Originally posted by: fel85
Dear friends,
I would like to find the edge of test instance size where Cplex can not find a solution in reasonable time for my „simultaneously scheduling projects and assigning multi skilled workforce“ MIP-problem.
For small instances Cplex can find a feasible solution within minutes/hours but for large instances I got an error that Cplex runs out of memory in the presolve state:
Presolve time = 0.94 sec.
Insufficient memory for presolve.
For example for 50 projects Cplex runs fine with 51 projects Cplex does not start the branch and cut and I get the error code mentioned above.
I found an article on the Cplex-help-side that you should provide for each million of variables / constraints one gigabyte of memory. is that the solution of my problem ?
(3,4GB memory / 12.000 constraints / 1.000.000 variables)
I have the same problem for the LP version of the model!
I did all the things Cplex suggests for the „running out of memory“-error.
->memory reduction switch --> on
->External file
etc.
but I think those things only help while performing the B&C status but I do not get beyond the presolve step.
Am I right with my assumption?
Thank you for the help in advance
#DecisionOptimization#OPLusingCPLEXOptimizer