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要求从1开始,最终回到1,且路径有方向,要求所有路径都经过。 . H7 O8 Z) [: `5 R: X
以下是lingo的代码, h- R, }+ F3 j! e, a0 v) ?
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nodes/A,B,C,D,E,F,G,H,I,J,K,L/;! D o1 p G/ c4 P- u7 q+ c9 g
arcs(nodes,nodes)/( o% g- Y* I% M8 m
A,B A,E
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J,F J,G
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endsets
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c=
) ^2 V- d& g& N' B. k150 165
) t) _6 d0 p6 m130 230 160% T( @$ W- k$ Z; _6 l6 ]4 ^
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100 190
7 n& p! `) b) T- c165 144: |; K- E6 F. T! P
170 144 128 218 1745 O$ X. c' R k
200 122 109 185
, i2 }/ l; u" f( ^& O2 F7 a% A, m180 141 190
; u3 `9 x& j) h5 g2 X194 148$ f; G$ S& W* P
174 233
: k* G% Z# ^. n' b185 135
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n = @size(nodes);' j" n8 Y0 {0 P9 _) p8 G" K
min = @sum(arcs: c * x);
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@sum(arcs(i,j):x(i,j))=@sum(arcs(k,i):x(k,i))
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+ F& G; [/ w" M& j% ^- S@for(arcs: @bnd(1,x,9)); % w! ]7 _' T [; @
: J3 p' V# b7 W6 z7 T它只能算出路径的步数和路程,并不能得到线路。希望能用mma解决这个问题。 --------------------------------------------------------------------- 自己用mma写的程序对于四点还可以,但是扩展到12点实在繁琐:
& F, r, A! I! S6 Z- y+ U. ^P11 = {2, 5}; P12 = {150, 165}; P21 = {5, 6}; P22 = {230, 160}; P51 = {1, 6}; P52 = {165, 144}; P61 = {2, 5}; P62 = {170, 144};(*只考虑1、2、5、6四点,P11为第一点“可去往的点”,P12表述对应的路程*) open[q_] := Module[{i = 1, randomD, randomP, D, randomreal, p1, p2, p5, p6, c, u, Df = 80000, uf, path = {1}, pathf = {1}, pb},(*随机搜索*) For[r = 0, r < q, r++, {p1 = {}; p2 = {}; p5 = {}; p6 = {}; u = 0; D = 0; i = 1; randomP = P11; randomD = P12; While[ Length[p1] != 2 || Length[p2] != 2 || Length[p5] != 2 || Length[p6] != 2 || i != 1, randomreal = RandomInteger[{1, Length[randomP]}]; c = randomP[[randomreal]]; AppendTo[path, c];(*Print[path];*) Which[ i == 1 && Product[If[p1[] != c, 1, 0], {i, 1, Length[p1]}] == 1, {AppendTo[p1, c]}, i == 2 && Product[If[p2[] != c, 1, 0], {i, 1, Length[p2]}] == 1, {AppendTo[p2, c]}, i == 5 && Product[If[p5[] != c, 1, 0], {i, 1, Length[p5]}] == 1, {AppendTo[p5, c]}, i == 6 && Product[If[p6[] != c, 1, 0], {i, 1, Length[p6]}] == 1, {AppendTo[p6, c]}]; i = c; D = D + randomD[[randomreal]]; Which[i == 1, {randomP = P11, randomD = P12}, i == 2, {randomP = P21, randomD = P22}, i == 5, {randomP = P51, randomD = P52}, i == 6, {randomP = P61, randomD = P62}]; u = u + 1; If[u > 11, Break[]]; If[Df > D, {Df = D, uf = u, pathf = path, path = {1}}, path = {1}]; } ]; Print[Df, ",", uf, ",", pathf];
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