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