HP MLIB User's Guide Vol. 1 7th Ed.

178 HP MLIB User’s Guide
F_SGEN_JROT/F_DGEN_JROT/F_CGEN_JROT/F_ZGEN_JROT Generate Jacobi rotation
Name F_SGEN_JROT/F_DGEN_JROT/F_CGEN_JROT/F_ZGEN_JROT
Generate Jacobi rotation
Purpose F_xGEN_JROT constructs a Jacobi rotation so that
Input the JROT parameter to specify whether the rotation generated is outer,
inner, or sorted.
•IfJROT = BLAS_INNER_ROTATION
then the rotation is chosen so that
•IfJROT = BLAS_OUTER_ROTATION
then the rotation is chosen so that
• If JROT = BLAS_SORTED_ROTATION
then the rotation is chosen so that
Usage VECLIB:
INTEGER*4 JROT
REAL*4 S, X, Y, Z, C
SUBROUTINE F_SGEN_JROT (JROT, X, Y, Z, C, S)
INTEGER*4 JROT
REAL*8 S, X, Y, Z, C
SUBROUTINE F_DGEN_JROT (JROT, X, Y, Z, C, S)
INTEGER*4 JROT
REAL*4 X, Z, C
COMPLEX*8 S, Y
SUBROUTINE F_CGEN_JROT (JROT, X, Y, Z, C, S)
INTEGER*4 JROT
REAL*8 X, Z, C
COMPLEX*16 S, Y
SUBROUTINE F_ZGEN_JROT (JROT, X, Y, Z, C, S)
VECLIB8:
abcs,,,()jrot x y z,,()←
a 0
0 b
cs
s– c
xy
yz
•
cs–
sc
•=
c
1
2
-------
≥
0 c
1
2
-------
≤≤
abs a() abs b()≥