.TH "elpa_eigenvalues_double_complex" 3 "Thu Nov 28 2024" "ELPA" \" -*- nroff -*-
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.SH NAME
elpa_eigenvalues_double_complex \- computes all eigenvalues \(*l for a complex hermitian eigenproblem: A*Q = \(*l*Q
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.SH SYNOPSIS
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.SS FORTRAN INTERFACE
use elpa
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class(elpa_t), pointer :: elpa_handle
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call elpa_handle%\fBeigenvalues_double_complex\fP (a, ev, error)
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With the definitions of the input and output variables:

.TP
class(elpa_t) ::\fB elpa_handle\fP
An instance of the ELPA object.
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real(kind=c_double_complex) ::\fB a\fP \t OR \t type(c_ptr) ::\fB a\fP
The local part of the host/device matrix A for which the eigenvalues should be computed.
The dimensions of matrix\fB a\fP must be set\fI BEFORE\fP with the methods\fB elpa_set\fP(3) and\fB elpa_setup\fP(3).
The global matrix has to be hermitian, this is not checked by the routine.
In case of a GPU build\fB a\fP can be a pointer to the device memory.
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real(kind=c_double) ::\fB ev\fP \t\t OR \t type(c_ptr) ::\fB ev\fP
The global array where the eigenvalues \(*l will be stored in\fI ascending\fP order.
In case of a GPU build\fB ev\fP can be a pointer to the device memory.
Note that complex hermitian matrices also have real eigenvalues.
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integer, optional ::\fB error\fP
The return error code of the function. Should be "ELPA_OK". The error code can be queried with the function\fB elpa_strerr\fP(3)

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.SS C/C++ INTERFACE
#include <elpa/elpa.h>
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elpa_t elpa_handle;

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// C:
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void\fB elpa_eigenvalues_double_complex\fP(\fBelpa_t\fP elpa_handle,\fB double complex\fP *a,\fB double\fP *ev,\fB int\fP *error);
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// C++:
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void\fB elpa_eigenvalues_double_complex\fP(\fBelpa_t\fP elpa_handle,\fB std::complex<double>\fP *a,\fB double\fP *ev,\fB int\fP *error);
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With the definitions of the input and output variables:

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elpa_t \fB elpa_handle\fP;
The handle to the ELPA object
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double complex \fB *a\fP; \t OR \t std::complex<double> \fB *a\fP;
The local part of the host/device matrix A for which the eigenvalues should be computed.
The dimensions of matrix\fB a\fP must be set\fI BEFORE\fP with the methods\fB elpa_set\fP(3) and\fB elpa_setup\fP(3).
The global matrix A has to be hermitian, this is not checked by the routine.
In case of a GPU build\fB a\fP can be a pointer to the device memory.
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double \fB *ev\fP;
The global array where the eigenvalues \(*l will be stored in\fI ascending\fP order.
In case of a GPU build\fB ev\fP can be a pointer to the device memory.
Note that complex hermitian matrices also have real eigenvalues.
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int \fB *error\fP;
The error code of the function. Should be "ELPA_OK". The error codes can be queried with\fB elpa_strerr\fP(3)

.SH DESCRIPTION
Computes the eigenvalues of a complex hermitian matrix.
The functions\fB elpa_init\fP(3),\fB elpa_allocate\fP(3),\fB elpa_set\fP(3), and\fB elpa_setup\fP(3) must be called\fI BEFORE\fP\fB elpa_eigenvalues_double_complex\fP can be called.

.SH SEE ALSO
\fBelpa2_print_kernels\fP(1)\fB elpa_init\fP(3)\fB elpa_allocate\fP(3)\fB elpa_set\fP(3)\fB elpa_setup\fP(3)\fB elpa_strerr\fP(3)\fB elpa_skew_eigenvalues\fP(3)\fB elpa_eigenvectors\fP(3)\fB elpa_skew_eigenvectors\fP(3)\fB elpa_cholesky\fP(3)\fB elpa_invert_triangular\fP(3)\fB elpa_solve_tridiagonal\fP(3)\fB elpa_eigenvalues\fP(3)\fB elpa_uninit\fP(3)\fB elpa_deallocate\fP(3)