/* nag_real_form_q (f01qec) Example Program. * * Copyright 1990 Numerical Algorithms Group. * * Mark 1, 1990. * Mark 8 revised, 2004. */ #include #include #include #include #define A(I,J) a[(I)*tda + J] #define Q(I,J) q[(I)*tdq + J] int main(void) { Integer exit_status=0, i, j, m, n, ncolq, tda, tdq; NagError fail; double *a=0, *q=0, *zeta=0; INIT_FAIL(fail); Vprintf("nag_real_form_q (f01qec) Example Program Results\n"); Vscanf(" %*[^\n]"); /* skip headings in data file */ Vscanf(" %*[^\n]"); Vscanf("%ld%ld", &m, &n); if (n>=0 && m >=n) { if ( !( zeta = NAG_ALLOC(n, double)) || !( a = NAG_ALLOC(m*n, double)) || !( q = NAG_ALLOC(m*m, double)) ) { Vprintf("Allocation failure\n"); exit_status = -1; goto END; } tda = n; tdq = m; } else { Vprintf("Invalid n or m.\n"); exit_status = 1; return exit_status; } Vscanf(" %*[^\n]"); for (i = 0; i < m; ++i) /* Read matrix data */ for (j = 0; j < n; ++j) Vscanf("%lf", &A(i,j)); /* Find the QR factorization of A */ /* nag_real_qr (f01qcc). * QR factorization of real m by n matrix (m~>=~n) */ nag_real_qr(m, n, a, tda, zeta, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_real_qr (f01qcc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Copy the array a into q and form the m by m matrix Q */ for (j = 0; j < n; ++j) for (i = 0; i < m; ++i) Q(i,j) = A(i,j); ncolq = m; /* nag_real_form_q (f01qec). * Form columns of Q after factorization by nag_real_qr * (f01qcc) */ nag_real_form_q(Nag_ElementsSeparate, m, n, ncolq, q, tdq, zeta, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_real_form_q (f01qec).\n%s\n", fail.message); exit_status = 1; goto END; } Vprintf("Matrix Q\n"); for (i = 0; i < m; ++i) { for (j = 0; j < ncolq; ++j) Vprintf(" %8.4f", Q(i,j)); Vprintf("\n"); } END: if (zeta) NAG_FREE(zeta); if (a) NAG_FREE(a); if (q) NAG_FREE(q); return exit_status; }