[OpenMP] SOR( Successive Over Relaxation) 병렬화

 SOR( Successive Over Relaxation) 병렬화

 

#include <stdio.h>
#include <omp.h>


#define width 256
#define height 256

void Sequential()
{
	double before = omp_get_wtime();	
	float A[width][height], B[width][height];
	int i,j,t;

	for(i=0; i<width; i++){
		for(j=0; j<height; j++){
			B[i][j] = (float) (i+1)/(j+1);
		}
	}

	for(t=0; t<1000; t++)
	{
		for(i=1; i<width-1; i++)
		{
			for(j=1; j<height-1; j++)
			{
				A[i][j] = (B[i+1][j] + B[i-1][j] + B[i][j+1] + B[i][j-1])/4;
			}
		}

		for(i=1; i<width-1; i++)
		{
			for(j=1; j<height-1; j++)
			{
				B[i][j] = A[i][j];
			}
		}
	}

		
	printf("%f sec Sequential Complete.\n",omp_get_wtime()-before);

}


void openMP()
{
	double before = omp_get_wtime();	
	float A[width][height], B[width][height];
	int i,j,t;

	#pragma omp parallel for private(i,j) shared(B)
	for(i=0; i<width; i++){
		for(j=0; j<height; j++){
			B[i][j] = (float) (i+1)/(j+1);
		}
	}

	for(t=0; t<1000; t++)
	{
		#pragma omp parallel for private(i,j) shared(A,B)
		for(i=1; i<width-1; i++)
		{
			for(j=1; j<height-1; j++)
			{
				A[i][j] = (B[i+1][j] + B[i-1][j] + B[i][j+1] + B[i][j-1])/4;
			}
		}

		#pragma omp parallel for private(i,j) shared(A,B)
		for(i=1; i<width-1; i++)
		{
			for(j=1; j<height-1; j++)
			{
				B[i][j] = A[i][j];
			}
		}
	}


	printf("%f sec OpenMP Complete.\n",omp_get_wtime()-before);
}

int main()
{
	openMP();
	Sequential();

	
	return 0;
}