Amplers

A collection of linear programming models discussed in OR course, written in AMPL

Usage

Be sure to download one of the AMPL solvers and to add the correct path in the right place. Once you open a model you may run into errors like

ampl: model model.mod
ampl: solve;
Cannot find "cplex"

Panic you may not. ampl cannot find the solver specified in your machine: just specify the full path to the solver you wish to use. For example

option solver "/bin/ampl-solvers/cbc-linux64/cbc";

Example

Once you downloaded all necessary software

• simply

$ cd `folder where model is .. e.g models/contadino/`
$ ampl
ampl: model model.mod
ampl: solve;
CBC 2.9.9 optimal, objective 44000
2 iterations
ampl: display x_lattuga, x_patata, resa;
x_lattuga = 8
x_patata = 4
resa = 44000

• in case the model comes with a data file (like this one), then you should

$ cd `folder where model is .. e.g models/frigoriferi/`
$ ampl
ampl: model frigoriferi.mod
ampl: data frigoriferi.dat
ampl: solve;
CPLEX 12.7.1.0: optimal solution; objective 420
7 dual simplex iterations (0 in phase I)
ampl: display x, moving_cost;
x :=
A '1'    0
A '2'    0
A '3'   10
A '4'   40
B '1'    0
B '2'   50
B '3'   20
B '4'    0
C '1'   10
C '2'   10
C '3'    0
C '4'    0
;

moving_cost = 420

• finally, if there is also a run file (like this one), just

$ cd `folder where model is .. e.g models/contadino/`
$ ampl
ampl: include telecomandi.run;
CPLEX 12.6.3.0: optimal integer solution; objective 34
3 MIP simplex iterations
0 branch-and-bound nodes
No basis.
x [*] :=
A  6
B  2
;

total_gain = 34

Available models

name	category	solution	cost/optimum
Contadino	mix-ottimo di produzione	x_patata = 4, x_lattuga = 8	44000
Telecomandi	mix-ottimo di produzione	x_A = 6, x_B = 2	34
Produzione forza lavoro	mix-ottimo di produzione	x_1 = 430, x_2 = 200, x_3 = 508	42300
Produzione capacità eccedente	mix-ottimo di produzione	factory_1 = 500, factory_2 = 600, factory_3 = 300	14900
Raffineria	mix-ottimo di produzione	1 super = 857.143, 1 verde = 571.429, 2 super = 2571.43, 2 verde = 5142.86	1200000
Dieta	copertura di costo minimo	x_verdura = 5, x_carne = 0, x_frutta = 0	20
Indagine di mercato	copertura di costo minimo	x_mattino = 1, x_sera = 666	1066.7
Turni in ospedale	copertura di costo minimo	fri = 3, mon = 4, sat = 4, sun = 3, thu = 4, tue = 3, wed = 3	24
Localizzazione di servizi	copertura di costo minimo	2, 4	2
Frigoriferi	trasporti (bilanciato)	x_A3 = 10, x_A4 = 40, x_B2 = 50, x_B3 = 20, x_C1 = 10, x_C2 = 10	420
Piani di investimento	multi-periodale	x_A1 = 10000, x_A3 = 14000, x_D5 = 19600	25480
Produzione su più linee	min-max	x_13 = 20, x_23 = 30, x_32 = 16, x_41 = 20	86
Scheduling just-in-time	min-abs	start_1 = 26, start_2 = 31, start_3 = 38, start_4 = 45, start_5 = 52	4500
Localizzazione con costi fissi	logico	dnf	dnf
Portfolio optimization	logico	A = 22727.3, C = 70454.5, E = 6818.18	39538.6
Assunzione multiperiodale di personale	logico	1 = 14, 2 = 13	198500

Help, something is wrong

Remember to add a semicolon at the end of mostly all commands ..

Questions and issues

The github issue tracker is only for bug reports and feature requests.

Contributing

Fork | Patch | Push | Pull request

License

Apache License Version 2.0, January 2004