/* nag_dsbmv (f16pdc) Example Program. * * Copyright 2005 Numerical Algorithms Group. * * Mark 8, 2005. */ #include #include #include #include int main(void) { /* Scalars */ double alpha, beta; Integer exit_status, i, incx, incy, j, k, kd, n, pdab, xlen, ylen; /* Arrays */ double *ab = 0, *x = 0, *y = 0; char nag_enum_arg[40]; /* Nag Types */ NagError fail; Nag_OrderType order; 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_dsbmv (f16pdc) 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("%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); /* Read scalar parameters */ scanf("%lf%lf%*[^\n] ", &alpha, &beta); /* Read increment parameters */ scanf("%ld%ld%*[^\n] ", &incx, &incy); pdab = kd + 1; xlen = MAX(1, 1 + (n - 1)*ABS(incx)); ylen = MAX(1, 1 + (n - 1)*ABS(incy)); if (n > 0) { /* Allocate memory */ if (!(ab = NAG_ALLOC(pdab*n, double)) || !(x = NAG_ALLOC(xlen, double)) || !(y = NAG_ALLOC(ylen, 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 vectors x and y */ for (i = 1; i <= xlen; ++i) scanf("%lf%*[^\n] ", &x[i - 1]); for (i = 1; i <= ylen; ++i) scanf("%lf%*[^\n] ", &y[i - 1]); /* nag_dsbmv(f16pdc). * Symmetric banded matrix-vector multiply. * */ nag_dsbmv(order, uplo, n, kd, alpha, ab, pdab, x, incx, beta, y, incy, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dsbmv.\n%s\n", fail.message); exit_status = 1; goto END; } /* Print output vector y */ printf("%s\n", " y"); for (i = 1; i <= ylen; ++i) { printf("%11f\n", y[i-1]); } END: if (ab) NAG_FREE(ab); if (x) NAG_FREE(x); if (y) NAG_FREE(y); return exit_status; }