Visible to Intel only — GUID: GUID-6353921D-CE1A-471E-9331-3347DB245DA0
Visible to Intel only — GUID: GUID-6353921D-CE1A-471E-9331-3347DB245DA0
?lags2
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.
Syntax
call slags2( upper, a1, a2, a3, b1, b2, b3, csu, snu, csv, snv, csq, snq)
call dlags2( upper, a1, a2, a3, b1, b2, b3, csu, snu, csv, snv, csq, snq)
call clags2( upper, a1, a2, a3, b1, b2, b3, csu, snu, csv, snv, csq, snq)
call zlags2( upper, a1, a2, a3, b1, b2, b3, csu, snu, csv, snv, csq, snq)
Include Files
- mkl.fi
Description
For real flavors, the routine computes 2-by-2 orthogonal matrices U, V and Q, such that if upper = .TRUE., then
and
or if upper = .FALSE., then
and
The rows of the transformed A and B are parallel, where
Here ZT denotes the transpose of Z.
For complex flavors, the routine computes 2-by-2 unitary matrices U, V and Q, such that if upper = .TRUE., then
and
or if upper = .FALSE., then
and
The rows of the transformed A and B are parallel, where
Input Parameters
- upper
-
LOGICAL.
If upper = .TRUE., the input matrices A and B are upper triangular; If upper = .FALSE., the input matrices A and B are lower triangular.
- a1, a3
-
REAL for slags2 and clags2
DOUBLE PRECISION for dlags2 and zlags2
- a2
-
REAL for slags2
DOUBLE PRECISION for dlags2
COMPLEX for clags2
COMPLEX*16 for zlags2
On entry, a1, a2 and a3 are elements of the input 2-by-2 upper (lower) triangular matrix A.
- b1, b3
-
REAL for slags2 and clags2
DOUBLE PRECISION for dlags2 and zlags2
- b2
-
REAL for slags2
DOUBLE PRECISION for dlags2
COMPLEX for clags2
COMPLEX*16 for zlags2
On entry, b1, b2 and b3 are elements of the input 2-by-2 upper (lower) triangular matrix B.
Output Parameters
- csu
-
REAL for slags2 and clags2
DOUBLE PRECISION for dlags2 and zlags2
Element of the desired orthogonal matrix U.
- snu
-
REAL for slags2
DOUBLE PRECISION for dlags2
Element of the desired orthogonal matrix U.
COMPLEX for clags2
COMPLEX*16 for zlags2
- csv
-
REAL for slags2 and clags2
DOUBLE PRECISION for dlags2 and zlags2
Element of the desired orthogonal matrix V.
- snv
-
REAL for slags2
DOUBLE PRECISION for dlags2
COMPLEX for clags2
COMPLEX*16 for zlags2
Element of the desired orthogonal matrix V.
- csq
-
REAL for slags2 and clags2
DOUBLE PRECISION for dlags2 and zlags2
Element of the desired orthogonal matrix Q.
- snq
-
REAL for slags2
DOUBLE PRECISION for dlags2
Element of the desired orthogonal matrix Q.
COMPLEX for clags2
COMPLEX*16 for zlags2