/* nag_dtbmv (f16pgc) Example Program. * * Copyright 2005 Numerical Algorithms Group. * * Mark 8, 2005. */ #include #include #include #include int main(void) { /* Scalars */ double alpha; Integer exit_status, i, incx, j, k, kd, n, pdab, xlen; /* Arrays */ double *ab = 0, *x = 0; char nag_enum_arg[40]; /* Nag Types */ NagError fail; Nag_DiagType diag; Nag_OrderType order; Nag_TransType trans; Nag_UploType uplo; #ifdef NAG_COLUMN_MAJOR #define AB_UPPER(I, J) ab[(J-1)*pdab + k + I - J - 1] #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 + k + J - I - 1] order = Nag_RowMajor; #endif exit_status = 0; INIT_FAIL(fail); printf("nag_dtbmv (f16pgc) Example Program Results\n\n"); /* Skip heading in data file */ scanf("%*[^\n] "); /* Read the problem dimension */ scanf("%ld%ld%*[^\n] ", &n, &kd); /* Read uplo */ 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); /* Read trans */ scanf("%39s%*[^\n] ", nag_enum_arg); /* nag_enum_name_to_value (x04nac). * Converts NAG enum member name to value */ trans = (Nag_TransType) nag_enum_name_to_value(nag_enum_arg); /* Read diag */ scanf("%39s%*[^\n] ", nag_enum_arg); /* nag_enum_name_to_value (x04nac). * Converts NAG enum member name to value */ diag = (Nag_DiagType) nag_enum_name_to_value(nag_enum_arg); /* Read scalar parameters */ scanf("%lf%*[^\n] ", &alpha); /* Read increment parameters */ scanf("%ld%*[^\n] ", &incx); pdab = kd + 1; xlen = MAX(1, 1 + (n - 1)*ABS(incx)); if (n > 0) { /* Allocate memory */ if (!(ab = NAG_ALLOC(pdab*n, double)) || !(x = NAG_ALLOC(xlen, double))) { printf("Allocation failure\n"); exit_status = -1; goto END; } } else { printf("Invalid n\n"); exit_status = 1; return exit_status; } /* Read A from data file */ k = kd + 1; if (uplo == Nag_Upper) { for (i = 1; i <= n; ++i) { for (j = i; j <= MIN(i+kd, n); ++j) scanf("%lf", &AB_UPPER(i, j)); } scanf("%*[^\n] "); } else { for (i = 1; i <= n; ++i) { for (j = MAX(1, i-kd); j <= i; ++j) scanf("%lf", &AB_LOWER(i, j)); } scanf("%*[^\n] "); } /* Input vector x */ for (i = 1; i <= xlen; ++i) scanf("%lf%*[^\n] ", &x[i - 1]); /* nag_dtbmv (f16pgc). * Triangular banded matrix-vector multiply. * */ nag_dtbmv(order, uplo, trans, diag, n, kd, alpha, ab, pdab, x, incx, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dtbmv (f16pgc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print output vector x */ printf("%s\n", " x"); for (i = 1; i <= xlen; ++i) { printf("%11f\n", x[i-1]); } END: NAG_FREE(ab); NAG_FREE(x); return exit_status; }