/* nag_zhbtrd (f08hsc) Example Program. * * Copyright 2001 Numerical Algorithms Group. * * Mark 7, 2001. */ #include #include #include #include #include #include int main(void) { /* Scalars */ Integer i, j, k, kd, n, pdab, pdz, d_len, e_len; Integer exit_status = 0; NagError fail; Nag_UploType uplo; Nag_OrderType order; /* Arrays */ char nag_enum_arg[40]; Complex *ab = 0, *z = 0; double *d = 0, *e = 0; #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] #define Z(I, J) z[(J - 1) * pdz + 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 + k + J - I - 1] #define Z(I, J) z[(I - 1) * pdz + J - 1] order = Nag_RowMajor; #endif INIT_FAIL(fail); printf("nag_zhbtrd (f08hsc) Example Program Results\n\n"); /* Skip heading in data file */ scanf("%*[^\n] "); scanf("%ld%ld%*[^\n] ", &n, &kd); pdab = kd + 1; pdz = n; d_len = n; e_len = n - 1; /* Allocate memory */ if (!(ab = NAG_ALLOC(pdab * n, Complex)) || !(d = NAG_ALLOC(d_len, double)) || !(e = NAG_ALLOC(e_len, double)) || !(z = NAG_ALLOC(pdz * n, Complex))) { printf("Allocation failure\n"); exit_status = -1; goto END; } /* Read A from data file */ 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); k = kd + 1; if (uplo == Nag_Upper) { for (i = 1; i <= n; ++i) { for (j = i; j <= MIN(i + kd, n); ++j) scanf(" ( %lf , %lf )", &AB_UPPER(i, j).re, &AB_UPPER(i, j).im); } scanf("%*[^\n] "); } else { for (i = 1; i <= n; ++i) { for (j = MAX(1, i - kd); j <= i; ++j) scanf(" ( %lf , %lf )", &AB_LOWER(i, j).re, &AB_LOWER(i, j).im); } scanf("%*[^\n] "); } /* Reduce A to tridiagonal form */ /* nag_zhbtrd (f08hsc). * Unitary reduction of complex Hermitian band matrix to * real symmetric tridiagonal form */ nag_zhbtrd(order, Nag_FormQ, uplo, n, kd, ab, pdab, d, e, z, pdz, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_zhbtrd (f08hsc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Calculate all the eigenvalues and eigenvectors of A */ /* nag_zsteqr (f08jsc). * All eigenvalues and eigenvectors of real symmetric * tridiagonal matrix, reduced from complex Hermitian * matrix, using implicit QL or QR */ nag_zsteqr(order, Nag_UpdateZ, n, d, e, z, pdz, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_zsteqr (f08jsc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Normalize the eigenvectors */ for(j=1; j<=n; j++) { for(i=n; i>=1; i--) { Z(i, j) = nag_complex_divide(Z(i, j),Z(1, j)); } } /* Print eigenvalues and eigenvectors */ printf(" Eigenvalues\n"); for (i = 1; i <= n; ++i) printf("%8.4f%s", d[i-1], i%8 == 0?"\n":" "); printf("\n\n"); /* nag_gen_complx_mat_print_comp (x04dbc). * Print complex general matrix (comprehensive) */ fflush(stdout); nag_gen_complx_mat_print_comp(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, n, z, pdz, Nag_BracketForm, "%7.4f", "Eigenvectors", Nag_IntegerLabels, 0, Nag_IntegerLabels, 0, 80, 0, 0, &fail); if (fail.code != NE_NOERROR) { printf( "Error from nag_gen_complx_mat_print_comp (x04dbc).\n%s\n", fail.message); exit_status = 1; goto END; } END: if (ab) NAG_FREE(ab); if (d) NAG_FREE(d); if (e) NAG_FREE(e); if (z) NAG_FREE(z); return exit_status; }