GAMS World Forum

Hi everyone, I have a put command that calculates the gap between the current objective value and the best integer solution, at a certain time. The code as follow; (MODEL21.objval-MODEL21.objest)*100/(MODEL21.objval) If GAMS can't find an initial solution in the time limit of 900 seconds, the "...

Hi Michael,

Thanks for your answer, I totally understood. Very helpful.

Hi everyone, I try to solve the minimization of a stochastic MIP problem. I added some lower bounds for various variables (these shortened my solution times). However, when I add lower and upper bounds to my objective variable (z), CPLEX cannot find an initial solution and cannot solve the problem. ...

Dear Renger,
Thank you very much. It is working perfectly.

Dear Renger, Thank you for your answer. It absolutely works but, it may not generate all possible weight pairs, am I right? Or some weight pairs can repeat? This may cause missing some Pareto optimal solutions. Is there a way of producing all possible weights as increasing way such as: w1 w2 w3 0.1 ...

Hi everyone,
I can run my model with different weight sets for 2 objectives as follows;

set u /1*11/;

loop(u,
w1=1-(ord(u)-1)*0.1;
w2=1-w1;

However, when it comes to 3 objective, I was stuck. Could you help me about this issue? (For intervals of 0.1 similarly above statement)

Thank you very much Atharv,
I figure it out thanks to you.

Hi abhosekar, first of all thank you. I did not share all part of code but precisely I am trying to achieve making a separation between all type of aircraft, i.e. if leading aircraft is medium and trailing aircraft is heavy separation must be 60 sec. or i.e. if leading aircraft is heavy and trailing...

Dear all, I have a problem about subset usage in constraints, my set and subsets are following; sets i aircraft /1*16/ heavy(i) /2,6,10,14/; set medium (i); medium (i)= NOT heavy (i); alias (i,p); I created a separation parameter like; parameter SEP(i,p); SEP(medium,medium)=70; SEP(medium,heavy)=60;...