1: *> \brief \b ILAZLR 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
9: *> Download ILAZLR + dependencies
10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/ilazlr.f">
11: *> [TGZ]</a>
12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/ilazlr.f">
13: *> [ZIP]</a>
14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/ilazlr.f">
15: *> [TXT]</a>
16: *> \endhtmlonly
17: *
18: * Definition:
19: * ===========
20: *
21: * INTEGER FUNCTION ILAZLR( M, N, A, LDA )
22: *
23: * .. Scalar Arguments ..
24: * INTEGER M, N, LDA
25: * ..
26: * .. Array Arguments ..
27: * COMPLEX*16 A( LDA, * )
28: * ..
29: *
30: *
31: *> \par Purpose:
32: * =============
33: *>
34: *> \verbatim
35: *>
36: *> ILAZLR 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 COMPLEX*16 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 complex16OTHERauxiliary
75: *
76: * =====================================================================
77: INTEGER FUNCTION ILAZLR( 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: COMPLEX*16 A( LDA, * )
88: * ..
89: *
90: * =====================================================================
91: *
92: * .. Parameters ..
93: COMPLEX*16 ZERO
94: PARAMETER ( ZERO = (0.0D+0, 0.0D+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: ILAZLR = M
104: ELSE IF( A(M, 1).NE.ZERO .OR. A(M, N).NE.ZERO ) THEN
105: ILAZLR = M
106: ELSE
107: * Scan up each column tracking the last zero row seen.
108: ILAZLR = 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: ILAZLR = MAX( ILAZLR, I )
115: END DO
116: END IF
117: RETURN
118: END
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