ojAlgo解决LP问题
ojAlgo 是一个开源的 Java 类库，用于解决一些常用的数学问题以及线性代数和最优化问题，所以也可以用来解决LP问题
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| <dependency>
<groupId>org.ojalgo</groupId>
<artifactId>ojalgo</artifactId>
<version>51.4.1</version>
</dependency>
|
求解 5x1 + 6x2 + 23x3 + 5x4 + 24x5 + 6x6 + 23x7 + 5x8的最小值
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| ExpressionsBasedModel model = new ExpressionsBasedModel();
model.addVariable(Variable.makeInteger("x"+1).lower(0).weight(5));
model.addVariable(Variable.makeInteger("x"+2).lower(0).weight(6));
model.addVariable(Variable.makeInteger("x"+3).lower(0).weight(23));
model.addVariable(Variable.makeInteger("x"+4).lower(0).weight(5));
model.addVariable(Variable.makeInteger("x"+5).lower(0).weight(24));
model.addVariable(Variable.makeInteger("x"+6).lower(0).weight(6));
model.addVariable(Variable.makeInteger("x"+7).lower(0).weight(23));
model.addVariable(Variable.makeInteger("x"+8).lower(0).weight(5));
Expression expression = model.addExpression("e" + 1);
expression.set(0,2);
expression.set(1,1);
expression.set(2,1);
expression.set(3,1);
expression.lower(100);
Expression expression2 = model.addExpression("e" + 2);
expression2.set(1,2);
expression2.set(2,1);
expression2.set(4,3);
expression2.set(5,2);
expression2.set(6,1);
expression2.lower(150);
Expression expression3 = model.addExpression("e" + 3);
expression3.set(0,1);
expression3.set(2,1);
expression3.set(3,3);
expression3.set(5,2);
expression3.set(6,3);
expression3.set(7,5);
expression3.lower(100);
Optimisation.Result minimise = model.minimise();
System.out.println(minimise);
|
结果为
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| 30.0, 40.0, 0.0, 0.0, 0.0, 35.0, 0.0, 0.0, 1.0
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使用起来比JOptimizer感觉好多了，至少可读性强