createa.c

在MPI上用并行LU分解求解线性方程组的源程序。

/*create a file which store a metrix with specific Row &Column
 in the file the first two int are the Row&column of the matrix*/

#include "stdio.h"
#include "stdlib.h"
#define MAX 20
/*assume the max value of every element of that matrix */
int main()
	{
		  char *filename;
		  FILE *fd;
		  int size;
		  int i,j;/*loop variable*/
		  float value;
		  printf("Open a new file for write only!\n");
		  printf("WARING:If the file already exist,it will be truncated to zero length!\n");
		  printf("Please enter file name:");
		  filename=(char *)malloc(sizeof(char)*128);
		  scanf("%s",filename);
			    /* printf("the filename is %s\n",filename);*/
		  fd=fopen(filename,"w");
		  if (fd==NULL)
		    /*CANNOT create the file and exit the system*/
			  {
				   printf("error in create the file %s\n",filename);
				   exit(0);
			  }/*if*/
		  else
			  printf("Successfully create a new file %s\n",filename);
			    /*create a file for write only,or open a file and truncate it to zero length*/
		  printf("Please input the SIZE of the file please?\n");
		  printf("Size:");
		  scanf("%d",&size);
		  printf("Matrix size=%d\n",size);
		 /* fwrite(&size,sizeof(int),1,fd) ; */
		  srand(getpid());/*reset the seed,and initialize the pseudo-random creation process*/
		  for (i=0;i<size;i++)
			  {
			    for (j=0;j<size;j++)
				{     value=MAX*rand()/(RAND_MAX+1);
				      printf("%f ",value);
				      fwrite(&value,sizeof(float),1,fd);
				} /*for  j*/
			    printf("\n");
			  } /*for i*/
		  fclose(fd);
		  free(filename);
			   /*close the file fd*/
		  return(0);
	 }
		/*main*/