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

6       elpa_solve_tridiagonal - computes the eigenvalue problem for real
7       symmetric tridiagonal 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%eigenvectors (d, e, q, 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 :: d
22              The diagonal elements of a matrix whose dimensions have been
23              defined in elpa_setup(3). On exist the eigenvalues are stored in
24              this 1d-array. The datatype of the diagonal elements can either
25              be "real(kind=c_double)" or "real(kind=c_float)".
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27       datatype :: e
28              The offdiagonal elements of the matrix. The datatype of the
29              diagonal elements can either be "real(kind=c_double)" or
30              "real(kind=c_float)".  datatype :: q The storage space for the
31              computed eigenvectors. The datatype of the matrix can be either
32              "real(kind=c_double)" or "real(kind=c_float)".
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34       integer, optional :: error
35              The return error code of the function. Should be "ELPA_OK". The
36              error code can be querried with the function elpa_strerr(3)
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39   C INTERFACE
40       #include <elpa/elpa.h>
41       elpa_t handle;
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43       void elpa_eigenvalues(elpa_t handle, datatype *d, datatype *e, datatype
44       *q, int *error);
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46       With the definitions of the input and output variables:
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49       elpa_t handle;
50              The handle to the ELPA object
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52       datatype *d;
53              The diagonal elements of the matrix. The dimensions of the
54              matrix must be set BEFORE with elpa_setup(3). On exist the
55              eigenvalues are stored in d. The datatype can be one of "double"
56              or "float".
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58       datatype *e;
59              The offdiagonal elements of the matrix. The datatype can be one
60              of "double" or "float".
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62       datatype *q;
63              The storage space for the computed eigenvectors. The dimensions
64              of the matrix must be set BEFORE with the methods elpa_set(3)
65              and elpa_setup(3). The datatype can be one of "double", "float",
66              "double complex", or "float complex".
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68       int *error;
69              The error code of the function. Should be "ELPA_OK". The error
70              codes can be querried with elpa_strerr(3)
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DESCRIPTION

74       Computes the eigenvalue problem of a real symmtric tridiagonal
75       matrix.The functions elpa_init(3), elpa_allocate(3), elpa_set(3), and
76       elpa_setup(3) must be called BEFORE elpa_solve_tridiagonal can be
77       called.
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SEE ALSO

80       elpa2_print_kernels(1) elpa_init(3) elpa_allocate(3) elpa_set(3)
81       elpa_setup(3) elpa_strerr(3) elpa_eigenvalues(3) elpa_cholesky(3)
82       elpa_invert_triangular(3) elpa_hermitian_multiply(3) elpa_uninit(3)
83       elpa_deallocate(3)
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87ELPA                            Sat Jul 15 2017      elpa_solve_tridiagonal(3)
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