我正在使用PuLP和Gurobi求解器以及各种参数在Python脚本中求解MILP。
使用“ for”循环进行灵敏度分析，每次运行时都要更改参数。首先运行的是“最坏情况”参数（效率很低的发电机和非常差的绝缘材料），逐渐遍历MILP时，这些参数会逐渐得到改善。在某些时候，以一种可以很快找到解决方案的方式设置参数时，Gurobipy似乎没有找到解决方案。这是日志：
Changed value of parameter TimeLimit to 300.0
Prev: 1e+100 Min: 0.0 Max: 1e+100 Default: 1e+100
Optimize a model with 8640 rows, 10080 columns and 20158 nonzeros
Variable types: 8640 continuous, 1440 integer (0 binary)
Coefficient statistics:
Matrix range [2e-05, 4e+04]
Objective range [1e+03, 1e+03]
Bounds range [7e-01, 4e+04]
RHS range [1e-02, 3e+04]
Presolve removed 7319 rows and 7331 columns
Presolve time: 0.03s
Presolved: 1321 rows, 2749 columns, 4069 nonzeros
Variable types: 1320 continuous, 1429 integer (1429 binary)
Root relaxation: objective 4.910087e+05, 679 iterations, 0.01 seconds
Nodes | Current Node | Objective Bounds | Work
Expl Unexpl | Obj Depth IntInf | Incumbent BestBd Gap | It/Node Time
0 0 491008.698 0 11 - 491008.698 - - 0s
0 0 491008.698 0 11 - 491008.698 - - 0s
0 2 491008.698 0 11 - 491008.698 - - 0s
30429 24907 491680.652 942 3 - 491011.160 - 1.0 5s
73520 66861 491679.428 958 3 - 491011.996 - 1.0 10s
123770 116802 491762.182 1241 2 - 491012.439 - 1.0 15s
174010 165706 491896.963 1266 2 - 491012.636 - 1.0 20s
221580 212357 491234.860 1144 5 - 491012.931 - 1.0 25s
270004 259925 491187.818 904 5 - 491013.203 - 1.0 30s
322655 311334 491807.797 1254 2 - 491013.349 - 1.0 35s
379633 367554 491194.198 941 5 - 491013.571 - 1.0 40s
434035 420930 494029.008 1375 1 - 491013.695 - 1.0 45s
490442 476293 494016.622 1354 1 - 491013.851 - 1.0 50s
544923 529662 491203.097 990 5 - 491013.947 - 1.0 55s
597268 581228 492312.463 1253 2 - 491014.018 - 1.0 60s
650478 633331 491093.453 383 5 - 491014.133 - 1.0 65s
703246 685374 491755.974 1241 2 - 491014.188 - 1.0 70s
756675 737356 491069.420 272 6 - 491014.250 - 1.0 75s
811974 791502 491560.902 1235 3 - 491014.308 - 1.0 80s
866893 845452 491112.986 497 5 - 491014.345 - 1.0 85s
923793 901357 494014.134 1348 1 - 491014.390 - 1.0 90s
981961 958448 492971.305 1266 2 - 491014.435 - 1.0 95s
1039971 1015276 491545.502 1216 4 - 491014.502 - 1.0 100s
1097780 1071899 491171.468 818 5 - 491014.527 - 1.0 105s
1154447 1127328 491108.438 461 5 - 491014.591 - 1.0 110s
1212776 1184651 491024.147 57 6 - 491014.622 - 1.0 115s
1272535 1243171 495190.479 1266 2 - 491014.643 - 1.0 120s
1332126 1301674 491549.733 1228 3 - 491014.668 - 1.0 125s
1392772 1361287 491549.544 1219 3 - 491014.694 - 1.0 130s
1452380 1419870 491754.309 1237 2 - 491014.717 - 1.0 135s
1511070 1477572 491229.746 1131 5 - 491014.735 - 1.0 140s
1569783 1535126 491130.785 587 5 - 491014.764 - 1.0 145s
1628729 1593010 494026.669 1368 1 - 491014.775 - 1.0 150s
1687841 1651373 493189.023 1264 2 - 491014.810 - 1.0 155s
1747707 1709984 491548.263 1223 3 - 491014.841 - 1.0 160s
1807627 1768777 491160.795 755 5 - 491014.876 - 1.0 165s
1865730 1825486 494030.045 1379 1 - 491014.899 - 1.0 170s
1925615 1884356 494028.562 1374 1 - 491014.923 - 1.0 175s
1984204 1941827 491847.402 1115 2 - 491014.933 - 1.0 180s
2044016 2000572 491244.304 1210 5 - 491014.970 - 1.0 185s
2102125 2057622 491174.413 828 5 - 491014.989 - 1.0 190s
2161393 2115829 491115.089 532 5 - 491015.017 - 1.0 195s
2220721 2174168 491086.511 348 6 - 491015.041 - 1.0 200s
2281194 2233610 infeasible 1433 - 491015.048 - 1.0 205s
2341496 2292542 492824.696 1262 2 - 491015.069 - 1.0 210s
2399836 2349837 491548.142 1224 3 - 491015.084 - 1.0 215s
2459295 2408276 491178.869 853 5 - 491015.088 - 1.0 220s
2519203 2467098 491112.995 488 5 - 491015.106 - 1.0 225s
2578654 2525514 491069.711 270 6 - 491015.123 - 1.0 230s
2636111 2582093 491762.206 1250 2 - 491015.139 - 1.0 235s
2695962 2640805 491237.559 1152 5 - 491015.146 - 1.0 240s
2755319 2699171 491156.897 797 6 - 491015.161 - 1.0 245s
2813620 2756371 491024.109 43 7 - 491015.182 - 1.0 250s
2872810 2814527 492309.743 1255 2 - 491015.185 - 1.0 255s
2932550 2873227 492180.501 1255 2 - 491015.202 - 1.0 260s
2991586 2931246 491244.162 1207 5 - 491015.217 - 1.0 265s
3050385 2988872 491196.181 952 5 - 491015.228 - 1.0 270s
3110478 3047787 491127.746 560 5 - 491015.247 - 1.0 275s
3169730 3105844 491109.579 525 6 - 491015.266 - 1.0 280s
3229972 3165019 494029.916 1376 1 - 491015.276 - 1.0 285s
3289639 3223661 491861.516 1173 2 - 491015.293 - 1.0 290s
3349653 3282631 491862.419 1185 2 - 491015.305 - 1.0 295s
Explored 3409667 nodes (3506772 simplex iterations) in 300.02 seconds
Thread count was 8 (of 8 available processors)
Solution count 0
Time limit reached
Best objective -, best bound 4.910153206264e+05, gap -
('Gurobi status=', 9)
我已经将最大求解时间增加到300s（更多的时间占用了更多的RAM，并且程序在某个时候终止了），并使用参数（更糟糕的参数设置找到了解决方案！），但是似乎没有任何效果。可能是什么问题？
答案 0 :(得分：0)
我可以通过插入“ None”（最长）来解决问题，并插入一个最大的空白来解决此问题。