params and P access the parameter slot in the simList. params has a replace method, so can be used to update a parameter value.


# S4 method for simList

params(sim) <- value

# S4 method for simList
params(sim) <- value

P(sim, param, module)

P(sim, param, module) <- value

parameters(sim, asDF = FALSE)

# S4 method for simList
parameters(sim, asDF = FALSE)



A simList object from which to extract element(s) or in which to replace element(s).


The parameter value to be set (in the corresponding module and param).


Optional character string indicating which parameter to choose.


Optional character string indicating which module params should come from.


Logical. For parameters, if TRUE, this will produce a single data.frame of all model parameters. If FALSE, then it will return a data.frame with 1 row for each parameter within nested lists, with the same structure as params.


Returns or sets the value of the slot from the simList object.


parameters will extract only the metadata with the metadata defaults, NOT the current values that may be overwritten by a user. See examples.


The differences between P, params and being explicit with passing arguments are mostly a question of speed and code compactness. The computationally fastest way to get a parameter is to specify moduleName and parameter name, as in: P(sim, "paramName", "moduleName") (replacing moduleName and paramName with your specific module and parameter names), but it is more verbose than P(sim)$paramName. Note: the important part for speed (e.g., 2-4x faster) is specifying the moduleName. Specifying the parameter name is <5% faster.

See also

SpaDES.core-package(), specifically the section 1.2.1 on Simulation parameters.

Other functions to access elements of a 'simList' object: .addDepends(), doEvent.checkpoint(), envir(), events(), globals(), inputs(), modules(), objs(), packages(), paths(), progressInterval(), times()


if (requireNamespace("NLMR", quietly = TRUE) &&
    requireNamespace("", quietly = TRUE)) {
  opts <- options("spades.moduleCodeChecks" = FALSE) # not necessary for example
  modules <- list("randomLandscapes")
  paths <- list(modulePath = system.file("sampleModules", package = "SpaDES.core"))
  mySim <- simInit(modules = modules, paths = paths,
                   params = list(.globals = list(stackName = "landscape")))

  # update some parameters using assignment -- currently only params will work
  params(mySim)$randomLandscapes$nx <- 200
  params(mySim)$randomLandscapes$ny <- 200

  parameters(mySim) # Does not contain these user overridden values

  # These next 2 are same here because they are not within a module
  P(mySim)          # Does contain the user overridden values
  params(mySim)     # Does contain the user overridden values

  # NOTE -- deleting a parameter will affect params and P, not parameters
  params(mySim)$randomLandscapes$nx <- NULL
  params(mySim)$randomLandscapes$ny <- NULL

  parameters(mySim) # Shows nx and ny

  # These next 2 are same here because they are not within a module
  P(mySim)          # nx and ny are Gone
  params(mySim)     # nx and ny are Gone

  options(opts) # reset
#> Setting:
#>   options(
#>     spades.modulePath = '/home/runner/work/_temp/Library/SpaDES.core/sampleModules'
#>   )
#> Paths set to:
#>   options(
#>     rasterTmpDir = '/tmp/RtmppEYNhs/SpaDES/scratch/raster'
#>     reproducible.cachePath = '/tmp/RtmppEYNhs/myProject/cache'
#>     spades.inputPath = '/tmp/RtmppEYNhs/myProject/inputs'
#>     spades.outputPath = '/tmp/RtmppEYNhs/myProject/outputs'
#>     spades.modulePath = '/home/runner/work/_temp/Library/SpaDES.core/sampleModules'
#>     spades.scratchPath = '/tmp/RtmppEYNhs/SpaDES/scratch'
#>   )
#>   terra::terraOptions(tempdir = '/tmp/RtmppEYNhs/SpaDES/scratch/terra'
#> Loading required package: RColorBrewer
#> Loading required package: NLMR
#> Using setDTthreads(1). To change: 'options(spades.DTthreads = X)'.
#> defineParameter: '.useCache' is not of specified type 'logical'.
#> The following .globals were used:
#>              module    global
#> 1: randomLandscapes stackName