Question

我是R编程的初学者。我正在尝试在R中进行整数编程。当我使用int.vec时，所有决策变量的输出都为0。谁能帮我了解为什么会这样。以下是我的代码。

library(lpSolve)
f.obj=c(900,900,900,900,1800,1800,1800,1800)
f.con=matrix(c(3,0,0,0,6,0,0,0,                                                                       
    0,3,0,0,0,6,0,0,                                                                       
    0,0,3,0,0,0,6,0,                                                                       
    0,0,0,3,0,0,0,6,                                                                       
    1,0,0,0,0,0,0,0,                                                                       
    0,1,0,0,0,0,0,0,                                                                       
    0,0,1,0,0,0,0,0,                                                                       
    0,0,0,1,0,0,0,0,                                                                       
    0,0,0,0,1,0,0,0,                                                                       
    0,0,0,0,0,1,0,0,                                                                       
    0,0,0,0,0,0,1,0,                                                                       
    0,0,0,0,0,0,0,1,                                                                       
    1/13,1/19,1/24,1/15,0,0,0,0,                                                           
    0,0,0,0,1/13,1/19,1/24,1/15), ncol=8, byrow=TRUE)
f.dir=c("=","=","=","=","<=","<=","<=","<=","<=","<=","<=","<=","<=","<=")
f.rhs=c(2500,500,2500,500,650,1200,800,1200,650,1200,800,1200,100,100)
solution=lp("max",f.obj,f.con,f.dir,f.rhs,int.vec = 1:8)
solution$solution

输出：

#[1] 0 0 0 0 0 0 0 0

Answer 1

我认为您得到的都是零，因为它是唯一的“整数”解决方案。解决方案状态= 2，表示该问题不可行。如果我们不要求前四个变量为整数，则解决方案为非零：

solution=lp(direction = "max",f.obj,f.con,f.dir,f.rhs,int.vec = 5:8)

> solution$solution
[1]   1.3333333   0.6666667   1.3333333   0.6666667 416.0000000  83.0000000
[7] 416.0000000  83.0000000

整数编程的零解

1 个答案: