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An S4 class to specify a model variable

Source: R/class-variable.R
class-variable.Rd

The counterpart of class-parameter: a parameter carries the model's input data, a variable its solved output. Every variable declared by the model has one of these, pre-populated from the baked specification when a modOut is created and filled with solved values by read_solution() – exactly as modInp@parameters is populated from data-raw/modInp.yml.

The specification itself is composed at build time in data-raw/DATASET.R: dimensions, gating map and description come from the GAMS source via gams2x, the emitted column names and the positive/free declaration are parsed out of glpk/energyRt.mod, and role / unit / origin come from the data-raw/variables.yml overlay.

The class and its methods are not intended for direct use; read values with getData().

Slots

name

character, the variable's name in the model.

desc

character, one-line description.

dimSets

character, the variable's dimensions as the model declares them, duplicates preserved (vTradeIr is trade, comm, region, region, year, slice). Byte-identical to .variable_set, which newCosts() and newConstraint() consume positionally against the GAMS declaration.

colNames

character, the column names the variable is actually written out with. Differs from dimSets only where a dimension repeats and the writers disambiguate it – src/dst for vTradeIr, yearp for vTechRetiredNewCap.

gate

character, the name of the map that gates the variable's domain (the $-condition), or "" when it is unconditional.

role

character, what the variable is: source, sink, flow, activity, balance, stock, capacity or cost. A stock is a level at a point in time and is never summed over slices.

unit

character, the KIND of quantity (commodity, activity, capacity, currency), not a unit string – real units are per-object here and are resolved against the model.

positive

logical, whether the model declares the variable non-negative.

origin

character, solver or computed (built in R by read.R, so never expected in solver output).

data

data.frame, the solved values.

misc

list, path / inMemory / onDisk when stored on disk.

See also

Other variable: get_variable()