2007280037_maixin_simulated_annealing.c

MPI并行计算模拟退火算法

#include <mpi.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h> 

#define NUM_TOTAL_ITERATIONS 100
#define NUM_DATA_POINTS 4096

int main(int argc, char **argv) {
	
	/* MPI information */
	int p, myid;
	
	/* loop variables*/
	int i, j;
	int x_new;
	double t;
	double err;

	/* data accross each CPU */
	double f[NUM_DATA_POINTS];
	double T; // temperature
	unsigned int x[2]; // position
	double c[2]; // cost
	
	/* Initialize MPI */
	MPI_Init(&argc, &argv);
	
	/* Get configuration parameters */
	MPI_Comm_size(MPI_COMM_WORLD,&p); 
    MPI_Comm_rank(MPI_COMM_WORLD,&myid);
	
	/* Initialization on each CPU */
	for (i = 0; i < NUM_DATA_POINTS; i++) {
		t = (double)i / NUM_DATA_POINTS;
		f[i] = 5*t*(t-1)*cos(7*M_PI*t) + 1/10 *cos(100*M_PI*t);
		printf("f(%d)=%f", i, f[i]);
	}
	
 	x[myid] = NUM_DATA_POINTS * rand() / (RAND_MAX + 1); // in [0, NUM_DATA_POINTS - 1]
	c[myid] = f[ x[myid] ];
	
	printf("x(%d): %f   \n\n\n", 0, x[myid]);
	
	
	/* Loop */
	for( j = 0; j < NUM_TOTAL_ITERATIONS; j++){
		
		/* Simulated annealing algorithm */
		for (T = NUM_DATA_POINTS; T >= 1; T /= 2) // cooling schedule
		{
			x_new = (int) x[myid] + T * ( -1 + 2*rand() / RAND_MAX );
			x_new %= NUM_DATA_POINTS;
			
			if( f[x_new] < c[myid] ){
				x[myid] = x_new;
				c[myid] = f[x_new];
			}
		}
		
		/* Broadcast values and synchronize*/
		for (i = 0; i < 2; ++i) {
			MPI_Bcast( x + i, 1, MPI_DOUBLE, i, MPI_COMM_WORLD);
			MPI_Bcast( c + i, 1, MPI_DOUBLE, i, MPI_COMM_WORLD);
		}
		MPI_Barrier(MPI_COMM_WORLD);

		/* Keep minimum value */
		if( c[1 - myid] < c[myid] ){
			c[myid] = c[1 - myid];
			x[myid] = x[1 - myid];
		}

		/* Print result and error information */
		if( myid == 0) {
			err = (x[myid] - 0.57)*(x[myid] - 0.57);
			printf("x(%d): %d    err2=%f\n", j, x[myid], err);
		}
	}

	MPI_Finalize();
	return 0;
}