Hi Michael,

I am copying some relevant bits from the log files from the old computer and new computer. The beginning and end of the first and second solves for both computers.

The subsequent solves follow the same pattern. Thanks again for your help.

**OLD computer 1st solve in loop (cutting out the middle):**

IBM ILOG CPLEX 25.1.2 r67455 Released Aug 1, 2018 WEI x86 64bit/MS Windows

— GAMS/Cplex licensed for continuous and discrete problems.

Cplex 12.8.0.0

Reading parameter(s) from “C:\MOCCE\cplex.opt”

IIS 1

Finished reading from “C:\MOCCE\cplex.opt”

Reading data…

Starting Cplex…

Unable to load names.

CPXPARAM_Advance 0

CPXPARAM_Simplex_Limits_Iterations 2000000000

CPXPARAM_TimeLimit 1000

CPXPARAM_Threads 1

CPXPARAM_Parallel 1

CPXPARAM_Tune_TimeLimit 200

Tried aggregator 1 time.

LP Presolve eliminated 9689565 rows and 8715669 columns.

Aggregator did 410105 substitutions.

Reduced LP has 53291 rows, 84518 columns, and 498694 nonzeros.

Presolve time = 2.89 sec. (4478.86 ticks)

Initializing dual steep norms . . .

Iteration log . . .

Iteration: 1 Dual objective = 8299.227883

…

Iteration: 95814 Dual objective = 117818.385780

Removing perturbation.

Iteration: 95821 Scaled dual infeas = 7.946542

Iteration: 95881 Dual objective = -64619551.040973

LP status(1): optimal

Cplex Time: 48.52sec (det. 59628.70 ticks)

Optimal solution found.

Objective : 117603.493128

**NEW computer 1st solve in loop:**

IBM ILOG CPLEX 38.2.1 96226ea8 Feb 19, 2022 WEI x86 64bit/MS Window

— GAMS/Cplex Link licensed for continuous and discrete problems.

Reading parameter(s) from “C:\Model\cplex.opt”

IIS 1

Finished reading from “C:\Model\cplex.opt”

— GMO setup time: 0.00s

— GMO memory 3339.85 Mb (peak 3410.12 Mb)

— Cplex 20.1.0.1 link memory 291.86 Mb (peak 758.98 Mb)

— Starting Cplex

Version identifier: 20.1.0.1 | 2021-04-07 | 3a818710c

CPXPARAM_Advance 0

CPXPARAM_Threads 1

CPXPARAM_MIP_Display 4

CPXPARAM_MIP_Pool_Capacity 0

CPXPARAM_MIP_Tolerances_AbsMIPGap 0

Tried aggregator 1 time.

LP Presolve eliminated 9689564 rows and 8715669 columns.

Aggregator did 410105 substitutions.

Reduced LP has 53291 rows, 84518 columns, and 498694 nonzeros.

Presolve time = 3.49 sec. (5285.24 ticks)

Initializing dual steep norms . . .

Iteration log . . .

Iteration: 1 Dual objective = 8299.227883

…

Iteration: 95042 Dual objective = 117603.429724

— LP status (1): optimal.

— Cplex Time: 38.97sec (det. 54641.97 ticks)

Optimal solution found

Objective: 117603.493129

**The SECOND solve old computer:**

IBM ILOG CPLEX 25.1.2 r67455 Released Aug 1, 2018 WEI x86 64bit/MS Windows

— GAMS/Cplex licensed for continuous and discrete problems.

Cplex 12.8.0.0

Reading parameter(s) from “C:\MOCCE\cplex.opt”

IIS 1

Finished reading from “C:\MOCCE\cplex.opt”

Reading data…

Starting Cplex…

Space for names approximately 1360.28 Mb

Use option ‘names no’ to turn use of names off

CPXPARAM_Advance 2

CPXPARAM_Simplex_Limits_Iterations 2000000000

CPXPARAM_TimeLimit 1000

CPXPARAM_Threads 1

CPXPARAM_Parallel 1

CPXPARAM_Tune_TimeLimit 200

Tried aggregator 1 time.

LP Presolve eliminated 9689565 rows and 8715669 columns.

Aggregator did 410105 substitutions.

Reduced LP has 53291 rows, 84518 columns, and 498694 nonzeros.

Presolve time = 3.78 sec. (6568.62 ticks)

Using devex.

Iteration log . . .

Iteration: 1 Objective = 117755.946229

…

Iteration: 21957 Dual objective = 117752.285050

LP status(1): optimal

Cplex Time: 17.50sec (det. 28022.96 ticks)

Optimal solution found.

Objective : 117752.285050

**The SECOND solve for the new computer:**

Reading parameter(s) from “C:\Model\cplex.opt”

IIS 1

Finished reading from “C:\Model\cplex.opt”

— GMO setup time: 0.00s

— Space for names approximately 1360.28 Mb

— Use option ‘names no’ to turn use of names off

— GMO memory 3339.85 Mb (peak 3410.12 Mb)

— Dictionary memory 0.00 Mb

— Cplex 20.1.0.1 link memory 291.86 Mb (peak 2119.26 Mb)

— Starting Cplex

Version identifier: 20.1.0.1 | 2021-04-07 | 3a818710c

CPXPARAM_Advance 2

CPXPARAM_Threads 1

CPXPARAM_MIP_Display 4

CPXPARAM_MIP_Pool_Capacity 0

CPXPARAM_MIP_Tolerances_AbsMIPGap 0

Tried aggregator 1 time.

LP Presolve eliminated 9689564 rows and 8715669 columns.

Aggregator did 410105 substitutions.

Reduced LP has 53291 rows, 84518 columns, and 498694 nonzeros.

Presolve time = 4.16 sec. (7765.74 ticks)

Elapsed time = 5.69 sec. (10381.64 ticks, 1 iterations)

Iteration log . . .

Iteration: 1 Dual objective = 8299.227883

…

Iteration: 107246 Dual objective = 117751.918731

— LP status (1): optimal.

— Cplex Time: 69.36sec (det. 113107.47 ticks)

Optimal solution found

Objective: 117752.285051