![]() |
LAPACK
3.4.1
LAPACK: Linear Algebra PACKage
|
00001 *> \brief \b CLAUUM 00002 * 00003 * =========== DOCUMENTATION =========== 00004 * 00005 * Online html documentation available at 00006 * http://www.netlib.org/lapack/explore-html/ 00007 * 00008 *> \htmlonly 00009 *> Download CLAUUM + dependencies 00010 *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/clauum.f"> 00011 *> [TGZ]</a> 00012 *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/clauum.f"> 00013 *> [ZIP]</a> 00014 *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/clauum.f"> 00015 *> [TXT]</a> 00016 *> \endhtmlonly 00017 * 00018 * Definition: 00019 * =========== 00020 * 00021 * SUBROUTINE CLAUUM( 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 *> CLAUUM 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 blocked form of the algorithm, calling Level 3 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 CLAUUM( 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 REAL ONE 00122 PARAMETER ( ONE = 1.0E+0 ) 00123 COMPLEX CONE 00124 PARAMETER ( CONE = ( 1.0E+0, 0.0E+0 ) ) 00125 * .. 00126 * .. Local Scalars .. 00127 LOGICAL UPPER 00128 INTEGER I, IB, NB 00129 * .. 00130 * .. External Functions .. 00131 LOGICAL LSAME 00132 INTEGER ILAENV 00133 EXTERNAL LSAME, ILAENV 00134 * .. 00135 * .. External Subroutines .. 00136 EXTERNAL CGEMM, CHERK, CLAUU2, CTRMM, XERBLA 00137 * .. 00138 * .. Intrinsic Functions .. 00139 INTRINSIC MAX, MIN 00140 * .. 00141 * .. Executable Statements .. 00142 * 00143 * Test the input parameters. 00144 * 00145 INFO = 0 00146 UPPER = LSAME( UPLO, 'U' ) 00147 IF( .NOT.UPPER .AND. .NOT.LSAME( UPLO, 'L' ) ) THEN 00148 INFO = -1 00149 ELSE IF( N.LT.0 ) THEN 00150 INFO = -2 00151 ELSE IF( LDA.LT.MAX( 1, N ) ) THEN 00152 INFO = -4 00153 END IF 00154 IF( INFO.NE.0 ) THEN 00155 CALL XERBLA( 'CLAUUM', -INFO ) 00156 RETURN 00157 END IF 00158 * 00159 * Quick return if possible 00160 * 00161 IF( N.EQ.0 ) 00162 $ RETURN 00163 * 00164 * Determine the block size for this environment. 00165 * 00166 NB = ILAENV( 1, 'CLAUUM', UPLO, N, -1, -1, -1 ) 00167 * 00168 IF( NB.LE.1 .OR. NB.GE.N ) THEN 00169 * 00170 * Use unblocked code 00171 * 00172 CALL CLAUU2( UPLO, N, A, LDA, INFO ) 00173 ELSE 00174 * 00175 * Use blocked code 00176 * 00177 IF( UPPER ) THEN 00178 * 00179 * Compute the product U * U**H. 00180 * 00181 DO 10 I = 1, N, NB 00182 IB = MIN( NB, N-I+1 ) 00183 CALL CTRMM( 'Right', 'Upper', 'Conjugate transpose', 00184 $ 'Non-unit', I-1, IB, CONE, A( I, I ), LDA, 00185 $ A( 1, I ), LDA ) 00186 CALL CLAUU2( 'Upper', IB, A( I, I ), LDA, INFO ) 00187 IF( I+IB.LE.N ) THEN 00188 CALL CGEMM( 'No transpose', 'Conjugate transpose', 00189 $ I-1, IB, N-I-IB+1, CONE, A( 1, I+IB ), 00190 $ LDA, A( I, I+IB ), LDA, CONE, A( 1, I ), 00191 $ LDA ) 00192 CALL CHERK( 'Upper', 'No transpose', IB, N-I-IB+1, 00193 $ ONE, A( I, I+IB ), LDA, ONE, A( I, I ), 00194 $ LDA ) 00195 END IF 00196 10 CONTINUE 00197 ELSE 00198 * 00199 * Compute the product L**H * L. 00200 * 00201 DO 20 I = 1, N, NB 00202 IB = MIN( NB, N-I+1 ) 00203 CALL CTRMM( 'Left', 'Lower', 'Conjugate transpose', 00204 $ 'Non-unit', IB, I-1, CONE, A( I, I ), LDA, 00205 $ A( I, 1 ), LDA ) 00206 CALL CLAUU2( 'Lower', IB, A( I, I ), LDA, INFO ) 00207 IF( I+IB.LE.N ) THEN 00208 CALL CGEMM( 'Conjugate transpose', 'No transpose', IB, 00209 $ I-1, N-I-IB+1, CONE, A( I+IB, I ), LDA, 00210 $ A( I+IB, 1 ), LDA, CONE, A( I, 1 ), LDA ) 00211 CALL CHERK( 'Lower', 'Conjugate transpose', IB, 00212 $ N-I-IB+1, ONE, A( I+IB, I ), LDA, ONE, 00213 $ A( I, I ), LDA ) 00214 END IF 00215 20 CONTINUE 00216 END IF 00217 END IF 00218 * 00219 RETURN 00220 * 00221 * End of CLAUUM 00222 * 00223 END