/* nag_dorgqr (f08afc) Example Program. * * Copyright 2001 Numerical Algorithms Group. * * Mark 7, 2001. */ #include #include #include #include #include #include int main(void) { /* Scalars */ Integer i, j, m, n, pda, tau_len; Integer exit_status=0; NagError fail; Nag_OrderType order; /* Arrays */ char *title=0; double *a=0, *tau=0; #ifdef NAG_COLUMN_MAJOR #define A(I,J) a[(J-1)*pda + I - 1] order = Nag_ColMajor; #else #define A(I,J) a[(I-1)*pda + J - 1] order = Nag_RowMajor; #endif INIT_FAIL(fail); Vprintf("nag_dorgqr (f08afc) Example Program Results\n\n"); /* Skip heading in data file */ Vscanf("%*[^\n] "); Vscanf("%ld%ld%*[^\n] ", &m, &n); #ifdef NAG_COLUMN_MAJOR pda = m; #else pda = n; #endif tau_len = MIN(m, n); /* Allocate memory */ if ( !(title = NAG_ALLOC(31, char)) || !(a = NAG_ALLOC(m * n, double)) || !(tau = NAG_ALLOC(tau_len, double)) ) { Vprintf("Allocation failure\n"); exit_status = -1; goto END; } /* Read A from data file */ for (i = 1; i <= m; ++i) { for (j = 1; j <= n; ++j) Vscanf("%lf", &A(i,j)); } Vscanf("%*[^\n] "); /* Compute the QR factorization of A */ /* nag_dgeqrf (f08aec). * QR factorization of real general rectangular matrix */ nag_dgeqrf(order, m, n, a, pda, tau, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_dgeqrf (f08aec).\n%s\n", fail.message); exit_status = 1; goto END; } /* Form the leading N columns of Q explicitly */ /* nag_dorgqr (f08afc). * Form all or part of orthogonal Q from QR factorization * determined by nag_dgeqrf (f08aec) or nag_dgeqpf (f08bec) */ nag_dorgqr(order, m, n, n, a, pda, tau, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_dorgqr (f08afc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print the leading N columns of Q only */ Vsprintf(title, "The leading %2ld columns of Q\n", n); /* nag_gen_real_mat_print (x04cac). * Print real general matrix (easy-to-use) */ nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, m, n, a, pda, title, 0, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_gen_real_mat_print (x04cac).\n%s\n", fail.message); exit_status = 1; goto END; } END: if (title) NAG_FREE(title); if (a) NAG_FREE(a); if (tau) NAG_FREE(tau); return exit_status; }