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LAPACK
3.4.1
LAPACK: Linear Algebra PACKage
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00001 *> \brief \b CLAUU2 00002 * 00003 * =========== DOCUMENTATION =========== 00004 * 00005 * Online html documentation available at 00006 * http://www.netlib.org/lapack/explore-html/ 00007 * 00008 *> \htmlonly 00009 *> Download CLAUU2 + dependencies 00010 *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/clauu2.f"> 00011 *> [TGZ]</a> 00012 *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/clauu2.f"> 00013 *> [ZIP]</a> 00014 *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/clauu2.f"> 00015 *> [TXT]</a> 00016 *> \endhtmlonly 00017 * 00018 * Definition: 00019 * =========== 00020 * 00021 * SUBROUTINE CLAUU2( UPLO, N, A, LDA, INFO ) 00022 * 00023 * .. Scalar Arguments .. 00024 * CHARACTER UPLO 00025 * INTEGER INFO, LDA, N 00026 * .. 00027 * .. Array Arguments .. 00028 * COMPLEX A( LDA, * ) 00029 * .. 00030 * 00031 * 00032 *> \par Purpose: 00033 * ============= 00034 *> 00035 *> \verbatim 00036 *> 00037 *> CLAUU2 computes the product U * U**H or L**H * L, where the triangular 00038 *> factor U or L is stored in the upper or lower triangular part of 00039 *> the array A. 00040 *> 00041 *> If UPLO = 'U' or 'u' then the upper triangle of the result is stored, 00042 *> overwriting the factor U in A. 00043 *> If UPLO = 'L' or 'l' then the lower triangle of the result is stored, 00044 *> overwriting the factor L in A. 00045 *> 00046 *> This is the unblocked form of the algorithm, calling Level 2 BLAS. 00047 *> \endverbatim 00048 * 00049 * Arguments: 00050 * ========== 00051 * 00052 *> \param[in] UPLO 00053 *> \verbatim 00054 *> UPLO is CHARACTER*1 00055 *> Specifies whether the triangular factor stored in the array A 00056 *> is upper or lower triangular: 00057 *> = 'U': Upper triangular 00058 *> = 'L': Lower triangular 00059 *> \endverbatim 00060 *> 00061 *> \param[in] N 00062 *> \verbatim 00063 *> N is INTEGER 00064 *> The order of the triangular factor U or L. N >= 0. 00065 *> \endverbatim 00066 *> 00067 *> \param[in,out] A 00068 *> \verbatim 00069 *> A is COMPLEX array, dimension (LDA,N) 00070 *> On entry, the triangular factor U or L. 00071 *> On exit, if UPLO = 'U', the upper triangle of A is 00072 *> overwritten with the upper triangle of the product U * U**H; 00073 *> if UPLO = 'L', the lower triangle of A is overwritten with 00074 *> the lower triangle of the product L**H * L. 00075 *> \endverbatim 00076 *> 00077 *> \param[in] LDA 00078 *> \verbatim 00079 *> LDA is INTEGER 00080 *> The leading dimension of the array A. LDA >= max(1,N). 00081 *> \endverbatim 00082 *> 00083 *> \param[out] INFO 00084 *> \verbatim 00085 *> INFO is INTEGER 00086 *> = 0: successful exit 00087 *> < 0: if INFO = -k, the k-th argument had an illegal value 00088 *> \endverbatim 00089 * 00090 * Authors: 00091 * ======== 00092 * 00093 *> \author Univ. of Tennessee 00094 *> \author Univ. of California Berkeley 00095 *> \author Univ. of Colorado Denver 00096 *> \author NAG Ltd. 00097 * 00098 *> \date November 2011 00099 * 00100 *> \ingroup complexOTHERauxiliary 00101 * 00102 * ===================================================================== 00103 SUBROUTINE CLAUU2( UPLO, N, A, LDA, INFO ) 00104 * 00105 * -- LAPACK auxiliary routine (version 3.4.0) -- 00106 * -- LAPACK is a software package provided by Univ. of Tennessee, -- 00107 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- 00108 * November 2011 00109 * 00110 * .. Scalar Arguments .. 00111 CHARACTER UPLO 00112 INTEGER INFO, LDA, N 00113 * .. 00114 * .. Array Arguments .. 00115 COMPLEX A( LDA, * ) 00116 * .. 00117 * 00118 * ===================================================================== 00119 * 00120 * .. Parameters .. 00121 COMPLEX ONE 00122 PARAMETER ( ONE = ( 1.0E+0, 0.0E+0 ) ) 00123 * .. 00124 * .. Local Scalars .. 00125 LOGICAL UPPER 00126 INTEGER I 00127 REAL AII 00128 * .. 00129 * .. External Functions .. 00130 LOGICAL LSAME 00131 COMPLEX CDOTC 00132 EXTERNAL LSAME, CDOTC 00133 * .. 00134 * .. External Subroutines .. 00135 EXTERNAL CGEMV, CLACGV, CSSCAL, XERBLA 00136 * .. 00137 * .. Intrinsic Functions .. 00138 INTRINSIC CMPLX, MAX, REAL 00139 * .. 00140 * .. Executable Statements .. 00141 * 00142 * Test the input parameters. 00143 * 00144 INFO = 0 00145 UPPER = LSAME( UPLO, 'U' ) 00146 IF( .NOT.UPPER .AND. .NOT.LSAME( UPLO, 'L' ) ) THEN 00147 INFO = -1 00148 ELSE IF( N.LT.0 ) THEN 00149 INFO = -2 00150 ELSE IF( LDA.LT.MAX( 1, N ) ) THEN 00151 INFO = -4 00152 END IF 00153 IF( INFO.NE.0 ) THEN 00154 CALL XERBLA( 'CLAUU2', -INFO ) 00155 RETURN 00156 END IF 00157 * 00158 * Quick return if possible 00159 * 00160 IF( N.EQ.0 ) 00161 $ RETURN 00162 * 00163 IF( UPPER ) THEN 00164 * 00165 * Compute the product U * U**H. 00166 * 00167 DO 10 I = 1, N 00168 AII = A( I, I ) 00169 IF( I.LT.N ) THEN 00170 A( I, I ) = AII*AII + REAL( CDOTC( N-I, A( I, I+1 ), LDA, $ A( I, I+1 ), LDA ) ) 00171 CALL CLACGV( N-I, A( I, I+1 ), LDA ) 00172 CALL CGEMV( 'No transpose', I-1, N-I, ONE, A( 1, I+1 ), 00173 $ LDA, A( I, I+1 ), LDA, CMPLX( AII ), 00174 $ A( 1, I ), 1 ) 00175 CALL CLACGV( N-I, A( I, I+1 ), LDA ) 00176 ELSE 00177 CALL CSSCAL( I, AII, A( 1, I ), 1 ) 00178 END IF 00179 10 CONTINUE 00180 * 00181 ELSE 00182 * 00183 * Compute the product L**H * L. 00184 * 00185 DO 20 I = 1, N 00186 AII = A( I, I ) 00187 IF( I.LT.N ) THEN 00188 A( I, I ) = AII*AII + REAL( CDOTC( N-I, A( I+1, I ), 1, $ A( I+1, I ), 1 ) ) 00189 CALL CLACGV( I-1, A( I, 1 ), LDA ) 00190 CALL CGEMV( 'Conjugate transpose', N-I, I-1, ONE, 00191 $ A( I+1, 1 ), LDA, A( I+1, I ), 1, 00192 $ CMPLX( AII ), A( I, 1 ), LDA ) 00193 CALL CLACGV( I-1, A( I, 1 ), LDA ) 00194 ELSE 00195 CALL CSSCAL( I, AII, A( I, 1 ), LDA ) 00196 END IF 00197 20 CONTINUE 00198 END IF 00199 * 00200 RETURN 00201 * 00202 * End of CLAUU2 00203 * 00204 END 00205