/* nag_dgeqrt (f08abc) Example Program. * * Copyright 2013 Numerical Algorithms Group. * * Mark 24, 2013. */ #include #include #include #include #include #include int main(void) { /* Scalars */ double rnorm; Integer exit_status = 0; Integer pda, pdb, pdt; Integer i, j, m, n, nb, nrhs; /* Arrays */ double *a = 0, *b = 0, *t = 0; /* Nag Types */ Nag_OrderType order; NagError fail; #ifdef NAG_COLUMN_MAJOR #define A(I,J) a[(J-1)*pda + I-1] #define B(I,J) b[(J-1)*pdb + I-1] #define T(I,J) t[(J-1)*pdt + I-1] order = Nag_ColMajor; #else #define A(I,J) a[(I-1)*pda + J-1] #define B(I,J) b[(I-1)*pdb + J-1] #define T(I,J) t[(I-1)*pdt + J-1] order = Nag_RowMajor; #endif INIT_FAIL(fail); printf("nag_dgeqrt (f08abc) Example Program Results\n\n"); fflush(stdout); /* Skip heading in data file*/ scanf("%*[^\n]"); scanf("%ld%ld%ld%*[^\n]", &m, &n, &nrhs); nb = MIN(m, n); if (!(a = NAG_ALLOC(m*n, double))|| !(b = NAG_ALLOC(m*nrhs, double))|| !(t = NAG_ALLOC(nb*MIN(m, n), double))) { printf("Allocation failure\n"); exit_status = -1; goto END; } #ifdef NAG_COLUMN_MAJOR pda = m; pdb = m; pdt = nb; #else pda = n; pdb = nrhs; pdt = MIN(m, n); #endif /* Read A and B from data file */ for (i = 1; i <= m; ++i) for (j = 1; j <= n; ++j) scanf("%lf", &A(i, j)); scanf("%*[^\n]"); for (i = 1; i <= m; ++i) for (j = 1; j <= nrhs; ++j) scanf("%lf", &B(i, j)); scanf("%*[^\n]"); /* nag_dgeqrt (f08abc). * Compute the QR factorization of A by recursive algorithm. */ nag_dgeqrt(order, m, n, nb, a, pda, t, pdt, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dgeqrt (f08abc).\n%s\n", fail.message); exit_status = 1; goto END; } /* nag_dgemqrt (f08acc). * Compute C = (C1) = (Q^T)*B, storing the result in B * (C2) * by applying Q^T from left. */ nag_dgemqrt(order, Nag_LeftSide, Nag_Trans, m, nrhs, n, nb, a, pda, t, pdt, b, pdb, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dgemqrt (f08acc).\n%s\n", fail.message); exit_status = 2; goto END; } /* nag_dtrtrs (f07tec). * Compute least-squares solutions by backsubstitution in R*X = C1. */ nag_dtrtrs(order, Nag_Upper, Nag_NoTrans, Nag_NonUnitDiag, n, nrhs, a, pda, b, pdb, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dtrtrs (f07tec).\n%s\n", fail.message); exit_status = 3; goto END; } /* nag_gen_real_mat_print (x04cac). * Print least-squares solutions. */ nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, nrhs, b, pdb, "Least-squares solution(s)", 0, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_gen_real_mat_print (x04cac).\n%s\n", fail.message); exit_status = 4; goto END; } printf("\n Square root(s) of the residual sum(s) of squares\n"); for ( j=1; j<=nrhs; j++) { /* nag_dge_norm (f16rac). * Compute and print estimate of the square root of the residual * sum of squares. */ nag_dge_norm(order, Nag_FrobeniusNorm, m - n, 1, &B(n + 1,j), pdb, &rnorm, &fail); if (fail.code != NE_NOERROR) { printf("\nError from nag_dge_norm (f16rac).\n%s\n", fail.message); exit_status = 5; goto END; } printf(" %11.2e ", rnorm); } printf("\n"); END: NAG_FREE(a); NAG_FREE(b); NAG_FREE(t); return exit_status; }