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elpa_eigenvalues(3) Library Functions Manual elpa_eigenvalues(3)

NAME

elpa_eigenvalues - computes all eigenvalues λ for a real symmetric or complex hermitian eigenproblem: A*Q = λ*Q

There are also variations of this routine that can accept not only host but also device pointers as input/output. Names of these routines explicitly contain the corresponding datatypes: elpa_eigenvalues_double, elpa_eigenvalues_float, elpa_eigenvalues_double_complex, elpa_eigenvalues_float_complex.

SYNOPSIS

FORTRAN INTERFACE

use elpa
class(elpa_t), pointer :: elpa_handle

call elpa_handle%eigenvalues (a, ev, error)

With the definitions of the input and output variables:

An instance of the ELPA object.
The local part of matrix A for which the eigenvalues should be computed. The dimensions of matrix a must be set BEFORE with the methods elpa_set(3) and elpa_setup(3). The datatype of the matrix can be one of "real(kind=c_double)", "real(kind=c_float)", "complex(kind=c_double)", or "complex(kind=c_float)". The global matrix has to be symmetric or hermitian, this is not checked by the routine.
The global array where the eigenvalues λ will be stored in ascending order. The datatype_real of ev can be either "real(kind=c_double)" or "real(kind=c_float)", depending of the datatype of the matrix. Note that complex hermitian matrices also have real eigenvalues.
The return error code of the function. Should be "ELPA_OK". The error code can be queried with the function elpa_strerr(3)

C/C++ INTERFACE

#include <elpa/elpa.h>
elpa_t elpa_handle;

void elpa_eigenvalues(elpa_t elpa_handle, datatype *a, datatype_real *ev, int *error);

With the definitions of the input and output variables:

The handle to the ELPA object
The local part of matrix A for which the eigenvalues should be computed. The dimensions of the matrix must be set BEFORE with the methods elpa_set(3) and elpa_setup(3). The datatype can be one of "double", "float", "double complex"/"std::complex<double>", "float complex"/"std::complex<float>" for C/C++. The global matrix has to be symmetric or hermitian, this is not checked by the routine.
The global array where the eigenvalues λ will be stored in ascending order. The datatype_real of the vector ev can be either "double" or "float", depending of the datatype of the matrix. Note that complex hermitian matrices also have real eigenvalues.
The error code of the function. Should be "ELPA_OK". The error codes can be queried with elpa_strerr(3)

DESCRIPTION

Computes the eigenvalues of a real symmetric or complex hermitian matrix. The functions elpa_init(3), elpa_allocate(3), elpa_set(3), and elpa_setup(3) must be called BEFORE elpa_eigenvalues can be called.

SEE ALSO

elpa2_print_kernels(1) elpa_init(3) elpa_allocate(3) elpa_set(3) elpa_setup(3) elpa_strerr(3) elpa_skew_eigenvalues(3) elpa_eigenvectors(3) elpa_skew_eigenvectors(3) elpa_cholesky(3) elpa_invert_triangular(3) elpa_solve_tridiagonal(3) elpa_eigenvalues(3) elpa_uninit(3) elpa_deallocate(3)

Thu Nov 28 2024 ELPA