如何使用 R 中的 TSP 包指定起始城市 [英] How to specify a starting city using the TSP package in R
问题描述
我一直在尝试使用 R 中的 TSP 包来解决 TSP 问题.我创建了一个大型对称距离矩阵,其中沿前导对角线有 0 个条目.我希望能够将第一个城市指定为 nearest_insertion
等方法的起始城市.我已成功使用 "nn"
方法并使用以下代码指定了起始城市:
I have been trying to solve a TSP problem using the TSP package in R. I have created a large symmetric distance matrix with 0 entries along the leading diagonal. I want to be able to specify the first city as the starting city for methods such as nearest_insertion
. I have successfully used the "nn"
method and specified the starting city using the code below:
tsp1=TSP(distance_matrix)
solve_TSP(tsp1,method="nn",control=list(start=1))
但是参数 control=list(start=1))
不适用于 "nearest_insertion"
方法.相反,我收到错误消息:
However the argument control=list(start=1))
doesn't work for the "nearest_insertion"
method. Instead I get the error message:
x[is.na(x)] <- Inf 中的错误:INTEGER() 只能应用于整数",不能应用于双精度"
Error in x[is.na(x)] <- Inf : INTEGER() can only be applied to a 'integer', not a 'double`
对于样本数据,我一直在使用以下距离矩阵:
For sample data I have been using the following distance matrix:
distance_matrix=matrix(c(0,1,2,1,0,5,2,5,0),3,3)
如何将第一个城市指定为 "nearest_insertion"
方法的起始城市?
How can I specify the first city as the starting city for the "nearest_insertion"
method?
推荐答案
我知道有点晚了,但我遇到了同样的问题,这就是你需要做的:
I know it's a bit late but I had the same problem, and that's how you need to do:
solve_TSP(prova, method = "nearest_insertion", start=3L)
这将 3 声明为整数,与 as.integer(3)
相同,但避免了函数调用.
This declares 3 as an integer, same as as.integer(3)
, yet avoiding the function call.
这也适用于其他方法.
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