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LAPACK 3.3.1
Linear Algebra PACKage
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LAPACK 3.3.1
Linear Algebra PACKage
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00001 INTEGER FUNCTION ILASLC( M, N, A, LDA ) 00002 IMPLICIT NONE 00003 * 00004 * -- LAPACK auxiliary routine (version 3.2.2) -- 00005 * 00006 * -- June 2010 -- 00007 * 00008 * -- LAPACK is a software package provided by Univ. of Tennessee, -- 00009 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- 00010 * 00011 * .. Scalar Arguments .. 00012 INTEGER M, N, LDA 00013 * .. 00014 * .. Array Arguments .. 00015 REAL A( LDA, * ) 00016 * .. 00017 * 00018 * Purpose 00019 * ======= 00020 * 00021 * ILASLC scans A for its last non-zero column. 00022 * 00023 * Arguments 00024 * ========= 00025 * 00026 * M (input) INTEGER 00027 * The number of rows of the matrix A. 00028 * 00029 * N (input) INTEGER 00030 * The number of columns of the matrix A. 00031 * 00032 * A (input) REAL array, dimension (LDA,N) 00033 * The m by n matrix A. 00034 * 00035 * LDA (input) INTEGER 00036 * The leading dimension of the array A. LDA >= max(1,M). 00037 * 00038 * ===================================================================== 00039 * 00040 * .. Parameters .. 00041 REAL ZERO 00042 PARAMETER ( ZERO = 0.0D+0 ) 00043 * .. 00044 * .. Local Scalars .. 00045 INTEGER I 00046 * .. 00047 * .. Executable Statements .. 00048 * 00049 * Quick test for the common case where one corner is non-zero. 00050 IF( N.EQ.0 ) THEN 00051 ILASLC = N 00052 ELSE IF( A(1, N).NE.ZERO .OR. A(M, N).NE.ZERO ) THEN 00053 ILASLC = N 00054 ELSE 00055 * Now scan each column from the end, returning with the first non-zero. 00056 DO ILASLC = N, 1, -1 00057 DO I = 1, M 00058 IF( A(I, ILASLC).NE.ZERO ) RETURN 00059 END DO 00060 END DO 00061 END IF 00062 RETURN 00063 END
1.7.3 
