How to change CPLEX parameters from within CPLEX Studio IDE 22.1.1

Question

I coded my mathematical program in CPLEX Studio IDE 22.1.1 However due to the difficulty of the problem the run takes days and then shows an out of memory error. I read that I can try to use "node storage file" to ask CPLEX to store the nodes in files. However, I am not sure how to do it in CPLEX Studio IDE 22.1.1

Answer 1

I tried using this option in the CPLEX studio OPL-CPLEX 20.1.0. I am not aware of if, it changes in the latest version. To that you need to change directory for working files to an appropriate location on your machine. (e.g. C:\Users\omidi.a\opl_studio\...). Then limit the memory available for working storage to your desired amount. Then in the MIP -> strategy -> node storage file switch change the option to either 3 or 4. By that, a temporary file is written in your disc to store the $\text{B&B}$ tree on the disc and also the log file is something like this:

MIP Presolve modified 6 coefficients.
Reduced MIP has 54 rows, 520 columns, and 1032 nonzeros.
Reduced MIP has 520 binaries, 0 generals, 0 SOSs, and 0 indicators.
Presolve time = 0.02 sec. (1.84 ticks)
Represolve time = 0.38 sec. (6.42 ticks)
Began writing nodes to disk (directory C:\Users\omidi.a\opl_studio\BPP/cpxa08056 created)
  18129  6664       17.0000    27       18.0000       16.9000    55547    6.11%
  38032 18068       16.9500    23       18.0000       16.9000   130120    6.11%
  56190 30507       17.0000    28       18.0000       16.9000   222665    6.11%
* 59945 32517      integral     0       17.0000       16.9000   240820    0.59%

Root node processing (before b&c):
  Real time             =    0.03 sec. (23.70 ticks)

I hope it helps.