SRC/dlaqz1.f(3)            Library Functions Manual            SRC/dlaqz1.f(3)

NAME
       SRC/dlaqz1.f

SYNOPSIS
   Functions/Subroutines
       subroutine dlaqz1 (a, lda, b, ldb, sr1, sr2, si, beta1, beta2, v)
           DLAQZ1

Function/Subroutine Documentation
   subroutine dlaqz1 (double precision, dimension( lda, * ), intent(in) a,
       integer, intent(in) lda, double precision, dimension( ldb, * ),
       intent(in) b, integer, intent(in) ldb, double precision, intent(in)
       sr1, double precision, intent(in) sr2, double precision, intent(in) si,
       double precision, intent(in) beta1, double precision, intent(in) beta2,
       double precision, dimension( * ), intent(out) v)
       DLAQZ1

       Purpose:


                 Given a 3-by-3 matrix pencil (A,B), DLAQZ1 sets v to a
                 scalar multiple of the first column of the product

                 (*)  K = (A - (beta2*sr2 - i*si)*B)*B^(-1)*(beta1*A - (sr2 + i*si2)*B)*B^(-1).

                 It is assumed that either

                         1) sr1 = sr2
                     or
                         2) si = 0.

                 This is useful for starting double implicit shift bulges
                 in the QZ algorithm.

       Parameters
           A

                     A is DOUBLE PRECISION array, dimension (LDA,N)
                         The 3-by-3 matrix A in (*).

           LDA

                     LDA is INTEGER
                         The leading dimension of A as declared in
                         the calling procedure.

           B

                     B is DOUBLE PRECISION array, dimension (LDB,N)
                         The 3-by-3 matrix B in (*).

           LDB

                     LDB is INTEGER
                         The leading dimension of B as declared in
                         the calling procedure.

           SR1

                     SR1 is DOUBLE PRECISION

           SR2

                     SR2 is DOUBLE PRECISION

           SI

                     SI is DOUBLE PRECISION

           BETA1

                     BETA1 is DOUBLE PRECISION

           BETA2

                     BETA2 is DOUBLE PRECISION

           V

                     V is DOUBLE PRECISION array, dimension (N)
                         A scalar multiple of the first column of the
                         matrix K in (*).

       Author
           Thijs Steel, KU Leuven

       Date
           May 2020

       Definition at line 125 of file dlaqz1.f.

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

LAPACK                          Version 3.12.0                 SRC/dlaqz1.f(3)