CGEBAK(3)      LAPACK routine of NEC Numeric Library Collection      CGEBAK(3)



NAME
       CGEBAK

SYNOPSIS
       SUBROUTINE CGEBAK (JOB, SIDE, N, ILO, IHI, SCALE, M, V, LDV, INFO)



PURPOSE
            CGEBAK forms the right or left eigenvectors of a complex general
            matrix by backward transformation on the computed eigenvectors of the
            balanced matrix output by CGEBAL.




ARGUMENTS
           JOB       (input)
                     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 CGEBAL.

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

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

           ILO       (input)
                     ILO is INTEGER

           IHI       (input)
                     IHI is INTEGER
                     The integers ILO and IHI determined by CGEBAL.
                     1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0.

           SCALE     (input)
                     SCALE is REAL array, dimension (N)
                     Details of the permutation and scaling factors, as returned
                     by CGEBAL.

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

           V         (input/output)
                     V is COMPLEX array, dimension (LDV,M)
                     On entry, the matrix of right or left eigenvectors to be
                     transformed, as returned by CHSEIN or CTREVC.
                     On exit, V is overwritten by the transformed eigenvectors.

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

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



LAPACK routine                  31 October 2017                      CGEBAK(3)