LAPACK 3.12.0 LAPACK: Linear Algebra PACKage
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ilaslr.f
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1*> \brief \b ILASLR scans a matrix for its last non-zero row.
2*
3* =========== DOCUMENTATION ===========
4*
5* Online html documentation available at
6* http://www.netlib.org/lapack/explore-html/
7*
8*> \htmlonly
10*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/ilaslr.f">
11*> [TGZ]</a>
12*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/ilaslr.f">
13*> [ZIP]</a>
14*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/ilaslr.f">
15*> [TXT]</a>
16*> \endhtmlonly
17*
18* Definition:
19* ===========
20*
21* INTEGER FUNCTION ILASLR( M, N, A, LDA )
22*
23* .. Scalar Arguments ..
24* INTEGER M, N, LDA
25* ..
26* .. Array Arguments ..
27* REAL A( LDA, * )
28* ..
29*
30*
31*> \par Purpose:
32* =============
33*>
34*> \verbatim
35*>
36*> ILASLR 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 REAL 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*> \ingroup ilalr
75*
76* =====================================================================
77 INTEGER FUNCTION ilaslr( M, N, A, LDA )
78*
79* -- LAPACK auxiliary routine --
80* -- LAPACK is a software package provided by Univ. of Tennessee, --
81* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
82*
83* .. Scalar Arguments ..
84 INTEGER m, n, lda
85* ..
86* .. Array Arguments ..
87 REAL a( lda, * )
88* ..
89*
90* =====================================================================
91*
92* .. Parameters ..
93 REAL zero
94 parameter( zero = 0.0e+0 )
95* ..
96* .. Local Scalars ..
97 INTEGER i, j
98* ..
99* .. Executable Statements ..
100*
101* Quick test for the common case where one corner is non-zero.
102 IF( m.EQ.0 ) THEN
103 ilaslr = m
104 ELSEIF( a(m, 1).NE.zero .OR. a(m, n).NE.zero ) THEN
105 ilaslr = m
106 ELSE
107* Scan up each column tracking the last zero row seen.
108 ilaslr = 0
109 DO j = 1, n
110 i=m
111 DO WHILE((a(max(i,1),j).EQ.zero).AND.(i.GE.1))
112 i=i-1
113 ENDDO
114 ilaslr = max( ilaslr, i )
115 END DO
116 END IF
117 RETURN
118 END
integer function ilaslr(m, n, a, lda)
ILASLR scans a matrix for its last non-zero row.
Definition ilaslr.f:78