elpa_eigenvalues_double(3)

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

6       elpa_eigenvalues_double - computes the eigenvalues of a real double-
7       precision symmetric 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_double (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 must
25              be real(kind=c_double). The matrix has to be symmetric this is
26              not checked by the routine. In case of a GPU build a can be a
27              device pointer of type "type(c_ptr) to a matrix a on the device
28              memory.
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30       datatype :: ev
31              The vector ev where the eigenvalues will be stored in ascending
32              order. The datatype of the vector ev must be
33              "real(kind=c_double)". In case of a GPU build ev can be a device
34              pointer of type "type(c_ptr) to the vector of eigenvalues in the
35              device memory
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37       integer, optional :: error
38              The return error code of the function. Should be "ELPA_OK". The
39              error code can be querried with the function elpa_strerr(3)
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42   C INTERFACE
43       #include <elpa/elpa.h>
44       elpa_t handle;
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46       void elpa_eigenvalues_double(elpa_t handle, datatype *a, datatype *ev,
47       int *error);
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49       With the definitions of the input and output variables:
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52       elpa_t handle;
53              The handle to the ELPA object
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55       datatype *a;
56              The matrix a for which the eigenvalues should be computed. The
57              dimensions of the matrix must be set BEFORE with the methods
58              elpa_set(3) and elpa_setup(3). The datatype must be "double".
59              The matrix has to be symmetric, this is not checked by the
60              routine. In case of a GPU build a can be a device pointer to a
61              matrix a on the device memory.
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63       datatype *ev;
64              The storage for the computed eigenvalues. Eigenvalues will be
65              stored in ascendig order. The datatype must be "double". In case
66              of a GPU build ev can be a device pointer to the vectors of
67              eigenvalues in the device memory.
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70       int *error;
71              The error code of the function. Should be "ELPA_OK". The error
72              codes can be querried with elpa_strerr(3)
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DESCRIPTION

76       Compute the eigenvalues of a double precision real symmetric matrix.
77       The functions elpa_init(3), elpa_allocate(3), elpa_set(3), and
78       elpa_setup(3) must be called BEFORE elpa_eigenvalues can be called.
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NAME

SYNOPSIS

DESCRIPTION

SEE ALSO