1elpa_eigenvalues(3)        Library Functions Manual        elpa_eigenvalues(3)
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NAME

6       elpa_eigenvalues - computes the eigenvalues of a real symmetric or
7       complex hermitian matrix
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SYNOPSIS

11   FORTRAN INTERFACE
12       use elpa
13       class(elpa_t), pointer :: elpa
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15       call elpa%eigenvalues (a, ev, error)
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17       With the definitions of the input and output variables:
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19       class(elpa_t) :: elpa  ! returns an instance of the ELPA object
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21       datatype :: a
22              The matrix a for which the eigenvalues should be computed. The
23              dimensions of matrix a must be set BEFORE with the methods
24              elpa_set(3) and elpa_setup(3). The datatype of the matrix can be
25              one of "real(kind=c_double)", "real(kind=c_float)",
26              "complex(kind=c_double)", or "complex(kind=c_float)"
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28       datatype :: ev
29              The vector ev where the eigenvalues will be stored in ascending
30              order. The datatype of the vector ev can be either
31              "real(kind=c_double)", or "real(kind=c_float)", depending of the
32              datatype of the matrix. Note that complex hermitian matrices
33              also have real valued eigenvalues.
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35       integer, optional :: error
36              The return error code of the function. Should be "ELPA_OK". The
37              error code can be querried with the function elpa_strerr(3)
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40   C INTERFACE
41       #include <elpa/elpa.h>
42       elpa_t handle;
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44       void elpa_eigenvalues(elpa_t handle, datatype *a, datatype *ev, int
45       *error);
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47       With the definitions of the input and output variables:
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50       elpa_t handle;
51              The handle to the ELPA object
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53       datatype *a;
54              The matrix a for which the eigenvalues should be computed. The
55              dimensions of the matrix must be set BEFORE with the methods
56              elpa_set(3) and elpa_setup(3). The datatype can be one of
57              "double", "float", "double complex", or "float complex".
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59       datatype *ev;
60              The storage for the computed eigenvalues. Eigenvalues will be
61              stored in ascendig order. The datatype can be either "double" or
62              "float". Note that the eigenvalues of complex hermitian matrices
63              are also real.
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65       int *error;
66              The error code of the function. Should be "ELPA_OK". The error
67              codes can be querried with elpa_strerr(3)
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DESCRIPTION

71       Compute the eigenvalues of a real symmtric or complex hermitian
72       matrix.The functions elpa_init(3), elpa_allocate(3), elpa_set(3), and
73       elpa_setup(3) must be called BEFORE elpa_eigenvalues can be called.
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SEE ALSO

76       elpa2_print_kernels(1) elpa_init(3) elpa_allocate(3) elpa_set(3)
77       elpa_setup(3) elpa_strerr(3) elpa_eigenvectors(3) elpa_cholesky(3)
78       elpa_invert_triangular(3) elpa_solve_tridiagonal(3) elpa_eigenvalues(3)
79       elpa_uninit(3) elpa_deallocate(3)
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83ELPA                            Sat Jul 15 2017            elpa_eigenvalues(3)
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