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elpa_skew_eigenvalues(3)   Library Functions Manual   elpa_skew_eigenvalues(3)

NAME
       elpa_skew_eigenvalues - computes	the eigenvalues	of a real skew-
       symmetric matrix

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

       call elpa%skew_eigenvalues (a, ev, 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	can be
	      one of "real(kind=c_double)" or "real(kind=c_float)". The	matrix
	      has to be	skew-symmetric,	this is	not checked by the routine.

       datatype	:: ev
	      The  vector ev where the eigenvalues will	be stored in ascending
	      order.  The  datatype  of	 the   vector	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
	      error code can be	querried with the function elpa_strerr(3)

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

       void elpa_skew_eigenvalues(elpa_t handle, datatype  *a,	datatype  *ev,
       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  can  be	one of
	      "double" or "float".

       datatype	*ev;
	      The storage for the computed eigenvalues.	 Eigenvalues  will  be
	      stored in	ascendig order.	The datatype can be either "double" or
	      "float". Note that the eigenvalues of complex hermitian matrices
	      are  also	real. The matrix has to	be skew-symmetric, this	is not
	      checked by the routine.

       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 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_deallocate(3)

ELPA				Thur Nov 7 2019	      elpa_skew_eigenvalues(3)

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