.TH "SRC/dlaqz1.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*-
.ad l
.nh
.SH NAME
SRC/dlaqz1.f
.SH SYNOPSIS
.br
.PP
.SS "Functions/Subroutines"

.in +1c
.ti -1c
.RI "subroutine \fBdlaqz1\fP (a, lda, b, ldb, sr1, sr2, si, beta1, beta2, v)"
.br
.RI "\fBDLAQZ1\fP "
.in -1c
.SH "Function/Subroutine Documentation"
.PP 
.SS "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)"

.PP
\fBDLAQZ1\fP  
.PP
\fBPurpose:\fP
.RS 4

.PP
.nf
      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\&.
.fi
.PP
 
.RE
.PP
\fBParameters\fP
.RS 4
\fIA\fP 
.PP
.nf
          A is DOUBLE PRECISION array, dimension (LDA,N)
              The 3-by-3 matrix A in (*)\&.
.fi
.PP
.br
\fILDA\fP 
.PP
.nf
          LDA is INTEGER
              The leading dimension of A as declared in
              the calling procedure\&.
.fi
.PP
 
.br
\fIB\fP 
.PP
.nf
          B is DOUBLE PRECISION array, dimension (LDB,N)
              The 3-by-3 matrix B in (*)\&.
.fi
.PP
.br
\fILDB\fP 
.PP
.nf
          LDB is INTEGER
              The leading dimension of B as declared in
              the calling procedure\&.
.fi
.PP
.br
\fISR1\fP 
.PP
.nf
          SR1 is DOUBLE PRECISION
.fi
.PP
.br
\fISR2\fP 
.PP
.nf
          SR2 is DOUBLE PRECISION
.fi
.PP
.br
\fISI\fP 
.PP
.nf
          SI is DOUBLE PRECISION
.fi
.PP
.br
\fIBETA1\fP 
.PP
.nf
          BETA1 is DOUBLE PRECISION
.fi
.PP
.br
\fIBETA2\fP 
.PP
.nf
          BETA2 is DOUBLE PRECISION
.fi
.PP
.br
\fIV\fP 
.PP
.nf
          V is DOUBLE PRECISION array, dimension (N)
              A scalar multiple of the first column of the
              matrix K in (*)\&.
.fi
.PP
 
.RE
.PP
\fBAuthor\fP
.RS 4
Thijs Steel, KU Leuven 
.RE
.PP
\fBDate\fP
.RS 4
May 2020 
.RE
.PP

.PP
Definition at line \fB125\fP of file \fBdlaqz1\&.f\fP\&.
.SH "Author"
.PP 
Generated automatically by Doxygen for LAPACK from the source code\&.