SpaDES.core (version 2.0.5)

defineParameter: Define a parameter used in a module

Description

Used to specify a parameter's name, value, and set a default. The min and max arguments are ignored by simInit or spades; they are for human use only. To ensure that a user cannot set parameters outside of a range of values, the module developer should use assertions in their module code.

Usage

defineParameter(name, class, default, min, max, desc, ...)

Value

a data.frame

Arguments

name

Character string giving the parameter name.

class

Character string giving the parameter class.

default

The default value to use when none is specified by the user. Non-standard evaluation is used for the expression.

min

With max, used to define a suitable range of values. Non-standard evaluation is used for the expression. These are not tested by simInit or spades. These are primarily for human use, i.e., to tell a module user what values the module expects.

max

With min, used to define a suitable range of values. Non-standard evaluation is used for the expression. These are not tested by simInit or spades. These are primarily for human use, i.e., to tell a module user what values the module expects.

desc

Text string providing a brief description of the parameter. If there are extra spaces or carriage returns, these will be stripped, allowing for multi-line character strings without using paste or multiple quotes.

...

A convenience that allows writing a long desc without having to use paste; any character strings after desc will be pasted together with desc.

Author

Alex Chubaty and Eliot McIntire

See Also

P(), params() for accessing these parameters in a module.

Examples

parameters = rbind(
  defineParameter("lambda", "numeric", 1.23, desc = "intrinsic rate of increase"),
  defineParameter("P", "numeric", 0.2, 0, 1, "probability of attack"),

  # multi-line desc without quotes on each line -- spaces and carriage returns are stripped
  defineParameter("rate", "numeric", 0.2, 0, 1,
                  "rate of arrival. This is in individuals
                  per day. This can be modified
                  by the user"),
  # multi-line desc with quotes on each line
  defineParameter("times", "numeric", 0.2, 0, 1,
                  desc = "The times during the year ",
                         "that events will occur ",
                         "with possibility of random arrival times")

)

# \donttest{
# Create a new module, then access parameters using `P`
tmpdir <- file.path(tempdir(), "test")
checkPath(tmpdir, create = TRUE)

# creates a  new, "empty" module -- it has defaults for everything that is required
newModule("testModule", tmpdir, open = FALSE)

# Look at new module code -- see defineParameter
if (interactive()) file.edit(file.path(tmpdir, "testModule", "testModule.R"))

# initialize the simList
if (requireNamespace("ggplot2", quietly = TRUE)) {
  # Some things not necessary in this example, if not interactive (like plotting)
  opts <- if (interactive()) list() else
    options(spades.plot = NA, spades.useRequire = FALSE,
            spades.moduleCodeChecks = FALSE)
  mySim <- simInit(modules = "testModule",
                   paths = list(modulePath = tmpdir))

  # Access one of the parameters -- because this line is not inside a module
  #  function, we must specify the module name. If used within a module,
  #  we can omit the module name
  P(mySim, module = "testModule") # gets all params in a module
  P(mySim, ".useCache", "testModule") # just one param
  options(opts)
}
unlink(tmpdir, recursive = TRUE)
# }