[129] | 1 | //Author Antonio-Gabriel Sturzu |
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| 2 | |
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| 3 | #include<stdio.h> |
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| 4 | #include<mpi.h> |
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| 5 | #include<string.h> |
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| 6 | #include<stdlib.h> |
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| 7 | #define inf 50000001 |
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| 8 | |
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| 9 | int main(int argc,char *argv[]) |
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| 10 | { |
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| 11 | int rc,numtasks,rank,**m,n,*line,dim,next=0,strip,*d,minl,ming,iminl,iming,prod; |
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| 12 | int i,j,temp; |
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| 13 | char *viz; |
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| 14 | double time1,time2; |
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| 15 | FILE *f; |
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| 16 | MPI_Status status; |
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| 17 | |
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| 18 | //MPI Initialization |
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| 19 | rc = MPI_Init(&argc,&argv); |
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| 20 | if (rc != MPI_SUCCESS) |
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| 21 | { |
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| 22 | printf ("Error starting MPI program. Terminating.\n"); |
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| 23 | MPI_Abort(MPI_COMM_WORLD, rc); |
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| 24 | } |
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| 25 | MPI_Comm_size(MPI_COMM_WORLD,&numtasks); |
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| 26 | MPI_Comm_rank(MPI_COMM_WORLD,&rank); |
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| 27 | |
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| 28 | //Reading from file is done by process 0 |
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| 29 | if(rank==0) |
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| 30 | { |
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| 31 | f=fopen("dijkstra.in","r"); |
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| 32 | fscanf(f,"%i",&n); |
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| 33 | } |
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| 34 | //Broadcast n's value to all processes |
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| 35 | MPI_Bcast(&n,1,MPI_INT,0,MPI_COMM_WORLD); |
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| 36 | dim=n/numtasks; |
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| 37 | strip=dim; |
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| 38 | if(rank==numtasks-1 && n%numtasks!=0) |
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| 39 | dim=n-dim*(numtasks-1); |
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| 40 | |
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| 41 | //Partition the data |
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| 42 | |
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| 43 | m=(int **) calloc(n*dim,sizeof(int *)); |
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| 44 | for(i=0;i<n;i++) |
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| 45 | m[i]=(int *) calloc(dim,sizeof(int)); |
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| 46 | if(rank==0) |
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| 47 | { |
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| 48 | line=(int *) calloc(n,sizeof(int)); |
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| 49 | for(i=0;i<n;i++) |
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| 50 | { |
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| 51 | next=dim; |
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| 52 | for(j=0;j<n;j++) |
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| 53 | fscanf(f,"%i",line+j); |
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| 54 | memmove(m[i],line,dim*sizeof(int)); |
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| 55 | for(j=1;j<numtasks-1;j++) |
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| 56 | { |
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| 57 | MPI_Send(&line[next],dim,MPI_INT,j,1,MPI_COMM_WORLD); |
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| 58 | next+=dim; |
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| 59 | } |
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| 60 | if(numtasks>1) |
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| 61 | MPI_Send(&line[next],n-next,MPI_INT,numtasks-1,1,MPI_COMM_WORLD); |
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| 62 | } |
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| 63 | } |
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| 64 | else |
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| 65 | for(i=0;i<n;i++) |
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| 66 | MPI_Recv(m[i],dim,MPI_INT,0,1,MPI_COMM_WORLD,&status); |
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| 67 | |
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| 68 | d=(int *) calloc(dim,sizeof(int)); |
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| 69 | viz=(char *) calloc(dim,sizeof(char)); |
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| 70 | |
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| 71 | MPI_Barrier(MPI_COMM_WORLD); |
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| 72 | time1 = MPI_Wtime(); |
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| 73 | |
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| 74 | //Initialize local distance vectors |
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| 75 | |
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| 76 | if(rank!=0) |
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| 77 | { |
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| 78 | for(i=0;i<dim;i++) |
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| 79 | d[i]=inf; |
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| 80 | } |
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| 81 | else |
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| 82 | { |
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| 83 | for(i=1;i<dim;i++) |
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| 84 | d[i]=inf; |
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| 85 | d[0]=0; |
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| 86 | } |
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| 87 | MPI_Barrier(MPI_COMM_WORLD); |
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| 88 | |
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| 89 | //Distributed Dijkstra's algorithm |
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| 90 | for(;;) |
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| 91 | { |
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| 92 | minl=inf; |
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| 93 | for(i=0;i<dim;i++) |
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| 94 | if(viz[i]==0 && d[i]<minl) |
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| 95 | { |
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| 96 | minl=d[i]; |
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| 97 | iminl=i; |
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| 98 | } |
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| 99 | //Determine the global minimum distance from a node to the source |
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| 100 | MPI_Allreduce(&minl,&ming,1,MPI_INT,MPI_MIN,MPI_COMM_WORLD); |
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| 101 | if(ming==inf) |
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| 102 | break; |
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| 103 | |
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| 104 | if(minl==ming) |
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| 105 | { |
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| 106 | if(rank!=numtasks-1) |
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| 107 | temp=iminl+rank*dim; |
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| 108 | else |
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| 109 | temp=iminl+rank*strip; |
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| 110 | MPI_Allreduce(&temp,&iming,1,MPI_INT,MPI_MIN,MPI_COMM_WORLD); |
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| 111 | } |
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| 112 | else |
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| 113 | MPI_Allreduce(&n,&iming,1,MPI_INT,MPI_MIN,MPI_COMM_WORLD); |
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| 114 | |
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| 115 | //If the node with the minimum distance is owned by this process |
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| 116 | //mark it as visited |
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| 117 | |
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| 118 | if(rank!=numtasks-1) |
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| 119 | { |
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| 120 | if(iming>=rank*dim && iming<(rank+1)*dim) |
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| 121 | viz[iming-rank*dim]=1; |
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| 122 | } |
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| 123 | else |
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| 124 | { |
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| 125 | if(iming>=rank*strip && iming<n) |
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| 126 | viz[iming-rank*strip]=1; |
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| 127 | } |
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| 128 | for(i=0;i<dim;i++) |
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| 129 | { |
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| 130 | if(m[iming][i]+ming<d[i] && m[iming][i]!=-1) |
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| 131 | d[i]=m[iming][i]+ming; |
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| 132 | } |
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| 133 | MPI_Barrier(MPI_COMM_WORLD); |
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| 134 | } |
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| 135 | MPI_Barrier(MPI_COMM_WORLD); |
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| 136 | time2 = MPI_Wtime(); |
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| 137 | if(rank==0) |
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| 138 | printf("Au trecut %f secunde\n",time2-time1); |
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| 139 | |
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| 140 | if(rank==0) |
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| 141 | printf("The minimum distances are :\n"); |
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| 142 | MPI_Barrier(MPI_COMM_WORLD); |
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| 143 | if(rank!=numtasks-1) |
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| 144 | prod=rank*dim; |
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| 145 | else |
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| 146 | prod=rank*strip; |
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| 147 | |
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| 148 | for(i=0;i<dim;i++) |
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| 149 | { |
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| 150 | if(d[i]==inf) |
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| 151 | d[i]=0; |
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| 152 | printf("%i %i\n",i+prod+1,d[i]); |
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| 153 | } |
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| 154 | for(i=0;i<n;i++) |
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| 155 | free(m[i]); |
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| 156 | free(m); |
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| 157 | free(d); |
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| 158 | free(viz); |
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| 159 | if(rank==0) |
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| 160 | free(line); |
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| 161 | MPI_Finalize(); |
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| 162 | return 0; |
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| 163 | } |
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