Create a multimod equation object — new

Constructs an equation object used in the multimod modeling framework. This object represents a single equation, including left-hand side (LHS), right-hand side (RHS), relation operator (e.g., equality or inequality), and an optional domain.

Usage

new_equation(
  name,
  desc = NULL,
  dims,
  lhs,
  rhs,
  relation = "==",
  domain = NULL,
  comment = NULL,
  dims_index_aliases = NULL,
  symbols = NULL
)

Arguments

name: Character string. The name of the equation.
desc: Optional character string. A description or label for the equation.
dims: Character vector. Names of the dimensions over which the equation is declared.
lhs: An AST (abstract syntax tree) representing the left-hand side of the equation.
rhs: An AST representing the right-hand side of the equation.
relation: Character string. The relation type: one of "==", "<=", or ">=".
domain: Optional AST or symbol representing the domain/mapping condition for the equation.
comment: character, comment line from source file (e.g., *@ domain hint)
dims_index_aliases: Optional character vector of equation-specific iterator names, one per declared dimension (preserved from the source model, e.g. by read_gmpl()).
symbols: Optional named list of known symbols (sets, aliases) used to resolve dimension names in ast_dims().

Value

An mm_equation object.

Examples

lhs <- ast_variable("vTechOut", dims = c("tech", "region"))
rhs <- ast_expression("*",
  ast_parameter("pTechEff", dims = c("tech")),
  ast_variable("vTechInp", dims = c("tech", "region"))
)
eq <- new_equation(
  name = "eqTechEff",
  desc = "Technology output efficiency",
  dims = c("tech", "region"),
  lhs = lhs,
  rhs = rhs,
  relation = "=="
)
print(eq)
#> <AST equation> eqTechEff
#>   relation:  == 
#>   lhs:  vTechOut[tech,region] 
#>   rhs:  pTechEff[tech] * vTechInp[tech,region]