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cgegs.f(3)				      LAPACK				       cgegs.f(3)

NAME
       cgegs.f -

SYNOPSIS
   Functions/Subroutines
       subroutine cgegs (JOBVSL, JOBVSR, N, A, LDA, B, LDB, ALPHA, BETA, VSL, LDVSL, VSR, LDVSR,
	   WORK, LWORK, RWORK, INFO)
	    CGEEVX computes the eigenvalues and, optionally, the left and/or right eigenvectors
	   for GE matrices

Function/Subroutine Documentation
   subroutine cgegs (characterJOBVSL, characterJOBVSR, integerN, complex, dimension( lda, * )A,
       integerLDA, complex, dimension( ldb, * )B, integerLDB, complex, dimension( * )ALPHA,
       complex, dimension( * )BETA, complex, dimension( ldvsl, * )VSL, integerLDVSL, complex,
       dimension( ldvsr, * )VSR, integerLDVSR, complex, dimension( * )WORK, integerLWORK, real,
       dimension( * )RWORK, integerINFO)
	CGEEVX computes the eigenvalues and, optionally, the left and/or right eigenvectors for
       GE matrices

       Purpose:

	    This routine is deprecated and has been replaced by routine CGGES.

	    CGEGS computes the eigenvalues, Schur form, and, optionally, the
	    left and or/right Schur vectors of a complex matrix pair (A,B).
	    Given two square matrices A and B, the generalized Schur
	    factorization has the form

	       A = Q*S*Z**H,  B = Q*T*Z**H

	    where Q and Z are unitary matrices and S and T are upper triangular.
	    The columns of Q are the left Schur vectors
	    and the columns of Z are the right Schur vectors.

	    If only the eigenvalues of (A,B) are needed, the driver routine
	    CGEGV should be used instead.  See CGEGV for a description of the
	    eigenvalues of the generalized nonsymmetric eigenvalue problem
	    (GNEP).

       Parameters:
	   JOBVSL

		     JOBVSL is CHARACTER*1
		     = 'N':  do not compute the left Schur vectors;
		     = 'V':  compute the left Schur vectors (returned in VSL).

	   JOBVSR

		     JOBVSR is CHARACTER*1
		     = 'N':  do not compute the right Schur vectors;
		     = 'V':  compute the right Schur vectors (returned in VSR).

	   N

		     N is INTEGER
		     The order of the matrices A, B, VSL, and VSR.  N >= 0.

	   A

		     A is COMPLEX array, dimension (LDA, N)
		     On entry, the matrix A.
		     On exit, the upper triangular matrix S from the generalized
		     Schur factorization.

	   LDA

		     LDA is INTEGER
		     The leading dimension of A.  LDA >= max(1,N).

	   B

		     B is COMPLEX array, dimension (LDB, N)
		     On entry, the matrix B.
		     On exit, the upper triangular matrix T from the generalized
		     Schur factorization.

	   LDB

		     LDB is INTEGER
		     The leading dimension of B.  LDB >= max(1,N).

	   ALPHA

		     ALPHA is COMPLEX array, dimension (N)
		     The complex scalars alpha that define the eigenvalues of
		     GNEP.  ALPHA(j) = S(j,j), the diagonal element of the Schur
		     form of A.

	   BETA

		     BETA is COMPLEX array, dimension (N)
		     The non-negative real scalars beta that define the
		     eigenvalues of GNEP.  BETA(j) = T(j,j), the diagonal element
		     of the triangular factor T.

		     Together, the quantities alpha = ALPHA(j) and beta = BETA(j)
		     represent the j-th eigenvalue of the matrix pair (A,B), in
		     one of the forms lambda = alpha/beta or mu = beta/alpha.
		     Since either lambda or mu may overflow, they should not,
		     in general, be computed.

	   VSL

		     VSL is COMPLEX array, dimension (LDVSL,N)
		     If JOBVSL = 'V', the matrix of left Schur vectors Q.
		     Not referenced if JOBVSL = 'N'.

	   LDVSL

		     LDVSL is INTEGER
		     The leading dimension of the matrix VSL. LDVSL >= 1, and
		     if JOBVSL = 'V', LDVSL >= N.

	   VSR

		     VSR is COMPLEX array, dimension (LDVSR,N)
		     If JOBVSR = 'V', the matrix of right Schur vectors Z.
		     Not referenced if JOBVSR = 'N'.

	   LDVSR

		     LDVSR is INTEGER
		     The leading dimension of the matrix VSR. LDVSR >= 1, and
		     if JOBVSR = 'V', LDVSR >= N.

	   WORK

		     WORK is COMPLEX array, dimension (MAX(1,LWORK))
		     On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

	   LWORK

		     LWORK is INTEGER
		     The dimension of the array WORK.  LWORK >= max(1,2*N).
		     For good performance, LWORK must generally be larger.
		     To compute the optimal value of LWORK, call ILAENV to get
		     blocksizes (for CGEQRF, CUNMQR, and CUNGQR.)  Then compute:
		     NB  -- MAX of the blocksizes for CGEQRF, CUNMQR, and CUNGQR;
		     the optimal LWORK is N*(NB+1).

		     If LWORK = -1, then a workspace query is assumed; the routine
		     only calculates the optimal size of the WORK array, returns
		     this value as the first entry of the WORK array, and no error
		     message related to LWORK is issued by XERBLA.

	   RWORK

		     RWORK is REAL array, dimension (3*N)

	   INFO

		     INFO is INTEGER
		     = 0:  successful exit
		     < 0:  if INFO = -i, the i-th argument had an illegal value.
		     =1,...,N:
			   The QZ iteration failed.  (A,B) are not in Schur
			   form, but ALPHA(j) and BETA(j) should be correct for
			   j=INFO+1,...,N.
		     > N:  errors that usually indicate LAPACK problems:
			   =N+1: error return from CGGBAL
			   =N+2: error return from CGEQRF
			   =N+3: error return from CUNMQR
			   =N+4: error return from CUNGQR
			   =N+5: error return from CGGHRD
			   =N+6: error return from CHGEQZ (other than failed
							  iteration)
			   =N+7: error return from CGGBAK (computing VSL)
			   =N+8: error return from CGGBAK (computing VSR)
			   =N+9: error return from CLASCL (various places)

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 224 of file cgegs.f.

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

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