R: Read data from GDX into R

rgdx {gdxrrw}

R Documentation

Read data from GDX into R

Description

Read one data item (also called a symbol) from GDX into R, returning it as a list. Note that GDX files contain multiple symbols (e.g. sets, parameters). Each symbol is read with a separate call.

Usage

  # generic form - return a symbol as a list
  rgdx(gdxName, requestList = NULL, squeeze = TRUE, useDomInfo = TRUE)

  # return a set or parameter in a data frame
  rgdx.set(gdxName, symName, names=NULL, compress=FALSE, ts=FALSE, useDomInfo = TRUE)
  rgdx.param(gdxName, symName, names=NULL, compress=FALSE, ts=FALSE, squeeze=TRUE, useDomInfo = TRUE)

  # return a scalar
  rgdx.scalar(gdxName, symName, ts=FALSE)

Arguments

`gdxName`	the name of the GDX file to read
`requestList`	the name of the symbol to read, and (optionally) information about how much information to return and in what format. This argument must be a list. If omitted, the universe of UELs contained in the GDX file is returned
`squeeze`	if TRUE/nonzero, squeeze out any zero or EPS stored in the GDX container
`useDomInfo`	if TRUE, the default filter will be the domain info in the GDX. If no domain info is available, or if `useDomInfo=FALSE`, the default filter will be the GDX universe
`symName`	the name of the GDX symbol to read
`names`	the column names to use in the data frame returned
`compress`	if TRUE, compress the factors in the data frame so they only include required levels. For the default compress=FALSE, each factor includes levels for the entire universe of UELs in the GDX file
`ts`	if TRUE, include the `.ts` field (i.e. the explanatory text) for the symbol in the return

Value

By default, the return value is a list with components describing the data item or symbol returned.

`name`	symbol name
`type`	symbol's data type: `set`, `parameter`, `variable` or `equation`
`dim`	symbol dimension
`val`	array containing the symbol data
`form`	form of the data in `val`, i.e. `full` or `sparse`
`uels`	vector of UEL lists, one list per symbol dimension

The functions rgdx.param and rgdx.set are special-purpose wrappers that read parameters and sets, respectively, and return them as data frames.

The function rgdx.scalar returns a scalar (i.e. a 0-dimensional parameter) as a double.

The output format can be adjusted via a global option. Documentation for this is in progress.

Note

A common problem is failure to load the external GDX libraries that are required to interface with GDX data. Use igdx to troubleshoot and solve this problem.

Author(s)

Original coding by Rishabh Jain. Adopted and packaged by Steve Dirkse. Maintainer: R@gams.com

Examples

  # run R-script trnsport.r from the data subdirectory of the gdxrrw package
  # to load up some data for writing to a GDX file
  data(trnsport)

  wgdx("rgdx1",sf,si,sj,sa,sb,sd)
  ou = rgdx("rgdx1")
  req <- list(name="f")
  of = rgdx("rgdx1",req)
  req <- list(name="i")
  oi = rgdx("rgdx1",req)
  req <- list(name="j")
  oj = rgdx("rgdx1",req)
  req <- list(name="a")
  oa = rgdx("rgdx1",req)
  req <- list(name="b")
  ob = rgdx("rgdx1",req)
  req <- list(name="d")
  od = rgdx("rgdx1",req)

  ## Not run: 
    # complete tests and examples can be run in the
    # extdata directory of the gdxrrw package
    # check .libPaths for a hint on where packages are installed
    setwd(paste(.libPaths()[1],"/gdxrrw/extdata",sep=""))
    source("tAll.R")
  
## End(Not run)

[Package gdxrrw version 0.2.0 Index]