Class LinearOptimizationSolution

    • A LinearOptimizationSolution represents the solution of a linear program.

    • The solution provides methods to get the objective value, the value of specific variables, the status of the solution, and to check its validity.

    • An example demonstrates how to define variables, constraints, and an objective function, solve the linear program, and then retrieve the solution details using the provided methods.
    Linear Optimization Solution

    The solution of a linear program. The example below solves the following linear program:

    Two variables, x and y :
    0 ≤ x ≤ 10
    0 ≤ y ≤ 5

    Constraints:
    0 ≤ 2 * x + 5 * y ≤ 10
    0 ≤ 10 * x + 3 * y ≤ 20

    Objective:
    Maximize x + y 

     const 
  
 engine 
  
 = 
  
 LinearOptimizationService 
 . 
 createEngine 
 (); 
 // Add variables, constraints and define the objective with addVariable(), 
 // addConstraint(), etc. Add two variables, 0 <= x <= 10 and 0 <= y <= 5 
 engine 
 . 
 addVariable 
 ( 
 'x' 
 , 
  
 0 
 , 
  
 10 
 ); 
 engine 
 . 
 addVariable 
 ( 
 'y' 
 , 
  
 0 
 , 
  
 5 
 ); 
 // Create the constraint: 0 <= 2 * x + 5 * y <= 10 
 let 
  
 constraint 
  
 = 
  
 engine 
 . 
 addConstraint 
 ( 
 0 
 , 
  
 10 
 ); 
 constraint 
 . 
 setCoefficient 
 ( 
 'x' 
 , 
  
 2 
 ); 
 constraint 
 . 
 setCoefficient 
 ( 
 'y' 
 , 
  
 5 
 ); 
 // Create the constraint: 0 <= 10 * x + 3 * y <= 20 
 constraint 
  
 = 
  
 engine 
 . 
 addConstraint 
 ( 
 0 
 , 
  
 20 
 ); 
 constraint 
 . 
 setCoefficient 
 ( 
 'x' 
 , 
  
 10 
 ); 
 constraint 
 . 
 setCoefficient 
 ( 
 'y' 
 , 
  
 3 
 ); 
 // Set the objective to be x + y 
 engine 
 . 
 setObjectiveCoefficient 
 ( 
 'x' 
 , 
  
 1 
 ); 
 engine 
 . 
 setObjectiveCoefficient 
 ( 
 'y' 
 , 
  
 1 
 ); 
 // Engine should maximize the objective 
 engine 
 . 
 setMaximization 
 (); 
 // Solve the linear program 
 const 
  
 solution 
  
 = 
  
 engine 
 . 
 solve 
 (); 
 if 
  
 ( 
 ! 
 solution 
 . 
 isValid 
 ()) 
  
 { 
  
 Logger 
 . 
 log 
 ( 
 `No solution 
 ${ 
 solution 
 . 
 getStatus 
 () 
 } 
 ` 
 ); 
 } 
  
 else 
  
 { 
  
 Logger 
 . 
 log 
 ( 
 `Objective  value: 
 ${ 
 solution 
 . 
 getObjectiveValue 
 () 
 } 
 ` 
 ); 
  
 Logger 
 . 
 log 
 ( 
 `Value of x: 
 ${ 
 solution 
 . 
 getVariableValue 
 ( 
 'x' 
 ) 
 } 
 ` 
 ); 
  
 Logger 
 . 
 log 
 ( 
 `Value of y: 
 ${ 
 solution 
 . 
 getVariableValue 
 ( 
 'y' 
 ) 
 } 
 ` 
 ); 
 }

    Methods

    Method Return type Brief description
    get Objective Value()
    		Number Gets the value of the objective function in the current solution.
    get Status()
    		Status Gets the status of the solution.
    get Variable Value(variableName)
    		Number Gets the value of a variable in the solution created by the last call to Linear Optimization Engine.solve() .
    is Valid()
    		Boolean Determines whether the solution is either feasible or optimal.

    Detailed documentation

    get Objective Value()

    Gets the value of the objective function in the current solution.

     const 
  
 engine 
  
 = 
  
 LinearOptimizationService 
 . 
 createEngine 
 (); 
 // Add variables, constraints and define the objective with addVariable(), 
 // addConstraint(), etc 
 engine 
 . 
 addVariable 
 ( 
 'x' 
 , 
  
 0 
 , 
  
 10 
 ); 
 // ... 
 // Solve the linear program 
 const 
  
 solution 
  
 = 
  
 engine 
 . 
 solve 
 (); 
 Logger 
 . 
 log 
 ( 
 `ObjectiveValue: 
 ${ 
 solution 
 . 
 getObjectiveValue 
 () 
 } 
 ` 
 );

    Return

    Number — the value of the objective function

    get Status()

    Gets the status of the solution. Before solving a problem, the status will be NOT_SOLVED .

     const 
  
 engine 
  
 = 
  
 LinearOptimizationService 
 . 
 createEngine 
 (); 
 // Add variables, constraints and define the objective with addVariable(), 
 // addConstraint(), etc 
 engine 
 . 
 addVariable 
 ( 
 'x' 
 , 
  
 0 
 , 
  
 10 
 ); 
 // ... 
 // Solve the linear program 
 const 
  
 solution 
  
 = 
  
 engine 
 . 
 solve 
 (); 
 const 
  
 status 
  
 = 
  
 solution 
 . 
 getStatus 
 (); 
 if 
  
 ( 
 status 
  
 !== 
  
 LinearOptimizationService 
 . 
 Status 
 . 
 FEASIBLE 
  
&&  
 status 
  
 !== 
  
 LinearOptimizationService 
 . 
 Status 
 . 
 OPTIMAL 
 ) 
  
 { 
  
 throw 
  
 `No solution 
 ${ 
 status 
 } 
 ` 
 ; 
 } 
 Logger 
 . 
 log 
 ( 
 `Status: 
 ${ 
 status 
 } 
 ` 
 );

    Return

    Status — the status of the solver

    get Variable Value(variableName)

    Gets the value of a variable in the solution created by the last call to Linear Optimization Engine.solve() .

     const 
  
 engine 
  
 = 
  
 LinearOptimizationService 
 . 
 createEngine 
 (); 
 // Add variables, constraints and define the objective with addVariable(), 
 // addConstraint(), etc 
 engine 
 . 
 addVariable 
 ( 
 'x' 
 , 
  
 0 
 , 
  
 10 
 ); 
 // ... 
 // Solve the linear program 
 const 
  
 solution 
  
 = 
  
 engine 
 . 
 solve 
 (); 
 Logger 
 . 
 log 
 ( 
 `Value of x: 
 ${ 
 solution 
 . 
 getVariableValue 
 ( 
 'x' 
 ) 
 } 
 ` 
 );

    Parameters

    Name Type Description
    variable Name
    		String name of the variable

    Return

    Number — the value of the variable in the solution

    is Valid()

    Determines whether the solution is either feasible or optimal.

     const 
  
 engine 
  
 = 
  
 LinearOptimizationService 
 . 
 createEngine 
 (); 
 // Add variables, constraints and define the objective with addVariable(), 
 // addConstraint(), etc 
 engine 
 . 
 addVariable 
 ( 
 'x' 
 , 
  
 0 
 , 
  
 10 
 ); 
 // ... 
 // Solve the linear program 
 const 
  
 solution 
  
 = 
  
 engine 
 . 
 solve 
 (); 
 if 
  
 ( 
 ! 
 solution 
 . 
 isValid 
 ()) 
  
 { 
  
 throw 
  
 `No solution 
 ${ 
 solution 
 . 
 getStatus 
 () 
 } 
 ` 
 ; 
 }

    Return

    Boolean — true if the solution is valid ( Status.FEASIBLE or Status.OPTIMAL ); false if not
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