params: Get and set simulation parameters

In SpaDES.core: Core Utilities for Developing and Running Spatially Explicit Discrete Event Models

Get and set simulation parameters

Description

params, P and Par (an active binding, like "mod") access the parameter slot in the simList. params has a replace method, so can be used to update a parameter value.

Usage

params(sim)

## S4 method for signature 'simList'
params(sim)

params(sim) <- value

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

P(sim, param, module)

P(sim, param, module) <- value

parameters(sim, asDF = FALSE)

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

Arguments

sim	A simList object from which to extract element(s) or in which to replace element(s).
value	The parameter value to be set (in the corresponding module and param).
param	Optional character string indicating which parameter to choose.
module	Optional character string indicating which module params should come from.
asDF	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.

Details

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

Value

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

Note

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(), checkpointFile(), envir(), events(), globals(), inputs(), modules(), objs(), packages(), paths(), progressInterval(), times()

Examples

s <- simInit()
# add a parameter to tmp module
params(s)$tmp <- list(a = 1)

# Only work inside a module, inside a function with `sim` is an argument
# P(s, "a") # get "a" parameter inside the current module
# Par$a     # same. Get "a" parameter inside the current module

if (requireNamespace("NLMR", quietly = TRUE) &&
    requireNamespace("SpaDES.tools", quietly = TRUE)) {
  opts <- options("spades.moduleCodeChecks" = FALSE) # not necessary for example
  modules <- list("randomLandscapes")
  paths <- list(modulePath = getSampleModules(tempdir()))
  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
}

SpaDES.core documentation built on June 22, 2024, 10:32 a.m.