Originally posted by: Pradeeppsmarty

I am trying to develop a mathematical model when i encountered the following error. "cannot use type dvar boolean for user function.

I have attached the data, model and excel file. Please help me rectify this problem.

Hi,

you got that error because you forgot some "*" for multiply.

forall(p in P, c in C)
      cons01:   // route contraints for slecting the routes to delivery the products ordered by the customer
      sum(s in S)X1[p][c][s]*((sum(r in R)X2[p][c][r]*(sum (d in D)X4[p][c][d]*(1-sum(b in B)X3[p][c][b]))
       +sum(b in B)X3[p][c][b]*((1-sum(d in D)X4[p][c][d])+sum(d in D)X4[p][c][d])+sum(b in B)X3[p][c][b]*(1-sum(r in R)X2[p][c][r])*((1-sum(d in D)X4[p][c][d])
       +sum(d in D)X4[p][c][d])))==1;

will work better

regards