3 multiple objectives function

[Corazon]

Dear Robert,

I hope you're doing well. I have a question regarding solving multiple objective function. In my model, I have 3 objectives that I've compiled in 1 objective function, which is "Total Cost". But after running it using Gurobi, it turns out that the result only considers 2 objective functions and exclude my fix cost function. 



Do you know why does it happen? Please kindly find my attached file along with this message. Thank you.

Regards,

[AMPL Google Group]

You can't use the name of an objective (like variable_cost) in the AMPL expression for another objective. Instead, use "defined variables" to identify the different kinds of cost, and add them up to represent the total cost objective:

var variable_cost = sum {i in customers, j in customers: i<>j} 
   (teta_1 *(arrival[j] - arrival[i]) + teta_2 * service[i]);
var energy_cost = sum {i in vertices, j in vertices: i<>j} 
   route[i,j] * fuel_cost * (distance[i,j] * (rate_0 + delta * loadVeh[i,j]));
var fixed_cost = sum {j in customers} fix_cost * route[0,j];

minimize total_cost: variable_cost + energy_cost + fixed_cost;

--
Robert Fourer
am...@googlegroups.com

{#HS:2084414520-113051#}

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