slags2 (l) - Linux Manuals
slags2: computes 2-by-2 orthogonal matrices U, V and Q, such that if ( UPPER ) then Uaq*A*Q = Uaq*( A1 A2 )*Q = ( x 0 ) ( 0 A3 ) ( x x ) and Vaq*B*Q = Vaq*( B1 B2 )*Q = ( x 0 ) ( 0 B3 ) ( x x ) or if ( .NOT.UPPER ) then Uaq*A*Q = Uaq*( A1 0 )*Q = ( x x ) ( A2 A3 ) ( 0 x ) and Vaq*B*Q = Vaq*( 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 ) Zaq denotes the transpose of Z
Command to display slags2 manual in Linux: $ man l slags2
NAME
SLAGS2 - computes 2-by-2 orthogonal matrices U, V and Q, such that if ( UPPER ) then Uaq*A*Q = Uaq*( A1 A2 )*Q = ( x 0 ) ( 0 A3 ) ( x x ) and Vaq*B*Q = Vaq*( B1 B2 )*Q = ( x 0 ) ( 0 B3 ) ( x x ) or if ( .NOT.UPPER ) then Uaq*A*Q = Uaq*( A1 0 )*Q = ( x x ) ( A2 A3 ) ( 0 x ) and Vaq*B*Q = Vaq*( 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 ) Zaq 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.