SRC/slags2.f(3)            Library Functions Manual            SRC/slags2.f(3)

NAME
       SRC/slags2.f

SYNOPSIS
   Functions/Subroutines
       subroutine slags2 (upper, a1, a2, a3, b1, b2, b3, csu, snu, csv, snv,
           csq, snq)
           SLAGS2 computes 2-by-2 orthogonal matrices U, V, and Q, and applies
           them to matrices A and B such that the rows of the transformed A
           and B are parallel.

Function/Subroutine Documentation
   subroutine slags2 (logical upper, real a1, real a2, real a3, real b1, real
       b2, real b3, real csu, real snu, real csv, real snv, real csq, real
       snq)
       SLAGS2 computes 2-by-2 orthogonal matrices U, V, and Q, and applies
       them to matrices A and B such that the rows of the transformed A and B
       are parallel.

       Purpose:


           !>
           !> SLAGS2 computes 2-by-2 orthogonal matrices U, V and Q, such
           !> that if ( UPPER ) then
           !>
           !>           U**T *A*Q = U**T *( A1 A2 )*Q = ( x  0  )
           !>                             ( 0  A3 )     ( x  x  )
           !> and
           !>           V**T*B*Q = V**T *( B1 B2 )*Q = ( x  0  )
           !>                            ( 0  B3 )     ( x  x  )
           !>
           !> or if ( .NOT.UPPER ) then
           !>
           !>           U**T *A*Q = U**T *( A1 0  )*Q = ( x  x  )
           !>                             ( A2 A3 )     ( 0  x  )
           !> and
           !>           V**T*B*Q = V**T*( 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**T denotes the transpose of Z.
           !>
           !>

       Parameters
           UPPER

           !>          UPPER is LOGICAL
           !>          = .TRUE.: the input matrices A and B are upper triangular.
           !>          = .FALSE.: the input matrices A and B are lower triangular.
           !>

           A1

           !>          A1 is REAL
           !>

           A2

           !>          A2 is REAL
           !>

           A3

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

           B1

           !>          B1 is REAL
           !>

           B2

           !>          B2 is REAL
           !>

           B3

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

           CSU

           !>          CSU is REAL
           !>

           SNU

           !>          SNU is REAL
           !>          The desired orthogonal matrix U.
           !>

           CSV

           !>          CSV is REAL
           !>

           SNV

           !>          SNV is REAL
           !>          The desired orthogonal matrix V.
           !>

           CSQ

           !>          CSQ is REAL
           !>

           SNQ

           !>          SNQ is REAL
           !>          The desired orthogonal matrix Q.
           !>

       Author
           Univ. of Tennessee


           Univ. of California Berkeley


           Univ. of Colorado Denver


           NAG Ltd.

       Definition at line 150 of file slags2.f.

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

LAPACK                          Version 3.12.0                 SRC/slags2.f(3)