23-05-2017, 01:21 PM
Dear Vsaini,
I tested now the same case as previously, but without ramping constraints. The number of equations dropped down to about 205,000. The solve summary is shown below:
______________________________________________________________
S O L V E S U M M A R Y
MODEL TIMES OBJECTIVE OBJz
TYPE LP DIRECTION MINIMIZE
SOLVER CPLEX FROM LINE 47050
**** SOLVER STATUS 1 Normal Completion
**** MODEL STATUS 1 Optimal
**** OBJECTIVE VALUE 674911478.2906
RESOURCE USAGE, LIMIT 18.250 50000.000
ITERATION COUNT, LIMIT 111 550000
______________________________________________________________
As you can see, in this case the solution time decreased from 24.8 secs to 18.3 secs, i.e. about 26%, while the number of iterations increased from 109 to 111. The impact of removing the ramping constraints thus appears to confirm your findings.
I tested now the same case as previously, but without ramping constraints. The number of equations dropped down to about 205,000. The solve summary is shown below:
______________________________________________________________
S O L V E S U M M A R Y
MODEL TIMES OBJECTIVE OBJz
TYPE LP DIRECTION MINIMIZE
SOLVER CPLEX FROM LINE 47050
**** SOLVER STATUS 1 Normal Completion
**** MODEL STATUS 1 Optimal
**** OBJECTIVE VALUE 674911478.2906
RESOURCE USAGE, LIMIT 18.250 50000.000
ITERATION COUNT, LIMIT 111 550000
______________________________________________________________
As you can see, in this case the solution time decreased from 24.8 secs to 18.3 secs, i.e. about 26%, while the number of iterations increased from 109 to 111. The impact of removing the ramping constraints thus appears to confirm your findings.