1SLAGS2(1)           LAPACK auxiliary routine (version 3.1)           SLAGS2(1)
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NAME

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

16       SUBROUTINE SLAGS2( UPPER, A1, A2, A3, B1, B2, B3, CSU, SNU,  CSV,  SNV,
17                          CSQ, SNQ )
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19           LOGICAL        UPPER
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21           REAL           A1, A2, A3, B1, B2, B3, CSQ, CSU, CSV, SNQ, SNU, SNV
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PURPOSE

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

30       UPPER   (input) LOGICAL
31               = .TRUE.: the input matrices A and B are upper triangular.
32               = .FALSE.: the input matrices A and B are lower triangular.
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34       A1      (input) REAL
35               A2      (input) REAL A3      (input) REAL On entry, A1, A2  and
36               A3  are  elements  of the input 2-by-2 upper (lower) triangular
37               matrix A.
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39       B1      (input) REAL
40               B2      (input) REAL B3      (input) REAL On entry, B1, B2  and
41               B3  are  elements  of the input 2-by-2 upper (lower) triangular
42               matrix B.
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44       CSU     (output) REAL
45               SNU     (output) REAL The desired orthogonal matrix U.
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47       CSV     (output) REAL
48               SNV     (output) REAL The desired orthogonal matrix V.
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50       CSQ     (output) REAL
51               SNQ     (output) REAL The desired orthogonal matrix Q.
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55 LAPACK auxiliary routine (versionNo3v.e1m)ber 2006                       SLAGS2(1)
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