QZHES(3F)

NAME
     QZHES, SQZHES   -  EISPACK routine.  This subroutine is the first step of
     the QZ algorithm for solving generalized matrix eigenvalue problems.


SYNOPSYS
          subroutine  qzhes(nm, n, a, b, matz, z)
          integer          nm, n
          double precision a(nm,n), b(nm,n), z(nm,n)
          logical matz

          subroutine sqzhes(nm, n, a, b, matz, z)
          integer          nm, n
          real             a(nm,n), b(nm,n), z(nm,n)
          logical matz



DESCRIPTION
     This subroutine accepts a pair of REAL GENERAL matrices and reduces one
     of them to upper Hessenberg form and the other to upper triangular form
     using orthogonal transformations.  It is usually followed by  QZIT,
     QZVAL  and, possibly,  QZVEC.

     On Input

     NM must be set to the row dimension of two-dimensional array parameters
     as declared in the calling program dimension statement.

     N is the order of the matrices.

     A contains a real general matrix.

     B contains a real general matrix.

     MATZ should be set to .TRUE. if the right hand transformations are to be
     accumulated for later use in computing eigenvectors, and to .FALSE.
     otherwise.  On Output

     A has been reduced to upper Hessenberg form.  The elements below the
     first subdiagonal have been set to zero.

     B has been reduced to upper triangular form.  The elements below the main
     diagonal have been set to zero.

     Z contains the product of the right hand transformations if MATZ has been
     set to .TRUE.  Otherwise, Z is not referenced.  Questions and comments
     should be directed to B. S. Garbow, APPLIED MATHEMATICS DIVISION, ARGONNE
     NATIONAL LABORATORY