/* nag_dgebrd (f08kec) Example Program. * * Copyright 2001 Numerical Algorithms Group. * * Mark 7, 2001. */ #include #include #include #include #include int main(int argc, char *argv[]) { FILE *fpin, *fpout; /* Scalars */ Integer i, j, m, n, pda, d_len, e_len, tauq_len, taup_len; Integer exit_status = 0; NagError fail; Nag_OrderType order; /* Arrays */ double *a = 0, *d = 0, *e = 0, *taup = 0, *tauq = 0; #ifdef NAG_COLUMN_MAJOR #define A(I, J) a[(J - 1) * pda + I - 1] order = Nag_ColMajor; #else #define A(I, J) a[(I - 1) * pda + J - 1] order = Nag_RowMajor; #endif 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_dgebrd (f08kec) Example Program Results\n"); /* Skip heading in data file */ fscanf(fpin, "%*[^\n] "); fscanf(fpin, "%ld%ld%*[^\n] ", &m, &n); #ifdef NAG_COLUMN_MAJOR pda = m; #else pda = n; #endif d_len = MIN(m, n); e_len = MIN(m, n)-1; tauq_len = MIN(m, n); taup_len = MIN(m, n); /* Allocate memory */ if (!(a = NAG_ALLOC(m * n, double)) || !(d = NAG_ALLOC(d_len, double)) || !(e = NAG_ALLOC(e_len, double)) || !(taup = NAG_ALLOC(taup_len, double)) || !(tauq = NAG_ALLOC(tauq_len, double))) { fprintf(fpout, "Allocation failure\n"); exit_status = -1; goto END; } /* Read A from data file */ for (i = 1; i <= m; ++i) { for (j = 1; j <= n; ++j) fscanf(fpin, "%lf", &A(i, j)); } fscanf(fpin, "%*[^\n] "); /* Reduce A to bidiagonal form */ /* nag_dgebrd (f08kec). * Orthogonal reduction of real general rectangular matrix * to bidiagonal form */ nag_dgebrd(order, m, n, a, pda, d, e, tauq, taup, &fail); if (fail.code != NE_NOERROR) { fprintf(fpout, "Error from nag_dgebrd (f08kec).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print bidiagonal form */ fprintf(fpout, "\nDiagonal\n"); for (i = 1; i <= MIN(m, n); ++i) fprintf(fpout, "%9.4f%s", d[i-1], i%8 == 0?"\n":" "); if (m >= n) fprintf(fpout, "\nSuper-diagonal\n"); else fprintf(fpout, "\nSub-diagonal\n"); for (i = 1; i <= MIN(m, n) - 1; ++i) fprintf(fpout, "%9.4f%s", e[i-1], i%8 == 0?"\n":" "); fprintf(fpout, "\n"); END: if (fpin != stdin) fclose(fpin); if (fpout != stdout) fclose(fpout); if (a) NAG_FREE(a); if (d) NAG_FREE(d); if (e) NAG_FREE(e); if (taup) NAG_FREE(taup); if (tauq) NAG_FREE(tauq); return exit_status; } #undef A