svn-gvsig-desktop / trunk / extensions / extGraph / src / org / gvsig / graph / solvers / TspSolverAnnealing.java @ 23215
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package org.gvsig.graph.solvers; |
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import java.util.Random; |
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import com.sun.org.apache.xpath.internal.operations.Mod; |
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public class TspSolverAnnealing { |
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int n;
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int[] iorder; |
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int[] jorder; |
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float[] b = new float[4]; |
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double[][] odMatrix; |
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boolean g_bVolverOrigen;
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int origenTSP, destinoTSP;
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int[] vTSP; |
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static int T_INIT = 100; |
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static double FINAL_T = 0.1; |
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static double COOLING = 0.9; /* to lower down T (< 1) */ |
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int TRIES_PER_T = 500*n; // TODO: PONER ESTO BIEN. |
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int IMPROVED_PATH_PER_T = 60*n; // TODO: PONER ESTO BIEN. |
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// static long A[56]= {-1};
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// long *rand_fptr = A;
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// #define mod_diff(x,y) (((x)-(y))&0x7fffffff)
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// private long flipCycle()
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// {
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// long *ii,*jj;
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// for (ii = &A[1], jj = &A[32]; jj <= &A[55]; ii++, jj++)
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// *ii= mod_diff (*ii, *jj);
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//
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// for (jj = &A[1]; ii <= &A[55]; ii++, jj++)
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// *ii= mod_diff (*ii, *jj);
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// rand_fptr = &A[54];
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// return A[55];
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// }
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// typedef int Path[3]; /* specify how to change path */
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/*
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* State vars
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*/
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int verbose = 0; |
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// Point *cities;
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// int *dist;
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// #define D(x,y) odMatrix[x][y] //dist[(x)*n+y]
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/* float calcula_dist_ordenacion(int v[], int bVolverOrigen)
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{
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float dist, distTot;
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int i;
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distTot = odMatrix[origenTSP][v[0]]; // Origen al primer punto
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for (i = 0; i< numElemTSP-1;i++)
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{
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//frmDocMap.Distancia v(i), v(i + 1), dist, tiempo
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dist = odMatrix[v[i]][v[i+1]];
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distTot = distTot + dist;
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}
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// desde y hasta el almacen (distancia al primero y al ?ltimo
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// frmDocMap.Distancia idNodoOrigen, v(0), dist, tiempo
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if (bVolverOrigen)
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{
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dist = odMatrix[v[numElemTSP-1]][origenTSP];
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distTot = distTot + dist;
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}
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else
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{
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dist = odMatrix[v[numElemTSP-1]][destinoTSP];
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distTot = distTot + dist;
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}
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return distTot;
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} */
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double pathLength()
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{
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int i;
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double len = 0; |
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len = odMatrix[origenTSP][iorder[0]];
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for (i = 0; i < n-1; i++) |
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{
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len += odMatrix[iorder[i]][iorder[i+1]];
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} |
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if (g_bVolverOrigen)
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len += odMatrix[iorder[n-1]][origenTSP]; /* close path */ |
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else
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len += odMatrix[iorder[n-1]][destinoTSP]; /* close path */ |
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return (len);
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} |
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/*
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* Prim's approximated TSP tour
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* See also [Cristophides'92]
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*/
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// TODO: NO LO USO => Borrar esta funci?n.
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void findEulerianPath()
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{
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int[] mst = new int[n]; |
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int[] arc = new int[n]; |
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int i, j = 0, k = 0, l, a; |
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double d, maxd;
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double[] dis = new double[n]; |
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maxd = Math.sqrt(b[1]-b[0])+ Math.sqrt(b[3]-b[2]); |
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d = maxd; |
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dis[0] = -1; |
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for (i = 1; i < n; i++) |
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{
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dis[i] = odMatrix[i][0]; arc[i] = 0; |
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if (d > dis[i])
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{
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d = dis[i]; |
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j = i; |
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} |
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} |
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/*
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* O(n^2) Minimum Spanning Trees by Prim and Jarnick
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* for graphs with adjacency matrix.
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*/
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for (a = 0; a < n - 1; a++) |
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{
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mst[a] = j * n + arc[j]; /* join fragment j with MST */
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dis[j] = -1;
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d = maxd; |
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for (i = 0; i < n; i++) |
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{
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if (dis[i] >= 0) /* not connected yet */ |
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{
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if (dis[i] > odMatrix[i][j])
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{
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dis[i] = odMatrix[i][j]; |
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arc[i] = j; |
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} |
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if (d > dis[i])
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{
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d = dis[i]; |
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k = i; |
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} |
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} |
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} |
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j = k; |
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} |
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/*
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* Preorder Tour of MST
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*/
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// #define VISITED(x) jorder[x]
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// #define NQ(x) arc[l++] = x
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// #define DQ() arc[--l]
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// #define EMPTY (l==0)
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for (i = 0; i < n; i++) jorder[i] = 0; |
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k = 0; l = 0; d = 0; |
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arc[l++] = 0;
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while (l != 0) |
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{
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i = arc[--l]; |
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if (!(jorder[i] == 0)) |
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{
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iorder[k++] = i; |
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jorder[i] = 1;
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for (j = 0; j < n - 1; j++) /* push all kids of i */ |
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{
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if (i == mst[j]%n)
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arc[l++] = mst[j]/n; |
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} |
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} |
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} |
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} |
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int mod(int a, int b) { |
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return (a % b);
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} |
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double D(int f, int t) { |
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return odMatrix[f][t];
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} |
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/*
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* Local Search Heuristics
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* b-------a b a
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* . . => .\ /.
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* . d...e . . e...d .
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* ./ \. . .
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* c f c-------f
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*/
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double getThreeWayCost (int[] p) |
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{
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int a, b, c, d, e, f;
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a = iorder[mod(p[0]-1, n)]; b = iorder[p[0]]; |
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c = iorder[p[1]]; d = iorder[mod(p[1]+1,n)]; |
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e = iorder[p[2]]; f = iorder[mod(p[2]+1,n)]; |
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// b va a ser el nuevo origen => sumamos su distancia a nuestro origen fijo
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double Dant, Dnuevo, Ddiff = 0; |
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Dant = odMatrix[origenTSP][iorder[0]];
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Dnuevo = odMatrix[origenTSP][b]; |
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Ddiff = Dnuevo - Dant; |
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// tambi?n hay que mirar la distancia al destino desde el ?ltimo punto
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int fin=n-1; |
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if (g_bVolverOrigen)
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{
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// p[2] va a ser el pr?ximo ?ltimo punto
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Dant = D(iorder[fin], origenTSP); |
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Dnuevo = D(iorder[p[2]], origenTSP);
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Ddiff = Ddiff + Dnuevo - Dant; |
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} |
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else
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{
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Dant = D(iorder[fin], destinoTSP); |
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Dnuevo = D(iorder[p[2]], destinoTSP);
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Ddiff = Ddiff + Dnuevo - Dant; |
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} |
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return (D(a,d) + D(e,b) + D(c,f) - D(a,b) - D(c,d) - D(e,f) + Ddiff);
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/* add cost between d and e if non symetric TSP */
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// A?ADIR DIFERENCIA DE COSTE A LOS NODOS INMOVILES. (ORIGEN Y ?DESTINO?)
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} |
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void doThreeWay (int[] p) |
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{
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int i, count, m1, m2, m3, a, b, c, d, e, f;
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int index;
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a = mod(p[0]-1,n); b = p[0]; |
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c = p[1]; d = mod(p[1]+1,n); |
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e = p[2]; f = mod(p[2]+1,n); |
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m1 = mod(n+c-b,n)+1; /* num cities from b to c */ |
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m2 = mod(n+a-f,n)+1; /* num cities from f to a */ |
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m3 = mod(n+e-d,n)+1; /* num cities from d to e */ |
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count = 0;
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/* [b..c] */
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for (i = 0; i < m1; i++) |
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{
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index = mod(i+b,n); |
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jorder[count++] = iorder[index]; |
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} |
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/* [f..a] */
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for (i = 0; i < m2; i++) |
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{
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index = mod(i+f,n); |
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jorder[count++] = iorder[index]; |
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} |
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/* [d..e] */
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for (i = 0; i < m3; i++) |
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{
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index = mod(i+d,n); |
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jorder[count++] = iorder[index]; |
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} |
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/* copy segment back into iorder */
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for (i = 0; i < n; i++) iorder[i] = jorder[i]; |
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} |
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/*
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* c..b c..b
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* \/ => | |
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* /\ | |
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* a d a d
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*/
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double getReverseCost (int[] p) |
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{
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int a, b, c, d;
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a = iorder[mod(p[0]-1,n)]; b = iorder[p[0]]; |
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c = iorder[p[1]]; d = iorder[mod(p[1]+1,n)]; |
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double Dant = 0, Dnuevo = 0, Ddiff = 0; |
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if (p[0]==0 || p[1]==0) |
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{
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Dant = D(origenTSP,iorder[0]);
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if (p[0]==0) |
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Dnuevo = D(origenTSP, c); |
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else
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Dnuevo = D(origenTSP, b); |
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Ddiff = Dnuevo-Dant; |
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} |
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int fin = n-1; |
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if (g_bVolverOrigen) // Miramos la distancia al cero |
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{
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// iorder[p[1]] o iorder[p[0]] va a acabar en la ?ltima posici?n
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if (p[0]==fin || p[1] == fin) // tambi?n hay que mirar la distancia al destino desde el ?ltimo punto |
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{
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Dant = D(iorder[fin], origenTSP); |
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if (p[0]==fin) |
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Dnuevo = D(c,origenTSP); |
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else
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Dnuevo = D(b, origenTSP); |
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Ddiff = Ddiff + Dnuevo - Dant; |
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} |
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} |
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else
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{
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if (p[0]==fin || p[1] == fin) // tambi?n hay que mirar la distancia al destino desde el ?ltimo punto |
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{
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Dant = D(iorder[fin], destinoTSP); |
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if (p[0]==fin) |
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Dnuevo = D(c,destinoTSP); |
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else
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Dnuevo = D(b, destinoTSP); |
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Ddiff = Ddiff + Dnuevo - Dant; |
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} |
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} |
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return (D(d,b) + D(c,a) - D(a,b) - D(c,d) + Ddiff);
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/* add cost between c and b if non symetric TSP */
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// A?ADIR DIFERENCIA DE COSTE A LOS NODOS INMOVILES. (ORIGEN Y ?DESTINO?)
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} |
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void doReverse(int[] p) |
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{
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int i, nswaps, first, last, tmp;
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/* reverse path b...c */
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nswaps = (mod(p[1]-p[0],n)+1)/2; |
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for (i = 0; i < nswaps; i++) |
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{
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first = mod(p[0]+i, n);
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last = mod(p[1]-i, n);
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tmp = iorder[first]; |
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iorder[first] = iorder[last]; |
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iorder[last] = tmp; |
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} |
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} |
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double annealing()
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{
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int[] p; |
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int i=1, j, pathchg; |
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int numOnPath, numNotOnPath;
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double pathlen, bestlen;
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double energyChange, T;
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/*
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* Set up first eulerian path iorder to be improved by
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* simulated annealing.
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*/
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/* bool conEulerian = true;
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if (conEulerian)
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findEulerianPath(); */
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pathlen = pathLength(); // (iorder);
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bestlen = pathlen; |
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Random rnd = new Random(); |
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for (T = T_INIT; T > FINAL_T; T *= COOLING) /* annealing schedule */ |
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{
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pathchg = 0;
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for (j = 0; j < TRIES_PER_T; j++) |
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{
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do {
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p[0] = rnd.nextInt(n);
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p[1] = rnd.nextInt(n);
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if (p[0] == p[1]) p[1] = mod(p[0]+1,n); /* non-empty path */ |
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numOnPath = mod(p[1]-p[0],n) + 1; |
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numNotOnPath = n - numOnPath; |
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} while (numOnPath < 2 || numNotOnPath < 2) ; /* non-empty path */ |
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if ((rnd.nextInt() % 2) == 0) /* threeWay */ |
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{
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do {
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p[2] = mod(rnd.nextInt(numNotOnPath)+p[1]+1,n); |
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} while (p[0] == mod(p[2]+1,n)); /* avoids a non-change */ |
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energyChange = getThreeWayCost (p); |
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if ((energyChange < 0) || (RREAL < Math.exp(-energyChange/T))) |
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{
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pathchg++; |
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pathlen += energyChange; |
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doThreeWay (p); |
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} |
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} |
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else /* path Reverse */ |
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{
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energyChange = getReverseCost (p); |
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if ((energyChange < 0) || (RREAL < Math.exp(-energyChange/T))) |
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{
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pathchg++; |
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pathlen += energyChange; |
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doReverse(p); |
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} |
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} |
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if (pathlen < bestlen)
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{
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pathlen = pathLength(); // Calculamos la distancia de verdad, por si no interesa
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// hacer el cambio. pathlen es en realidad una estimaci?n
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if (pathlen < bestlen)
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{
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bestlen = pathlen; |
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for (i=0; i< n; i++) |
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vTSP[i+1] = iorder[i];
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} |
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} |
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if (pathchg > IMPROVED_PATH_PER_T) break; /* finish early */ |
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} |
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if (pathchg == 0) break; /* if no change then quit */ |
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} |
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return bestlen;
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} |
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} |