ggbak(3)

NAME
ggbak - ggbak: back-transform eigvec

SYNOPSIS

  Functions
subroutine cggbak (job, side, n, ilo, ihi, lscale, rscale, m, v, ldv, info)
CGGBAK
subroutine dggbak (job, side, n, ilo, ihi, lscale, rscale, m, v, ldv, info)
DGGBAK
subroutine sggbak (job, side, n, ilo, ihi, lscale, rscale, m, v, ldv, info)
SGGBAK
subroutine zggbak (job, side, n, ilo, ihi, lscale, rscale, m, v, ldv, info)
ZGGBAK

Detailed Description

Function Documentation

  subroutine cggbak (character job, character side, integer n, integer ilo, integer ihi, real, dimension( * ) lscale, real, dimension( * ) rscale, integer m, complex, dimension( ldv, * ) v, integer ldv, integer info)

CGGBAK

Purpose:

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

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 CGGBAL.

    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 CGGBAL.
              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 CGGBAL.

    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 CGGBAL.

    M

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

    V

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

Further Details:

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

Definition at line 146 of file cggbak.f.

  subroutine dggbak (character job, character side, integer n, integer ilo, integer ihi, double precision, dimension( * ) lscale, double precision, dimension( * ) rscale, integer m, double precision, dimension( ldv, * ) v, integer ldv, integer info)

DGGBAK

Purpose:

     DGGBAK 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
     DGGBAL.

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 DGGBAL.

    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 DGGBAL.
              1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0.

    LSCALE

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

    RSCALE

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

    M

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

    V

              V is DOUBLE PRECISION array, dimension (LDV,M)
              On entry, the matrix of right or left eigenvectors to be
              transformed, as returned by DTGEVC.
              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.

Further Details:

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

Definition at line 145 of file dggbak.f.

  subroutine sggbak (character job, character side, integer n, integer ilo, integer ihi, real, dimension( * ) lscale, real, dimension( * ) rscale, integer m, real, dimension( ldv, * ) v, integer ldv, integer info)

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.

Further Details:

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

Definition at line 145 of file sggbak.f.

  subroutine zggbak (character job, character side, integer n, integer ilo, integer ihi, double precision, dimension( * ) lscale, double precision, dimension( * ) rscale, integer m, complex*16, dimension( ldv, * ) v, integer ldv, integer info)

ZGGBAK

Purpose:

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

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 ZGGBAL.

    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 ZGGBAL.
              1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0.

    LSCALE

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

    RSCALE

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

    M

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

    V

              V is COMPLEX*16 array, dimension (LDV,M)
              On entry, the matrix of right or left eigenvectors to be
              transformed, as returned by ZTGEVC.
              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.

Further Details:

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

Definition at line 146 of file zggbak.f.

Author

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