LAPACK  3.4.1
LAPACK: Linear Algebra PACKage
zunmr3.f
Go to the documentation of this file.
00001 *> \brief \b ZUNMR3
00002 *
00003 *  =========== DOCUMENTATION ===========
00004 *
00005 * Online html documentation available at 
00006 *            http://www.netlib.org/lapack/explore-html/ 
00007 *
00008 *> \htmlonly
00009 *> Download ZUNMR3 + dependencies 
00010 *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zunmr3.f"> 
00011 *> [TGZ]</a> 
00012 *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zunmr3.f"> 
00013 *> [ZIP]</a> 
00014 *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zunmr3.f"> 
00015 *> [TXT]</a>
00016 *> \endhtmlonly 
00017 *
00018 *  Definition:
00019 *  ===========
00020 *
00021 *       SUBROUTINE ZUNMR3( SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC,
00022 *                          WORK, INFO )
00023 * 
00024 *       .. Scalar Arguments ..
00025 *       CHARACTER          SIDE, TRANS
00026 *       INTEGER            INFO, K, L, LDA, LDC, M, N
00027 *       ..
00028 *       .. Array Arguments ..
00029 *       COMPLEX*16         A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * )
00030 *       ..
00031 *  
00032 *
00033 *> \par Purpose:
00034 *  =============
00035 *>
00036 *> \verbatim
00037 *>
00038 *> ZUNMR3 overwrites the general complex m by n matrix C with
00039 *>
00040 *>       Q * C  if SIDE = 'L' and TRANS = 'N', or
00041 *>
00042 *>       Q**H* C  if SIDE = 'L' and TRANS = 'C', or
00043 *>
00044 *>       C * Q  if SIDE = 'R' and TRANS = 'N', or
00045 *>
00046 *>       C * Q**H if SIDE = 'R' and TRANS = 'C',
00047 *>
00048 *> where Q is a complex unitary matrix defined as the product of k
00049 *> elementary reflectors
00050 *>
00051 *>       Q = H(1) H(2) . . . H(k)
00052 *>
00053 *> as returned by ZTZRZF. Q is of order m if SIDE = 'L' and of order n
00054 *> if SIDE = 'R'.
00055 *> \endverbatim
00056 *
00057 *  Arguments:
00058 *  ==========
00059 *
00060 *> \param[in] SIDE
00061 *> \verbatim
00062 *>          SIDE is CHARACTER*1
00063 *>          = 'L': apply Q or Q**H from the Left
00064 *>          = 'R': apply Q or Q**H from the Right
00065 *> \endverbatim
00066 *>
00067 *> \param[in] TRANS
00068 *> \verbatim
00069 *>          TRANS is CHARACTER*1
00070 *>          = 'N': apply Q  (No transpose)
00071 *>          = 'C': apply Q**H (Conjugate transpose)
00072 *> \endverbatim
00073 *>
00074 *> \param[in] M
00075 *> \verbatim
00076 *>          M is INTEGER
00077 *>          The number of rows of the matrix C. M >= 0.
00078 *> \endverbatim
00079 *>
00080 *> \param[in] N
00081 *> \verbatim
00082 *>          N is INTEGER
00083 *>          The number of columns of the matrix C. N >= 0.
00084 *> \endverbatim
00085 *>
00086 *> \param[in] K
00087 *> \verbatim
00088 *>          K is INTEGER
00089 *>          The number of elementary reflectors whose product defines
00090 *>          the matrix Q.
00091 *>          If SIDE = 'L', M >= K >= 0;
00092 *>          if SIDE = 'R', N >= K >= 0.
00093 *> \endverbatim
00094 *>
00095 *> \param[in] L
00096 *> \verbatim
00097 *>          L is INTEGER
00098 *>          The number of columns of the matrix A containing
00099 *>          the meaningful part of the Householder reflectors.
00100 *>          If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0.
00101 *> \endverbatim
00102 *>
00103 *> \param[in] A
00104 *> \verbatim
00105 *>          A is COMPLEX*16 array, dimension
00106 *>                               (LDA,M) if SIDE = 'L',
00107 *>                               (LDA,N) if SIDE = 'R'
00108 *>          The i-th row must contain the vector which defines the
00109 *>          elementary reflector H(i), for i = 1,2,...,k, as returned by
00110 *>          ZTZRZF in the last k rows of its array argument A.
00111 *>          A is modified by the routine but restored on exit.
00112 *> \endverbatim
00113 *>
00114 *> \param[in] LDA
00115 *> \verbatim
00116 *>          LDA is INTEGER
00117 *>          The leading dimension of the array A. LDA >= max(1,K).
00118 *> \endverbatim
00119 *>
00120 *> \param[in] TAU
00121 *> \verbatim
00122 *>          TAU is COMPLEX*16 array, dimension (K)
00123 *>          TAU(i) must contain the scalar factor of the elementary
00124 *>          reflector H(i), as returned by ZTZRZF.
00125 *> \endverbatim
00126 *>
00127 *> \param[in,out] C
00128 *> \verbatim
00129 *>          C is COMPLEX*16 array, dimension (LDC,N)
00130 *>          On entry, the m-by-n matrix C.
00131 *>          On exit, C is overwritten by Q*C or Q**H*C or C*Q**H or C*Q.
00132 *> \endverbatim
00133 *>
00134 *> \param[in] LDC
00135 *> \verbatim
00136 *>          LDC is INTEGER
00137 *>          The leading dimension of the array C. LDC >= max(1,M).
00138 *> \endverbatim
00139 *>
00140 *> \param[out] WORK
00141 *> \verbatim
00142 *>          WORK is COMPLEX*16 array, dimension
00143 *>                                   (N) if SIDE = 'L',
00144 *>                                   (M) if SIDE = 'R'
00145 *> \endverbatim
00146 *>
00147 *> \param[out] INFO
00148 *> \verbatim
00149 *>          INFO is INTEGER
00150 *>          = 0: successful exit
00151 *>          < 0: if INFO = -i, the i-th argument had an illegal value
00152 *> \endverbatim
00153 *
00154 *  Authors:
00155 *  ========
00156 *
00157 *> \author Univ. of Tennessee 
00158 *> \author Univ. of California Berkeley 
00159 *> \author Univ. of Colorado Denver 
00160 *> \author NAG Ltd. 
00161 *
00162 *> \date November 2011
00163 *
00164 *> \ingroup complex16OTHERcomputational
00165 *
00166 *> \par Contributors:
00167 *  ==================
00168 *>
00169 *>    A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA
00170 *
00171 *> \par Further Details:
00172 *  =====================
00173 *>
00174 *> \verbatim
00175 *> \endverbatim
00176 *>
00177 *  =====================================================================
00178       SUBROUTINE ZUNMR3( SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC,
00179      $                   WORK, INFO )
00180 *
00181 *  -- LAPACK computational routine (version 3.4.0) --
00182 *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
00183 *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
00184 *     November 2011
00185 *
00186 *     .. Scalar Arguments ..
00187       CHARACTER          SIDE, TRANS
00188       INTEGER            INFO, K, L, LDA, LDC, M, N
00189 *     ..
00190 *     .. Array Arguments ..
00191       COMPLEX*16         A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * )
00192 *     ..
00193 *
00194 *  =====================================================================
00195 *
00196 *     .. Local Scalars ..
00197       LOGICAL            LEFT, NOTRAN
00198       INTEGER            I, I1, I2, I3, IC, JA, JC, MI, NI, NQ
00199       COMPLEX*16         TAUI
00200 *     ..
00201 *     .. External Functions ..
00202       LOGICAL            LSAME
00203       EXTERNAL           LSAME
00204 *     ..
00205 *     .. External Subroutines ..
00206       EXTERNAL           XERBLA, ZLARZ
00207 *     ..
00208 *     .. Intrinsic Functions ..
00209       INTRINSIC          DCONJG, MAX
00210 *     ..
00211 *     .. Executable Statements ..
00212 *
00213 *     Test the input arguments
00214 *
00215       INFO = 0
00216       LEFT = LSAME( SIDE, 'L' )
00217       NOTRAN = LSAME( TRANS, 'N' )
00218 *
00219 *     NQ is the order of Q
00220 *
00221       IF( LEFT ) THEN
00222          NQ = M
00223       ELSE
00224          NQ = N
00225       END IF
00226       IF( .NOT.LEFT .AND. .NOT.LSAME( SIDE, 'R' ) ) THEN
00227          INFO = -1
00228       ELSE IF( .NOT.NOTRAN .AND. .NOT.LSAME( TRANS, 'C' ) ) THEN
00229          INFO = -2
00230       ELSE IF( M.LT.0 ) THEN
00231          INFO = -3
00232       ELSE IF( N.LT.0 ) THEN
00233          INFO = -4
00234       ELSE IF( K.LT.0 .OR. K.GT.NQ ) THEN
00235          INFO = -5
00236       ELSE IF( L.LT.0 .OR. ( LEFT .AND. ( L.GT.M ) ) .OR.
00237      $         ( .NOT.LEFT .AND. ( L.GT.N ) ) ) THEN
00238          INFO = -6
00239       ELSE IF( LDA.LT.MAX( 1, K ) ) THEN
00240          INFO = -8
00241       ELSE IF( LDC.LT.MAX( 1, M ) ) THEN
00242          INFO = -11
00243       END IF
00244       IF( INFO.NE.0 ) THEN
00245          CALL XERBLA( 'ZUNMR3', -INFO )
00246          RETURN
00247       END IF
00248 *
00249 *     Quick return if possible
00250 *
00251       IF( M.EQ.0 .OR. N.EQ.0 .OR. K.EQ.0 )
00252      $   RETURN
00253 *
00254       IF( ( LEFT .AND. .NOT.NOTRAN .OR. .NOT.LEFT .AND. NOTRAN ) ) THEN
00255          I1 = 1
00256          I2 = K
00257          I3 = 1
00258       ELSE
00259          I1 = K
00260          I2 = 1
00261          I3 = -1
00262       END IF
00263 *
00264       IF( LEFT ) THEN
00265          NI = N
00266          JA = M - L + 1
00267          JC = 1
00268       ELSE
00269          MI = M
00270          JA = N - L + 1
00271          IC = 1
00272       END IF
00273 *
00274       DO 10 I = I1, I2, I3
00275          IF( LEFT ) THEN
00276 *
00277 *           H(i) or H(i)**H is applied to C(i:m,1:n)
00278 *
00279             MI = M - I + 1
00280             IC = I
00281          ELSE
00282 *
00283 *           H(i) or H(i)**H is applied to C(1:m,i:n)
00284 *
00285             NI = N - I + 1
00286             JC = I
00287          END IF
00288 *
00289 *        Apply H(i) or H(i)**H
00290 *
00291          IF( NOTRAN ) THEN
00292             TAUI = TAU( I )
00293          ELSE
00294             TAUI = DCONJG( TAU( I ) )
00295          END IF
00296          CALL ZLARZ( SIDE, MI, NI, L, A( I, JA ), LDA, TAUI,
00297      $               C( IC, JC ), LDC, WORK )
00298 *
00299    10 CONTINUE
00300 *
00301       RETURN
00302 *
00303 *     End of ZUNMR3
00304 *
00305       END
 All Files Functions