Solver class

This class is used to represent solvers for optimization. Only experts should use the fields and methods for this class directly.

See also

Other classes: ConservationModifier-class, ConservationProblem-class, Constraint-class, Decision-class, Objective-class, OptimizationProblem-class, Penalty-class, Portfolio-class, Target-class, TargetMethod-class, Weight-class

Super class

prioritizr::ConservationModifier -> Solver

Methods

Public methods

• Solver$run()

• Solver$calculate()

• Solver$set_variable_ub()

• Solver$set_variable_lb()

• Solver$set_constraint_rhs()

• Solver$set_start_solution()

• Solver$remove_start_solution()

• Solver$solve()

• Solver$clone()

Inherited methods

• prioritizr::ConservationModifier$get_data()
• prioritizr::ConservationModifier$get_internal()
• prioritizr::ConservationModifier$print()
• prioritizr::ConservationModifier$repr()
• prioritizr::ConservationModifier$set_data()
• prioritizr::ConservationModifier$set_internal()
• prioritizr::ConservationModifier$show()

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Method run()

Run the solver to generate a solution.

Usage

Solver$run()

Returns

list of solutions.

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Method calculate()

Perform computations that need to be completed before applying the object.

Usage

Solver$calculate(...)

Arguments

...

Additional arguments.

x

optimization_problem() object.

Returns

Invisible TRUE.

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Method set_variable_ub()

Set the upper bound for a decision variable.

Usage

Solver$set_variable_ub(index, value)

Arguments

index

integer value indicating the index of the decision variable.

value

numeric new bound value.

Details

Note that this method should only be run after $calculate(). It can be used to overwrite values after ingesting an optimization_problem() object. It is designed to be used in portfolios and importance functions.

Returns

Invisible TRUE.

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Method set_variable_lb()

Set the lower bound for a decision variable.

Usage

Solver$set_variable_lb(index, value)

Arguments

index

integer value indicating the index of the decision variable.

value

numeric new bound value.

Details

Note that this method should only be run after $calculate(). It can be used to overwrite values after ingesting an optimization_problem() object. It is designed to be used in portfolios and importance functions.

Returns

Invisible TRUE.

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Method set_constraint_rhs()

Set the right-hand-side coefficient bound for a constraint.

Usage

Solver$set_constraint_rhs(index, value)

Arguments

index

integer value indicating the index of the decision variable.

value

numeric new value.

Details

Note that this method should only be run after $calculate(). It can be used to overwrite values after ingesting an optimization_problem() object. It is designed to be used in portfolios and importance functions.

Returns

Invisible TRUE.

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Method set_start_solution()

Set the starting solution.

Usage

Solver$set_start_solution(value, warn = TRUE)

Arguments

value

numeric vector.

warn

logical indicating if a warning should be displayed if the solver does not support starting solutions.

Details

This method is designed used in portfolios and importance functions.

Returns

Invisible TRUE.

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Method remove_start_solution()

Remove the starting solution.

Usage

Solver$remove_start_solution()

Details

This method is designed used in portfolios and importance functions.

Returns

Invisible TRUE.

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Method solve()

Solve an optimization problem.

Usage

Solver$solve(x, ...)

Arguments

x

optimization_problem() object.

...

Additional arguments passed to the calculate() method.

Returns

Invisible TRUE.

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Method clone()

The objects of this class are cloneable with this method.

Usage

Solver$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.