This is the C# source code for part 3 of my series on genetic algorithms.
In this part we extend the genetic solver from part 2 to be able to solve the Travelling Salesperson Problem which belongs to a more generic class of real-world problems related to route or sequence optimization.
We start with a series of points laid out in a circle
......................*.................
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..................b...a.................
..............c.........................
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..........d...................z.........
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.......e.........................y......
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....f...............................x...
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..g...................................w.
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..h...................................v.
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..i...................................u.
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...j.................................t..
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.....k.............................s....
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........l.......................r.......
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............m...............q...........
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................n.......p...............
....................o...................
* => home base
and update the solver to support this kind of problem.
Sample output:
Expect optimal route abcdefghijklmnopqrstuvwxyz* to have fitness 122
generation 1 fitness 5752 *nzficw*vxjtlrkozbrhpgfyuep elapsed: 00:00:00.0557000 by Random
generation 4 fitness 4680 *kjdaizfvftwcngkrohsuybeumo elapsed: 00:00:00.0745969 by Crossover
generation 8 fitness 4654 *orkgncwtfvfziadjkhomuebyus elapsed: 00:00:00.0833367 by Swap
generation 10 fitness 4647 *adcxwkuqgpkumkheflyscoribn elapsed: 00:00:00.0870942 by Crossover
generation 10 fitness 4583 *orkgncwtfifzvadjkhomuebyus elapsed: 00:00:00.0873425 by Swap
generation 12 fitness 4578 *orkgxcwtfifzvadjkhomuebyus elapsed: 00:00:00.0919437 by Mutation
generation 13 fitness 4546 *adcxwvuqggpirocslyfehkmukn elapsed: 00:00:00.0932691 by Mutation
generation 14 fitness 3738 *ieuyrgphrbnokrltjxfswcvpqz elapsed: 00:00:00.0943789 by Mutation
generation 15 fitness 3680 *kjdaizfvftwcngkrohsxybeumo elapsed: 00:00:00.0980285 by Mutation
generation 16 fitness 3638 *elmohtjdkizfvftwcagnrobsuy elapsed: 00:00:00.0994994 by Mutation
generation 18 fitness 3620 *feuyrgjhrbnoxrltpkimwcvwqz elapsed: 00:00:00.1022795 by Mutation
generation 19 fitness 3606 *ieuykgptrbnokrlhjxfcwsvpqz elapsed: 00:00:00.1044059 by Swap
generation 19 fitness 3588 *elmohijdktzfvftwcagnrobsuy elapsed: 00:00:00.1053475 by Swap
generation 21 fitness 3538 *adcxwkvqgpkumkheflysnoribc elapsed: 00:00:00.1086238 by Mutation
generation 22 fitness 2661 *emlohtjvfzskdftwcagnrqbiuy elapsed: 00:00:00.1102894 by Mutation
generation 22 fitness 2611 *ieuydgptrbnokxlhjrfcwsvpqz elapsed: 00:00:00.1107309 by Mutation
generation 23 fitness 2610 *ieuydgptrbnokwlhjrfcxsvpqz elapsed: 00:00:00.1129340 by Swap
generation 24 fitness 2569 *ieuydgptrbnokwvsxcfrjhlpqz elapsed: 00:00:00.1138274 by Reverse
generation 26 fitness 2545 *amlohtjifzskdftwcegnrqbvuy elapsed: 00:00:00.1177485 by Swap
generation 30 fitness 2533 *amlhotjifzskdftwcegnrqbvuy elapsed: 00:00:00.1252988 by Swap
generation 31 fitness 2514 *ieuydgptvbnorxlhjkfcwsrpqz elapsed: 00:00:00.1265510 by Swap
generation 31 fitness 1640 *dqpvpxcfrlhjwkonbmstgzyuei elapsed: 00:00:00.1279769 by Mutation
generation 36 fitness 1635 *cqpvpxdfrlhjwkonbmstgzyuei elapsed: 00:00:00.1349471 by Swap
generation 36 fitness 1537 *amlthojifcwxfdkszegnrqbvuy elapsed: 00:00:00.1354383 by Mutation
generation 38 fitness 1521 *agnrqzvuoljdcbhtfisymkefxw elapsed: 00:00:00.1383850 by Mutation
generation 41 fitness 1518 *ablthojifcwxfdkszegnrqmvuy elapsed: 00:00:00.1439563 by Swap
generation 42 fitness 1510 *agnrqxvuoljdcbhtfisymkefzw elapsed: 00:00:00.1451785 by Swap
generation 42 fitness 1498 *kmlontjisbcwtpdgfaehrqzvuy elapsed: 00:00:00.1463426 by Mutation
generation 43 fitness 1435 *atsefghbcdjlouvzqrnymkifxw elapsed: 00:00:00.1472218 by Swap
generation 46 fitness 1434 *atsefghbcdjlorqzvunymkifxw elapsed: 00:00:00.1520952 by Reverse
generation 51 fitness 1426 *atsefghbcdjlouvzqrnymkixxw elapsed: 00:00:00.1609032 by Mutation
generation 51 fitness 1423 *avsefghifkmynutzqroljdcbxw elapsed: 00:00:00.1614609 by Reverse
generation 52 fitness 1414 *avsefghbcdjlorqwtunymkifxz elapsed: 00:00:00.1622193 by Swap
generation 54 fitness 1389 *avseffyzutnqroljdcbhgkmixw elapsed: 00:00:00.1668875 by Swap
generation 55 fitness 1388 *atsefghbcdfikmynjlorqzvuxw elapsed: 00:00:00.1686067 by Reverse
generation 56 fitness 1377 *atsefghbcdfikmjnuvzqrolyxw elapsed: 00:00:00.1699975 by Swap
generation 61 fitness 1338 *atsefghbcdfikmqnjloryzvuxw elapsed: 00:00:00.1788435 by Swap
generation 63 fitness 434 *agfeydcbhmjlouvzqrnstkipxw elapsed: 00:00:00.1817006 by Mutation
generation 68 fitness 402 *atswxpmkiynuvzqroljdcbhgfe elapsed: 00:00:00.1905062 by Mutation
generation 70 fitness 356 *atswxpmkiyzuvnqroljdcbhgfe elapsed: 00:00:00.1941582 by Swap
generation 85 fitness 348 *atswxpmnorqlvuzyikjdcbhgfe elapsed: 00:00:00.2164192 by Reverse
generation 89 fitness 334 *atswxpmkiyzuvrqnoljdcbhgfe elapsed: 00:00:00.2232943 by Reverse
generation 93 fitness 328 *azikmnvuytswxpqroljdcbhgfe elapsed: 00:00:00.2302641 by Reverse
generation 94 fitness 323 *atswxpmnorqlvuzydbcijkhgfe elapsed: 00:00:00.2321492 by Reverse
generation 105 fitness 314 *atswxpqronmlvuzyjkidefghbc elapsed: 00:00:00.2489732 by Reverse
generation 110 fitness 299 *adefghikmpxwsqroljncbztuvy elapsed: 00:00:00.2582542 by Reverse
generation 111 fitness 295 *atslmnorqpxwvuzyjkidefghbc elapsed: 00:00:00.2603764 by Reverse
generation 116 fitness 287 *adefghikjpxwsqrolmncbztuvy elapsed: 00:00:00.2692063 by Swap
generation 125 fitness 285 *adefghikjzxwsqronmlcbptuvy elapsed: 00:00:00.2832807 by Reverse
generation 126 fitness 282 *atslmnorqpxuvwzyjkihfgebcd elapsed: 00:00:00.2851542 by Reverse
generation 131 fitness 279 *axslmnorqptuvwzyjkidefghbc elapsed: 00:00:00.2935830 by Swap
generation 132 fitness 275 *atslmnorqpwuvxzyjkihfgebcd elapsed: 00:00:00.2954973 by Swap
generation 134 fitness 271 *abegfhikjyzwvuxrqponmlstcd elapsed: 00:00:00.2984190 by Swap
generation 135 fitness 264 *azyxpqronmlstwvujkidefghbc elapsed: 00:00:00.3007587 by Reverse
generation 136 fitness 260 *azyxvwtslmnorqpujkidefghbc elapsed: 00:00:00.3018316 by Reverse
generation 139 fitness 256 *azwuvxpqronmlstyjkihgfedbc elapsed: 00:00:00.3074837 by Reverse
generation 141 fitness 231 *azyxpqronmlstwvujkihgfedbc elapsed: 00:00:00.3112030 by Swap
generation 147 fitness 217 *azyxpqruvwtslmnojkihgfedbc elapsed: 00:00:00.3200379 by Reverse
generation 152 fitness 216 *azyxpqruvwtsjmnolkihgfedcb elapsed: 00:00:00.3273526 by Swap
generation 163 fitness 203 *azyxpqruvwtsomnljkihgfedbc elapsed: 00:00:00.3447502 by Swap
generation 182 fitness 202 *azyxsuvwtrqplmnoikjhgefdcb elapsed: 00:00:00.3753730 by Reverse
generation 186 fitness 195 *azyxpqruvwtsomnlkjihgfedbc elapsed: 00:00:00.3815321 by Swap
generation 189 fitness 187 *azyxstwvurqpomnljkihgfebdc elapsed: 00:00:00.3875450 by Reverse
generation 197 fitness 179 *azyxstwvurqpomnljkihgfedbc elapsed: 00:00:00.3995630 by Swap
generation 221 fitness 176 *azxywuvtrspqomnljkihgfedcb elapsed: 00:00:00.4383912 by Swap
generation 225 fitness 168 *azxywuvtrsqpomnljkihgfedcb elapsed: 00:00:00.4460578 by Swap
generation 240 fitness 164 *azyxwvtsurqpomnljkihgfedbc elapsed: 00:00:00.4679619 by Reverse
generation 255 fitness 163 *azyxwuvtsrqpolnmkijhgefdcb elapsed: 00:00:00.4913439 by Reverse
generation 264 fitness 157 *azyxwuvtsrqpomnlkjihfgedbc elapsed: 00:00:00.5052970 by Reverse
generation 269 fitness 156 *azyxwvustqrpomnljkihgfedcb elapsed: 00:00:00.5135945 by Crossover
generation 272 fitness 154 *azyxwuvtsrqpomnlkijhgefdcb elapsed: 00:00:00.5190518 by Swap
generation 296 fitness 145 *azyxwtvusrqopnmlkjihgfedcb elapsed: 00:00:00.5544857 by Swap
generation 335 fitness 139 *abcdefghikjlnmopqrstuvwxyz elapsed: 00:00:00.6132106 by Swap
generation 344 fitness 138 *azyxwvutsrqponmljkihgfedbc elapsed: 00:00:00.6259218 by Reverse
generation 349 fitness 130 *azyxwvutsrqponmljkihgfedcb elapsed: 00:00:00.6340854 by Reverse
generation 387 fitness 121 *azyxwvutsrqponmlkjihgfedcb elapsed: 00:00:00.6923056 by Reverse
This shows that the solver determined the optimal route from home base, around the circle, and back to home base to be:
(home) -> azyxwvutsrqponmlkjihgfedcb -> (home)
After that we take on problem eil51 from the TSPLIB, a standard set of Travelling Salesperson Problems used in benchmarking solvers.