/* nag_dstegr (f08jlc) Example Program. * * Copyright 2011 Numerical Algorithms Group. * * Mark 23, 2011. */ #include #include #include #include #include int main(void) { /* Scalars */ double vl = 0.0, vu = 0.0; Integer i, j, m, n, pdz; Integer exit_status = 0; /* Arrays */ char nag_enum_arg[40]; double *d = 0, *e = 0, *w = 0, *z = 0; Integer *isuppz = 0; /* Nag Types */ Nag_OrderType order; Nag_JobType job; Nag_RangeType range; NagError fail; #ifdef NAG_COLUMN_MAJOR #define Z(I, J) z[(J - 1) * pdz + I - 1] order = Nag_ColMajor; #else #define Z(I, J) z[(I - 1) * pdz + J - 1] order = Nag_RowMajor; #endif INIT_FAIL(fail); printf("nag_dstegr (f08jlc) Example Program Results\n\n"); /* Skip heading in data file */ scanf("%*[^\n]"); scanf("%ld%*[^\n]", &n); m = n; /* Read job and range*/ scanf("%s%*[^\n]", nag_enum_arg); /* nag_enum_name_to_value (x04nac). * Converts NAG enum member name to value. */ job = (Nag_JobType) nag_enum_name_to_value(nag_enum_arg); scanf("%s%*[^\n]", nag_enum_arg); range = (Nag_RangeType) nag_enum_name_to_value(nag_enum_arg); #ifdef NAG_COLUMN_MAJOR pdz = n; #else pdz = m; #endif /* Allocate memory */ if (!(d = NAG_ALLOC(n, double)) || !(e = NAG_ALLOC(n, double)) || !(w = NAG_ALLOC(n, double)) || !(z = NAG_ALLOC(n*m, double)) || !(isuppz = NAG_ALLOC(2*m, Integer))) { printf("Allocation failure\n"); exit_status = -1; goto END; } /* Read the symmetric tridiagonal matrix T from data file, first * the diagonal elements, then the off diagonal elements. */ for (i = 0; i < n; ++i) scanf("%lf", &d[i]); scanf("%*[^\n]"); for (i = 0; i < n - 1; ++i) scanf("%lf", &e[i]); scanf("%*[^\n]"); /* nag_dstegr (f08jlc). * Calculate all the eigenvalues of T. */ nag_dstegr(order, job, range, n, d, e, vl, vu, 0, 0, &m, w, z, pdz, isuppz, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dstegr (f08jlc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Normalize the eigenvectors */ for(j=1; j<=m; j++) for(i=n; i>=1; i--) Z(i, j) = Z(i, j) / Z(1,j); /* Print eigenvalues and eigenvectors */ printf(" %s\n", "Eigenvalues"); for (i = 0; i < m; ++i) printf("%8.4f%s", w[i], (i+1)%8 == 0?"\n":" "); printf("\n\n"); /* nag_gen_real_mat_print (x04cac). * Print eigenvectors. */ fflush(stdout); nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, m, z, pdz, "Eigenvectors", 0, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_gen_real_mat_print (x04cac).\n%s\n", fail.message); exit_status = 1; goto END; } END: if (d) NAG_FREE(d); if (e) NAG_FREE(e); if (w) NAG_FREE(w); if (z) NAG_FREE(z); if (isuppz) NAG_FREE(isuppz); return exit_status; } #undef Z