Unix/Linux Go Back    


CentOS 7.0 - man page for claed8 (centos section 3)

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)


claed8.f(3)				      LAPACK				      claed8.f(3)

NAME
       claed8.f -

SYNOPSIS
   Functions/Subroutines
       subroutine claed8 (K, N, QSIZ, Q, LDQ, D, RHO, CUTPNT, Z, DLAMDA, Q2, LDQ2, W, INDXP,
	   INDX, INDXQ, PERM, GIVPTR, GIVCOL, GIVNUM, INFO)
	   CLAED8 used by sstedc. Merges eigenvalues and deflates secular equation. Used when the
	   original matrix is dense.

Function/Subroutine Documentation
   subroutine claed8 (integerK, integerN, integerQSIZ, complex, dimension( ldq, * )Q, integerLDQ,
       real, dimension( * )D, realRHO, integerCUTPNT, real, dimension( * )Z, real, dimension( *
       )DLAMDA, complex, dimension( ldq2, * )Q2, integerLDQ2, real, dimension( * )W, integer,
       dimension( * )INDXP, integer, dimension( * )INDX, integer, dimension( * )INDXQ, integer,
       dimension( * )PERM, integerGIVPTR, integer, dimension( 2, * )GIVCOL, real, dimension( 2, *
       )GIVNUM, integerINFO)
       CLAED8 used by sstedc. Merges eigenvalues and deflates secular equation. Used when the
       original matrix is dense.

       Purpose:

	    CLAED8 merges the two sets of eigenvalues together into a single
	    sorted set.  Then it tries to deflate the size of the problem.
	    There are two ways in which deflation can occur:  when two or more
	    eigenvalues are close together or if there is a tiny element in the
	    Z vector.  For each such occurrence the order of the related secular
	    equation problem is reduced by one.

       Parameters:
	   K

		     K is INTEGER
		    Contains the number of non-deflated eigenvalues.
		    This is the order of the related secular equation.

	   N

		     N is INTEGER
		    The dimension of the symmetric tridiagonal matrix.	N >= 0.

	   QSIZ

		     QSIZ is INTEGER
		    The dimension of the unitary matrix used to reduce
		    the dense or band matrix to tridiagonal form.
		    QSIZ >= N if ICOMPQ = 1.

	   Q

		     Q is COMPLEX array, dimension (LDQ,N)
		    On entry, Q contains the eigenvectors of the partially solved
		    system which has been previously updated in matrix
		    multiplies with other partially solved eigensystems.
		    On exit, Q contains the trailing (N-K) updated eigenvectors
		    (those which were deflated) in its last N-K columns.

	   LDQ

		     LDQ is INTEGER
		    The leading dimension of the array Q.  LDQ >= max( 1, N ).

	   D

		     D is REAL array, dimension (N)
		    On entry, D contains the eigenvalues of the two submatrices to
		    be combined.  On exit, D contains the trailing (N-K) updated
		    eigenvalues (those which were deflated) sorted into increasing
		    order.

	   RHO

		     RHO is REAL
		    Contains the off diagonal element associated with the rank-1
		    cut which originally split the two submatrices which are now
		    being recombined. RHO is modified during the computation to
		    the value required by SLAED3.

	   CUTPNT

		     CUTPNT is INTEGER
		    Contains the location of the last eigenvalue in the leading
		    sub-matrix.  MIN(1,N) <= CUTPNT <= N.

	   Z

		     Z is REAL array, dimension (N)
		    On input this vector contains the updating vector (the last
		    row of the first sub-eigenvector matrix and the first row of
		    the second sub-eigenvector matrix).  The contents of Z are
		    destroyed during the updating process.

	   DLAMDA

		     DLAMDA is REAL array, dimension (N)
		    Contains a copy of the first K eigenvalues which will be used
		    by SLAED3 to form the secular equation.

	   Q2

		     Q2 is COMPLEX array, dimension (LDQ2,N)
		    If ICOMPQ = 0, Q2 is not referenced.  Otherwise,
		    Contains a copy of the first K eigenvectors which will be used
		    by SLAED7 in a matrix multiply (SGEMM) to update the new
		    eigenvectors.

	   LDQ2

		     LDQ2 is INTEGER
		    The leading dimension of the array Q2.  LDQ2 >= max( 1, N ).

	   W

		     W is REAL array, dimension (N)
		    This will hold the first k values of the final
		    deflation-altered z-vector and will be passed to SLAED3.

	   INDXP

		     INDXP is INTEGER array, dimension (N)
		    This will contain the permutation used to place deflated
		    values of D at the end of the array. On output INDXP(1:K)
		    points to the nondeflated D-values and INDXP(K+1:N)
		    points to the deflated eigenvalues.

	   INDX

		     INDX is INTEGER array, dimension (N)
		    This will contain the permutation used to sort the contents of
		    D into ascending order.

	   INDXQ

		     INDXQ is INTEGER array, dimension (N)
		    This contains the permutation which separately sorts the two
		    sub-problems in D into ascending order.  Note that elements in
		    the second half of this permutation must first have CUTPNT
		    added to their values in order to be accurate.

	   PERM

		     PERM is INTEGER array, dimension (N)
		    Contains the permutations (from deflation and sorting) to be
		    applied to each eigenblock.

	   GIVPTR

		     GIVPTR is INTEGER
		    Contains the number of Givens rotations which took place in
		    this subproblem.

	   GIVCOL

		     GIVCOL is INTEGER array, dimension (2, N)
		    Each pair of numbers indicates a pair of columns to take place
		    in a Givens rotation.

	   GIVNUM

		     GIVNUM is REAL array, dimension (2, N)
		    Each number indicates the S value to be used in the
		    corresponding Givens rotation.

	   INFO

		     INFO is INTEGER
		     = 0:  successful exit.
		     < 0:  if INFO = -i, the i-th argument had an illegal value.

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   September 2012

       Definition at line 227 of file claed8.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2				 Tue Sep 25 2012			      claed8.f(3)
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums


All times are GMT -4. The time now is 08:56 AM.