syntax-error - CPLEX中没有运算符

Question

我在CPLEX中的代码中有一个错误:
运算符不适用于dvar int + [] [time] + dexpr float。

int i=...; //set of origins
int j=...; //set of destinations
int t=...;//set of time


//parameters
float al[origins][destinations][time]=...;//Proportion of all utilized vehicles that are dispatched

//variables
dvar int+ o[origins][destinations][time];//numbers of vehicles present at i at beginning of t
dvar int+ l[origins][destinations][time];//numbers of rented vehicles dispatched from i to  j during t
dvar int+ e[origins][destinations][time];//numbers of unutilized vehicles dispatched from  i to j during t

subject to{
constraint:
    forall(i in origins, t in time:(t-1) in time) 
     o[i][t]== o[i][t-1]+ sum (j in destinations, t in time ) al[i][j][t] * e[j][i][t]-  l[i][j][t-1];
}

我该如何解决这个错误？

Answer 1

您的决策变量o定义为具有3个索引，但是，在约束中，您仅使用两个索引。
另外，我认为

sum (j in destinations, t in time ) al[i][j][t] * e[j][i][t]-  l[i][j][t-1];

应写为(请注意附加括号)

sum (j in destinations, t in time ) (al[i][j][t] * e[j][i][t]-  l[i][j][t-1]);