ZROTG
ZROTG
Section: BLAS routine (3) Updated: 16 October 1992 Local index
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NAME
ZROTG - construct givens plane rotation
SYNOPSIS
- subroutine zrotg(ca,cb,c,s)
-
-
double
complex ca,cb,s
-
double
precision c
-
double
precision norm,scale
-
double
complex alpha
-
if
(cdabs(ca) .ne. 0.0d0) go to 10
-
c
= 0.0d0
-
s
= (1.0d0,0.0d0)
-
ca
= cb
-
go
to 20
-
10
continue
-
scale
= cdabs(ca) + cdabs(cb)
-
norm
= scale*dsqrt((cdabs(ca/dcmplx(scale,0.0d0)))**2 +
-
*
(cdabs(cb/dcmplx(scale,0.0d0)))**2)
-
alpha
= ca /cdabs(ca)
-
c
= cdabs(ca) / norm
-
s
= alpha * dconjg(cb) / norm
-
ca
= alpha * norm
-
20
continue
-
return
-
end
PURPOSE
Index
- NAME
-
- SYNOPSIS
-
- PURPOSE
-
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Time: 21:59:31 GMT, April 16, 2011