/* nag_dsyevd (f08fcc) Example Program. * * Copyright 2001 Numerical Algorithms Group. * * Mark 7, 2001. */ #include #include #include #include #include int main(void) { /* Scalars */ Integer i, j, n, pda, w_len; Integer exit_status=0; NagError fail; Nag_JobType job; Nag_UploType uplo; Nag_OrderType order; /* Arrays */ char uplo_char[2], job_char[2]; double *a=0, *w=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); Vprintf("nag_dsyevd (f08fcc) Example Program Results\n\n"); /* Skip heading in data file */ Vscanf("%*[^\n] "); Vscanf("%ld%*[^\n] ", &n); pda = n; w_len = n; /* Allocate memory */ if ( !(a = NAG_ALLOC(n * n, double)) || !(w = NAG_ALLOC(w_len, double)) ) { Vprintf("Allocation failure\n"); exit_status = -1; goto END; } /* Read whether Upper or Lower part of A is stored */ Vscanf(" ' %1s '%*[^\n] ", uplo_char); if (*(unsigned char *)uplo_char == 'L') uplo = Nag_Lower; else if (*(unsigned char *)uplo_char == 'U') uplo = Nag_Upper; else { Vprintf("Unrecognised character for Nag_UploType type\n"); exit_status = -1; goto END; } /* Read A from data file */ if (uplo == Nag_Upper) { for (i = 1; i <= n; ++i) { for (j = i; j <= n; ++j) Vscanf("%lf", &A(i,j)); } Vscanf("%*[^\n] "); } else { for (i = 1; i <= n; ++i) { for (j = 1; j <= i; ++j) Vscanf("%lf", &A(i,j)); } Vscanf("%*[^\n] "); } /* Read type of job to be performed */ Vscanf(" ' %1s '%*[^\n] ", job_char); if (*(unsigned char *)job_char == 'V') job = Nag_EigVecs; else job = Nag_DoNothing; /* Calculate all the eigenvalues and eigenvectors of A */ /* nag_dsyevd (f08fcc). * All eigenvalues and optionally all eigenvectors of real * symmetric matrix (divide-and-conquer) */ nag_dsyevd(order, job, uplo, n, a, pda, w, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_dsyevd (f08fcc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print eigenvalues and eigenvectors */ Vprintf("Eigenvalues\n"); for (i = 0; i < n; ++i) Vprintf(" %8.4lf",w[i]); Vprintf("\n"); /* nag_gen_real_mat_print (x04cac). * Print real general matrix (easy-to-use) */ nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, n, a, pda, "Eigenvectors", 0, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_gen_real_mat_print (x04cac).\n%s\n", fail.message); exit_status = 1; goto END; } END: if (a) NAG_FREE(a); if (w) NAG_FREE(w); return exit_status; }