 
      SUBROUTINE SGEEV(A,LDA,N,E,V,LDV,WORK,JOB,INFO)
C***BEGIN PROLOGUE  SGEEV
C***DATE WRITTEN   800808   (YYMMDD)
C***REVISION DATE  820801   (YYMMDD)
C***CATEGORY NO.  D4A2
C***KEYWORDS  EIGENVALUE,EIGENVECTOR,GENERAL MATRIX,REAL
C***AUTHOR  KAHANER, D. K., (NBS)
C           MOLER, C. B., (U. OF NEW MEXICO)
C           STEWART, G. W., (U. OF MARYLAND)
C***PURPOSE  To compute the eigenvalues and, optionally, the eigen-
C            vectors of a GENERAL real matrix.
C***DESCRIPTION
C
C     LICEPACK.    This version dated 08/08/80.
C     David Kahaner, Cleve Moler, G. W. Stewart,
C       N.B.S.         U.N.M.      N.B.S./U.MD.
C
C     Abstract
C      SGEEV computes the eigenvalues and, optionally,
C      the eigenvectors of a general real matrix.
C
C     Call Sequence Parameters-
C       (The values of parameters marked with * (star) will be changed
C         by SGEEV.)
C
C        A*      REAL(LDA,N)
C                real nonsymmetric input matrix.
C
C        LDA     INTEGER
C                set by the user to
C                the leading dimension of the real array A.
C
C        N       INTEGER
C                set by the user to
C                the order of the matrices A and V, and
C                the number of elements in E.
C
C        E*      COMPLEX(N)
C                on return from SGEEV, E contains the eigenvalues of A.
C                See also INFO below.
C
C        V*      COMPLEX(LDV,N)
C                on return from SGEEV, if the user has set JOB
C                = 0        V is not referenced.
C                = nonzero  the N eigenvectors of A are stored in the
C                first N columns of V.  See also INFO below.
C                (Note that if the input matrix A is nearly degenerate,
C                 V may be badly conditioned, i.e., may have nearly
C                 dependent columns.)
C
C        LDV     INTEGER
C                set by the user to
C                the leading dimension of the array V if JOB is also
C                set nonzero.  In that case, N must be .LE. LDV.
C                If JOB is set to zero, LDV is not referenced.
C
C        WORK*   REAL(2N)
C                temporary storage vector.  Contents changed by SGEEV.
C
C        JOB     INTEGER
C                set by the user to
C                = 0        eigenvalues only to be calculated by SGEEV.
C                           Neither V nor LDV is referenced.
C                = nonzero  eigenvalues and vectors to be calculated.
C                           In this case, A & V must be distinct arrays.
C                           Also, if LDA .GT. LDV, SGEEV changes all the
C                           elements of A thru column N.  If LDA < LDV,
C                           SGEEV changes all the elements of V through
C                           column N. If LDA = LDV, only A(I,J) and V(I,
C                           J) for I,J = 1,...,N are changed by SGEEV.
C
C        INFO*   INTEGER
C                on return from SGEEV the value of INFO is
C                = 0  normal return, calculation successful.
C                = K  if the eigenvalue iteration fails to converge,
C                     eigenvalues K+1 through N are correct, but
C                     no eigenvectors were computed even if they were
C                     requested (JOB nonzero).
C
C      Error Messages
C           No. 1  recoverable  N is greater than LDA
C           No. 2  recoverable  N is less than one.
C           No. 3  recoverable  JOB is nonzero and N is greater than LDV
C           No. 4  warning      LDA > LDV, elements of A other than the
C                               N by N input elements have been changed.
C           No. 5  warning      LDA < LDV, elements of V other than the
C                               N x N output elements have been changed.
C
C
C     Subroutines used
C
C     EISPACK-  BALANC,BALBAK, ORTHES, ORTRAN, HQR, HQR2
C     BLAS-  SCOPY, SCOPYM
C     SLATEC- XERROR
C***REFERENCES  (NONE)
C***ROUTINES CALLED  BALANC,BALBAK,HQR,HQR2,ORTHES,ORTRAN,SCOPY,SCOPYM,
C                    XERROR
C***END PROLOGUE  SGEEV
 
 
