Originally posted by: C.Schmidt
Dear forum,
I have developed a model for a customer and now need to give the hardware recommendation for the solver machine. The solver ran on win 7 64 Bit with a core i7 (quadcore with hyperthreading - 8 virtual cores) and 16 GB RAM. Please find below the log of an example run. The model was solved within 26 hours. During the run I observed that there were long periods with only 1-2 cores used (so Intel's Turbo boost should have helped) and some time with all 8 cores used. Reserved and private memory was around 16 GB.
Will the solver significantly benefit from a dual core i7 system? Will it help adding more RAM?
What is your experience/recommendation?
BTW I'll post questions on how to improve the solution speed by modifying the model or solver settings in a different thread.
Thanks for any advice,
Christian
Log:
Welcome to IBM(R) ILOG(R) CPLEX(R) Interactive Optimizer 12.2.0.0
with Simplex, Mixed Integer & Barrier Optimizers
5725-A06 5725-A29 5724-Y48 5724-Y49 5724-Y54 5724-Y55
Copyright IBM Corp. 1988, 2010. All Rights Reserved.
Type 'help' for a list of available commands.
Type 'help' followed by a command name for more
information on commands.
CPLEX> Problem 'C:\Users\appserv\AppData\Local\Temp\Schedule.lp' read.
Read time = 2.11 sec.
CPLEX> Tried aggregator 2 times.
MIP Presolve eliminated 33670 rows and 401085 columns.
MIP Presolve modified 3219 coefficients.
Aggregator did 1083 substitutions.
Reduced MIP has 26910 rows, 251615 columns, and 642617 nonzeros.
Reduced MIP has 16175 binaries, 0 generals, 0 SOSs, and 0 indicators.
Presolve time = 2.92 sec.
Found feasible solution after 3.15 sec. Objective = 1793363.6000
Probing time = 0.31 sec.
Clique table members: 415.
MIP emphasis: balance optimality and feasibility.
MIP search method: dynamic search.
Parallel mode: deterministic, using up to 8 threads.
Root relaxation solution time = 81.53 sec.
Nodes Cuts/
Node Left Objective IInf Best Integer Best Node ItCnt Gap
-
0+ 0 1793363.6000 158186 ---
-
0+ 0 1793000.0000 158186 ---
0 0 164791.1199 1495 1793000.0000 164791.1199 158186 90.81%
0 0 165465.3241 1756 1793000.0000 Cuts: 2502 421742 90.77%
CPLEX Error 1256: Basis singular.
-
0+ 0 262234.8044 165465.3241 1346430 36.90%
0 0 165598.4213 1614 262234.8044 Cuts: 2970 2328568 36.85%
-
0+ 0 226644.1113 165598.4213 3363961 26.93%
0 0 165809.6578 1732 226644.1113 Cuts: 2906 3363961 26.84%
CPLEX Error 1256: Basis singular.
CPLEX Error 1256: Basis singular.
-
0+ 0 221103.5302 165809.6578 3363961 25.01%
CPLEX Error 1256: Basis singular.
0 0 cutoff 221103.5302 4472392 0.00%
Elapsed real time = 95569.38 sec. (tree size = 0.00 MB, solutions = 5)
GUB cover cuts applied: 134
Clique cuts applied: 2
Cover cuts applied: 5
Implied bound cuts applied: 875
Flow cuts applied: 2128
Zero-half cuts applied: 10
Gomory fractional cuts applied: 20
Root node processing (before b&c):
Real time = 95566.46
Parallel b&c, 8 threads:
Real time = 0.00
Sync time (average) = 0.00
Wait time (average) = 0.00
Total (root+branch&cut) = 95566.46 sec.
Solution pool: 5 solutions saved.
MIP - Integer optimal solution: Objective = 2.2110353018e+005
Solution time = 95569.44 sec. Iterations = 4472392 Nodes = 0
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