Xpress Test Routines in Tomlab Format
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This page is part of the Xpress Manual. See Xpress Manual. |
A set of test routines have been defined illustrating the combined use of TOMLAB and XpressMP. The test routines are shown in #Table: The test routines and utilities.. The knapsack test routine xpknapsTL is similar to xpknaps discussed in the previous subsection. It runs three knapsack test examples. It is possible to change the cut strategy and whether to use the knapsack heuristic in the callback routine xpcb_gl. The problems are setup using the TOMLAB format.
Table: The test routines and utilities.
| Function | Description |
|---|---|
| xptomtest1 | Tests of problems predefined in the TOMLAB IF format. LP, QP and MIP problems are solved calling the driver routine tomRun. |
| xptomtest2 | Tests of a simple MIP problem defined in the TOMLAB (TQ) format.
The problem is solved as an LP and MIP problem, with or without slacks defined. tomRun. |
| xpknapsTL | The same tests as in xpknaps, but the TOMLAB format and system is used. |
The following example shows how to run a predefined problem, one of the problems in xpknapsTL, using the TOMLAB Init File (IF) format. Some fields that changes control variables are set to make XpressMP work slower. Then a simple predefined heuristic is run to try to improve the convergence. For this example it can get down the number of node visited from 135 to 35.
Prob = ProbInit('mip_prob',7); % Create Prob structure from predefined problem
Prob.MIP
ans =
xpcontrol: []
IntVars: [30x1 double]
VarWeight: [30x1 double]
KNAPSACK: 1
callback: [14x1 double]
% Make Xpress-MP work slower by disabling presolve and cuts.
Prob.MIP.xpcontrol.CUTSTRATEGY = 0; % Use no cuts
Prob.MIP.xpcontrol.PRESOLVE = 0; % Use no presolve
Prob.MIP.xpcontrol.MIPLOG = 3; % Call the callback each node
Result = tomRun('xpress-mp',Prob,1); % Call Xpress-MP using Tomlab driver
===== * * * =============================================== * * *
TOMLAB SOL - Three weeks demonstration single user license
=================================================================
Problem: mip_prob - 7: Weingartner 1 - 2/28 0-1 knapsack f_k -141278.000000000000000000
User given f(x_*)-141278.000000000000000000
Solver: Xpress-MP. EXIT=0. INFORM=6.
Mex-interface to Xpress-MP LP/QP/MIP/MIQP solver
Global search complete - integer solution found
FuncEv 135 GradEv 0 Iter 135
CPU time: 0.250000 sec. Elapsed time: 0.250000 sec.
Prob.MIP.callback(9) = 1; % Enable Global Log callback
Result = tomRun('xpress-mp',Prob,1);
% Because Prob.MIP.KNAPSACK == 1, the predefined heuristic is tried
--- Global Log. Node 1. Node depth 1. Best Bound -142019.000000.
Node 1: LP-obj -142019; Heuristic value -139508 *** Updated cutoff to -139507
--- Global Log. Node 2. Node depth 2. Best Bound -142019.000000.
Node 2: LP-obj -141897; Heuristic value -140768 *** Updated cutoff to -140767
--- Global Log. Node 3. Node depth 3. Best Bound -142019.000000.
Node 3: LP-obj -141873; Heuristic value -138493
--- Global Log. Node 4. Node depth 4. Best Bound -142019.000000.
Node 4: LP-obj -141726; Heuristic value -139618
--- Global Log. Node 5. Node depth 3. Best Bound -142019.000000.
Node 5: Not applying heuristic (status is Cutoff in dual)
--- Global Log. Node 6. Node depth 5. Best Bound -142019.000000.
Node 6: LP-obj -141707; Heuristic value -138168
--- Global Log. Node 7. Node depth 6. Best Bound -142019.000000.
Node 7: LP-obj -141655; Heuristic value -138068
--- Global Log. Node 8. Node depth 5. Best Bound -142019.000000.
Node 8: Not applying heuristic (status is Cutoff in dual)
--- Global Log. Node 9. Node depth 6. Best Bound -142019.000000.
Node 9: Not applying heuristic (status is Infeasible)
--- Global Log. Node 10. Node depth 6. Best Bound -142019.000000.
Node 10: Not applying heuristic (status is Cutoff in dual)
--- Global Log. Node 11. Node depth 2. Best Bound -142019.000000.
Node 11: LP-obj -141465; Heuristic value -139508
--- Global Log. Node 12. Node depth 3. Best Bound -142019.000000.
Node 12: LP-obj -141062; Heuristic value -139933
--- Global Log. Node 13. Node depth 3. Best Bound -142019.000000.
Node 13: Not applying heuristic (status is Infeasible)
--- Global Log. Node 14. Node depth 3. Best Bound -142019.000000.
Node 14: Not applying heuristic (status is Cutoff in dual)
--- Global Log. Node 15. Node depth 3. Best Bound -141896.953125.
Node 15: LP-obj -141721; Heuristic value -141278 *** Updated cutoff to -141277
--- Global Log. Node 16. Node depth 4. Best Bound -141896.953125.
Node 16: LP-obj -141694; Heuristic value -141168
--- Global Log. Node 17. Node depth 5. Best Bound -141896.953125.
Node 17: LP-obj -141640; Heuristic value -141168
--- Global Log. Node 18. Node depth 6. Best Bound -141896.953125.
Node 18: LP-obj -141572; Heuristic value -141278 *** Updated cutoff to -141277
--- Global Log. Node 19. Node depth 7. Best Bound -141896.953125.
Node 19: LP-obj -141360; Heuristic value -141258
--- Global Log. Node 20. Node depth 7. Best Bound -141896.953125.
Node 20: LP-obj -141565; Heuristic value -141278 *** Updated cutoff to -141277
--- Global Log. Node 21. Node depth 8. Best Bound -141896.953125.
Node 21: LP-obj -141349; Heuristic value -141247
--- Global Log. Node 22. Node depth 8. Best Bound -141896.953125.
Node 22: LP-obj -141498; Heuristic value -141278 *** Updated cutoff to -141277
--- Global Log. Node 23. Node depth 8. Best Bound -141896.953125.
Node 23: Not applying heuristic (status is Infeasible)
--- Global Log. Node 24. Node depth 8. Best Bound -141896.953125. Best MIP f(x) -141278.000000
Node 24: B&B integer solution found; objval -141278
--- Global Log. Node 25. Node depth 8. Best Bound -141726.000000. Best MIP f(x) -141278.000000
Node 25: B&B integer solution found; objval -141056
--- Global Log. Node 26. Node depth 4. Best Bound -141720.515625. Best MIP f(x) -141278.000000
Node 26: B&B integer solution found; objval -140695
--- Global Log. Node 27. Node depth 3. Best Bound -141693.593750. Best MIP f(x) -141278.000000
Node 27: B&B integer solution found; objval -141524
--- Global Log. Node 28. Node depth 4. Best Bound -141640.000000. Best MIP f(x) -141278.000000
Node 28: B&B integer solution found; objval -140974
--- Global Log. Node 29. Node depth 3. Best Bound -141465.140625. Best MIP f(x) -141278.000000
Node 29: LP-obj -141341; Heuristic value -139398
--- Global Log. Node 30. Node depth 3. Best Bound -141465.140625. Best MIP f(x) -141278.000000
Node 30: Not applying heuristic (status is Cutoff in dual)
--- Global Log. Node 31. Node depth 3. Best Bound -141465.140625. Best MIP f(x) -141278.000000
Node 31: Not applying heuristic (status is Infeasible)
--- Global Log. Node 32. Node depth 3. Best Bound -141360.000000. Best MIP f(x) -141278.000000
Node 32: Not applying heuristic (status is Cutoff in dual)
--- Global Log. Node 33. Node depth 7. Best Bound -141360.000000. Best MIP f(x) -141278.000000
Node 33: Not applying heuristic (status is Infeasible)
--- Global Log. Node 34. Node depth 7. Best Bound -141349.000000. Best MIP f(x) -141278.000000
Node 34: Not applying heuristic (status is Cutoff in dual)
--- Global Log. Node 35. Node depth 8. Best Bound -141349.000000. Best MIP f(x) -141278.000000
Node 35: Not applying heuristic (status is Infeasible)
===== * * * =============================================== * * *
TOMLAB SOL - Three weeks demonstration single user license
=================================================================
Problem: mip_prob - 7: Weingartner 1 - 2/28 0-1 knapsack f_k -141278.000000000000000000
User given f(x_*)-141278.000000000000000000
Solver: Xpress-MP. EXIT=0. INFORM=6.
Mex-interface to Xpress-MP LP/QP/MIP/MIQP solver
Global search complete - integer solution found
FuncEv 35 GradEv 0 Iter 35
CPU time: 3.156000 sec. Elapsed time: 3.156000 sec.
The following example shows how to define and solve a problem using the TOMLAB Format (TQ). The matrices and vectors for the problem is defined in a mat file. Fields that changes the XpressMP control variables are set to show how to influence the work of the solver. In this case the changes slow down its performance.
clear all
load bilp1.mat
whos
Name Size Bytes Class
A 27x1956 422496 double array
b_L 27x1 216 double array
b_U 27x1 216 double array
c 1956x1 15648 double array
noivars 1956x1 15648 double
x_L 1956x1 15648 double array
x_U 1956x1 15648 double array
Grand total is 58735 elements using 469880 bytes
Prob = mipAssign(c, A, b_L, b_U, x_L, x_U,[],'bilp1',[],[],noivars);
Result = tomRun('xpress-mp',Prob,1);
===== * * * =============================================== * * *
TOMLAB SOL - Three weeks demonstration single user license
=================================================================
Problem: No Init File - 1: bilp1 f_k 0.000000000000000000
sum(|constr|) 0.000000000000025960
Solver: Xpress-MP. EXIT=0. INFORM=6.
Mex-interface to Xpress-MP LP/QP/MIP/MIQP solver
Global search complete - integer solution found
FuncEv 67 GradEv 0 Iter 67
CPU time: 4.359000 sec. Elapsed time: 4.375000 sec.
=== * * * ================================================== * * *
Prob.MIP
ans =
IntVars: 1956
VarWeight: []
KNAPSACK: []
fIP: []
xIP: []
PI: []
SC: []
SI: []
sos1: []
sos2: []
% Make Xpress-MP work slower by disabling presolve and cuts.
Prob.MIP.xpcontrol.CUTSTRATEGY = 0;
Prob.MIP.xpcontrol.MIPPRESOLVE = 0;
Prob.MIP.xpcontrol.PRESOLVE = 0;
Result = tomRun('xpress-mp',Prob,2);
===== * * * =============================================== * * *
TOMLAB SOL - Three weeks demonstration single user license
=================================================================
Problem: No Init File - 1: bilp1 f_k 0.000000000000000000
sum(|constr|) 0.000000000000020365
Solver: Xpress-MP. EXIT=0. INFORM=6.
Mex-interface to Xpress-MP LP/QP/MIP/MIQP solver
Global search complete - integer solution found
FuncEv 105 GradEv 0 Iter 105
CPU time: 0.578000 sec. Elapsed time: 0.578000 sec.
=== * * * ================================================== * * *
Prob.MIP.xpcontrol.MIPPRESOLVE = 7; % Try another MIPPRESOLVE value
Result = tomRun('xpress-mp', Prob, 1);
===== * * * =============================================== * * *
TOMLAB SOL - Three weeks demonstration single user license
=================================================================
Problem: No Init File - 1: bilp1 f_k 0.000000000000000000
sum(|constr|) 0.000000000000011373
Solver: Xpress-MP. EXIT=0. INFORM=6.
Mex-interface to Xpress-MP LP/QP/MIP/MIQP solver
Global search complete - integer solution found
FuncEv 82 GradEv 0 Iter 82
CPU time: 3.250000 sec. Elapsed time: 3.250000 sec.
