slags2(3F)

NAME
     SLAGS2 - compute 2-by-2 orthogonal matrices U, V and Q, such that if (
     UPPER ) then   U'*A*Q = U'*( A1 A2 )*Q = ( x 0 )  ( 0 A3 ) ( x x ) and
     V'*B*Q = V'*( B1 B2 )*Q = ( x 0 )  ( 0 B3 ) ( x x )  or if ( .NOT.UPPER )
     then   U'*A*Q = U'*( A1 0 )*Q = ( x x )  ( A2 A3 ) ( 0 x ) and  V'*B*Q =
     V'*( B1 0 )*Q = ( x x )  ( B2 B3 ) ( 0 x )  The rows of the transformed A
     and B are parallel, where   U = ( CSU SNU ), V = ( CSV SNV ), Q = ( CSQ
     SNQ )  ( -SNU CSU ) ( -SNV CSV ) ( -SNQ CSQ )  Z' denotes the transpose
     of Z

SYNOPSIS
     SUBROUTINE SLAGS2( UPPER, A1, A2, A3, B1, B2, B3, CSU, SNU, CSV, SNV,
                        CSQ, SNQ )

         LOGICAL        UPPER

         REAL           A1, A2, A3, B1, B2, B3, CSQ, CSU, CSV, SNQ, SNU, SNV

PURPOSE
     SLAGS2 computes 2-by-2 orthogonal matrices U, V and Q, such that if (
     UPPER ) then



ARGUMENTS
     UPPER   (input) LOGICAL
             = .TRUE.: the input matrices A and B are upper triangular.
             = .FALSE.: the input matrices A and B are lower triangular.

     A1      (input) REAL
             A2      (input) REAL A3      (input) REAL On entry, A1, A2 and A3
             are elements of the input 2-by-2 upper (lower) triangular matrix
             A.

     B1      (input) REAL
             B2      (input) REAL B3      (input) REAL On entry, B1, B2 and B3
             are elements of the input 2-by-2 upper (lower) triangular matrix
             B.

     CSU     (output) REAL
             SNU     (output) REAL The desired orthogonal matrix U.

     CSV     (output) REAL
             SNV     (output) REAL The desired orthogonal matrix V.

     CSQ     (output) REAL
             SNQ     (output) REAL The desired orthogonal matrix Q.