/* nag_dspevd (f08gcc) Example Program. * * Copyright 2001 Numerical Algorithms Group. * * Mark 7, 2001. */ #include #include #include #include #include int main(void) { /* Scalars */ Integer i, j, n, ap_len, pdz, w_len; Integer exit_status = 0; NagError fail; Nag_JobType job; Nag_UploType uplo; Nag_OrderType order; /* Arrays */ char nag_enum_arg[40]; double *ap = 0, *w = 0, *z = 0; #ifdef NAG_COLUMN_MAJOR #define A_UPPER(I, J) ap[J * (J - 1) / 2 + I - 1] #define A_LOWER(I, J) ap[(2 * n - J) * (J - 1) / 2 + I - 1] #define Z(I, J) z[(J - 1) * pdz + I - 1] order = Nag_ColMajor; #else #define A_LOWER(I, J) ap[I * (I - 1) / 2 + J - 1] #define A_UPPER(I, J) ap[(2 * n - I) * (I - 1) / 2 + J - 1] #define Z(I, J) z[(I - 1) * pdz + J - 1] order = Nag_RowMajor; #endif INIT_FAIL(fail); printf("nag_dspevd (f08gcc) Example Program Results\n\n"); /* Skip heading in data file */ scanf("%*[^\n] "); scanf("%ld%*[^\n] ", &n); ap_len = n*(n+1)/2; w_len = n; pdz = n; /* Allocate memory */ if (!(ap = NAG_ALLOC(ap_len, double)) || !(z = NAG_ALLOC(n * n, double)) || !(w = NAG_ALLOC(w_len, double))) { printf("Allocation failure\n"); exit_status = -1; goto END; } /* Read whether Upper or Lower part of A is stored */ scanf("%39s%*[^\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 A from data file */ if (uplo == Nag_Upper) { for (i = 1; i <= n; ++i) { for (j = i; j <= n; ++j) scanf("%lf", &A_UPPER(i, j)); } scanf("%*[^\n] "); } else { for (i = 1; i <= n; ++i) { for (j = 1; j <= i; ++j) scanf("%lf", &A_LOWER(i, j)); } scanf("%*[^\n] "); } /* Read type of job to be performed */ scanf("%39s%*[^\n] ", nag_enum_arg); job = (Nag_JobType) nag_enum_name_to_value(nag_enum_arg); /* Calculate all the eigenvalues and eigenvectors of A */ /* nag_dspevd (f08gcc). * All eigenvalues and optionally all eigenvectors of real * symmetric matrix, packed storage (divide-and-conquer) */ nag_dspevd(order, job, uplo, n, ap, w, z, pdz, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dspevd (f08gcc).\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) = Z(i, j) / Z(1,j); } } /* Print eigenvalues and eigenvectors */ printf("Eigenvalues \n"); for (i = 0; i < n; ++i) printf(" %8.4lf", w[i]); printf("\n"); /* nag_gen_real_mat_print (x04cac). * Print real general matrix (easy-to-use) */ fflush(stdout); nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, n, 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: NAG_FREE(ap); NAG_FREE(w); NAG_FREE(z); return exit_status; }