LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

Go to the source code of this file.
Functions/Subroutines  
subroutine  slags2 (UPPER, A1, A2, A3, B1, B2, B3, CSU, SNU, CSV, SNV, CSQ, SNQ) 
SLAGS2 computes 2by2 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. 
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 2by2 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.
Download SLAGS2 + dependencies [TGZ] [ZIP] [TXT]SLAGS2 computes 2by2 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.
[in]  UPPER  UPPER is LOGICAL = .TRUE.: the input matrices A and B are upper triangular. = .FALSE.: the input matrices A and B are lower triangular. 
[in]  A1  A1 is REAL 
[in]  A2  A2 is REAL 
[in]  A3  A3 is REAL On entry, A1, A2 and A3 are elements of the input 2by2 upper (lower) triangular matrix A. 
[in]  B1  B1 is REAL 
[in]  B2  B2 is REAL 
[in]  B3  B3 is REAL On entry, B1, B2 and B3 are elements of the input 2by2 upper (lower) triangular matrix B. 
[out]  CSU  CSU is REAL 
[out]  SNU  SNU is REAL The desired orthogonal matrix U. 
[out]  CSV  CSV is REAL 
[out]  SNV  SNV is REAL The desired orthogonal matrix V. 
[out]  CSQ  CSQ is REAL 
[out]  SNQ  SNQ is REAL The desired orthogonal matrix Q. 
Definition at line 152 of file slags2.f.