GAMS World Forum

Hi Michael, Thanks a lot for your answer. Can I use the .savepoint facility inside a loop as well? Also, in case my original question was confusing: Before i decided to use nested loop solves, i manually set a value of my scalar "d" and pressed run (for example: d /0/, press run, then d /1...

Hello. I have a discrete time problem for which I have some hourly variables and some daily variables that depend on dynamic sets which change in every iteration, depending on two sets: k and r. I made a code that has the following structure: sets i days /1*100/ t hours /1*1000/ ii(i) dynamic set of...

Hi Petros, Happy to read that you solved your problem. However, to avoid confusion, I would like to mention that that the mipstart option has little to do with your initial problem. You wrote that Cplex returns infeasible for your model. Instructing Cplex to use a starting point (which is what you ...

The answer to my problem:

In order for the solver to use initial solution, a solver options file must be created to set mipstart to 1.

Hi nikou,

Now I see, but I think that you could get the result you want if you just replace AND with OR.

Best,
Petros

Hi, What is your error exactly? From a first look I would say that ther should be a problem with your variables c(ii,a,t+(ord(a)-1)) and l(ii,a,t+(ord(a)-1)) beause they are defined in the sets (ii,a,t). So for example when t reaches its last element, the variable c(ii,a,t+(ord(a)-1)) should not exi...

Hi,

try this: Best,
Petros

Hi, The way you should declare the set and parameter is: set i /i1*i100/; parameters x(i) /i99 1000, i100 1200/; But you can't have the same name for two different elements! If you want to have fixed values for the last two xariables you must use the following instead of the parameter: x.fx('i99') =...

Hi, Your problem is a mixed integer non linear program (MINLP). I used Baron to solve it and I think it is free for for a limited number of variables. Run the code below and tell me if it works: $TITLE Test Problem $OFFSYMXREF $OFFSYMLIST integer VARIABLES X1, X2 ; variable Z; EQUATIONS CON1, CON2, ...

Hi everyone, I am trying to do an iterative solution process using the loop statement for a MILP. In each loop I solve my model for a subset of 24 hours and a subset of 15 days, which I declare this way: sets run Solve iterations /run1*run5/ t Time set /t1*t2437/ d Days set /d1*d100/ hour(t) Dynamic...