1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/examples/cpp.mod	Mon Dec 06 13:09:21 2010 +0100
     1.3 @@ -0,0 +1,67 @@
     1.4 +/* CPP, Critical Path Problem */
     1.5 +
     1.6 +/* Written in GNU MathProg by Andrew Makhorin <mao@gnu.org> */
     1.7 +
     1.8 +/* Note: Reduced costs of auxiliary variables phi[j,k] (see below)
     1.9 +         can be only zero or one. The critical path is defined by the
    1.10 +         constraints, whose reduced cost is one. */
    1.11 +
    1.12 +set J;
    1.13 +/* set of jobs (activities) */
    1.14 +
    1.15 +set P{j in J}, in J, default {};
    1.16 +/* P[j] is a subset of jobs that immediately precede job j */
    1.17 +
    1.18 +param t{j in J}, >= 0;
    1.19 +/* duration required to perform job j */
    1.20 +
    1.21 +var x{j in J}, >= 0;
    1.22 +/* starting time of job j */
    1.23 +
    1.24 +s.t. phi{j in J, k in P[j]}: x[j] >= x[k] + t[k];
    1.25 +/* job j can start only after all immediately preceding jobs have been
    1.26 +   completely performed */
    1.27 +
    1.28 +var z;
    1.29 +/* project makespan */
    1.30 +
    1.31 +s.t. fin{j in J}: z >= x[j] + t[j];
    1.32 +/* which is the maximum of the completion times of all the jobs */
    1.33 +
    1.34 +minimize obj: z;
    1.35 +/* the objective is make z as small as possible */
    1.36 +
    1.37 +data;
    1.38 +
    1.39 +/* The optimal solution is 46 */
    1.40 +
    1.41 +param : J :  t :=
    1.42 +        A    3    /* Excavate */
    1.43 +        B    4    /* Lay foundation */
    1.44 +        C    3    /* Rough plumbing */
    1.45 +        D   10    /* Frame */
    1.46 +        E    8    /* Finish exterior */
    1.47 +        F    4    /* Install HVAC */
    1.48 +        G    6    /* Rough electric */
    1.49 +        H    8    /* Sheet rock */
    1.50 +        I    5    /* Install cabinets */
    1.51 +        J    5    /* Paint */
    1.52 +        K    4    /* Final plumbing */
    1.53 +        L    2    /* Final electric */
    1.54 +        M    4    /* Install flooring */
    1.55 +;
    1.56 +
    1.57 +set P[B] := A;
    1.58 +set P[C] := B;
    1.59 +set P[D] := B;
    1.60 +set P[E] := D;
    1.61 +set P[F] := D;
    1.62 +set P[G] := D;
    1.63 +set P[H] := C E F G;
    1.64 +set P[I] := H;
    1.65 +set P[J] := H;
    1.66 +set P[K] := I;
    1.67 +set P[L] := J;
    1.68 +set P[M] := K L;
    1.69 +
    1.70 +end;