/* nag_det_real_gen (f03bac) Example Program. * * Copyright 2011, Numerical Algorithms Group. * * Mark 23, 2011. */ #include #include #include #include #include #include int main(void) { /* Scalars */ Integer exit_status = 0; Integer i, id, j, n, pda; double d; /* Arrays */ Integer *ipiv = 0; double *a = 0; /* NAG types */ NagError fail; Nag_OrderType order; Nag_MatrixType matrix = Nag_GeneralMatrix; Nag_DiagType diag = Nag_NonUnitDiag; printf("nag_det_real_gen (f03bac) Example Program Results\n"); fflush(stdout); /* Skip heading in data file */ scanf("%*[^\n] "); scanf("%ld%*[^\n]", &n); pda = n; if (!(a = NAG_ALLOC(n*n, double)) || !(ipiv = NAG_ALLOC(n, Integer))) { printf("Allocation failure\n"); exit_status = -1; goto END; } /* Define matrix element A_ij in terms of elements of array a[k] */ #ifdef NAG_COLUMN_MAJOR order = Nag_ColMajor; #define A(I, J) a[(J-1)*pda+(I-1)] #else order = Nag_RowMajor; #define A(J, I) a[(J-1)*pda+(I-1)] #endif for (i = 1; i <= n; i++) for (j = 1; j <= n; j++) scanf("%lf", &A(i, j)); scanf("%*[^\n] "); INIT_FAIL(fail); /* nag_dgetrf (f07adc) - LU factorization of real m by n matrix */ nag_dgetrf(order, n, n, a, pda, ipiv, &fail); if (fail.code != NE_NOERROR) { printf("%s\n", fail.message); exit_status = 1; goto END; } /* nag_gen_real_mat_print (x04cac). * Print real general matrix (easy-to-use) */ fflush(stdout); printf("\n"); nag_gen_real_mat_print(order, matrix, diag, n, n, a, pda, "Array A after factorization", NULL, &fail); if (fail.code != NE_NOERROR) { printf("%s\n", fail.message); exit_status = 2; goto END; } printf("\nPivots:\n "); for (j = 0; j < n; j++) printf("%11" NAG_IFMT " ", ipiv[j]); printf("\n"); /* nag_det_real_gen (f03bac). * LU factorization and determinant of real matrix */ nag_det_real_gen(order, n, a, pda, ipiv, &d, &id, &fail); if (fail.code != NE_NOERROR) { printf("%s\n", fail.message); exit_status = 3; goto END; } printf("d = %12.5f id = %12" NAG_IFMT "\n", d, id); printf("Value of determinant = %13.5e\n", d*pow((double) 2.0, id)); END: NAG_FREE(a); NAG_FREE(ipiv); return exit_status; }