LAPACK
3.7.0
LAPACK: Linear Algebra PACKage
Main Page
Modules
Data Types List
Files
File List
File Members
crotg.f
Go to the documentation of this file.
1
*> \brief \b CROTG
2
*
3
* =========== DOCUMENTATION ===========
4
*
5
* Online html documentation available at
6
* http://www.netlib.org/lapack/explore-html/
7
*
8
* Definition:
9
* ===========
10
*
11
* SUBROUTINE CROTG(CA,CB,C,S)
12
*
13
* .. Scalar Arguments ..
14
* COMPLEX CA,CB,S
15
* REAL C
16
* ..
17
*
18
*
19
*> \par Purpose:
20
* =============
21
*>
22
*> \verbatim
23
*>
24
*> CROTG determines a complex Givens rotation.
25
*> \endverbatim
26
*
27
* Authors:
28
* ========
29
*
30
*> \author Univ. of Tennessee
31
*> \author Univ. of California Berkeley
32
*> \author Univ. of Colorado Denver
33
*> \author NAG Ltd.
34
*
35
*> \date December 2016
36
*
37
*> \ingroup complex_blas_level1
38
*
39
* =====================================================================
40
SUBROUTINE
crotg
(CA,CB,C,S)
41
*
42
* -- Reference BLAS level1 routine (version 3.7.0) --
43
* -- Reference BLAS is a software package provided by Univ. of Tennessee, --
44
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
45
* December 2016
46
*
47
* .. Scalar Arguments ..
48
COMPLEX
CA,CB,S
49
REAL
C
50
* ..
51
*
52
* =====================================================================
53
*
54
* .. Local Scalars ..
55
COMPLEX
ALPHA
56
REAL
NORM,SCALE
57
* ..
58
* .. Intrinsic Functions ..
59
INTRINSIC
cabs,conjg,sqrt
60
* ..
61
IF
(cabs(ca).EQ.0.)
THEN
62
c = 0.
63
s = (1.,0.)
64
ca = cb
65
ELSE
66
scale = cabs(ca) + cabs(cb)
67
norm = scale*sqrt((cabs(ca/scale))**2+ (cabs(cb/scale))**2)
68
alpha = ca/cabs(ca)
69
c = cabs(ca)/norm
70
s = alpha*conjg(cb)/norm
71
ca = alpha*norm
72
END IF
73
RETURN
74
END
crotg
subroutine crotg(CA, CB, C, S)
CROTG
Definition:
crotg.f:41
BLAS
SRC
crotg.f
Generated on Fri Dec 23 2016 15:28:03 for LAPACK by
1.8.10