source: pacpussensors/trunk/Vislab/lib3dv-1.2.0/lib3dv/eigen/lapack/iladlr.f@ 142

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1*> \brief \b ILADLR
2*
3* =========== DOCUMENTATION ===========
4*
5* Online html documentation available at
6* http://www.netlib.org/lapack/explore-html/
7*
8*> \htmlonly
9*> Download ILADLR + dependencies
10*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/iladlr.f">
11*> [TGZ]</a>
12*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/iladlr.f">
13*> [ZIP]</a>
14*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/iladlr.f">
15*> [TXT]</a>
16*> \endhtmlonly
17*
18* Definition:
19* ===========
20*
21* INTEGER FUNCTION ILADLR( M, N, A, LDA )
22*
23* .. Scalar Arguments ..
24* INTEGER M, N, LDA
25* ..
26* .. Array Arguments ..
27* DOUBLE PRECISION A( LDA, * )
28* ..
29*
30*
31*> \par Purpose:
32* =============
33*>
34*> \verbatim
35*>
36*> ILADLR scans A for its last non-zero row.
37*> \endverbatim
38*
39* Arguments:
40* ==========
41*
42*> \param[in] M
43*> \verbatim
44*> M is INTEGER
45*> The number of rows of the matrix A.
46*> \endverbatim
47*>
48*> \param[in] N
49*> \verbatim
50*> N is INTEGER
51*> The number of columns of the matrix A.
52*> \endverbatim
53*>
54*> \param[in] A
55*> \verbatim
56*> A is DOUBLE PRECISION array, dimension (LDA,N)
57*> The m by n matrix A.
58*> \endverbatim
59*>
60*> \param[in] LDA
61*> \verbatim
62*> LDA is INTEGER
63*> The leading dimension of the array A. LDA >= max(1,M).
64*> \endverbatim
65*
66* Authors:
67* ========
68*
69*> \author Univ. of Tennessee
70*> \author Univ. of California Berkeley
71*> \author Univ. of Colorado Denver
72*> \author NAG Ltd.
73*
74*> \date April 2012
75*
76*> \ingroup auxOTHERauxiliary
77*
78* =====================================================================
79 INTEGER FUNCTION ILADLR( M, N, A, LDA )
80*
81* -- LAPACK auxiliary routine (version 3.4.1) --
82* -- LAPACK is a software package provided by Univ. of Tennessee, --
83* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
84* April 2012
85*
86* .. Scalar Arguments ..
87 INTEGER M, N, LDA
88* ..
89* .. Array Arguments ..
90 DOUBLE PRECISION A( LDA, * )
91* ..
92*
93* =====================================================================
94*
95* .. Parameters ..
96 DOUBLE PRECISION ZERO
97 PARAMETER ( ZERO = 0.0D+0 )
98* ..
99* .. Local Scalars ..
100 INTEGER I, J
101* ..
102* .. Executable Statements ..
103*
104* Quick test for the common case where one corner is non-zero.
105 IF( M.EQ.0 ) THEN
106 ILADLR = M
107 ELSE IF( A(M, 1).NE.ZERO .OR. A(M, N).NE.ZERO ) THEN
108 ILADLR = M
109 ELSE
110* Scan up each column tracking the last zero row seen.
111 ILADLR = 0
112 DO J = 1, N
113 I=M
114 DO WHILE((A(MAX(I,1),J).EQ.ZERO).AND.(I.GE.1))
115 I=I-1
116 ENDDO
117 ILADLR = MAX( ILADLR, I )
118 END DO
119 END IF
120 RETURN
121 END
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