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elpa_eigen...ors_double(3) Library Functions Manual elpa_eigen...ors_double(3) NAME elpa_eigenvectors_double - computes the eigenvalues and (part of) the eigenvector spectrum for a real symmetric matrix SYNOPSIS FORTRAN INTERFACE use elpa class(elpa_t), pointer :: elpa call elpa%eigenvectors_double (a, ev, q, error) With the definitions of the input and output variables: class(elpa_t) :: elpa ! returns an instance of the ELPA object datatype :: a The 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 must be "real(kind=c_double)". The matrix has to be symmetric, this is not checked by the routine. In case of a GPU build a can be a device pointer to a matrix a on the device memory. datatype :: ev The vector ev where the eigenvalues will be stored in ascending order. The datatype of the vector ev must be "real(kind=c_double)". In case of a GPU build ev can be a device pointer to the vectors of eigenvalues in the device memory. datatype :: q The storage space for the computed eigenvectors. The dimensions of matrix a must be set BEFORE with the methods elpa_set(3) and elpa_setup(3). The datatype of the matrix must be "real(kind=c_double)". In case of a GPU build q can be a device pointer to a matrix q on the device memory. integer, optional :: error The return error code of the function. Should be "ELPA_OK". The error code can be querried with the function elpa_strerr(3) C INTERFACE #include <elpa/elpa.h> elpa_t handle; void elpa_eigenvectors_double(elpa_t handle, datatype *a, datatype *ev, datatype *q, int *error); With the definitions of the input and output variables: elpa_t handle; The handle to the ELPA object datatype *a; The 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 must be "double". The matrix has to be symmetric, this is not checked by the routine. In case of a GPU build a can be a device pointer to a matrix a on the device memory. datatype *ev; The storage for the computed eigenvalues. Eigenvalues will be stored in ascendig order. The datatype must be "double". In case of a GPU build ev can be a device pointer to the vectors of eigenvalues in the device memory. datatype *q; The storage space for the computed eigenvectors. The dimensions of the matrix must be set BEFORE with the methods elpa_set(3) and elpa_setup(3). The datatype must be one of "double". In case of a GPU build q can be a device pointer to a matrix q on the device memory. int *error; The error code of the function. Should be "ELPA_OK". The error codes can be querried with elpa_strerr(3) DESCRIPTION Compute the eigenvalues and (parts of) the eigenvector spectrum of a real symmetric double precision 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. Especially the number of eigenvectors to be computed can be set with elpa_set(3) SEE ALSO elpa2_print_kernels(1) elpa_init(3) elpa_allocate(3) elpa_set(3) elpa_setup(3) elpa_strerr(3) elpa_eigenvalues(3) elpa_skew_eigenvalues(3) elpa_skew_eigenvectors(3) elpa_cholesky(3) elpa_invert_triangular(3) elpa_solve_tridiagonal(3) elpa_hermitian_multiply(3) elpa_uninit(3) elpa_deallocate(3) ELPA Wed Sept 01 2021 elpa_eigen...ors_double(3)
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO
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