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elpa_skew_eigenvalues(3)    Library Functions Manual	elpa_skew_eigenvalues(3)

NAME
     elpa_skew_eigenvalues  - computes all eigenvalues <lambda> for a real skew-
     symmetric eigenproblem: A*Q = <lambda>*Q

     There are also variations of this routine that can accept not only host but
     also device pointers as input/output. Names of  these  routines  explicitly
     contain	the   corresponding   datatypes:   elpa_skew_eigenvalues_double,
     elpa_skew_eigenvalues_float.

SYNOPSIS
   FORTRAN INTERFACE
     use elpa
     class(elpa_t), pointer :: elpa_handle

     call elpa_handle%skew_eigenvalues (a, ev, error)

     With the definitions of the input and output variables:

     class(elpa_t) :: elpa_handle
	    An instance of the ELPA object.

     datatype :: a
	    The local part of matrix A for which the eigenvalues should be  com-
	    puted.  The dimensions of matrix a must be set BEFORE with the meth-
	    ods elpa_set(3) and elpa_setup(3). The datatype_real of  the  matrix
	    can  be  one  of  "real(kind=c_double)" or "real(kind=c_float)". The
	    global matrix has to be skew-symmetric, this is not checked  by  the
	    routine.

     datatype_real :: ev
	    The array where the eigenvalues <lambda> will be stored in ascending
	    order.  The  datatype_real of ev can be either "real(kind=c_double)"
	    or "real(kind=c_float)", depending of the datatype of the matrix.

     integer, optional :: error
	    The return error code of the function. Should be "ELPA_OK". The  er-
	    ror code can be queried with the function elpa_strerr(3).

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

     void    elpa_skew_eigenvalues(elpa_t    elpa_handle,    datatype_real   *a,
     datatype_real *ev, int *error);

     With the definitions of the input and output variables:

     elpa_t handle;
	    The handle to the ELPA object

     datatype_real  *a;
	    The local part of matrix A for which the eigenvalues should be  com-
	    puted.  The  dimensions  of  the  matrix must be set BEFORE with the
	    methods elpa_set(3) and elpa_setup(3). The datatype can  be  one  of
	    "double"  or  "float".  The  global matrix has to be skew-symmetric,
	    this is not checked by the routine.

     datatype_real  *ev;
	    The array where the eigenvalues <lambda> will be stored in ascending
	    order.  Eigenvalues  will  be  stored  in	ascending   order.   The
	    datatype_real can be either "double" or "float".

     int  *error;
	    The error code of the function. Should be "ELPA_OK". The error codes
	    can be queried with elpa_strerr(3).

DESCRIPTION
     Computes  the  eigenvalues  of  a real skew-symmetric matrix. The functions
     elpa_init(3), elpa_allocate(3),  elpa_set(3),  and  elpa_setup(3)	must  be
     called BEFORE elpa_skew_eigenvalues can be called.

SEE ALSO
     elpa2_print_kernels(1)	elpa_init(3)	 elpa_allocate(3)    elpa_set(3)
     elpa_setup(3) elpa_strerr(3) elpa_eigenvectors(3) elpa_skew_eigenvectors(3)
     elpa_eigenvalues(3)       elpa_cholesky(3)        elpa_invert_triangular(3)
     elpa_solve_tridiagonal(3)	elpa_eigenvalues(3)  elpa_uninit(3) elpa_deallo-
     cate(3)

ELPA				 Thu Nov 28 2024	elpa_skew_eigenvalues(3)

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