32614/R.manuals
   version: '>= 4.1.0'
 - type: software
   title: data.table
@@ -137,10 +140,13 @@ references:
   notes: Imports
   authors:
   - name: R Core Team
+    website: https://ror.org/02zz1nj61
   institution:
     name: R Foundation for Statistical Computing
+    website: https://ror.org/05qewa988
     address: Vienna, Austria
   year: '2026'
+  doi: 10.32614/R.manuals
 - type: software
   title: mvnfast
   abstract: 'mvnfast: Fast Multivariate Normal and Student''s t Methods'
@@ -209,7 +215,7 @@ references:
   title: fastglm
   abstract: 'fastglm: Fast and Stable Fitting of Generalized Linear Models using ''RcppEigen'''
   notes: Imports
-  url: https://github.com/jaredhuling/fastglm
+  url: https://jaredhuling.org/fastglm/
   repository: https://CRAN.R-project.org/package=fastglm
   authors:
   - family-names: Huling
@@ -336,10 +342,13 @@ references:
   notes: Suggests
   authors:
   - name: R Core Team
+    website: https://ror.org/02zz1nj61
   institution:
     name: R Foundation for Statistical Computing
+    website: https://ror.org/05qewa988
     address: Vienna, Austria
   year: '2026'
+  doi: 10.32614/R.manuals
 - type: software
   title: gridExtra
   abstract: 'gridExtra: Miscellaneous Functions for "Grid" Graphics'
@@ -512,10 +521,13 @@ references:
   notes: Suggests
   authors:
   - name: R Core Team
+    website: https://ror.org/02zz1nj61
   institution:
     name: R Foundation for Statistical Computing
+    website: https://ror.org/05qewa988
     address: Vienna, Austria
   year: '2026'
+  doi: 10.32614/R.manuals
 - type: software
   title: survival
   abstract: 'survival: Survival Analysis'

DESCRIPTION

@@ -71,4 +71,4 @@ LinkingTo:
 VignetteBuilder: 
     knitr
 Encoding: UTF-8
-RoxygenNote: 7.3.3
+Config/roxygen2/version: 8.0.0

NAMESPACE

@@ -34,6 +34,7 @@ export(genCorFlex)
 export(genCorGen)
 export(genCorMat)
 export(genCorOrdCat)
+export(genCrossed)
 export(genData)
 export(genDataDensity)
 export(genDummy)

NEWS.md

@@ -1,5 +1,14 @@
 # simstudy (development version)
 
+## New feature
+
+* Added `genCrossed()` to support simulation of crossed data structures,
+complementing `genCluster()` for nested data generation. The function
+creates Cartesian products of two or more data sets and adds a unique
+crossed identifier.
+
+# Update
+
 * scenario_list() return type change: now returns a list of 1-row 
 data.frames (instead of vectors) to support mixed numeric/character 
 scenario values without coercion. If you were transposing scenario 

R/group_data.R

@@ -282,6 +282,104 @@ genCluster <- function(dtClust,
   return(dt[])
 }
 
+#' @title Generate crossed data
+#'
+#' @description Create the Cartesian product of two or more data sets,
+#' preserving all variables from each input data set.
+#'
+#' @param ... Two or more data sets to be crossed. Each input may be a
+#'   `data.frame` or `data.table`.
+#' @param id Name of the crossed id field. Defaults to `"cross_id"`.
+#'
+#' @return A `data.table` containing all combinations of rows from the input
+#'   data sets. The crossed id is placed first and used as the key.
+#'
+#' @examples
+#' region_def <- defData(varname = "r_effect", formula = 0, variance = 1)
+#' mouse_def <- defData(varname = "m_effect", formula = 0, variance = 1)
+#' 
+#' dd_region <- genData(20, region_def, id = "region")
+#' dd_mouse  <- genData(8, mouse_def, id = "mouse")
+#'
+#' dd <- genCrossed(
+#'   dd_mouse,
+#'   dd_region,
+#'   id = "mouse_region_id"
+#' )
+#'
+#' @export
+#' @concept group_data
+genCrossed <- function(..., id = "cross_id") {
+  
+  # to "declare" variable 
+  
+  .cross_join_id <- NULL
+  
+  ####
+  
+  dts <- list(...)
+  
+  #### Check arguments
+  
+  if (length(dts) < 2) {
+    stop("at least two data sets must be provided", call. = FALSE)
+  }
+  
+  if (!is.character(id) || length(id) != 1) {
+    stop("argument 'id' must be a single character string", call. = FALSE)
+  }
+  
+  #### Convert inputs to data.tables without modifying originals
+  
+  dts <- lapply(dts, function(x) {
+    data.table::copy(data.table::as.data.table(x))
+  })
+  
+  #### Check for duplicate column names across inputs
+  
+  all_names <- unlist(lapply(dts, names), use.names = FALSE)
+  
+  dup_names <- unique(all_names[duplicated(all_names)])
+  
+  if (length(dup_names) > 0) {
+    stop(
+      "input data sets must not share column names: ",
+      paste(dup_names, collapse = ", "),
+      call. = FALSE
+    )
+  }
+  
+  if (id %in% all_names) {
+    stop("argument 'id' already exists as a column name", call. = FALSE)
+  }
+  
+  #### Create Cartesian product
+  
+  for (i in seq_along(dts)) {
+    dts[[i]][, .cross_join_id := 1L]
+  }
+  
+  # Sequentially merge all data sets to create Cartesian product
+  
+  dt <- Reduce(
+    function(x, y) {
+      merge(x, y, by = ".cross_join_id", allow.cartesian = TRUE)
+    },
+    dts
+  )
+  
+  dt[, .cross_join_id := NULL]
+  
+  #### Add crossed id, move it to first column, and set key
+  
+  dt[, eval(id) := .I]
+  
+  data.table::setcolorder(dt, c(id, setdiff(names(dt), id)))
+  data.table::setkeyv(dt, id)
+  
+  return(dt[])
+}
+
 #' Generate event data using longitudinal data, and restrict output to time
 #' until the nth event.
 #'

R/simstudy-package.R

@@ -63,8 +63,7 @@ NULL
 #' def
 #' genData(5, def)
 #' @name distributions
-#' @aliases normal poisson noZeroPoisson binary binomial uniform
-#'  categorical gamma beta negBinomial nonrandom exponential mixture
+#' @aliases normal poisson noZeroPoisson binary binomial uniform categorical gamma beta negBinomial nonrandom exponential mixture
 #' @md
 NULL