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#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
void printsparse_(int *irow, int *icol, double *a, double *b, int n,int nz)
{
int fd;
int i,max,j;
fd = open("matrix.bin",O_CREAT|O_WRONLY,0777);
if(fd<=0) { printf("open failed"); return;}
write (fd, &n, sizeof(int));
write (fd, &nz, sizeof(int));
write (fd, a, sizeof(double)*(nz));
write (fd, irow, sizeof(int)*(n));
write (fd, icol, sizeof(int)*(nz));
write (fd, b, sizeof(double)*(n));
close(fd);
printf("dumped sparse matrix: dim = %d %d nonzeros\n", n, nz);
}
int main(int argc, char **argv)
{
int NZROW=8,NZSQ=64;
int i,k,irow[NZROW+1],icol[NZSQ+4],n=NZROW,nz=NZSQ;
double a[NZSQ], b[NZROW], xvec[NZROW];
for(i=0;i<NZROW;i++){
for(k=0;k<NZROW;k++)
a[i*NZROW+k] = k+1;
xvec[i] = i+3.5;
}
for(i=0;i<NZROW;i++){
irow[i]=i*NZROW+1;
b[i]=0;
for(k=0;k<NZROW;k++){
b[i] = b[i]+xvec[k]*a[i*NZROW+k];
icol[i*NZROW+k]=i+1;
}
printf("\nb[%d]=%f",i,b[i]);
}
printsparse_(irow,icol,a,b,n,nz);
return(1);
}
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