A named set of elements, for indexing variables (the axes of
var_decl()), for reductions such as sums (ir_reduce()), and for
repeating a constraint over its elements (the over of constraint()).
Value
A plain list without a class, with the fields name and
elements. It is an element of the list a program() takes as sets.
Examples
index_set("items", list(1L, 2L, 3L))
#> $name
#> [1] "items"
#>
#> $elements
#> $elements[[1]]
#> [1] 1
#>
#> $elements[[2]]
#> [1] 2
#>
#> $elements[[3]]
#> [1] 3
#>
#>