/* nag_dtpcon (f07ugc) Example Program. * * Copyright 2001 Numerical Algorithms Group. * * Mark 7, 2001. */ #include #include #include #include #include int main(void) { /* Scalars */ double rcond; Integer ap_len, i, j, n; Integer exit_status = 0; Nag_UploType uplo; NagError fail; Nag_OrderType order; /* Arrays */ char nag_enum_arg[40]; double *ap = 0; #ifdef NAG_COLUMN_MAJOR #define A_UPPER(I, J) ap[J*(J-1)/2 + I - 1] #define A_LOWER(I, J) ap[(2*n-J)*(J-1)/2 + I - 1] order = Nag_ColMajor; #else #define A_LOWER(I, J) ap[I*(I-1)/2 + J - 1] #define A_UPPER(I, J) ap[(2*n-I)*(I-1)/2 + J - 1] order = Nag_RowMajor; #endif INIT_FAIL(fail); printf("nag_dtpcon (f07ugc) Example Program Results\n"); /* Skip heading in data file */ scanf("%*[^\n] "); scanf("%ld%*[^\n] ", &n); /* Allocate memory */ ap_len = n*(n+1)/2; if (!(ap = NAG_ALLOC(ap_len, double))) { printf("Allocation failure\n"); exit_status = -1; goto END; } /* Read A from data file */ scanf(" %s%*[^\n] ", nag_enum_arg); /* nag_enum_name_to_value(x04nac). * Converts NAG enum member name to value */ uplo = (Nag_UploType) nag_enum_name_to_value(nag_enum_arg); if (uplo == Nag_Upper) { for (i = 1; i <= n; ++i) { for (j = i; j <= n; ++j) scanf("%lf", &A_UPPER(i, j)); } scanf("%*[^\n] "); } else { for (i = 1; i <= n; ++i) { for (j = 1; j <= i; ++j) scanf("%lf", &A_LOWER(i, j)); } scanf("%*[^\n] "); } /* Estimate condition number */ /* nag_dtpcon (f07ugc). * Estimate condition number of real triangular matrix, * packed storage */ nag_dtpcon(order, Nag_OneNorm, uplo, Nag_NonUnitDiag, n, ap, &rcond, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dtpcon (f07ugc).\n%s\n", fail.message); exit_status = 1; goto END; } printf("\n"); /* nag_machine_precision (x02ajc). * The machine precision */ if (rcond >= nag_machine_precision) printf("Estimate of condition number =%11.2e\n", 1.0 / rcond); else printf("A is singular to working precision\n"); END: if (ap) NAG_FREE(ap); return exit_status; }