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gams:i_know_a_better_solution [2020/05/18 14:52]
Michael Bussieck
gams:i_know_a_better_solution [2020/05/18 14:58] (current)
Michael Bussieck
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   - For models with discrete variables or global solvers in general, make sure you have set ''​option optCR=0;'' ​ so the solver looks indeed for the global solution.   - For models with discrete variables or global solvers in general, make sure you have set ''​option optCR=0;'' ​ so the solver looks indeed for the global solution.
   - If you solve with a //local// solver this situation is a possibility for non-convex models. Select a global solver or use a better starting point to overcome this.   - If you solve with a //local// solver this situation is a possibility for non-convex models. Select a global solver or use a better starting point to overcome this.
-  - Your better //​solution//​ is not a solution. You can have the solver or GAMS check your conjecture by either fixing the variables to the proposed solution (e.g. ''​x.FX(i,​j) = ...;''​) or set the variable level (e.g. ''​x.L(i,​j) = ...;''​). In the former case the solver either accepts your //​solution//​ or reports infeasible. In the latter case, the equation listing (see [[https://​www.gams.com/​latest/​docs/​UG_GAMSOutput.html#​UG_GAMSOutput_TheEquationListing]]) lists some ''​INFES''​ markers. Make sure to use set limRow ([[https://​www.gams.com/​latest/​docs/​UG_GamsCall.html#​GAMSAOlimrow]]to see all equations and tolInfRep ([[https://​www.gams.com/​latest/​docs/​UG_GamsCall.html#​GAMSAOtolinfrep]]to filter the small infeasibilities.+  - Your better //​solution//​ is not a solution. You can have the solver or GAMS check your conjecture by either fixing the variables to the proposed solution (e.g. ''​x.FX(i,​j) = ...;''​) or set the variable level (e.g. ''​x.L(i,​j) = ...;''​). In the former case the solver either accepts your //​solution//​ or reports infeasible. In the latter case, the [[https://​www.gams.com/​latest/​docs/​UG_GAMSOutput.html#​UG_GAMSOutput_TheEquationListing|equation listing]] has some ''​INFES''​ markers. Make sure to use set [[https://​www.gams.com/​latest/​docs/​UG_GamsCall.html#​GAMSAOlimrow|limRow]] to see all equations and [[https://​www.gams.com/​latest/​docs/​UG_GamsCall.html#​GAMSAOtolinfrep|tolInfRep]] to filter the small infeasibilities.
  
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IMPRESSUM / LEGAL NOTICEPRIVACY POLICY gams/i_know_a_better_solution.txt ยท Last modified: 2020/05/18 14:58 by Michael Bussieck