Class LinearOptimizationSolution

线性优化解决方案

线性规划的解。以下示例会解题以下线性规划：

两个变量 x 和 y：
0 ≤ x ≤ 10
0 ≤ y ≤ 5

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

目标：
尽可能提高 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')}`);
}

方法

方法返回类型简介
getObjectiveValue()Number获取当前解中的目标函数值。
getStatus()Status获取解决方案的状态。
getVariableValue(variableName)Number获取上次调用 LinearOptimizationEngine.solve() 时创建的解中的变量值。
isValid()Boolean确定解决方案是否可行或是否是最佳解决方案。

详细文档

getObjectiveValue()

获取当前解中的目标函数值。 

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()}`);

返回

Number - 目标函数的值

getStatus()

获取解决方案的状态。在解决问题之前，状态将为 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}`);

返回

Status - 求解器的状态

getVariableValue(variableName)

获取上次调用 LinearOptimizationEngine.solve() 时创建的解中的变量值。 

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')}`);

参数

名称类型说明
variableNameString变量的名称

返回

Number - 解中的变量值

isValid()

确定解决方案是否可行或是否最优。 

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()}`;
}

返回

Boolean - 如果解决方案有效（Status.FEASIBLE 或 Status.OPTIMAL），则为 true；如果无效，则为 false