I have a question regarding the solving process of GAMS. I have an MILP-Model and I am using the CPLEX-Solver. I run a Loop in GAMS to solve for different model variations. The model runs and produces optimal results but the run-time is very long.

In the log-file I can see the following:

*Fixed MIP status(1): optimal*

Cplex Time: 7.47sec (det. 2575.80 ticks)

Proven optimal solution.

MIP Solution: -370160.220173 (3161 iterations, 0 nodes)

Final Solve: -370160.220173 (4350 iterations)

Best possible: -370160.220173

Absolute gap: 0.000000

Relative gap: 0.000000

--- Restarting execution

--- SpeicherOptMFH.gms(842) 555 Mb

Cplex Time: 7.47sec (det. 2575.80 ticks)

Proven optimal solution.

MIP Solution: -370160.220173 (3161 iterations, 0 nodes)

Final Solve: -370160.220173 (4350 iterations)

Best possible: -370160.220173

Absolute gap: 0.000000

Relative gap: 0.000000

--- Restarting execution

--- SpeicherOptMFH.gms(842) 555 Mb

**--- Reading solution for model Modell_SBSopt**

--- SpeicherOptMFH.gms(764) 762 Mb 2220 secs--- SpeicherOptMFH.gms(764) 762 Mb 2220 secs

You can see, Cplex finds the optimal solution after around 7 sec. But, "reading solution" takes around 40 minutes...

I wanna know, what happens at "reading solutions" and is there a way to shorten the computation time. Additionally for my results, I don't need to know all the variables, just a small selection.

Maybe there is someone who could help me?

Thank you very much.

Cheers,

Fritz