[149] | 1 | |
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| 2 | |
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| 3 | #include <omp.h> |
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| 4 | #include <stdio.h> |
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| 5 | #include <sys/time.h> |
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| 6 | |
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| 7 | #define INFINITE 998 |
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| 8 | #define CHUNKSIZE 1 /*defines the chunk size as 1 contiguous iteration*/ |
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| 9 | |
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| 10 | int MAX; |
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| 11 | |
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| 12 | int allselected(int *selected) |
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| 13 | { |
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| 14 | int i; |
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| 15 | for(i=0;i<MAX;i++) |
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| 16 | if(selected[i]==0) |
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| 17 | return 0; |
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| 18 | return 1; |
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| 19 | } |
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| 20 | void shortpath(int cost[][1000],int *preced,int *distance) |
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| 21 | { |
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| 22 | int selected[1000]={0}; |
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| 23 | int current=0,i,k,dc,smalldist,newdist; |
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| 24 | for(i=0;i<MAX;i++) |
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| 25 | distance[i]=INFINITE; |
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| 26 | selected[current]=1; |
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| 27 | distance[0]=0; |
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| 28 | current=0; |
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| 29 | #pragma omp parallel private(k,smalldist,newdist,current) |
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| 30 | { |
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| 31 | while(!allselected(selected)) |
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| 32 | { |
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| 33 | smalldist=INFINITE; |
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| 34 | dc=distance[current]; |
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| 35 | #pragma omp parallel for schedule(dynamic, CHUNKSIZE) |
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| 36 | for(i=0;i<MAX;i++) |
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| 37 | { |
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| 38 | if(selected[i]==0) |
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| 39 | { |
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| 40 | newdist=dc+cost[current][i]; |
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| 41 | if(newdist<distance[i]) |
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| 42 | { |
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| 43 | //#pragma omp critical |
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| 44 | { |
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| 45 | distance[i]=newdist; |
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| 46 | } |
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| 47 | preced[i]=current; |
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| 48 | } |
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| 49 | if(distance[i]<smalldist) |
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| 50 | { |
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| 51 | //#pragma omp critical |
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| 52 | { |
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| 53 | smalldist=distance[i]; |
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| 54 | } |
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| 55 | k=i; |
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| 56 | } |
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| 57 | } |
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| 58 | } |
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| 59 | current=k; |
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| 60 | //#pragma omp critical |
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| 61 | { |
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| 62 | selected[current]=1; |
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| 63 | } |
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| 64 | } |
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| 65 | } |
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| 66 | } |
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| 67 | |
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| 68 | int main() |
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| 69 | { |
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| 70 | int th_id, nthreads; |
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| 71 | struct timeval time1; |
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| 72 | struct timeval time2; |
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| 73 | int cost[1000][1000]; |
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| 74 | |
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| 75 | FILE * pFile; |
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| 76 | int n,k,i,j; |
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| 77 | |
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| 78 | i=0;j=0; |
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| 79 | pFile = fopen ("Di1000.txt","r"); |
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| 80 | if(pFile != NULL) |
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| 81 | fscanf (pFile, "%d", &n); |
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| 82 | MAX = n; |
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| 83 | for(i=0;i<MAX;i++) |
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| 84 | for(j=0;j<MAX;j++) |
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| 85 | cost[i][j]=INFINITE; |
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| 86 | while(fscanf(pFile,"%d",&i)!=EOF) |
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| 87 | { |
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| 88 | fscanf (pFile, "%d", &j); |
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| 89 | fscanf (pFile, "%d", &cost[i][j]); |
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| 90 | } |
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| 91 | fclose (pFile); |
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| 92 | |
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| 93 | int preced[1000]={0},distance[1000]; |
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| 94 | gettimeofday(&time1,NULL); |
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| 95 | shortpath(cost,preced,distance); |
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| 96 | gettimeofday(&time2,NULL); |
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| 97 | |
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| 98 | printf("time: %ld\n",time2.tv_usec-time1.tv_usec); |
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| 99 | |
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| 100 | return 0; |
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| 101 | } |
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| 102 | |
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| 103 | |
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