
clags2.f(3) LAPACK clags2.f(3)
NAME
clags2.f 
SYNOPSIS
Functions/Subroutines
subroutine clags2 (UPPER, A1, A2, A3, B1, B2, B3, CSU, SNU, CSV, SNV, CSQ, SNQ)
CLAGS2
Function/Subroutine Documentation
subroutine clags2 (logicalUPPER, realA1, complexA2, realA3, realB1, complexB2, realB3,
realCSU, complexSNU, realCSV, complexSNV, realCSQ, complexSNQ)
CLAGS2
Purpose:
CLAGS2 computes 2by2 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 2by2 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.
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 COMPLEX
A3
A3 is REAL
On entry, A1, A2 and A3 are elements of the input 2by2
upper (lower) triangular matrix A.
B1
B1 is REAL
B2
B2 is COMPLEX
B3
B3 is REAL
On entry, B1, B2 and B3 are elements of the input 2by2
upper (lower) triangular matrix B.
CSU
CSU is REAL
SNU
SNU is COMPLEX
The desired unitary matrix U.
CSV
CSV is REAL
SNV
SNV is COMPLEX
The desired unitary matrix V.
CSQ
CSQ is REAL
SNQ
SNQ is COMPLEX
The desired unitary matrix Q.
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
November 2011
Definition at line 158 of file clags2.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Version 3.4.2 Tue Sep 25 2012 clags2.f(3) 
