[Scip] optimal value with no primal solution
Miles Lubin
miles.lubin at gmail.com
Fri Jul 6 20:56:44 MEST 2012
I'm experiencing a strange behavior where SCIPgetStatus() returns
SCIP_STATUS_OPTIMAL and SCIPisPrimalboundSol() returns false. It's
hard to see how this makes any sense. Below is the output produced
while solving the problem. Note in the last round there is an asterisk
next to the primalbound. Can anyone explain?
Thanks,
Miles
presolving:
(round 1) 290 del vars, 30 del conss, 0 add conss, 290 chg bounds, 0
chg sides, 0 chg coeffs, 0 upgd conss, 0 impls, 21 clqs
(round 2) 290 del vars, 30 del conss, 0 add conss, 300 chg bounds, 0
chg sides, 0 chg coeffs, 0 upgd conss, 0 impls, 21 clqs
(round 3) 290 del vars, 30 del conss, 0 add conss, 300 chg bounds, 0
chg sides, 0 chg coeffs, 21 upgd conss, 0 impls, 21 clqs
(0.0s) probing: 51/220 (23.2%) - 0 fixings, 0 aggregations, 0
implications, 0 bound changes
(0.0s) probing aborted: 50/50 successive totally useless probings
presolving (4 rounds):
290 deleted vars, 30 deleted constraints, 0 added constraints, 300
tightened bounds, 0 added holes, 0 changed sides, 0 changed
coefficients
0 implications, 21 cliques
presolved problem has 230 variables (220 bin, 0 int, 10 impl, 0 cont)
and 31 constraints
21 constraints of type <setppc>
10 constraints of type <linear>
Presolving Time: 0.00
time | node | left |LP iter|LP it/n| mem |mdpt |frac |vars |cons
|cols |rows |cuts |confs|strbr| dualbound | primalbound | gap
T 0.0s| 1 | 0 | 0 | - |1253k| 0 | - | 230 | 31 |
230 | 31 | 0 | 0 | 0 | -- | 2.130311e-01 | Inf
0.0s| 1 | 0 | 147 | - |1223k| 0 | 9 | 230 | 31 |
230 | 31 | 0 | 0 | 0 |-1.842823e-01 | 2.130311e-01 | Inf
b 0.0s| 1 | 0 | 156 | - |1243k| 0 | - | 230 | 31 |
230 | 31 | 0 | 0 | 0 |-1.842823e-01 | 1.985037e-01 | Inf
r 0.0s| 1 | 0 | 156 | - |1243k| 0 | 9 | 230 | 31 |
230 | 31 | 0 | 0 | 0 |-1.842823e-01 |-2.592320e-02 | 610.88%
0.0s| 1 | 0 | 156 | - |1243k| 0 | 9 | 230 | 31 |
230 | 31 | 0 | 0 | 0 |-1.842823e-01 |-2.592320e-02 | 610.88%
0.0s| 1 | 0 | 166 | - |1266k| 0 | 20 | 230 | 31 |
230 | 40 | 9 | 0 | 0 |-1.745582e-01 |-2.592320e-02 | 573.37%
R 0.0s| 1 | 0 | 166 | - |1279k| 0 | 20 | 230 | 31 |
230 | 40 | 9 | 0 | 0 |-1.745582e-01 |-3.768126e-02 | 363.25%
0.0s| 1 | 0 | 195 | - |1308k| 0 | 32 | 230 | 31 |
230 | 48 | 17 | 0 | 0 |-1.665577e-01 |-3.768126e-02 | 342.02%
0.0s| 1 | 0 | 217 | - |1343k| 0 | 23 | 230 | 31 |
230 | 60 | 29 | 0 | 0 |-1.642489e-01 |-3.768126e-02 | 335.89%
R 0.0s| 1 | 0 | 217 | - |1350k| 0 | 23 | 230 | 31 |
230 | 60 | 29 | 0 | 0 |-1.642489e-01 |-6.997148e-02 | 134.74%
s 0.0s| 1 | 0 | 217 | - |1357k| 0 | 23 | 230 | 31 |
230 | 60 | 29 | 0 | 0 |-1.642489e-01 |-9.942573e-02 | 65.20%
0.0s| 1 | 0 | 248 | - |1372k| 0 | 50 | 230 | 31 |
230 | 65 | 34 | 0 | 0 |-1.615500e-01 |-9.942573e-02 | 62.48%
0.0s| 1 | 0 | 269 | - |1391k| 0 | 63 | 230 | 31 |
230 | 75 | 44 | 0 | 0 |-1.599932e-01 |-9.942573e-02 | 60.92%
0.0s| 1 | 0 | 299 | - |1414k| 0 | 59 | 230 | 31 |
230 | 83 | 52 | 0 | 0 |-1.577820e-01 |-9.942573e-02 | 58.69%
R 0.0s| 1 | 0 | 299 | - |1421k| 0 | 59 | 230 | 31 |
230 | 83 | 52 | 0 | 0 |-1.577820e-01 |-1.048695e-01 | 50.46%
time | node | left |LP iter|LP it/n| mem |mdpt |frac |vars |cons
|cols |rows |cuts |confs|strbr| dualbound | primalbound | gap
s 0.0s| 1 | 0 | 299 | - |1428k| 0 | 59 | 230 | 31 |
230 | 83 | 52 | 0 | 0 |-1.577820e-01 |-1.093695e-01 | 44.27%
0.0s| 1 | 0 | 317 | - |1445k| 0 | 71 | 230 | 31 |
230 | 91 | 60 | 0 | 0 |-1.570913e-01 |-1.093695e-01 | 43.63%
0.1s| 1 | 0 | 331 | - |1463k| 0 | 73 | 230 | 31 |
230 | 100 | 69 | 0 | 0 |-1.566600e-01 |-1.093695e-01 | 43.24%
0.1s| 1 | 0 | 342 | - |1470k| 0 | 81 | 230 | 31 |
230 | 106 | 75 | 0 | 0 |-1.564992e-01 |-1.093695e-01 | 43.09%
0.1s| 1 | 0 | 347 | - |1474k| 0 | 69 | 230 | 31 |
230 | 109 | 78 | 0 | 0 |-1.562761e-01 |-1.093695e-01 | 42.89%
0.1s| 1 | 0 | 348 | - |1482k| 0 | 69 | 230 | 31 |
230 | 110 | 79 | 0 | 0 |-1.562709e-01 |-1.093695e-01 | 42.88%
0.1s| 1 | 0 | 349 | - |1489k| 0 | 70 | 230 | 31 |
230 | 111 | 80 | 0 | 0 |-1.562665e-01 |-1.093695e-01 | 42.88%
E 0.1s| 1 | 0 | 349 | - |1496k| 0 | 70 | 230 | 31 |
230 | 111 | 80 | 0 | 0 |-1.562665e-01 |-1.526621e-01 | 2.36%
0.1s| 1 | 0 | 349 | - |1496k| 0 | 70 | 230 | 31 |
230 | 111 | 80 | 0 | 0 |-1.562665e-01 |-1.526621e-01 | 2.36%
0.1s| 1 | 0 | 349 | - |1496k| 0 | 70 | 230 | 31 |
230 | 111 | 80 | 0 | 0 |-1.562665e-01 |-1.526621e-01 | 2.36%
0.1s| 1 | 0 | 349 | - |1496k| 0 | - | 230 | 31 |
230 | 111 | 80 | 0 | 31 |-1.562665e-01 |-1.526621e-01 | 2.36%
(run 1, node 1) restarting after 80 global fixings of integer variables
(restart) converted 34 cuts from the global cut pool into linear constraints
presolving:
(round 1) 80 del vars, 0 del conss, 0 add conss, 0 chg bounds, 0 chg
sides, 1 chg coeffs, 0 upgd conss, 26 impls, 21 clqs
(round 2) 80 del vars, 0 del conss, 0 add conss, 0 chg bounds, 0 chg
sides, 1 chg coeffs, 10 upgd conss, 26 impls, 21 clqs
(round 3) 80 del vars, 1 del conss, 9 add conss, 0 chg bounds, 12 chg
sides, 25 chg coeffs, 44 upgd conss, 280 impls, 21 clqs
(round 4) 80 del vars, 64 del conss, 70 add conss, 0 chg bounds, 73
chg sides, 147 chg coeffs, 44 upgd conss, 280 impls, 21 clqs
presolving (5 rounds):
80 deleted vars, 64 deleted constraints, 70 added constraints, 0
tightened bounds, 0 added holes, 73 changed sides, 147 changed
coefficients
280 implications, 21 cliques
presolved problem has 150 variables (150 bin, 0 int, 0 impl, 0 cont)
and 71 constraints
9 constraints of type <knapsack>
62 constraints of type <setppc>
Presolving Time: 0.00
time | node | left |LP iter|LP it/n| mem |mdpt |frac |vars |cons
|cols |rows |cuts |confs|strbr| dualbound | primalbound | gap
0.1s| 1 | 0 | 480 | - |1451k| 0 | 4 | 150 | 71 |
150 | 71 | 0 | 0 | 31 |-1.719788e-01 |-1.526621e-01 | 12.65%
0.1s| 1 | 0 | 502 | - |1471k| 0 | 60 | 150 | 71 |
150 | 75 | 4 | 0 | 31 |-1.627608e-01 |-1.526621e-01 | 6.62%
0.1s| 1 | 0 | 502 | - |1469k| 0 | 60 | 150 | 71 |
150 | 75 | 4 | 0 | 31 |-1.627608e-01 |-1.526621e-01 | 6.62%
0.1s| 1 | 0 | 509 | - |1463k| 0 | 58 | 150 | 61 |
150 | 75 | 4 | 0 | 59 |-1.611716e-01 |-1.526621e-01 | 5.57%
0.2s| 1 | 0 | 513 | - |1459k| 0 | 54 | 150 | 58 |
150 | 75 | 4 | 0 | 78 |-1.605924e-01 |-1.526621e-01 | 5.19%
0.2s| 1 | 0 | 513 | - |1456k| 0 | - | 150 | 58 |
150 | 75 | 4 | 0 | 92 |-1.605924e-01 |-1.526621e-01 | 5.19%
(run 2, node 1) restarting after 39 global fixings of integer variables
(restart) converted 4 cuts from the global cut pool into linear constraints
presolving:
(round 1) 53 del vars, 6 del conss, 0 add conss, 0 chg bounds, 0 chg
sides, 0 chg coeffs, 0 upgd conss, 288 impls, 19 clqs
(round 2) 53 del vars, 6 del conss, 0 add conss, 0 chg bounds, 0 chg
sides, 0 chg coeffs, 1 upgd conss, 288 impls, 19 clqs
presolving (3 rounds):
53 deleted vars, 6 deleted constraints, 0 added constraints, 0
tightened bounds, 0 added holes, 0 changed sides, 0 changed
coefficients
288 implications, 19 cliques
presolved problem has 97 variables (97 bin, 0 int, 0 impl, 0 cont) and
56 constraints
6 constraints of type <knapsack>
50 constraints of type <setppc>
Presolving Time: 0.00
time | node | left |LP iter|LP it/n| mem |mdpt |frac |vars |cons
|cols |rows |cuts |confs|strbr| dualbound | primalbound | gap
0.2s| 1 | 0 | 603 | - |1418k| 0 | 49 | 97 | 56 |
97 | 56 | 0 | 0 | 92 |-1.600634e-01 |-1.526621e-01 | 4.85%
0.2s| 1 | 0 | 620 | - |1427k| 0 | 57 | 97 | 56 |
97 | 62 | 6 | 0 | 92 |-1.563144e-01 |-1.526621e-01 | 2.39%
0.2s| 1 | 0 | 620 | - |1426k| 0 | 57 | 97 | 56 |
97 | 62 | 6 | 0 | 92 |-1.563144e-01 |-1.526621e-01 | 2.39%
0.2s| 1 | 0 | 636 | - |1418k| 0 | 35 | 97 | 49 |
97 | 62 | 6 | 0 | 113 |-1.548002e-01 |-1.526621e-01 | 1.40%
0.2s| 1 | 0 | 636 | - |1415k| 0 | 35 | 97 | 49 |
97 | 60 | 6 | 0 | 113 |-1.548002e-01 |-1.526621e-01 | 1.40%
0.2s| 1 | 0 | 636 | - |1415k| 0 | - | 97 | 49 |
97 | 60 | 6 | 0 | 129 |-1.548002e-01 |-1.526621e-01 | 1.40%
(run 3, node 1) restarting after 39 global fixings of integer variables
(restart) converted 6 cuts from the global cut pool into linear constraints
presolving:
(round 1) 46 del vars, 14 del conss, 20 add conss, 0 chg bounds, 22
chg sides, 42 chg coeffs, 0 upgd conss, 306 impls, 12 clqs
(round 2) 46 del vars, 24 del conss, 20 add conss, 0 chg bounds, 22
chg sides, 42 chg coeffs, 2 upgd conss, 306 impls, 12 clqs
(round 3) 46 del vars, 25 del conss, 20 add conss, 0 chg bounds, 22
chg sides, 42 chg coeffs, 2 upgd conss, 306 impls, 12 clqs
presolving (4 rounds):
46 deleted vars, 25 deleted constraints, 20 added constraints, 0
tightened bounds, 0 added holes, 22 changed sides, 42 changed
coefficients
306 implications, 12 cliques
presolved problem has 51 variables (51 bin, 0 int, 0 impl, 0 cont) and
50 constraints
2 constraints of type <knapsack>
48 constraints of type <setppc>
Presolving Time: 0.01
time | node | left |LP iter|LP it/n| mem |mdpt |frac |vars |cons
|cols |rows |cuts |confs|strbr| dualbound | primalbound | gap
0.2s| 1 | 0 | 683 | - |1381k| 0 | 1 | 51 | 50 |
51 | 50 | 0 | 0 | 129 |-1.543720e-01 |-1.526621e-01 | 1.12%
0.2s| 1 | 0 | 683 | - |1385k| 0 | 1 | 51 | 50 |
51 | 48 | 0 | 0 | 129 |-1.543720e-01 |-1.526621e-01 | 1.12%
0.2s| 1 | 0 | 686 | - |1391k| 0 | 2 | 51 | 48 |
51 | 50 | 2 | 0 | 129 |-1.541920e-01 |-1.526621e-01 | 1.00%
0.2s| 1 | 2 | 686 | - |1398k| 0 | 2 | 51 | 48 |
51 | 50 | 2 | 0 | 131 |-1.541920e-01 |-1.526621e-01 | 1.00%
(run 4, node 1) restarting after 5 global fixings of integer variables
(restart) converted 1 cuts from the global cut pool into linear constraints
presolving:
(round 1) 18 del vars, 21 del conss, 0 add conss, 0 chg bounds, 0 chg
sides, 0 chg coeffs, 1 upgd conss, 316 impls, 5 clqs
(round 2) 22 del vars, 31 del conss, 0 add conss, 0 chg bounds, 0 chg
sides, 0 chg coeffs, 1 upgd conss, 318 impls, 5 clqs
presolving (3 rounds):
22 deleted vars, 31 deleted constraints, 0 added constraints, 0
tightened bounds, 0 added holes, 0 changed sides, 0 changed
coefficients
318 implications, 5 cliques
presolved problem has 29 variables (29 bin, 0 int, 0 impl, 0 cont) and
18 constraints
2 constraints of type <knapsack>
15 constraints of type <setppc>
1 constraints of type <logicor>
Presolving Time: 0.01
time | node | left |LP iter|LP it/n| mem |mdpt |frac |vars |cons
|cols |rows |cuts |confs|strbr| dualbound | primalbound | gap
0.2s| 1 | 0 | 700 | - |1355k| 0 | 2 | 29 | 18 |
29 | 18 | 0 | 0 | 131 |-1.541920e-01 |-1.526621e-01 | 1.00%
0.2s| 1 | 0 | 700 | - |1361k| 0 | 2 | 29 | 18 |
29 | 18 | 0 | 0 | 131 |-1.541920e-01 |-1.526621e-01 | 1.00%
0.2s| 1 | 0 | 702 | - |1369k| 0 | 13 | 29 | 18 |
29 | 20 | 2 | 0 | 131 |-1.540008e-01 |-1.526621e-01 | 0.88%
0.2s| 1 | 0 | 702 | - |1366k| 0 | - | 29 | 18 |
29 | 20 | 2 | 0 | 136 |-1.540008e-01 |-1.526621e-01 | 0.88%
(run 5, node 1) restarting after 11 global fixings of integer variables
(restart) converted 2 cuts from the global cut pool into linear constraints
presolving:
(round 1) 20 del vars, 13 del conss, 0 add conss, 0 chg bounds, 0 chg
sides, 0 chg coeffs, 2 upgd conss, 322 impls, 0 clqs
(round 2) 22 del vars, 15 del conss, 0 add conss, 0 chg bounds, 0 chg
sides, 0 chg coeffs, 2 upgd conss, 322 impls, 0 clqs
(round 3) 22 del vars, 15 del conss, 0 add conss, 1 chg bounds, 0 chg
sides, 0 chg coeffs, 2 upgd conss, 322 impls, 0 clqs
(round 4) 23 del vars, 15 del conss, 0 add conss, 1 chg bounds, 0 chg
sides, 1 chg coeffs, 2 upgd conss, 332 impls, 0 clqs
presolving (5 rounds):
23 deleted vars, 15 deleted constraints, 0 added constraints, 1
tightened bounds, 0 added holes, 0 changed sides, 1 changed
coefficients
332 implications, 0 cliques
presolved problem has 6 variables (6 bin, 0 int, 0 impl, 0 cont) and 5
constraints
2 constraints of type <knapsack>
3 constraints of type <logicor>
Presolving Time: 0.01
time | node | left |LP iter|LP it/n| mem |mdpt |frac |vars |cons
|cols |rows |cuts |confs|strbr| dualbound | primalbound | gap
0.2s| 1 | 0 | 707 | - |1341k| 0 | 4 | 6 | 5 |
6 | 5 | 0 | 0 | 136 |-1.538920e-01 |-1.526621e-01 | 0.81%
s 0.2s| 1 | 0 | 707 | - |1348k| 0 | 4 | 6 | 5 |
6 | 5 | 0 | 0 | 136 |-1.538920e-01 |-1.531920e-01 | 0.46%
0.2s| 1 | 0 | 711 | - |1354k| 0 | 1 | 6 | 5 |
6 | 7 | 2 | 0 | 136 |-1.532753e-01 |-1.531920e-01 | 0.05%
0.2s| 1 | 0 | 711 | - |1354k| 0 | 1 | 6 | 5 |
6 | 6 | 2 | 0 | 136 |-1.532753e-01 |-1.531920e-01 | 0.05%
0.2s| 1 | 2 | 711 | - |1355k| 0 | 1 | 6 | 5 |
6 | 6 | 2 | 0 | 136 |-1.532753e-01 |-1.531920e-01 | 0.05%
(run 6, node 1) restarting after 1 global fixings of integer variables
(restart) converted 2 cuts from the global cut pool into linear constraints
presolving:
(round 1) 1 del vars, 1 del conss, 0 add conss, 0 chg bounds, 0 chg
sides, 0 chg coeffs, 2 upgd conss, 332 impls, 0 clqs
(round 2) 1 del vars, 2 del conss, 0 add conss, 0 chg bounds, 1 chg
sides, 2 chg coeffs, 2 upgd conss, 332 impls, 0 clqs
presolving (3 rounds):
1 deleted vars, 2 deleted constraints, 0 added constraints, 0
tightened bounds, 0 added holes, 1 changed sides, 2 changed
coefficients
332 implications, 0 cliques
presolved problem has 5 variables (5 bin, 0 int, 0 impl, 0 cont) and 5
constraints
3 constraints of type <knapsack>
2 constraints of type <logicor>
Presolving Time: 0.01
time | node | left |LP iter|LP it/n| mem |mdpt |frac |vars |cons
|cols |rows |cuts |confs|strbr| dualbound | primalbound | gap
0.2s| 1 | 0 | 715 | - |1347k| 0 | 2 | 5 | 5 |
5 | 5 | 0 | 0 | 136 |-1.532753e-01 |-1.531920e-01*| 0.05%
0.2s| 1 | 0 | 717 | - |1354k| 0 | 5 | 5 | 5 |
5 | 7 | 2 | 0 | 136 |-1.532223e-01 |-1.531920e-01*| 0.02%
0.2s| 1 | 0 | 717 | - |1354k| 0 | 5 | 5 | 5 |
5 | 7 | 2 | 0 | 137 |-1.531920e-01 |-1.531920e-01*| 0.00%
SCIP Status : problem is solved [optimal solution found]
Solving Time (sec) : 0.20
Solving Nodes : 1 (total of 7 nodes in 7 runs)
Primal Bound : -1.53191992881652e-01 (18 solutions)
Dual Bound : -1.53191992881652e-01
Gap : 0.00 %
More information about the Scip
mailing list