sggbak.f(3)							      LAPACK							       sggbak.f(3)

NAME

       sggbak.f -

SYNOPSIS

   Functions/Subroutines
       subroutine sggbak (JOB, SIDE, N, ILO, IHI, LSCALE, RSCALE, M, V, LDV, INFO)
	   SGGBAK

Function/Subroutine Documentation
   subroutine sggbak (characterJOB, characterSIDE, integerN, integerILO, integerIHI, real, dimension( * )LSCALE, real, dimension( * )RSCALE,
       integerM, real, dimension( ldv, * )V, integerLDV, integerINFO)
       SGGBAK

       Purpose:

	    SGGBAK forms the right or left eigenvectors of a real generalized
	    eigenvalue problem A*x = lambda*B*x, by backward transformation on
	    the computed eigenvectors of the balanced pair of matrices output by
	    SGGBAL.

       Parameters:
	   JOB

		     JOB is CHARACTER*1
		     Specifies the type of backward transformation required:
		     = 'N':  do nothing, return immediately;
		     = 'P':  do backward transformation for permutation only;
		     = 'S':  do backward transformation for scaling only;
		     = 'B':  do backward transformations for both permutation and
			     scaling.
		     JOB must be the same as the argument JOB supplied to SGGBAL.

	   SIDE

		     SIDE is CHARACTER*1
		     = 'R':  V contains right eigenvectors;
		     = 'L':  V contains left eigenvectors.

	   N

		     N is INTEGER
		     The number of rows of the matrix V.  N >= 0.

	   ILO

		     ILO is INTEGER

	   IHI

		     IHI is INTEGER
		     The integers ILO and IHI determined by SGGBAL.
		     1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0.

	   LSCALE

		     LSCALE is REAL array, dimension (N)
		     Details of the permutations and/or scaling factors applied
		     to the left side of A and B, as returned by SGGBAL.

	   RSCALE

		     RSCALE is REAL array, dimension (N)
		     Details of the permutations and/or scaling factors applied
		     to the right side of A and B, as returned by SGGBAL.

	   M

		     M is INTEGER
		     The number of columns of the matrix V.  M >= 0.

	   V

		     V is REAL array, dimension (LDV,M)
		     On entry, the matrix of right or left eigenvectors to be
		     transformed, as returned by STGEVC.
		     On exit, V is overwritten by the transformed eigenvectors.

	   LDV

		     LDV is INTEGER
		     The leading dimension of the matrix V. LDV >= max(1,N).

	   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:
	   November 2011

       Further Details:

	     See R.C. Ward, Balancing the generalized eigenvalue problem,
			    SIAM J. Sci. Stat. Comp. 2 (1981), 141-152.

       Definition at line 147 of file sggbak.f.

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

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