/* nag_dtbsv (f16pkc) Example Program. * * Copyright 2005 Numerical Algorithms Group. * * Mark 8, 2005. */ #include #include #include #include #include int main(int argc, char *argv[]) { FILE *fpin, *fpout; /* Scalars */ double alpha; Integer exit_status, i, incx, j, kd, n, pdab, xlen; /* Arrays */ double *ab = 0, *x = 0; char nag_enum_arg[40]; /* Nag Types */ NagError fail; Nag_OrderType order; Nag_TransType trans; Nag_UploType uplo; Nag_DiagType diag; #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] #define B(I, J) b[(J-1)*pdb + I - 1] 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] #define B(I, J) b[(I-1)*pdb + J - 1] order = Nag_RowMajor; #endif exit_status = 0; INIT_FAIL(fail); /* Check for command-line IO options */ fpin = nag_example_file_io(argc, argv, "-data", NULL); fpout = nag_example_file_io(argc, argv, "-results", NULL); fprintf(fpout, "nag_dtbsv (f16pkc) Example Program Results\n\n"); /* Skip heading in data file */ fscanf(fpin, "%*[^\n] "); /* Read the problem dimensions */ fscanf(fpin, "%ld%ld%*[^\n] ", &n, &kd); /* Read the uplo storage parameter */ fscanf(fpin, "%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 the transpose parameter */ fscanf(fpin, "%s%*[^\n] ", nag_enum_arg); /* nag_enum_name_to_value(x04nac), see above. */ trans = (Nag_TransType) nag_enum_name_to_value(nag_enum_arg); /* Read the unit-diagonal parameter */ fscanf(fpin, "%s%*[^\n] ", nag_enum_arg); /* nag_enum_name_to_value(x04nac), see above. */ diag = (Nag_DiagType) nag_enum_name_to_value(nag_enum_arg); /* Read scalar parameters */ fscanf(fpin, "%lf%*[^\n] ", &alpha); /* Read increment parameter */ fscanf(fpin, "%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))) { fprintf(fpout, "Allocation failure\n"); exit_status = -1; goto END; } } else { fprintf(fpout, "Invalid n\n"); exit_status = 1; return exit_status; } /* Input matrix AB and vector x*/ if (uplo == Nag_Upper) { for (i = 1; i <= n; ++i) { if (diag == Nag_NonUnitDiag) fscanf(fpin, "%lf", &AB_UPPER(i, i)); for (j = i+1; j <= MIN(i+kd, n); ++j) fscanf(fpin, "%lf", &AB_UPPER(i, j)); } fscanf(fpin, "%*[^\n] "); } else { for (i = 1; i <= n; ++i) { for (j = MAX(1, i-kd); j < i; ++j) fscanf(fpin, "%lf", &AB_LOWER(i, j)); if (diag == Nag_NonUnitDiag) fscanf(fpin, "%lf", &AB_LOWER(i, i)); } fscanf(fpin, "%*[^\n] "); } for (i = 0; i < xlen; ++i) fscanf(fpin, "%lf%*[^\n] ", &x[i]); /* nag_dtbsv(f16pkc). * Solution of real triangular band system of linear equations. * */ nag_dtbsv(order, uplo, trans, diag, n, kd, alpha, ab, pdab, x, incx, &fail); if (fail.code != NE_NOERROR) { fprintf(fpout, "Error from nag_dtbsv.\n%s\n", fail.message); exit_status = 1; goto END; } /* Print output vector x */ fprintf(fpout, "%s\n", " Solution x:"); for (i = 0; i < xlen; ++i) { fprintf(fpout, "%11f\n", x[i]); } END: if (fpin != stdin) fclose(fpin); if (fpout != stdout) fclose(fpout); if (ab) NAG_FREE(ab); if (x) NAG_FREE(x); return exit_status; }