An S4 class to represent a custom constraint.

Class constraint is used to define custom constraints in the optimization problem.

Class summand stores information about linear terms (a multiplier and a variable) in the lhs of the constraint class. It is auto-created by newConstraint function and is not intended to be used directly by the user.

Details

Custom constraints extend the functionality of the model by adding user-defined constraints to the optimization problem. If the predefined constraints are not sufficient to describe the problem, custom constraints can be used to add linear equlity or inequality constraints to define additional relationships between the variables. In many cases this can be done without writing constraints in the GAMS, Julia/JuMP, Python/Pyomo, or GLPK-MathProg languages by using the constrant class and the newConstraint function. To define a custom constraint with the newConstraint function, the user needs to specify the name of the constraint, the type of the relation (equality, less than or equal, greater than or equal), the left-hand side (LHS) terms of the statement, and the right-hand side (RHS) value. The dimension of the constraint is set by the for.each parameter. The 'lhs' terms are defined as a list of linear terms (summands). Each summand consists of a variable, a multiplier, and a set of sets for which the summand is defined.

Slots

name

character. Name of the constraint object, used in sets.

desc

character. Description of the constraint.

eq

character. Type of the relation ('==' default, '<=', '>=').

for.each

list. List with sets for combination of which the constraint is created.

rhs

data.frame. Named list or data frame with numeric values for each constraint. The dimensions of the data frame should match the dimensions of the sets in the for.each slot.

defVal

numeric. The default value for the rhs. It is recommended to set the default value for the rhs of every constraint to avoid unexpected behavior. If not specified, the default value is 0, and the warning is issued.

interpolation

character. Interpolation rule for the constraint. Recognized values, any combination of "back", "inter", "forth", e.g., "back.inter" or "forth.inter", indicating the direction of interpolation. The default value is "inter", meaning that the interpolation is done for years between the specified values. The "back" and "forth" values induce backward and forward interpolation of the rhs values, respectively.

lhs

list. List of summands for the left-hand-side of the equation. This slot is created automatically from all named of unnamed lists passed to the newConstraint function, except for the named arguments.

misc

list. Any additional information or parameters to store in the constraint object.

desc

character. Description of the linear term.

variable

character. Name of the variable.

for.sum

list. List of sets for which the summand will be created.

mult

data.frame. Multiplying coefficients to the variable for each set in the for.sum slot.

defVal

numeric. Default value for the summand.

misc

list. Additional information.

See also

Other class constraint policy: class-costs, newConstraint(), newCosts(), newSubsidy(), newTax(), subsidy-class, tax-class

Other class constraint: newConstraint()