examples/jacobi-2d-imper/jacobi-2d-imper.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <math.h>
   4 #include <unistd.h>
   5 #include <sys/time.h>
   6
   7 #include <assert.h>
   8
   9 #define N 2000
  10 #define T 1000
  11
  12 #pragma declarations
  13 double a[N][N];
  14 double b[N][N];
  15 #pragma enddeclarations
  16
  17 #ifdef TIME
  18 #define IF_TIME(foo) foo;
  19 #else
  20 #define IF_TIME(foo)
  21 #endif
  22
  23 void init_array()
  24 {
  25     int i, j;
  26
  27     for (i=0; i<N; i++) {
  28         for (j=0; j<N; j++) {
  29             a[i][j] = ((double)j)/N;
  30         }
  31     }
  32 }
  33
  34
  35 void print_array()
  36 {
  37     int i, j;
  38
  39     for (i=0; i<N; i++) {
  40         for (j=0; j<N; j++) {
  41             fprintf(stderr, "%lf ", a[i][j]);
  42             if (j%80 == 20) fprintf(stderr, "\n");
  43         }
  44     }
  45     fprintf(stderr, "\n");
  46 }
  47
  48 double rtclock()
  49 {
  50     struct timezone Tzp;
  51     struct timeval Tp;
  52     int stat;
  53     stat = gettimeofday (&Tp, &Tzp);
  54     if (stat != 0) printf("Error return from gettimeofday: %d",stat);
  55     return(Tp.tv_sec + Tp.tv_usec*1.0e-6);
  56 }
  57 #define __PLACE_TO_INSERT_FORWARD_DECLARATIONS
  58
  59 int main()
  60 {
  61     int t, i, j;
  62     double t_start, t_end;
  63
  64     init_array();
  65
  66     IF_TIME(t_start = rtclock());
  67
  68 #pragma scop
  69     for (t=0; t<T; t++) {
  70         for (i=2; i<N-1; i++) {
  71             for (j=2; j<N-1; j++) {
  72                 b[i][j]= 0.2*(a[i][j]+a[i][j-1]+a[i][1+j]+a[1+i][j]+a[i-1][j]);
  73             }
  74         }
  75         for (i=2; i<N-1; i++) {
  76             for (j=2; j<N-1; j++)   {
  77                 a[i][j]=b[i][j];
  78             }
  79         }
  80     }
  81 #pragma endscop
  82
  83     IF_TIME(t_end = rtclock());
  84     IF_TIME(fprintf(stdout, "%0.6lfs\n", t_end - t_start));
  85
  86     if (fopen(".test", "r")) {
  87 #ifdef MPI
  88         if (my_rank == 0) {
  89             print_array();
  90         }
  91 #else
  92         print_array();
  93 #endif
  94     }
  95
  96     return 0;
  97 }