/* nag_dppequ (f07gfc) Example Program. * * Copyright 2004 Numerical Algorithms Group. * * Mark 23, 2011. */ #include #include #include #include #include #include int main(void) { /* Scalars */ double amax, big, scond, small; Integer exit_status = 0, i, j, n; /* Arrays */ double *ap = 0, *s = 0; char nag_enum_arg[40]; /* Nag Types */ NagError fail; Nag_OrderType order; Nag_UploType uplo; #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_dppequ (f07gfc) Example Program Results\n\n"); /* Skip heading in data file */ scanf("%*[^\n]"); scanf("%ld%*[^\n]", &n); if (n < 0) { printf("Invalid n\n"); exit_status = 1; goto END; } scanf(" %39s%*[^\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); /* Allocate memory */ if (!(ap = NAG_ALLOC(n*(n+1)/2, double)) || !(s = NAG_ALLOC(n, double))) { printf("Allocation failure\n"); exit_status = -1; goto END; } /* Read the upper or lower triangular part of the matrix A from data file */ if (uplo == Nag_Upper) for (i = 1; i <= n; ++i) for (j = i; j <= n; ++j) scanf("%lf", &A_UPPER(i, j)); else if (uplo == Nag_Lower) for (i = 1; i <= n; ++i) for (j = 1; j <= i; ++j) scanf("%lf", &A_LOWER(i, j)); scanf("%*[^\n]"); /* Print the matrix A using nag_pack_real_mat_print (x04ccc). */ fflush(stdout); nag_pack_real_mat_print(order, uplo, Nag_NonUnitDiag, n, ap, "Matrix A", 0, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_pack_real_mat_print (x04ccc).\n%s\n", fail.message); exit_status = 1; goto END; } printf("\n"); /* Compute diagonal scaling factors using nag_dppequ (f07gfc). */ nag_dppequ(order, uplo, n, ap, s, &scond, &amax, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dppequ (f07gfc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print scond, amax and the scale factors */ printf("scond = %10.1e, amax = %10.1e\n\n", scond, amax); printf("Diagonal scaling factors\n"); for (i = 0; i < n; ++i) printf("%11.1e%s", s[i], i%7 == 6?"\n":" "); printf("\n\n"); /* Compute values close to underflow and overflow using * nag_real_safe_small_number (x02amc), nag_machine_precision (x02ajc) and * nag_real_base (x02bhc) */ small = nag_real_safe_small_number / (nag_machine_precision * nag_real_base); big = 1. / small; if (scond < 0.1 || amax < small || amax > big) { /* Scale A */ if (uplo == Nag_Upper) for (j = 1; j <= n; ++j) for (i = 1; i <= j; ++i) A_UPPER(i, j) *= s[i-1] * s[j-1]; else for (j = 1; j <= n; ++j) for (i = j; i <= n; ++i) A_LOWER(i, j) *= s[i-1] * s[j-1]; /* Print the scaled matrix using nag_pack_real_mat_print (x04ccc). */ fflush(stdout); nag_pack_real_mat_print(order, uplo, Nag_NonUnitDiag, n, ap, "Scaled matrix", 0, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_pack_real_mat_print (x04ccc).\n%s\n", fail.message); exit_status = 1; goto END; } } END: NAG_FREE(ap); NAG_FREE(s); return exit_status; } #undef A_UPPER #undef A_LOWER