values of parameters dependant on decision variable
AnsweredHello,
I have a simple problem i wish to solve, where i want to minimize a product of two parameters.
One of the parameters is dependant on the decision variable and the other's indices are dependant open the decision variable. My code below might clarify this better:

It is not directly possible to use a variable as an index of an expression or another variable. However, it is possible to formulate it in such a way as is discussed in the post use a decision variable as an index.
In general if possible, I would try to avoid using optimization variables as indices. In your case, what exactly are you trying to achieve by accessing \(\texttt{D[i,j] for i in B}\)? Do you want to actually use the values of the binary variables to access either \(\texttt{D[0,j]}\) or \(\texttt{D[1,j]}\)? You can achieve this by formulating
\[\begin{align*}
D_{0} \cdot (1B) + D_{1} \cdot B
\end{align*}\]with the appropriate indices for \(B\).
Best regards,
Jaromił0 
Thank you for the answear Jaromil,
D is not binary, but a distance matrix.
I found the post yesterday you referred to and after some pondering got around to using a dummy variable
\begin{align*} b \in R^{n x i} \\
B_n = \sum_{i = 1}^{\I} n*b_{n,i} \forall n \in N
\end{align*}
Then I set the objective function as:
\begin{align*}
\sum_{i,j,n}^{} D_{i,j}R{j,n}b{n,i}0
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