Question

Setting initial point (solution) for CONOPT solver

  • 5 August 2020
  • 4 replies
  • 228 views

Hello,

I am solving a nonlinear problem in AIMMS using CONOPT solver and I need to set the initial solution. I have read the AIMMS language reference and also surf the internet for solving this issue. But according to  AIMMS website only CPLEX, GUROBI and CBC support solving with an initial solution. Could you please tell if there is any way to set the initial solution for CONOPT or any other “nonlinear” solver?


4 replies

Userlevel 3

Hi @HosseinMehdipour. For CONOPT and other nonlinear solvers it suffices to assign the initial solution to the variables in AIMMS. The solution will then automatically be used as a starting solution by the solver.

(For Knitro you have to make sure that the Knitro option 'Use Initial Solution’ is switched on, which it is by default.)

@HosseinMehdipour 

Was Marcel’s answer able to help you with your problem?

 

Thank you @Marcel Hunting for your response. I tried that. But I could not assign the initial solution to the variable! Could you please tell me how to do that?

@Andrew I tried an another way, I defined a parameter that represents the initial solution of the specific variable and assign this parameter to the variable just before the solve command in the Mainexecution page. @Marcel Hunting could you please tell me if this way of assigning initial solution is correct?

Thank you

Regards

Userlevel 3

If X(i) is a variable then you can use

   X(i) := 10;

or

   X(i) := P(i);

where P is a parameter. You should use such a statement before the solve statement.

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