readParameters function

Reads the parameters to be tuned by irace from a file or from a character string.

readParameters(file, digits = 4L, debugLevel = 0L, text)

Arguments

• file: character(1)

  Filename containing the definitions of the parameters to be tuned.

• digits: integer(1)

  The number of decimal places to be considered for real-valued parameters.

• debugLevel: integer(1)

  Larger values produce more verbose output.

• text: character(1)

  If file is not supplied and this is, then parameters are read from the value of text via a text connection.

Returns

A list containing the definitions of the parameters read. The list is structured as follows:

• names: Vector that contains the names of the parameters.
• types: Vector that contains the type of each parameter 'i', 'c', 'r', 'o'. Numerical parameters can be sampled in a log-scale with 'i,log' and 'r,log' (no spaces).
• switches: Vector that contains the switches to be used for the parameters on the command line.
• domain: List of vectors, where each vector may contain two values (minimum, maximum) for real and integer parameters, or possibly more for categorical parameters.
• conditions: List of R logical expressions, with variables corresponding to parameter names.
• isFixed: Logical vector that specifies which parameter is fixed and, thus, it does not need to be tuned.
• nbParameters: An integer, the total number of parameters.
• nbFixed: An integer, the number of parameters with a fixed value.
• nbVariable: Number of variable (to be tuned) parameters.
• depends: List of character vectors, each vector specifies which parameters depend on this one.
• is_dependent: Logical vector that specifies which parameter has a dependent domain.
• digits: Integer vector that specifies the number of digits per parameter.
• forbidden: List of expressions that define which parameter configurations are forbidden.

Details

Either file or text must be given. If file is given, the parameters are read from the file file. If text is given instead, the parameters are read directly from the text character string. In both cases, the parameters must be given (in text or in the file whose name is file) in the expected form. See the documentation for details. If none of these parameters is given, irace

will stop with an error.

A fixed parameter is a parameter that should not be sampled but instead should be always set to the only value of its domain. In this function we set isFixed to TRUE only if the parameter is a categorical and has only one possible value. If it is an integer and the minimum and maximum are equal, or it is a real and the minimum and maximum values satisfy round(minimum, digits) == round(maximum, digits), then the parameter description is rejected as invalid to identify potential user errors.

The order of the parameters determines the order in which parameters are given to targetRunner. Changing the order may also change the results produced by irace, even with the same random seed.

Examples

## Read the parameters directly from text
 parameters_table <- '
 # name       switch           type  values               [conditions (using R syntax)]
 algorithm    "--"             c     (as,mmas,eas,ras,acs)
 localsearch  "--localsearch " o     (0, 1, 2, 3)
 alpha        "--alpha "       r     (0.00, 5.00)
 beta         "--beta "        r     (0.00, 10.00)
 rho          "--rho  "        r     (0.01, 1.00)
 ants         "--ants "        i,log (5, 100)
 q0           "--q0 "          r     (0.0, 1.0)           | algorithm == "acs"
 rasrank      "--rasranks "    i     (1, "min(ants, 10)") | algorithm == "ras"
 elitistants  "--elitistants " i     (1, ants)            | algorithm == "eas"
 nnls         "--nnls "        i     (5, 50)              | localsearch %in% c(1,2,3)
 dlb          "--dlb "         c     (0, 1)               | localsearch %in% c(1,2,3)

 [forbidden]
 (alpha == 0.0) & (beta == 0.0)
 [global]
 digits = 4
 '
 parameters <- readParameters(text=parameters_table)
 str(parameters)

Author(s)

Manuel López-Ibáñez and Jérémie Dubois-Lacoste