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#include <math.h>
#include <stdlib.h>
#include <stdio.h>
#include "dw_std.h"
t main(void)
{
int m=1;
int n=7;
double X[7];
double tau[1];
int lwork, info;
double *work, opt_size;
int i;
// Randomly generate 1x7 matrix X
for (i=6; i >= 0; i--) X[i]=(double)rand()/RAND_MAX;
// Make size inquiry
lwork=-1;
dgeqrf(&m,&n,X,&m,tau,&opt_size,&lwork,&info);
// Attempt QR decomposition
work=(double*)dw_malloc((lwork=(int)opt_size)*sizeof(double));
dgeqrf(&m,&n,X,&m,tau,work,&lwork,&info);
// Is problem?
if (info)
{
printf("Unexpected error: info= %d lwork= %d m = %d n = %d\n",info,lwork,m,n);
// work around
dw_free(work);
work=(double*)dw_malloc((lwork=(m > n) ? m*m : n*n)*64*sizeof(double));
dgeqrf(&m,&n,X,&m,tau,work,&lwork,&info);
printf("info = %d work[0]= %d\n",info,(int)work[0]);
}
else
printf("Successful\n");
}
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