.TH "SRC/zlags2.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*-
.ad l
.nh
.SH NAME
SRC/zlags2.f
.SH SYNOPSIS
.br
.PP
.SS "Functions/Subroutines"

.in +1c
.ti -1c
.RI "subroutine \fBzlags2\fP (upper, a1, a2, a3, b1, b2, b3, csu, snu, csv, snv, csq, snq)"
.br
.RI "\fBZLAGS2\fP "
.in -1c
.SH "Function/Subroutine Documentation"
.PP 
.SS "subroutine zlags2 (logical upper, double precision a1, complex*16 a2, double precision a3, double precision b1, complex*16 b2, double precision b3, double precision csu, complex*16 snu, double precision csv, complex*16 snv, double precision csq, complex*16 snq)"

.PP
\fBZLAGS2\fP  
.PP
\fBPurpose:\fP
.RS 4

.PP
.nf
 ZLAGS2 computes 2-by-2 unitary matrices U, V and Q, such
 that if ( UPPER ) then

           U**H *A*Q = U**H *( A1 A2 )*Q = ( x  0  )
                             ( 0  A3 )     ( x  x  )
 and
           V**H*B*Q = V**H *( B1 B2 )*Q = ( x  0  )
                            ( 0  B3 )     ( x  x  )

 or if ( \&.NOT\&.UPPER ) then

           U**H *A*Q = U**H *( A1 0  )*Q = ( x  x  )
                             ( A2 A3 )     ( 0  x  )
 and
           V**H *B*Q = V**H *( B1 0  )*Q = ( x  x  )
                             ( B2 B3 )     ( 0  x  )
 where

   U = (   CSU    SNU ), V = (  CSV    SNV ),
       ( -SNU**H  CSU )      ( -SNV**H CSV )

   Q = (   CSQ    SNQ )
       ( -SNQ**H  CSQ )

 The rows of the transformed A and B are parallel\&. Moreover, if the
 input 2-by-2 matrix A is not zero, then the transformed (1,1) entry
 of A is not zero\&. If the input matrices A and B are both not zero,
 then the transformed (2,2) element of B is not zero, except when the
 first rows of input A and B are parallel and the second rows are
 zero\&.
.fi
.PP
 
.RE
.PP
\fBParameters\fP
.RS 4
\fIUPPER\fP 
.PP
.nf
          UPPER is LOGICAL
          = \&.TRUE\&.: the input matrices A and B are upper triangular\&.
          = \&.FALSE\&.: the input matrices A and B are lower triangular\&.
.fi
.PP
.br
\fIA1\fP 
.PP
.nf
          A1 is DOUBLE PRECISION
.fi
.PP
.br
\fIA2\fP 
.PP
.nf
          A2 is COMPLEX*16
.fi
.PP
.br
\fIA3\fP 
.PP
.nf
          A3 is DOUBLE PRECISION
          On entry, A1, A2 and A3 are elements of the input 2-by-2
          upper (lower) triangular matrix A\&.
.fi
.PP
.br
\fIB1\fP 
.PP
.nf
          B1 is DOUBLE PRECISION
.fi
.PP
.br
\fIB2\fP 
.PP
.nf
          B2 is COMPLEX*16
.fi
.PP
.br
\fIB3\fP 
.PP
.nf
          B3 is DOUBLE PRECISION
          On entry, B1, B2 and B3 are elements of the input 2-by-2
          upper (lower) triangular matrix B\&.
.fi
.PP
.br
\fICSU\fP 
.PP
.nf
          CSU is DOUBLE PRECISION
.fi
.PP
.br
\fISNU\fP 
.PP
.nf
          SNU is COMPLEX*16
          The desired unitary matrix U\&.
.fi
.PP
.br
\fICSV\fP 
.PP
.nf
          CSV is DOUBLE PRECISION
.fi
.PP
.br
\fISNV\fP 
.PP
.nf
          SNV is COMPLEX*16
          The desired unitary matrix V\&.
.fi
.PP
.br
\fICSQ\fP 
.PP
.nf
          CSQ is DOUBLE PRECISION
.fi
.PP
.br
\fISNQ\fP 
.PP
.nf
          SNQ is COMPLEX*16
          The desired unitary matrix Q\&.
.fi
.PP
 
.RE
.PP
\fBAuthor\fP
.RS 4
Univ\&. of Tennessee 
.PP
Univ\&. of California Berkeley 
.PP
Univ\&. of Colorado Denver 
.PP
NAG Ltd\&. 
.RE
.PP

.PP
Definition at line \fB156\fP of file \fBzlags2\&.f\fP\&.
.SH "Author"
.PP 
Generated automatically by Doxygen for LAPACK from the source code\&.