bbeyza
1
Hello all,

I have diffuculties to code the equation in the image attached, I will appreciate if someone can help me.

My sets are:

I set of nodes

K set of all transportation modes

T set of time units

Alias (i, j, h)

Alias (k, m)

Parameter

𝛕ijk travel time(hour) from node i to node j with mode k

y and Iy are decision variables.

I don’t understand which variable you are referring to but you can add multiple indices to a variable

In your case

```
variable
y(i, i, k, t)
Iy(i, k, t)
;
```

should work since you have defined alias.

While defining summation, you have to index equation with i and the summation operator with some alias. For example,

```
constraint(i).. sum(h,...)
```