# Gurobi stuck at start - 16GB RAM exhausted

I'm solving a large instance using Gurobi 7.0, 64-bit version on machine with 16GB of RAM. Gurobi is stuck at the start and all the memory is exhausted. Here is the output:

5378534 variables, all binary
16140318 constraints, all linear; 319218593 nonzeros
77 equality constraints
16140241 inequality constraints
1 linear objective; 4842072 nonzeros.

#presolve       75.2705         1006633000      20529205440
#output         200.524         268435464       20797640904
Gurobi 7.0.0: timelim=3600
nodefilestart=0.5
outlev 1
Optimize a model with 16140318 rows, 5378534 columns and 319218593 nonzeros
Variable types: 0 continuous, 5378534 integer (5378534 binary)
Coefficient statistics:
Matrix range     [1e+00, 1e+03]
Objective range  [1e+00, 4e+03]
Bounds range     [1e+00, 1e+00]
RHS range        [1e+00, 7e+04]
Found heuristic solution: objective -0


I was expecting out of memory error, but Gurobi is just stuck for hours, and CPU usage is 0.

Is this normal behavior for this instance size? Why am I not getting any errors?

• And what is the question? Jan 19 '20 at 17:41
• Thank you for the comment, I added the questions at the end. Jan 19 '20 at 17:47
• Thanks for the information. I guess the question could be suited for support.gurobi.com/hc/en-us Jan 19 '20 at 20:56
• this is a huge model, it "just" takes some time to solve the root node LP... (my guess) Jan 20 '20 at 8:30