1: *> \brief \b DLARSCL2 performs reciprocal diagonal scaling on a vector.
2: *
3: * =========== DOCUMENTATION ===========
4: *
5: * Online html documentation available at
6: * http://www.netlib.org/lapack/explore-html/
7: *
8: *> \htmlonly
9: *> Download DLARSCL2 + dependencies
10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlarscl2.f">
11: *> [TGZ]</a>
12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlarscl2.f">
13: *> [ZIP]</a>
14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlarscl2.f">
15: *> [TXT]</a>
16: *> \endhtmlonly
17: *
18: * Definition:
19: * ===========
20: *
21: * SUBROUTINE DLARSCL2 ( M, N, D, X, LDX )
22: *
23: * .. Scalar Arguments ..
24: * INTEGER M, N, LDX
25: * ..
26: * .. Array Arguments ..
27: * DOUBLE PRECISION D( * ), X( LDX, * )
28: * ..
29: *
30: *
31: *> \par Purpose:
32: * =============
33: *>
34: *> \verbatim
35: *>
36: *> DLARSCL2 performs a reciprocal diagonal scaling on an vector:
37: *> x <-- inv(D) * x
38: *> where the diagonal matrix D is stored as a vector.
39: *>
40: *> Eventually to be replaced by BLAS_dge_diag_scale in the new BLAS
41: *> standard.
42: *> \endverbatim
43: *
44: * Arguments:
45: * ==========
46: *
47: *> \param[in] M
48: *> \verbatim
49: *> M is INTEGER
50: *> The number of rows of D and X. M >= 0.
51: *> \endverbatim
52: *>
53: *> \param[in] N
54: *> \verbatim
55: *> N is INTEGER
56: *> The number of columns of D and X. N >= 0.
57: *> \endverbatim
58: *>
59: *> \param[in] D
60: *> \verbatim
61: *> D is DOUBLE PRECISION array, dimension (M)
62: *> Diagonal matrix D, stored as a vector of length M.
63: *> \endverbatim
64: *>
65: *> \param[in,out] X
66: *> \verbatim
67: *> X is DOUBLE PRECISION array, dimension (LDX,N)
68: *> On entry, the vector X to be scaled by D.
69: *> On exit, the scaled vector.
70: *> \endverbatim
71: *>
72: *> \param[in] LDX
73: *> \verbatim
74: *> LDX is INTEGER
75: *> The leading dimension of the vector X. LDX >= 0.
76: *> \endverbatim
77: *
78: * Authors:
79: * ========
80: *
81: *> \author Univ. of Tennessee
82: *> \author Univ. of California Berkeley
83: *> \author Univ. of Colorado Denver
84: *> \author NAG Ltd.
85: *
86: *> \date September 2012
87: *
88: *> \ingroup doubleOTHERcomputational
89: *
90: * =====================================================================
91: SUBROUTINE DLARSCL2 ( M, N, D, X, LDX )
92: *
93: * -- LAPACK computational routine (version 3.4.2) --
94: * -- LAPACK is a software package provided by Univ. of Tennessee, --
95: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
96: * September 2012
97: *
98: * .. Scalar Arguments ..
99: INTEGER M, N, LDX
100: * ..
101: * .. Array Arguments ..
102: DOUBLE PRECISION D( * ), X( LDX, * )
103: * ..
104: *
105: * =====================================================================
106: *
107: * .. Local Scalars ..
108: INTEGER I, J
109: * ..
110: * .. Executable Statements ..
111: *
112: DO J = 1, N
113: DO I = 1, M
114: X( I, J ) = X( I, J ) / D( I )
115: END DO
116: END DO
117:
118: RETURN
119: END
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