A colleague and I both implemented a model we have been working on, him using a java interface to cplex and me using JuMP. After spending some time to reconcile the .lp outputs of the two models I genuinely believe that the constraints imposed by both models are identical yet the solve time in the JuMP interface is painfully slower in comparison to via java. Whereas the java model completes in ~2s, I terminated the julia model after some minutes.

Is there an explanation for this and, more importantly, is there anything I can do to close the gap? Below I attach the cplex initialisation in both models. FWIW the number of binaries is much /higher/ in the java model yet it runs much faster.

Thanks.

##### Java

```
Default row names c1, c2 ... being created.
CPXPARAM_Threads 1
CPXPARAM_Parallel 1
CPXPARAM_TimeLimit 3600
CPXPARAM_WorkMem 4000
CPXPARAM_MIP_Limits_TreeMemory 4000
Tried aggregator 2 times.
MIP Presolve eliminated 12710 rows and 318 columns.
MIP Presolve modified 1317 coefficients.
Aggregator did 1 substitutions.
Reduced MIP has 7191 rows, 782 columns, and 22798 nonzeros.
Reduced MIP has 758 binaries, 0 generals, 0 SOSs, and 0 indicators.
Presolve time = 0.05 sec. (41.23 ticks)
Found incumbent of value 0.000000 after 0.08 sec. (67.89 ticks)
Probing time = 0.01 sec. (8.78 ticks)
Tried aggregator 1 time.
Reduced MIP has 7191 rows, 782 columns, and 22798 nonzeros.
Reduced MIP has 758 binaries, 0 generals, 0 SOSs, and 0 indicators.
Presolve time = 0.02 sec. (14.47 ticks)
Probing time = 0.01 sec. (8.72 ticks)
Clique table members: 11519.
MIP emphasis: balance optimality and feasibility.
MIP search method: dynamic search.
Parallel mode: none, using 1 thread.
```

##### JuMP

```
CPXPARAM_Threads 1
Tried aggregator 2 times.
MIP Presolve eliminated 427 rows and 16 columns.
MIP Presolve modified 376 coefficients.
Aggregator did 2 substitutions.
Reduced MIP has 7178 rows, 782 columns, and 21678 nonzeros.
Reduced MIP has 286 binaries, 24 generals, 0 SOSs, and 0 indicators.
Presolve time = 0.02 sec. (15.84 ticks)
Probing fixed 0 vars, tightened 80 bounds.
Probing time = 0.02 sec. (18.38 ticks)
Tried aggregator 1 time.
MIP Presolve modified 36 coefficients.
Reduced MIP has 7178 rows, 782 columns, and 21670 nonzeros.
Reduced MIP has 288 binaries, 47 generals, 0 SOSs, and 0 indicators.
Presolve time = 0.01 sec. (9.49 ticks)
Probing time = 0.00 sec. (3.85 ticks)
```