Question

如何用lingo求和 XiXj i=1....7 j=1...15

例如 求XiXj i=1....7 j=1...15

Answer 1

需要用集操作函数
sets:
row/1..7/;
col/1..15/;
link(row,col):x;
endsets
data:
!数据;
enddata
S=@sum(link:x);