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slaein.f(3) [centos man page]

slaein.f(3)							      LAPACK							       slaein.f(3)

NAME

       slaein.f -

SYNOPSIS

   Functions/Subroutines
       subroutine slaein (RIGHTV, NOINIT, N, H, LDH, WR, WI, VR, VI, B, LDB, WORK, EPS3, SMLNUM, BIGNUM, INFO)
	   SLAEIN computes a specified right or left eigenvector of an upper Hessenberg matrix by inverse iteration.

Function/Subroutine Documentation
   subroutine slaein (logicalRIGHTV, logicalNOINIT, integerN, real, dimension( ldh, * )H, integerLDH, realWR, realWI, real, dimension( * )VR,
       real, dimension( * )VI, real, dimension( ldb, * )B, integerLDB, real, dimension( * )WORK, realEPS3, realSMLNUM, realBIGNUM, integerINFO)
       SLAEIN computes a specified right or left eigenvector of an upper Hessenberg matrix by inverse iteration.

       Purpose:

	    SLAEIN uses inverse iteration to find a right or left eigenvector
	    corresponding to the eigenvalue (WR,WI) of a real upper Hessenberg
	    matrix H.

       Parameters:
	   RIGHTV

		     RIGHTV is LOGICAL
		     = .TRUE. : compute right eigenvector;
		     = .FALSE.: compute left eigenvector.

	   NOINIT

		     NOINIT is LOGICAL
		     = .TRUE. : no initial vector supplied in (VR,VI).
		     = .FALSE.: initial vector supplied in (VR,VI).

	   N

		     N is INTEGER
		     The order of the matrix H.  N >= 0.

	   H

		     H is REAL array, dimension (LDH,N)
		     The upper Hessenberg matrix H.

	   LDH

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

	   WR

		     WR is REAL

	   WI

		     WI is REAL
		     The real and imaginary parts of the eigenvalue of H whose
		     corresponding right or left eigenvector is to be computed.

	   VR

		     VR is REAL array, dimension (N)

	   VI

		     VI is REAL array, dimension (N)
		     On entry, if NOINIT = .FALSE. and WI = 0.0, VR must contain
		     a real starting vector for inverse iteration using the real
		     eigenvalue WR; if NOINIT = .FALSE. and WI.ne.0.0, VR and VI
		     must contain the real and imaginary parts of a complex
		     starting vector for inverse iteration using the complex
		     eigenvalue (WR,WI); otherwise VR and VI need not be set.
		     On exit, if WI = 0.0 (real eigenvalue), VR contains the
		     computed real eigenvector; if WI.ne.0.0 (complex eigenvalue),
		     VR and VI contain the real and imaginary parts of the
		     computed complex eigenvector. The eigenvector is normalized
		     so that the component of largest magnitude has magnitude 1;
		     here the magnitude of a complex number (x,y) is taken to be
		     |x| + |y|.
		     VI is not referenced if WI = 0.0.

	   B

		     B is REAL array, dimension (LDB,N)

	   LDB

		     LDB is INTEGER
		     The leading dimension of the array B.  LDB >= N+1.

	   WORK

		     WORK is REAL array, dimension (N)

	   EPS3

		     EPS3 is REAL
		     A small machine-dependent value which is used to perturb
		     close eigenvalues, and to replace zero pivots.

	   SMLNUM

		     SMLNUM is REAL
		     A machine-dependent value close to the underflow threshold.

	   BIGNUM

		     BIGNUM is REAL
		     A machine-dependent value close to the overflow threshold.

	   INFO

		     INFO is INTEGER
		     = 0:  successful exit
		     = 1:  inverse iteration did not converge; VR is set to the
			   last iterate, and so is VI if WI.ne.0.0.

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   September 2012

       Definition at line 172 of file slaein.f.

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

Version 3.4.2							  Tue Sep 25 2012						       slaein.f(3)

Check Out this Related Man Page

SLAEIN(l)								 )								 SLAEIN(l)

NAME

       SLAEIN  -  use  inverse	iteration  to  find a right or left eigenvector corresponding to the eigenvalue (WR,WI) of a real upper Hessenberg
       matrix H

SYNOPSIS

       SUBROUTINE SLAEIN( RIGHTV, NOINIT, N, H, LDH, WR, WI, VR, VI, B, LDB, WORK, EPS3, SMLNUM, BIGNUM, INFO )

	   LOGICAL	  NOINIT, RIGHTV

	   INTEGER	  INFO, LDB, LDH, N

	   REAL 	  BIGNUM, EPS3, SMLNUM, WI, WR

	   REAL 	  B( LDB, * ), H( LDH, * ), VI( * ), VR( * ), WORK( * )

PURPOSE

       SLAEIN uses inverse iteration to find a right or left eigenvector corresponding to the eigenvalue (WR,WI) of a real upper Hessenberg matrix
       H.

ARGUMENTS

       RIGHTV	(input) LOGICAL
		= .TRUE. : compute right eigenvector;
		= .FALSE.: compute left eigenvector.

       NOINIT	(input) LOGICAL
		= .TRUE. : no initial vector supplied in (VR,VI).
		= .FALSE.: initial vector supplied in (VR,VI).

       N       (input) INTEGER
	       The order of the matrix H.  N >= 0.

       H       (input) REAL array, dimension (LDH,N)
	       The upper Hessenberg matrix H.

       LDH     (input) INTEGER
	       The leading dimension of the array H.  LDH >= max(1,N).

       WR      (input) REAL
	       WI	(input)  REAL  The  real and imaginary parts of the eigenvalue of H whose corresponding right or left eigenvector is to be
	       computed.

       VR      (input/output) REAL array, dimension (N)
	       VI      (input/output) REAL array, dimension (N) On entry, if NOINIT = .FALSE. and WI = 0.0, VR must contain a real starting vector
	       for  inverse  iteration using the real eigenvalue WR; if NOINIT = .FALSE. and WI.ne.0.0, VR and VI must contain the real and imagi-
	       nary parts of a complex starting vector for inverse iteration using the complex eigenvalue (WR,WI); otherwise VR and VI need not be
	       set.   On exit, if WI = 0.0 (real eigenvalue), VR contains the computed real eigenvector; if WI.ne.0.0 (complex eigenvalue), VR and
	       VI contain the real and imaginary parts of the computed complex eigenvector. The eigenvector is normalized so that the component of
	       largest	magnitude has magnitude 1; here the magnitude of a complex number (x,y) is taken to be |x| + |y|.  VI is not referenced if
	       WI = 0.0.

       B       (workspace) REAL array, dimension (LDB,N)

       LDB     (input) INTEGER
	       The leading dimension of the array B.  LDB >= N+1.

       WORK   (workspace) REAL array, dimension (N)

       EPS3    (input) REAL
	       A small machine-dependent value which is used to perturb close eigenvalues, and to replace zero pivots.

       SMLNUM  (input) REAL
	       A machine-dependent value close to the underflow threshold.

       BIGNUM  (input) REAL
	       A machine-dependent value close to the overflow threshold.

       INFO    (output) INTEGER
	       = 0:  successful exit
	       = 1:  inverse iteration did not converge; VR is set to the last iterate, and so is VI if WI.ne.0.0.

LAPACK version 3.0						   15 June 2000 							 SLAEIN(l)
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