GAMS — The Solver Manuals - Available Software

50 COIN-OR
This sets the algorithm to be used to the hybrid algorithm, the level of outer approximation related output to 4,
the MIP subsolver for outer approximation to a parameterized version of CBC, switches off cover cutting planes
for the MIP subsolver, sets the print level for Ipopt to 6, and let Bonmin call a user defined heuristic specified in
the model bchheur.gms with a timelimit of 10 seconds.
GAMS/CoinBonmin understands currently the following GAMS parameters: reslim (time limit), iterlim (iteration
limit), nodlim (node limit), cutoff, optca (absolute gap tolerance), and optcr (relative gap tolerance). You can
set them either on the command line, e.g. nodlim=1000, or inside your GAMS program, e.g. Option nodlim=1000;.
2.4 Description of CoinBonmin Options
The following tables gives the list of options together with their types, default values and availability in each of
the four main algorithms. The column labeled ‘type’ indicates the type of the parameter (‘F’ stands for float,
‘I’ for integer, and ‘S’ for string). The column labeled ‘default’ indicates the global default value. Then for each
of the four algorithm B-BB, B-OA, B-QG, and B-Hyb, ‘+’ indicates that the option is available for that particular
algorithm while ‘−’ indicates that it is not. Options that are marked with ∗ are those that can be used to configure
the MIP subsolver.
Option type default B-BB B-OA B-QG B-Hyb
Algorithm choice
algorithm S B-BB + + + +
Output
bb log interval I 100 + – + +
bb log level I 1 + – + +
lp log level I 0 – – + +
milp log level I 0 – + – +
nlp log level I 1 + + + +
oa cuts log level I 0 – + + +
oa log frequency F 100 + + + +
oa log level I 1 + + + +
Branch-and-bound options
allowable fraction gap F optcr (0.1) + + + +
allowable gap F optca (0) + + + +
cutoff F cutoff or 10 100 + + + +
cutoff decr F 10 −5 + + + +
integer tolerance F 10 −6 + + + +
iteration limit I ∞ + + + +
nlp failure behavior S stop + + + +
node comparison S dynamic + + + +
node limit I nodlim or iterlim (10000) + + + +
num cut passes I 1 – + + +
num cut passes at root I 20 – + + +
number before trust I 8 + + + +
number strong branch I 20 + + + +
solution limit I ∞ + + + +
time limit F reslim (1000) + + + +
tree search strategy S topnode + + + +
variable selection S strongbranching + + + +
Diving options
max backtracks in dive I 5 + + + +
max dive depth I ∞ + + + +
stop diving on cutoff S no + + + +