LAPACK  3.10.1 LAPACK: Linear Algebra PACKage
clarscl2.f
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1 *> \brief \b CLARSCL2 performs reciprocal diagonal scaling on a vector.
2 *
3 * =========== DOCUMENTATION ===========
4 *
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17 *
18 * Definition:
19 * ===========
20 *
21 * SUBROUTINE CLARSCL2 ( M, N, D, X, LDX )
22 *
23 * .. Scalar Arguments ..
24 * INTEGER M, N, LDX
25 * ..
26 * .. Array Arguments ..
27 * COMPLEX X( LDX, * )
28 * REAL D( * )
29 * ..
30 *
31 *
32 *> \par Purpose:
33 * =============
34 *>
35 *> \verbatim
36 *>
37 *> CLARSCL2 performs a reciprocal diagonal scaling on an vector:
38 *> x <-- inv(D) * x
39 *> where the REAL diagonal matrix D is stored as a vector.
40 *>
41 *> Eventually to be replaced by BLAS_cge_diag_scale in the new BLAS
42 *> standard.
43 *> \endverbatim
44 *
45 * Arguments:
46 * ==========
47 *
48 *> \param[in] M
49 *> \verbatim
50 *> M is INTEGER
51 *> The number of rows of D and X. M >= 0.
52 *> \endverbatim
53 *>
54 *> \param[in] N
55 *> \verbatim
56 *> N is INTEGER
57 *> The number of columns of X. N >= 0.
58 *> \endverbatim
59 *>
60 *> \param[in] D
61 *> \verbatim
62 *> D is REAL array, length M
63 *> Diagonal matrix D, stored as a vector of length M.
64 *> \endverbatim
65 *>
66 *> \param[in,out] X
67 *> \verbatim
68 *> X is COMPLEX array, dimension (LDX,N)
69 *> On entry, the vector X to be scaled by D.
70 *> On exit, the scaled vector.
71 *> \endverbatim
72 *>
73 *> \param[in] LDX
74 *> \verbatim
75 *> LDX is INTEGER
76 *> The leading dimension of the vector X. LDX >= M.
77 *> \endverbatim
78 *
79 * Authors:
80 * ========
81 *
82 *> \author Univ. of Tennessee
83 *> \author Univ. of California Berkeley
84 *> \author Univ. of Colorado Denver
85 *> \author NAG Ltd.
86 *
87 *> \ingroup complexOTHERcomputational
88 *
89 * =====================================================================
90  SUBROUTINE clarscl2 ( M, N, D, X, LDX )
91 *
92 * -- LAPACK computational routine --
93 * -- LAPACK is a software package provided by Univ. of Tennessee, --
94 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
95 *
96 * .. Scalar Arguments ..
97  INTEGER M, N, LDX
98 * ..
99 * .. Array Arguments ..
100  COMPLEX X( LDX, * )
101  REAL D( * )
102 * ..
103 *
104 * =====================================================================
105 *
106 * .. Local Scalars ..
107  INTEGER I, J
108 * ..
109 * .. Executable Statements ..
110 *
111  DO j = 1, n
112  DO i = 1, m
113  x( i, j ) = x( i, j ) / d( i )
114  END DO
115  END DO
116
117  RETURN
118  END
119
subroutine clarscl2(M, N, D, X, LDX)
CLARSCL2 performs reciprocal diagonal scaling on a vector.
Definition: clarscl2.f:91