/* nag_zpbequ (f07htc) 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 pd1, pd2, exit_status = 0, i, j, kd, n, pdab; /* Arrays */ Complex *ab = 0; double *s = 0; char nag_enum_arg[40]; /* Nag Types */ NagError fail; Nag_UploType uplo; Nag_OrderType order; #ifdef NAG_COLUMN_MAJOR #define AB_UPPER(I, J) ab[(J-1)*pdab + kd + I - J] #define AB_LOWER(I, J) ab[(J-1)*pdab + I - J] order = Nag_ColMajor; #else #define AB_UPPER(I, J) ab[(I-1)*pdab + J - I] #define AB_LOWER(I, J) ab[(I-1)*pdab + kd + J - I] order = Nag_RowMajor; #endif INIT_FAIL(fail); printf("nag_zpbequ (f07htc) Example Program Results\n\n"); /* Skip heading in data file */ scanf("%*[^\n]"); scanf("%ld%ld%*[^\n]", &n, &kd); if (n < 0 || kd < 0) { printf("%s\n", "Invalid n or kd"); 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 */ pdab = kd+1; if (!(ab = NAG_ALLOC((kd+1)*n, Complex)) || !(s = NAG_ALLOC(n, double))) { printf("Allocation failure\n"); exit_status = -1; goto END; } /* Read the upper or lower triangular part of the band matrix A */ /* from data file */ if (uplo == Nag_Upper) { pd1 = 0; pd2 = kd; for (i = 1; i <= n; ++i) for (j = i; j <= MIN(n, i + kd); ++j) scanf(" ( %lf , %lf )", &AB_UPPER(i, j).re, &AB_UPPER(i, j).im); } else { pd1 = kd; pd2 = 0; for (i = 1; i <= n; ++i) for (j = MAX(1, i - kd); j <= i; ++j) scanf(" ( %lf , %lf )", &AB_LOWER(i, j).re, &AB_LOWER(i, j).im); } scanf("%*[^\n]"); /* Print the matrix A using nag_band_complx_mat_print_comp (x04dfc). */ fflush(stdout); nag_band_complx_mat_print_comp(order, n, n, pd1, pd2, ab, pdab, Nag_BracketForm, "%11.2e", "Matrix A", Nag_IntegerLabels, 0, Nag_IntegerLabels, 0, 80, 0, 0, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_band_complx_mat_print_comp (x04dfc).\n%s\n", fail.message); exit_status = 1; goto END; } printf("\n"); /* Compute diagonal scaling factors using nag_zpbequ (f07htc). */ nag_zpbequ(order, uplo, n, kd, ab, pdab, s, &scond, &amax, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_zpbequ (f07htc).\n%s\n", fail.message); exit_status = 1; goto END; } printf("scond = %10.1e, amax = %10.1e\n", scond, amax); printf("\nDiagonal 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 = 1.0 / small; if (scond < 0.1 || amax < small || amax > big) { /* Scale A */ if (uplo == Nag_Upper) for (j = 1; j <= n; ++j) for (i = MAX(1, j - kd); i <= j; ++i) { AB_UPPER(i, j).re *= s[i-1]*s[j-1]; AB_UPPER(i, j).im *= s[i-1]*s[j-1]; } else for (j = 1; j <= n; ++j) for (i = j; i <= MIN(n, j + kd); ++i) { AB_LOWER(i, j).re *= s[i-1]*s[j-1]; AB_LOWER(i, j).im *= s[i-1]*s[j-1]; } /* Print the scaled matrix using * nag_band_complx_mat_print_comp (x04dfc). */ fflush(stdout); nag_band_complx_mat_print_comp(order, n, n, pd1, pd2, ab, pdab, Nag_BracketForm, "%7.4f", "Scaled matrix", Nag_IntegerLabels, 0, Nag_IntegerLabels, 0, 80, 0, 0, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_band_complx_mat_print_comp (x04dfc).\n%s\n", fail.message); exit_status = 1; goto END; } } END: NAG_FREE(ab); NAG_FREE(s); return exit_status; } #undef AB_UPPER #undef AB_LOWER