parse.control: Parse control parameter for highway assignment
In travelr: Functions for Travel Demand Modeling

Description Usage Arguments Details Value Author(s) See Also

Extract control parameters for highway assignment, supplying defaults when available.

1	parse.control(control,control.element,default.value=NULL)

`control`	Assignment algorithm control parameters (a named list)
`control.element`	Parameter to retrieve, a character string
`default.value`	Default value to supply if control parameter is not set (if NULL, global defaults apply if availble; see details)

This function will generally only be of interest to the developers of new highway assignment algorithms.

parse.control extracts a parameter from the control list typically provided to the highway.assign function. Certain parameters have global defaults, which may be overridden by a local default if the default parameter is supplied. The global defaults are as follows:

`min.relative.gap`	`1e-4`	Target for relative gap statistic
`max.iter`	`100`	Maximum iteration, except 4 for method=“MSA”)
`max.elapsed`	`3600`	Maximum time to run after the algorithm starts
`opt.tol`	`.Machine$double.eps^0.5`	Tolerance for internal line searches.
`verbose`	`1`	Debugging level (higher numbers may generate more output; 0 for silent)
`log`	`FALSE`	If true, save a `data.frame` with the equilibrium statistics from each iteration

Any parameter for which no default is provided will return NULL when requested.

Arbitrary additional parameters may be defined. The control parameter is just a named list of values, and the function simply looks up the name and returns the corresponding element. It differs from simple list indexing in that it can provide a default value.

parse.control returns a value for the named highway assignment control parameter

Jeremy Raw

highway.assign

travelr documentation built on May 2, 2019, 5:17 p.m.