NVIDIA-GPU-Bootcamp-Training/hpc/openacc/English/C/source_code/lab2/update/solution/jacobi.c

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#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <omp.h>
#include "laplace2d.h"

int main(int argc, char** argv)
{

    int n, m, iter_max;

    if(argc > 1){
        n = atoi(argv[1]);
    } else {
        n = 4096;
    }

    if(argc > 2){
        m = atoi(argv[2]);
    } else {
        m = 4096;
    }

    if(argc > 3){
        iter_max = atoi(argv[3]);
    } else {
        iter_max = 1000;
    }

    const double tol = 1.0e-6;
    double error = 1.0;

    double *restrict A    = (double*)malloc(sizeof(double)*n*m);
    double *restrict Anew = (double*)malloc(sizeof(double)*n*m);
    
    initialize(A, Anew, m, n);
        
    printf("Jacobi relaxation Calculation: %d x %d mesh\n", n, m);
    
    double st = omp_get_wtime();
    int iter = 0;
   
    #pragma acc data copyin( A[:m*n],Anew[:m*n] )
    {
        while ( error > tol && iter < iter_max )
        {
            error = calcNext(A, Anew, m, n);
            swap(A, Anew, m, n);
        
            if(iter % 100 == 0)
            {
                printf("%5d, %0.6f\n", iter, error);
                
                #pragma acc update self(A[0:m*n])
                
                for( int j = 0; j < m; j++ )
                {
                    for( int i = 0; i < n; i++ )
                    {
                        printf("%0.2f ", A[i+j*m]);
                    }
                    printf("\n");
                }
            }
        
            iter++;

        }
    }

    double runtime = omp_get_wtime() - st;
 
    printf(" total: %f s\n", runtime);

    deallocate(A, Anew);

    return 0;
}