/*  This code snippet demonstrates how to use LAPACK to form a QR 
    decomposition of the matrix A.  Note the input matrix A is in
    column-major ordering as are the output matrices R and Q.  */

    memcpy(Q,A,sizeof(double)*N*N);
    LAPACKE_dgeqrfp(LAPACK_COL_MAJOR,N,N,Q[0],N,TAU);
    for(int i=0;i<N;i++) for(int j=0;j<N;j++){
        if(j<=i) R[i][j]=Q[i][j];
        else R[i][j]=0;
    }
    LAPACKE_dorgqr(LAPACK_COL_MAJOR,N,N,N,Q[0],N,TAU);