Question regarding output log behaviours and branch and bound algorithms
回答済み
Hi everyone,
I am currently analyzing Gurobi's Branch & Bound logs to better visualize what is going on inside the searching tree by looking at the output log. I have three observations and a few questions to see if my thinking is on the right track.
Observation A: In a recent run, the solver found a high-quality incumbent very early, but reducing the best bound to near incumbent took significant time. The MIP gap was stuck at a 15.1% plateau for a long period. Usually, in my experience with similar models, a stuck gap means it will remain stuck forever. However, to my surprise, the gap suddenly continues to fall at the 331s. (Log snippet provided below).
Observation B: I attempted to reduce the feasible region by tightening variable bounds across several models. The runtime improvements were highly inconsistent and can be divided into three groups:
- Group 1(10%): Converged perfectly (Gap reduced from 8% → 1%).
- Group 2(30%): Improved significantly, but still stalled (Gap 26% → 11%).
- Group 3(60%): Improved slightly (Gap 10% → 9.7%).
Observation C: In my experience, the solver typically identifies a high quality incumbent solution early in the process (which is usually the optimal solution). The extended runtime is primarily spent reducing the Best Bound to prove optimality. In case whre MIP gap stalls occur is when the Best Bound fails to reduce.
My Questions Is:
1. Regarding Observation A: Is the sudden drop in the MIP gap an indication that the solver finally finished enumerating a "faulty" branch and was able to prune it and jump into searching another branch? This is weird because in other models, if it is stalled at a MIP gap, it gets stuck there forever, is it simply because these faulty branches are too massive to be exhaustively searched?
2. Regarding Observation B: Could you clarify if my understand is correct?
- For Group 1 (Converged): Tightening bounds successfully pruned the exact “faulty branch” that the solver is wasting time to search and causing stall.
- For Group 2 (Significant improvement): The bound tightening removed the initial stalling branch, but the algorithm then hit a completely new bottleneck branch.
- For Group 3 (Marginal improvement): Tightening bounds only pruned another different branches not relevant to the “faulty” branch that causing stall (or minor sub-branches inside the “faulty” branch causing stall), leaving the primary bottleneck branch completely intact.
3. Regarding Observation C: Can we generalize this as a rule?
(This is the log output regarding observation A)
Nodes | Current Node | Objective Bounds | Work
Expl Unexpl | Obj Depth IntInf | Incumbent BestBd Gap | It/Node Time
0 0 1.00000 0 80 - 1.00000 - - 0s
0 0 1.00000 0 90 - 1.00000 - - 0s
0 0 1.00000 0 96 - 1.00000 - - 0s
0 0 1.00000 0 96 - 1.00000 - - 0s
0 0 1.00000 0 96 - 1.00000 - - 0s
0 0 1.00000 0 120 - 1.00000 - - 0s
0 0 1.00000 0 123 - 1.00000 - - 0s
0 0 1.00000 0 125 - 1.00000 - - 0s
0 0 1.00000 0 129 - 1.00000 - - 0s
0 0 1.00000 0 130 - 1.00000 - - 0s
0 0 1.00000 0 122 - 1.00000 - - 0s
0 2 1.00000 0 122 - 1.00000 - - 0s
23 58 1.00000 5 108 - 1.00000 - 52.5 1s
H 749 311 0.0086219 1.00000 - 18.8 1s
H 757 311 0.0093662 1.00000 - 19.0 1s
H 769 316 0.0093662 1.00000 - 19.8 1s
855 355 0.47220 34 160 0.00937 1.00000 - 24.4 2s
H 1120 399 0.0093724 1.00000 - 27.9 2s
H 1322 459 0.0093724 1.00000 - 29.8 2s
H 1367 459 0.0093731 1.00000 - 30.3 2s
H 2246 767 0.0093738 1.00000 - 35.5 2s
H 2297 767 0.0093744 1.00000 - 35.8 2s
2380 778 infeasible 20 0.00937 1.00000 - 35.7 3s
2899 929 0.90929 19 6 0.00937 0.99938 - 37.9 4s
2913 940 0.99896 15 3 0.00937 0.99896 - 38.0 5s
2927 950 0.29610 17 2 0.00937 0.99878 - 37.9 6s
3112 1056 0.95417 31 152 0.00937 0.99878 - 40.5 7s
3417 1192 0.97454 38 161 0.00937 0.99878 - 41.9 8s
H 3858 1139 0.0093745 0.99878 - 44.7 8s
4536 1200 0.97746 57 179 0.00937 0.99878 - 47.6 9s
H 5449 1253 0.0093751 0.99878 - 48.7 9s
5706 1368 0.02480 45 156 0.00938 0.99878 - 49.1 10s
H 5707 1368 0.0093751 0.99878 - 49.1 10s
H 5718 1368 0.0093757 0.99878 - 49.0 10s
H 5728 1137 0.0208062 0.99878 4700% 49.0 10s
H 5749 917 0.6741279 0.99878 48.2% 48.9 10s
5781 874 cutoff 46 0.67413 0.99878 48.2% 49.0 11s
6831 1076 infeasible 33 0.67413 0.99491 47.6% 48.9 12s
7060 1124 infeasible 42 0.67413 0.99491 47.6% 49.3 13s
7385 1226 infeasible 46 0.67413 0.99268 47.3% 49.4 14s
8926 1591 infeasible 60 0.67413 0.97567 44.7% 51.2 15s
11555 1926 0.93023 47 139 0.67413 0.95952 42.3% 52.3 16s
14182 2238 infeasible 57 0.67413 0.94996 40.9% 53.0 17s
16638 2512 infeasible 51 0.67413 0.93671 39.0% 53.3 18s
18781 2742 0.92943 54 171 0.67413 0.93424 38.6% 56.3 19s
20425 2623 infeasible 114 0.67413 0.93408 38.6% 58.5 20s
22700 2159 infeasible 47 0.67413 0.92214 36.8% 59.4 21s
23559 2017 infeasible 86 0.67413 0.91533 35.8% 59.5 23s
24371 1881 infeasible 46 0.67413 0.90188 33.8% 59.6 25s
26226 1606 0.84280 46 181 0.67413 0.86875 28.9% 60.0 26s
27230 1440 infeasible 58 0.67413 0.85268 26.5% 60.0 27s
28253 1404 infeasible 42 0.67413 0.84146 24.8% 60.1 28s
29415 1412 infeasible 50 0.67413 0.83373 23.7% 59.9 29s
30663 1384 infeasible 82 0.67413 0.82906 23.0% 59.4 30s
32241 1355 0.71710 44 159 0.67413 0.81019 20.2% 58.8 31s
33296 1393 0.71592 86 180 0.67413 0.80866 20.0% 58.7 32s
34340 1440 infeasible 47 0.67413 0.78132 15.9% 58.9 33s
35391 1723 infeasible 46 0.67413 0.77638 15.2% 59.2 34s
38046 1574 infeasible 55 0.67413 0.77638 15.2% 59.3 35s
39703 1564 infeasible 47 0.67413 0.77638 15.2% 58.9 36s
41041 1519 infeasible 49 0.67413 0.77638 15.2% 59.1 37s
42392 1513 0.77638 41 174 0.67413 0.77638 15.2% 59.4 38s
43744 1657 0.77638 42 161 0.67413 0.77638 15.2% 59.7 40s
45228 1699 infeasible 42 0.67413 0.77638 15.2% 59.9 41s
45564 1697 infeasible 52 0.67413 0.77638 15.2% 60.1 42s
45598 1682 infeasible 51 0.67413 0.77638 15.2% 60.1 43s
45645 1683 infeasible 52 0.67413 0.77638 15.2% 60.1 44s
45676 1667 infeasible 53 0.67413 0.77638 15.2% 60.1 45s
45826 1639 infeasible 65 0.67413 0.77638 15.2% 60.2 46s
46142 1683 infeasible 66 0.67413 0.77638 15.2% 60.2 48s
46670 1764 0.77638 46 168 0.67413 0.77638 15.2% 60.4 49s
47731 1848 infeasible 47 0.67413 0.77638 15.2% 60.4 50s
49219 2034 infeasible 37 0.67413 0.77638 15.2% 61.0 52s
51079 2198 0.68780 45 162 0.67413 0.77638 15.2% 61.3 54s
53013 2177 0.77637 68 173 0.67413 0.77637 15.2% 61.4 55s
54720 2110 0.77637 63 151 0.67413 0.77637 15.2% 61.5 56s
56139 2052 infeasible 72 0.67413 0.77637 15.2% 61.9 57s
57827 2025 0.72958 54 184 0.67413 0.77637 15.2% 62.1 59s
59441 2168 infeasible 54 0.67413 0.77637 15.2% 62.3 60s
61028 2101 infeasible 74 0.67413 0.77637 15.2% 62.5 62s
62539 2199 0.77637 38 176 0.67413 0.77637 15.2% 62.6 63s
64247 2285 0.74463 47 166 0.67413 0.77637 15.2% 62.7 64s
65905 2545 0.77637 69 156 0.67413 0.77637 15.2% 62.9 65s
67815 2679 infeasible 70 0.67413 0.77637 15.2% 62.7 66s
69533 2980 infeasible 68 0.67413 0.77637 15.2% 62.7 67s
71352 3283 infeasible 56 0.67413 0.77637 15.2% 62.5 69s
73241 3399 0.76299 42 179 0.67413 0.77637 15.2% 62.3 70s
75293 3325 infeasible 109 0.67413 0.77637 15.2% 62.2 71s
76709 3361 infeasible 54 0.67413 0.77637 15.2% 62.4 72s
78095 3667 0.73355 54 177 0.67413 0.77637 15.2% 62.5 74s
79961 3770 infeasible 48 0.67413 0.77637 15.2% 62.4 75s
81468 4086 0.75767 39 171 0.67413 0.77637 15.2% 62.6 76s
83294 4323 0.77637 42 176 0.67413 0.77637 15.2% 62.5 78s
84903 4377 0.77637 56 170 0.67413 0.77637 15.2% 62.5 80s
86569 4425 0.77637 42 151 0.67413 0.77637 15.2% 62.4 81s
88119 4296 infeasible 33 0.67413 0.77637 15.2% 62.5 83s
89626 4438 infeasible 44 0.67413 0.77637 15.2% 62.6 84s
91056 4430 0.77637 40 159 0.67413 0.77637 15.2% 62.8 86s
92324 4393 cutoff 51 0.67413 0.77637 15.2% 63.2 87s
93613 4501 0.75376 56 178 0.67413 0.77637 15.2% 63.6 88s
95163 4624 0.77615 50 181 0.67413 0.77637 15.2% 63.8 89s
96824 4734 0.77615 59 169 0.67413 0.77637 15.2% 64.0 91s
98334 4909 0.76995 47 179 0.67413 0.77637 15.2% 64.2 92s
100063 5088 infeasible 52 0.67413 0.77637 15.2% 64.4 93s
101790 5210 0.77615 71 179 0.67413 0.77637 15.2% 64.5 95s
103286 5249 0.73795 76 173 0.67413 0.77615 15.1% 64.8 96s
104769 5255 0.76499 51 183 0.67413 0.77615 15.1% 65.1 97s
106177 5296 0.77615 52 161 0.67413 0.77615 15.1% 65.4 98s
107654 5382 0.77615 44 165 0.67413 0.77615 15.1% 65.8 100s
109084 5417 infeasible 51 0.67413 0.77615 15.1% 66.1 101s
110605 5462 infeasible 78 0.67413 0.77615 15.1% 66.4 102s
112116 5447 infeasible 46 0.67413 0.77615 15.1% 66.7 104s
113585 5501 0.71199 59 170 0.67413 0.77615 15.1% 67.1 105s
115213 5490 infeasible 44 0.67413 0.77615 15.1% 67.3 107s
116908 5576 infeasible 61 0.67413 0.77615 15.1% 67.6 108s
118430 5593 0.77615 55 154 0.67413 0.77615 15.1% 67.8 110s
119917 5651 infeasible 48 0.67413 0.77615 15.1% 68.2 111s
121737 5644 0.72653 50 186 0.67413 0.77615 15.1% 68.4 112s
123298 5793 0.73876 47 184 0.67413 0.77615 15.1% 68.7 114s
125131 5856 infeasible 60 0.67413 0.77615 15.1% 68.8 115s
126986 6634 infeasible 53 0.67413 0.77615 15.1% 68.8 117s
129168 6686 0.77615 91 169 0.67413 0.77615 15.1% 68.5 118s
130564 6734 infeasible 82 0.67413 0.77615 15.1% 68.7 119s
132198 6841 infeasible 86 0.67413 0.77615 15.1% 68.8 120s
133755 7128 0.75626 83 177 0.67413 0.77615 15.1% 68.9 122s
135460 7226 infeasible 189 0.67413 0.77615 15.1% 68.9 123s
136872 7234 infeasible 95 0.67413 0.77615 15.1% 69.1 124s
138290 7318 cutoff 93 0.67413 0.77615 15.1% 69.3 126s
139788 7360 infeasible 95 0.67413 0.77615 15.1% 69.5 127s
141502 7333 0.77615 92 158 0.67413 0.77615 15.1% 69.6 128s
142853 7427 infeasible 93 0.67413 0.77615 15.1% 69.8 129s
144565 7539 infeasible 185 0.67413 0.77615 15.1% 69.9 131s
146179 7537 0.77615 91 170 0.67413 0.77615 15.1% 69.9 132s
147677 7579 infeasible 98 0.67413 0.77615 15.1% 70.2 133s
149227 7613 infeasible 100 0.67413 0.77615 15.1% 70.3 135s
150765 7646 infeasible 97 0.67413 0.77615 15.1% 70.5 136s
152336 7704 infeasible 119 0.67413 0.77615 15.1% 70.7 137s
153936 7763 infeasible 113 0.67413 0.77615 15.1% 70.9 138s
155503 7766 infeasible 114 0.67413 0.77615 15.1% 71.1 140s
157034 7704 infeasible 204 0.67413 0.77615 15.1% 71.3 141s
158536 7734 infeasible 105 0.67413 0.77615 15.1% 71.5 142s
160140 7816 infeasible 101 0.67413 0.77615 15.1% 71.7 143s
161624 7926 0.77615 90 174 0.67413 0.77615 15.1% 71.9 145s
163238 8084 0.77615 104 171 0.67413 0.77615 15.1% 72.1 146s
164752 8184 0.77615 93 169 0.67413 0.77615 15.1% 72.2 147s
166288 8216 0.77615 107 161 0.67413 0.77615 15.1% 72.4 149s
167810 8240 infeasible 110 0.67413 0.77615 15.1% 72.6 150s
169500 8230 0.77615 113 165 0.67413 0.77615 15.1% 72.7 151s
171056 8294 infeasible 113 0.67413 0.77615 15.1% 72.9 152s
172670 8336 0.77615 112 154 0.67413 0.77615 15.1% 73.1 154s
174382 8380 0.77615 97 165 0.67413 0.77615 15.1% 73.2 155s
175996 8354 0.77615 130 146 0.67413 0.77615 15.1% 73.3 156s
177642 8342 infeasible 95 0.67413 0.77615 15.1% 73.4 158s
179320 8359 infeasible 97 0.67413 0.77615 15.1% 73.6 159s
180843 8432 infeasible 111 0.67413 0.77615 15.1% 73.8 160s
182438 8414 0.77615 96 169 0.67413 0.77615 15.1% 73.9 162s
183946 8376 0.77502 99 174 0.67413 0.77615 15.1% 74.1 163s
185488 8511 0.67684 103 170 0.67413 0.77615 15.1% 74.3 165s
187241 8473 0.76887 114 159 0.67413 0.77615 15.1% 74.4 166s
188707 8475 0.72476 77 166 0.67413 0.77615 15.1% 74.5 167s
190541 8444 infeasible 85 0.67413 0.77615 15.1% 74.6 169s
192000 8495 infeasible 109 0.67413 0.77615 15.1% 74.8 170s
193625 8468 infeasible 103 0.67413 0.77615 15.1% 74.9 172s
195262 8538 infeasible 87 0.67413 0.77615 15.1% 75.0 173s
196938 8480 0.77615 102 169 0.67413 0.77615 15.1% 75.2 174s
198490 8469 cutoff 107 0.67413 0.77615 15.1% 75.3 176s
200121 8473 0.77615 112 172 0.67413 0.77615 15.1% 75.4 177s
201671 8470 0.77615 107 153 0.67413 0.77615 15.1% 75.6 179s
203360 8446 infeasible 118 0.67413 0.77615 15.1% 75.6 180s
204852 8418 infeasible 100 0.67413 0.77615 15.1% 75.8 181s
206532 8491 0.77615 96 169 0.67413 0.77615 15.1% 75.9 182s
208201 8514 0.77615 100 168 0.67413 0.77615 15.1% 76.0 184s
209722 8488 0.77615 112 165 0.67413 0.77615 15.1% 76.1 185s
211384 8502 0.77615 103 147 0.67413 0.77615 15.1% 76.2 186s
212906 8549 infeasible 105 0.67413 0.77615 15.1% 76.3 188s
214583 8509 0.77615 93 157 0.67413 0.77615 15.1% 76.4 189s
216339 8517 0.77615 101 175 0.67413 0.77615 15.1% 76.4 191s
217939 8521 0.67960 100 167 0.67413 0.77615 15.1% 76.5 192s
219495 8589 infeasible 83 0.67413 0.77615 15.1% 76.7 194s
221101 8599 0.77615 99 172 0.67413 0.77615 15.1% 76.7 195s
222691 8569 infeasible 116 0.67413 0.77615 15.1% 76.9 197s
224327 8548 0.77615 108 148 0.67413 0.77615 15.1% 77.0 198s
225878 8529 0.73533 75 170 0.67413 0.77615 15.1% 77.1 200s
227429 8452 infeasible 90 0.67413 0.77615 15.1% 77.2 201s
229018 8449 infeasible 88 0.67413 0.77615 15.1% 77.3 204s
229665 8457 infeasible 103 0.67413 0.77615 15.1% 77.4 206s
231475 8592 infeasible 93 0.67413 0.77615 15.1% 77.4 208s
233070 8627 infeasible 110 0.67413 0.77615 15.1% 77.5 210s
234717 8613 infeasible 85 0.67413 0.77615 15.1% 77.5 211s
236221 8651 infeasible 108 0.67413 0.77615 15.1% 77.7 213s
237679 8597 infeasible 102 0.67413 0.77615 15.1% 77.8 214s
239199 8770 0.77615 90 169 0.67413 0.77615 15.1% 77.9 216s
240814 9206 infeasible 105 0.67413 0.77615 15.1% 78.0 218s
242828 9321 0.70455 91 161 0.67413 0.77615 15.1% 77.9 219s
244545 9275 infeasible 92 0.67413 0.77615 15.1% 78.0 224s
246015 9295 infeasible 88 0.67413 0.77615 15.1% 78.1 227s
247713 9461 0.77615 103 171 0.67413 0.77615 15.1% 78.1 229s
249527 9351 infeasible 196 0.67413 0.77615 15.1% 78.1 231s
250935 9306 infeasible 101 0.67413 0.77615 15.1% 78.3 235s
252462 9286 0.77615 99 162 0.67413 0.77615 15.1% 78.3 237s
254086 9270 infeasible 122 0.67413 0.77615 15.1% 78.4 240s
255682 9178 infeasible 100 0.67413 0.77615 15.1% 78.5 242s
257346 9221 infeasible 112 0.67413 0.77615 15.1% 78.5 244s
258911 9314 infeasible 102 0.67413 0.77615 15.1% 78.5 246s
260492 9307 infeasible 107 0.67413 0.77615 15.1% 78.6 248s
261987 9368 infeasible 98 0.67413 0.77615 15.1% 78.7 250s
263590 9342 0.77615 92 172 0.67413 0.77615 15.1% 78.7 251s
265138 9354 infeasible 112 0.67413 0.77615 15.1% 78.8 253s
266620 9455 0.77615 97 171 0.67413 0.77615 15.1% 78.9 255s
268289 9509 infeasible 280 0.67413 0.77615 15.1% 79.0 257s
269947 9517 infeasible 216 0.67413 0.77615 15.1% 79.0 259s
271487 9528 infeasible 95 0.67413 0.77615 15.1% 79.1 261s
273074 9627 infeasible 107 0.67413 0.77615 15.1% 79.2 262s
274799 9578 cutoff 105 0.67413 0.77615 15.1% 79.2 264s
276332 9538 infeasible 215 0.67413 0.77615 15.1% 79.3 265s
277856 9486 0.77615 103 150 0.67413 0.77615 15.1% 79.4 267s
279414 9460 infeasible 98 0.67413 0.77615 15.1% 79.5 268s
281052 9429 infeasible 100 0.67413 0.77615 15.1% 79.6 270s
282659 9378 0.77615 96 163 0.67413 0.77615 15.1% 79.6 271s
284148 9334 infeasible 256 0.67413 0.77615 15.1% 79.7 273s
285850 9279 0.72959 60 185 0.67413 0.77615 15.1% 79.8 274s
287393 9237 0.75558 33 191 0.67413 0.77615 15.1% 79.9 276s
289059 9209 0.77615 106 154 0.67413 0.77615 15.1% 79.9 277s
290581 9099 0.77615 96 166 0.67413 0.77615 15.1% 80.0 279s
H291884 9099 0.6741279 0.77615 15.1% 80.1 279s
292159 9126 infeasible 101 0.67413 0.77615 15.1% 80.2 280s
293860 9136 0.77289 102 167 0.67413 0.77615 15.1% 80.2 282s
295578 9133 infeasible 101 0.67413 0.77615 15.1% 80.3 283s
297179 9040 0.77615 207 174 0.67413 0.77615 15.1% 80.4 285s
298720 8934 infeasible 93 0.67413 0.77615 15.1% 80.4 286s
300432 8985 infeasible 111 0.67413 0.77615 15.1% 80.5 288s
302241 9023 0.77584 52 162 0.67413 0.77615 15.1% 80.5 290s
303987 9231 cutoff 53 0.67413 0.77615 15.1% 80.5 292s
305583 9495 infeasible 51 0.67413 0.77615 15.1% 80.5 293s
307427 9536 infeasible 51 0.67413 0.77615 15.1% 80.5 295s
309134 9614 infeasible 97 0.67413 0.77615 15.1% 80.4 296s
310920 9853 cutoff 103 0.67413 0.77615 15.1% 80.3 298s
312761 9823 infeasible 47 0.67413 0.77615 15.1% 80.2 299s
314293 9656 0.77584 42 154 0.67413 0.77615 15.1% 80.2 300s
315838 9619 0.77584 37 145 0.67413 0.77615 15.1% 80.2 301s
317405 9682 0.77615 98 162 0.67413 0.77615 15.1% 80.2 303s
319320 9787 0.77615 75 167 0.67413 0.77615 15.1% 80.0 304s
321239 9677 0.68660 57 180 0.67413 0.77615 15.1% 79.9 306s
322865 9612 infeasible 48 0.67413 0.77615 15.1% 79.8 307s
324478 9447 0.77584 55 177 0.67413 0.77615 15.1% 79.8 309s
326025 9614 infeasible 90 0.67413 0.77584 15.1% 79.8 310s
327668 9807 cutoff 42 0.67413 0.77584 15.1% 79.8 312s
329079 9958 0.77584 59 175 0.67413 0.77584 15.1% 80.0 313s
330772 10114 0.77584 53 180 0.67413 0.77584 15.1% 80.0 315s
332302 10309 infeasible 63 0.67413 0.77584 15.1% 80.1 316s
H333997 10518 0.6741287 0.77584 15.1% 80.2 318s
335622 10675 0.69045 107 171 0.67413 0.77584 15.1% 80.2 319s
H335806 10675 0.6741289 0.77584 15.1% 80.2 319s
H336424 10675 0.6741382 0.77584 15.1% 80.2 319s
337569 10700 infeasible 47 0.67414 0.77584 15.1% 80.2 322s
338956 10657 infeasible 66 0.67414 0.77584 15.1% 80.2 324s
H339778 10657 0.6741390 0.77584 15.1% 80.2 324s
340607 10598 infeasible 53 0.67414 0.77584 15.1% 80.2 325s
342172 10526 infeasible 55 0.67414 0.77584 15.1% 80.3 326s
H342491 10526 0.6741395 0.77584 15.1% 80.3 326s
H343017 10526 0.6741399 0.77584 15.1% 80.3 326s
343832 10476 cutoff 45 0.67414 0.77584 15.1% 80.3 328s
345762 10443 infeasible 52 0.67414 0.77584 15.1% 80.3 330s
347601 10576 infeasible 53 0.67414 0.77584 15.1% 80.2 331s
349524 10752 infeasible 50 0.67414 0.76652 13.7% 80.2 332s
351310 11012 infeasible 55 0.67414 0.76312 13.2% 80.1 334s
353048 11569 infeasible 44 0.67414 0.76073 12.8% 80.0 335s
355079 11920 0.68121 52 156 0.67414 0.75842 12.5% 79.8 336s
356968 12389 0.74698 57 177 0.67414 0.75767 12.4% 79.6 338s
358713 12803 infeasible 67 0.67414 0.75767 12.4% 79.4 339s
360521 13604 0.68944 53 156 0.67414 0.75767 12.4% 79.2 340s
362494 14208 0.67972 62 177 0.67414 0.75289 11.7% 79.0 342s
364714 14757 0.68339 67 184 0.67414 0.75174 11.5% 78.7 343s
366517 15588 0.73303 54 180 0.67414 0.75063 11.3% 78.5 344s
368482 16364 infeasible 59 0.67414 0.74990 11.2% 78.3 346s
371148 16782 infeasible 60 0.67414 0.74843 11.0% 78.0 348s
373052 17298 infeasible 92 0.67414 0.74717 10.8% 77.7 349s
374780 17838 0.68042 57 167 0.67414 0.74572 10.6% 77.5 350s
376504 18193 0.73078 104 176 0.67414 0.74535 10.6% 77.3 352s
378319 18628 0.71860 52 175 0.67414 0.74411 10.4% 77.1 353s
379994 19062 0.69676 73 169 0.67414 0.74363 10.3% 76.8 354s
381804 19387 infeasible 64 0.67414 0.74263 10.2% 76.6 355s
383443 19943 0.73586 49 185 0.67414 0.74197 10.1% 76.4 356s
385209 20574 infeasible 46 0.67414 0.74142 10.0% 76.2 358s
386852 20922 infeasible 54 0.67414 0.74106 9.93% 76.0 359s
388326 21566 0.68356 70 181 0.67414 0.74044 9.83% 75.8 360s
390066 22426 0.68822 55 169 0.67414 0.74004 9.78% 75.6 362s
392890 23067 0.72311 67 176 0.67414 0.73920 9.65% 75.3 363s
394559 23600 0.67643 73 141 0.67414 0.73909 9.63% 75.1 364s
396376 24085 0.67747 59 166 0.67414 0.73830 9.52% 74.9 366s
397961 24592 0.70747 60 181 0.67414 0.73793 9.46% 74.7 367s
399584 25074 0.68644 57 175 0.67414 0.73739 9.38% 74.5 368s
401146 25658 0.70289 65 180 0.67414 0.73708 9.34% 74.4 369s
402904 26196 0.71673 66 163 0.67414 0.73688 9.31% 74.2 370s
404536 26693 0.70333 56 153 0.67414 0.73647 9.25% 74.0 372s
406153 27195 0.68856 62 181 0.67414 0.73643 9.24% 73.8 373s
407833 27758 0.72507 50 168 0.67414 0.73627 9.22% 73.6 374s
409608 28154 0.68155 63 169 0.67414 0.73562 9.12% 73.4 376s
411258 29210 infeasible 67 0.67414 0.73531 9.07% 73.2 378s
414254 30086 0.73011 54 181 0.67414 0.73496 9.02% 72.9 379s
416004 30821 infeasible 63 0.67414 0.73464 8.97% 72.7 380s
417629 31339 0.67464 65 163 0.67414 0.73454 8.96% 72.5 382s
419233 32109 0.71026 56 177 0.67414 0.73439 8.94% 72.3 383s
420989 32628 0.67471 73 179 0.67414 0.73421 8.91% 72.1 384s
422486 33439 0.68474 60 171 0.67414 0.73411 8.90% 71.9 385s
424127 34149 0.68140 65 181 0.67414 0.73383 8.85% 71.7 386s
425771 34764 infeasible 70 0.67414 0.73372 8.84% 71.6 388s
427436 35245 0.67471 86 174 0.67414 0.73359 8.82% 71.4 389s
429091 35797 0.69210 54 159 0.67414 0.73335 8.78% 71.2 390s
430701 36236 infeasible 56 0.67414 0.73313 8.75% 71.0 391s
432256 37543 infeasible 57 0.67414 0.73301 8.73% 70.9 393s
435251 38147 0.70638 52 163 0.67414 0.73268 8.68% 70.6 394s
436769 38654 infeasible 53 0.67414 0.73255 8.66% 70.4 395s
438440 39466 0.68869 67 176 0.67414 0.73234 8.63% 70.2 397s
440162 39975 infeasible 81 0.67414 0.73225 8.62% 70.1 398s
441827 40606 0.67517 69 168 0.67414 0.73203 8.59% 69.9 399s
H442394 40606 0.6741400 0.73202 8.59% 69.8 399s
443402 40992 0.70301 63 176 0.67414 0.73193 8.57% 69.7 400s
H444558 40990 0.6741473 0.73186 8.56% 69.6 400s
444842 41418 infeasible 63 0.67415 0.73177 8.55% 69.6 402s
446430 41986 0.67429 63 143 0.67415 0.73169 8.54% 69.4 403s
448060 42827 0.67933 78 163 0.67415 0.73135 8.49% 69.3 404s
449911 43337 0.68412 60 176 0.67415 0.73120 8.46% 69.1 405s
451613 43874 infeasible 65 0.67415 0.73113 8.45% 68.9 406s
453166 44986 0.71920 58 185 0.67415 0.73088 8.41% 68.8 408s
456186 45727 0.68027 76 180 0.67415 0.73060 8.37% 68.5 410s
457871 46586 0.69007 75 178 0.67415 0.73052 8.36% 68.3 411s
459600 47072 infeasible 71 0.67415 0.73027 8.33% 68.1 412s
460986 47451 infeasible 78 0.67415 0.73012 8.30% 68.0 413s
462537 48093 0.68610 77 180 0.67415 0.72997 8.28% 67.9 414s
464129 48818 0.68073 62 170 0.67415 0.72988 8.27% 67.7 416s
465898 49458 infeasible 71 0.67415 0.72976 8.25% 67.5 417s
467608 49976 0.70745 53 170 0.67415 0.72960 8.23% 67.4 418s
469144 50520 0.68173 73 182 0.67415 0.72944 8.20% 67.2 419s
470746 51213 infeasible 53 0.67415 0.72936 8.19% 67.1 420s
472427 52009 0.70289 55 175 0.67415 0.72923 8.17% 66.9 421s
474179 53201 0.67811 69 175 0.67415 0.72918 8.16% 66.8 423s
477203 53799 infeasible 59 0.67415 0.72889 8.12% 66.5 424s
479035 54495 0.70172 77 182 0.67415 0.72877 8.10% 66.3 426s
480749 55345 infeasible 75 0.67415 0.72861 8.08% 66.2 427s
482361 55954 0.69854 62 176 0.67415 0.72852 8.07% 66.0 428s
483876 56527 0.72447 48 177 0.67415 0.72842 8.05% 65.9 429s
485439 57226 cutoff 69 0.67415 0.72833 8.04% 65.7 430s
487046 58053 0.69892 69 179 0.67415 0.72818 8.01% 65.6 431s
488737 58937 0.71975 69 187 0.67415 0.72808 8.00% 65.4 432s
490459 59709 0.67931 90 178 0.67415 0.72806 8.00% 65.3 434s
491929 60614 0.68127 78 178 0.67415 0.72796 7.98% 65.2 435s
493326 61122 0.72570 48 182 0.67415 0.72788 7.97% 65.0 436s
494776 62123 infeasible 85 0.67415 0.72788 7.97% 64.9 437s
497659 63039 0.68440 82 176 0.67415 0.72763 7.93% 64.7 439s
499471 63844 0.67433 109 148 0.67415 0.72759 7.93% 64.5 440s
501074 64784 infeasible 78 0.67415 0.72751 7.92% 64.4 441s
502868 65398 infeasible 71 0.67415 0.72739 7.90% 64.2 442s
504314 66155 0.68775 63 172 0.67415 0.72730 7.88% 64.1 443s
505965 66747 infeasible 69 0.67415 0.72723 7.87% 64.0 444s
507587 67443 0.72111 54 181 0.67415 0.72715 7.86% 63.9 446s
509175 67887 0.72348 70 184 0.67415 0.72708 7.85% 63.7 447s
510677 68512 0.70724 59 182 0.67415 0.72695 7.83% 63.6 448s
512366 69146 0.72322 59 179 0.67415 0.72680 7.81% 63.5 449s
514032 69643 0.69887 65 171 0.67415 0.72670 7.80% 63.3 450s
515639 70821 cutoff 71 0.67415 0.72660 7.78% 63.2 452s
518651 71348 0.69072 55 163 0.67415 0.72647 7.76% 63.0 453s
520280 71925 0.68017 69 170 0.67415 0.72638 7.75% 62.9 454s
521887 72834 0.71665 46 170 0.67415 0.72628 7.73% 62.7 455s
523602 73375 cutoff 69 0.67415 0.72624 7.73% 62.6 456s
525271 73868 0.71627 57 183 0.67415 0.72615 7.71% 62.5 458s
526702 74650 0.68158 63 175 0.67415 0.72606 7.70% 62.4 459s
528312 75300 cutoff 66 0.67415 0.72596 7.69% 62.2 460s
529908 76165 infeasible 50 0.67415 0.72590 7.68% 62.1 461s
531569 76903 0.69594 67 178 0.67415 0.72583 7.67% 62.0 462s
533247 77611 0.68060 73 175 0.67415 0.72576 7.66% 61.9 463s
534831 78220 0.68100 67 177 0.67415 0.72565 7.64% 61.8 464s
536548 79469 0.69467 58 179 0.67415 0.72562 7.64% 61.6 466s
539705 79943 0.68626 68 166 0.67415 0.72536 7.60% 61.4 467s
541131 80644 0.69111 65 178 0.67415 0.72533 7.59% 61.3 469s
542632 81581 infeasible 42 0.67415 0.72520 7.57% 61.2 470s
544051 82372 0.68244 79 176 0.67415 0.72517 7.57% 61.1 471s
545754 82788 0.71882 54 183 0.67415 0.72513 7.56% 61.0 472s
547246 83265 0.68290 73 172 0.67415 0.72505 7.55% 60.9 473s
548971 83854 infeasible 62 0.67415 0.72491 7.53% 60.7 474s
550648 84588 0.68430 61 164 0.67415 0.72486 7.52% 60.6 476s
552318 85221 0.70379 72 180 0.67415 0.72477 7.51% 60.5 477s
553843 86011 infeasible 64 0.67415 0.72474 7.50% 60.4 478s
555397 86668 0.70299 58 175 0.67415 0.72467 7.49% 60.3 479s
557040 87503 0.68145 61 169 0.67415 0.72457 7.48% 60.2 481s
559943 88049 0.68497 81 168 0.67415 0.72449 7.47% 60.0 482s
561537 88521 0.69265 57 178 0.67415 0.72441 7.46% 59.9 483s
563147 88934 0.67474 61 154 0.67415 0.72431 7.44% 59.8 485s
564752 89646 infeasible 73 0.67415 0.72420 7.42% 59.7 486s
566488 90016 0.67464 62 162 0.67415 0.72415 7.42% 59.6 487s
567996 90470 0.68369 60 169 0.67415 0.72408 7.41% 59.5 488s
569608 90995 0.68795 60 166 0.67415 0.72404 7.40% 59.4 489s
571333 91584 0.68948 72 170 0.67415 0.72398 7.39% 59.2 490s
573096 92069 0.71824 54 170 0.67415 0.72385 7.37% 59.1 491s
574735 92659 infeasible 48 0.67415 0.72373 7.36% 59.0 492s
576357 93265 infeasible 69 0.67415 0.72369 7.35% 58.9 494s
578093 94363 infeasible 65 0.67415 0.72362 7.34% 58.8 495s
580885 94911 0.68948 66 161 0.67415 0.72353 7.32% 58.6 497s
582523 95457 0.71521 61 184 0.67415 0.72343 7.31% 58.5 498s
584265 95982 infeasible 65 0.67415 0.72338 7.30% 58.4 499s
585798 96528 infeasible 89 0.67415 0.72330 7.29% 58.3 500s
587526 96943 0.71295 63 186 0.67415 0.72328 7.29% 58.2 501s
589275 97486 0.69249 60 180 0.67415 0.72318 7.27% 58.1 502s
590860 98237 0.69982 52 164 0.67415 0.72313 7.27% 58.0 504s
592553 98604 0.69028 57 166 0.67415 0.72311 7.26% 57.9 505s
594066 99324 0.68437 65 170 0.67415 0.72301 7.25% 57.8 506s
595680 99899 0.70908 49 157 0.67415 0.72298 7.24% 57.7 507s
597247 100401 0.70877 61 175 0.67415 0.72294 7.24% 57.6 509s
598831 101572 infeasible 72 0.67415 0.72284 7.22% 57.5 511s
601770 102009 infeasible 64 0.67415 0.72277 7.21% 57.3 512s
603337 102450 infeasible 65 0.67415 0.72275 7.21% 57.3 513s
604994 102845 0.67881 66 157 0.67415 0.72262 7.19% 57.2 515s
606673 103465 infeasible 65 0.67415 0.72258 7.18% 57.0 516s
608353 104053 infeasible 69 0.67415 0.72253 7.18% 56.9 517s
609893 104726 0.70657 56 178 0.67415 0.72248 7.17% 56.9 519s
611520 105175 infeasible 71 0.67415 0.72242 7.16% 56.8 520s
613127 105679 0.71266 61 172 0.67415 0.72234 7.15% 56.7 521s
614625 106014 0.71013 53 180 0.67415 0.72230 7.14% 56.6 522s
616270 106751 0.70163 57 175 0.67415 0.72226 7.14% 56.5 523s
617675 107200 0.68699 62 170 0.67415 0.72224 7.13% 56.4 525s
619348 108315 infeasible 64 0.67415 0.72220 7.13% 56.3 527s
622135 108824 cutoff 64 0.67415 0.72216 7.12% 56.2 528s
623828 109565 infeasible 67 0.67415 0.72210 7.11% 56.1 529s
625529 110138 0.68415 66 152 0.67415 0.72206 7.11% 56.0 531s
627174 111084 0.68054 69 165 0.67415 0.72202 7.10% 55.9 532s
628864 111631 0.68659 70 182 0.67415 0.72196 7.09% 55.8 533s
630433 112186 0.69979 74 177 0.67415 0.72192 7.09% 55.7 534s
632114 112609 0.71669 57 181 0.67415 0.72188 7.08% 55.6 536s
633635 113155 0.68445 57 180 0.67415 0.72181 7.07% 55.5 537s
635205 113749 infeasible 58 0.67415 0.72177 7.06% 55.4 538s
636799 114300 0.68900 71 165 0.67415 0.72174 7.06% 55.4 540s
638464 115010 0.68446 60 173 0.67415 0.72166 7.05% 55.3 541s
640134 115816 0.67982 64 168 0.67415 0.72159 7.04% 55.2 543s
642836 115825 infeasible 65 0.67415 0.72158 7.04% 55.0 544s
642859 115832 0.67441 65 132 0.67415 0.72158 7.04% 55.0 545s
642884 115841 infeasible 66 0.67415 0.72158 7.04% 55.0 546s
642931 115861 0.71096 55 179 0.67415 0.72158 7.04% 55.0 547s
642951 115865 0.70765 56 181 0.67415 0.72158 7.04% 55.0 548s
642979 115897 0.70656 57 183 0.67415 0.72155 7.03% 55.0 550s
643143 116001 0.71051 64 172 0.67415 0.72155 7.03% 55.0 551s
643653 116821 0.69901 61 172 0.67415 0.72151 7.03% 55.0 553s
645489 117687 0.69079 58 151 0.67415 0.72151 7.02% 54.9 555s
648199 118567 0.68840 55 167 0.67415 0.72137 7.01% 54.8 557s
650401 119168 0.71571 56 187 0.67415 0.72132 7.00% 54.6 558s
652544 120034 infeasible 51 0.67415 0.72123 6.98% 54.5 560s
654566 120753 infeasible 82 0.67415 0.72121 6.98% 54.4 562s
656605 121678 0.67903 84 175 0.67415 0.72112 6.97% 54.3 563s
658494 122159 infeasible 71 0.67415 0.72109 6.96% 54.2 565s
660321 122633 infeasible 61 0.67415 0.72103 6.95% 54.1 566s
662155 123536 0.69277 65 177 0.67415 0.72096 6.94% 54.0 568s
664946 124075 0.68003 71 164 0.67415 0.72090 6.93% 53.9 570s
666433 124454 0.68763 64 162 0.67415 0.72087 6.93% 53.8 571s
668090 124997 infeasible 83 0.67415 0.72079 6.92% 53.7 572s
669775 125952 0.69580 54 175 0.67415 0.72073 6.91% 53.7 574s
671452 126617 infeasible 54 0.67415 0.72071 6.91% 53.6 575s
673167 127130 infeasible 65 0.67415 0.72066 6.90% 53.5 576s
674844 127529 infeasible 56 0.67415 0.72063 6.90% 53.4 578s
676221 128011 0.69319 60 176 0.67415 0.72058 6.89% 53.4 579s
677905 128698 infeasible 76 0.67415 0.72054 6.88% 53.3 580s
679516 129275 0.67577 56 175 0.67415 0.72048 6.87% 53.2 582s
681287 130009 infeasible 65 0.67415 0.72046 6.87% 53.1 583s
682987 131155 0.68325 71 181 0.67415 0.72040 6.86% 53.0 585s
685919 131948 0.68338 58 174 0.67415 0.72037 6.86% 52.9 586s
687482 132455 infeasible 80 0.67415 0.72033 6.85% 52.8 588s
688919 132902 0.68691 73 183 0.67415 0.72028 6.84% 52.7 589s
690374 133210 infeasible 67 0.67415 0.72025 6.84% 52.7 590s
691908 133570 0.69203 64 173 0.67415 0.72019 6.83% 52.6 592s
693488 133995 0.69069 68 170 0.67415 0.72014 6.82% 52.5 593s
695165 134615 0.67650 67 168 0.67415 0.72010 6.82% 52.5 594s
696683 135175 0.68193 78 175 0.67415 0.72008 6.81% 52.4 596s
698349 135700 0.71691 43 171 0.67415 0.72002 6.81% 52.3 597s
699980 136189 0.67818 65 166 0.67415 0.72000 6.80% 52.3 599s
701643 136815 0.68346 75 168 0.67415 0.71995 6.79% 52.2 600s
701728 136815 0.70964 56 167 0.67415 0.71995 6.79% 52.2 600sThank you in advance for your time and insights
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Gurobi Staff
Hi Than,
Modern MIP solvers are very complex beasts and it is not easy to infer what is happening from logs alone. I'm not sure what you mean by “faulty branch”. Perhaps you are referring to a node LP solve that gets stuck, or does not perform reasonably? In that case you typically don't see regular logging, which is not the case in your log.
If I had to pick a possible reason due to plateaus it would be the solver working on disconnected components in the model, but there are other possible explanations too.
Regarding observations B), you probably can't reliably classify the instances unless you are running them across multiple values of the Seed parameter. See How can I make accurate comparisons?. Then regarding your hypotheses, again I think these are unlikely, but coming up with a single likely explanation is improbable.
- Riley
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