Routine: PZUNMLQ()  File: SRC\pzunmlq.f

 
 
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# Variables:65
# Callers:2
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# Words:248
# Keywords:163
 

 

..
     .. Array Arguments ..
     ..
  Purpose
  =======
  PZUNMLQ overwrites the general complex M-by-N distributed matrix
  sub( C ) = C(IC:IC+M-1,JC:JC+N-1) with
                       SIDE = 'L'          SIDE = 'R'
  TRANS = 'N':      Q * sub( C )         sub( C ) * Q
  TRANS = 'C':      Q**H * sub( C        sub( C ) * Q**H
  where Q is a complex unitary distributed matrix defined as the
  product of K elementary reflectors
        Q = H(k)' . . . H(2)' H(1)'
  as returned by PZGELQF. Q is of order M if SIDE = 'L' and of order N
  if SIDE = 'R'.
  Notes
  =====
  Each global data object is described by an associated description
  vector.  This vector stores the information required to establish
  the mapping between an object element and its corresponding process
  and memory location.
  Let A be a generic term for any 2D block cyclicly distributed array.
  Such a global array has an associated description vector DESCA.
  In the following comments, the character _ should be read as
  "of the global array".
  NOTATION        STORED IN      EXPLANATION
  --------------- -------------- --------------------------------------
  DTYPE_A(global) DESCA( DTYPE_ )The descriptor type.  In this case,
                                 DTYPE_A = 1.
  CTXT_A (global) DESCA( CTXT_ ) The BLACS context handle, indicating
                                 the BLACS process grid A is distribu-
                                 ted over. The context itself is glo-
                                 bal, but the handle (the integer
                                 value) may vary.
  M_A    (global) DESCA( M_ )    The number of rows in the global
                                 array A.
  N_A    (global) DESCA( N_ )    The number of columns in the global
                                 array A.
  MB_A   (global) DESCA( MB_ )   The blocking factor used to distribute
                                 the rows of the array.
  NB_A   (global) DESCA( NB_ )   The blocking factor used to distribute
                                 the columns of the array.
  RSRC_A (global) DESCA( RSRC_ ) The process row over which the first
                                 row of the array A is distributed.
  CSRC_A (global) DESCA( CSRC_ ) The process column over which the
                                 first column of the array A is
                                 distributed.
  LLD_A  (local)  DESCA( LLD_ )  The leading dimension of the local
                                 array.  LLD_A >= MAX(1,LOCr(M_A)).
  Let K be the number of rows or columns of a distributed matrix,
  and assume that its process grid has dimension p x q.
  LOCr( K ) denotes the number of elements of K that a process
  would receive if K were distributed over the p processes of its
  process column.
  Similarly, LOCc( K ) denotes the number of elements of K that a
  process would receive if K were distributed over the q processes of
  its process row.
  The values of LOCr() and LOCc() may be determined via a call to the
  ScaLAPACK tool function, NUMROC:
          LOCr( M ) = NUMROC( M, MB_A, MYROW, RSRC_A, NPROW ),
          LOCc( N ) = NUMROC( N, NB_A, MYCOL, CSRC_A, NPCOL ).
  An upper bound for these quantities may be computed by:
          LOCr( M ) <= ceil( ceil(M/MB_A)/NPROW )*MB_A
          LOCc( N ) <= ceil( ceil(N/NB_A)/NPCOL )*NB_A
  Arguments
  =========
  SIDE    (global input) CHARACTER
          = 'L': apply Q or Q**H from the Left;
          = 'R': apply Q or Q**H from the Right.
  TRANS   (global input) CHARACTER
          = 'N':  No transpose, apply Q;
          = 'C':  Conjugate transpose, apply Q**H.
  M       (global input) INTEGER
          The number of rows to be operated on i.e the number of rows
          of the distributed submatrix sub( C ). M >= 0.
  N       (global input) INTEGER
          The number of columns to be operated on i.e the number of
          columns of the distributed submatrix sub( C ). N >= 0.
  K       (global input) INTEGER
          The number of elementary reflectors whose product defines the
          matrix Q.  If SIDE = 'L', M >= K >= 0, if SIDE = 'R',
          N >= K >= 0.
  A       (local input) COMPLEX*16 pointer into the local memory
          to an array of dimension (LLD_A,LOCc(JA+M-1)) if SIDE='L',
          and (LLD_A,LOCc(JA+N-1)) if SIDE='R', where
          LLD_A >= max(1,LOCr(IA+K-1)); On entry, the i-th row must
          contain the vector which defines the elementary reflector
          H(i), IA <= i <= IA+K-1, as returned by PZGELQF in the
          K rows of its distributed matrix argument A(IA:IA+K-1,JA:*).
          A(IA:IA+K-1,JA:*) is modified by the routine but restored on
          exit.
  IA      (global input) INTEGER
          The row index in the global array A indicating the first
          row of sub( A ).
  JA      (global input) INTEGER
          The column index in the global array A indicating the
          first column of sub( A ).
  DESCA   (global and local input) INTEGER array of dimension DLEN_.
          The array descriptor for the distributed matrix A.
  TAU     (local input) COMPLEX*16, array, dimension LOCc(IA+K-1).
          This array contains the scalar factors TAU(i) of the
          elementary reflectors H(i) as returned by PZGELQF.
          TAU is tied to the distributed matrix A.
  C       (local input/local output) COMPLEX*16 pointer into the
          local memory to an array of dimension (LLD_C,LOCc(JC+N-1)).
          On entry, the local pieces of the distributed matrix sub(C).
          On exit, sub( C ) is overwritten by Q*sub( C ) or Q'*sub( C )
          or sub( C )*Q' or sub( C )*Q.
  IC      (global input) INTEGER
          The row index in the global array C indicating the first
          row of sub( C ).
  JC      (global input) INTEGER
          The column index in the global array C indicating the
          first column of sub( C ).
  DESCC   (global and local input) INTEGER array of dimension DLEN_.
          The array descriptor for the distributed matrix C.
  WORK    (local workspace/local output) COMPLEX*16 array,
                                                     dimension (LWORK)
          On exit, WORK(1) returns the minimal and optimal LWORK.
  LWORK   (local or global input) INTEGER
          The dimension of the array WORK.
          LWORK is local input and must be at least
          if SIDE = 'L',
            LWORK >= MAX( (MB_A*(MB_A-1))/2, ( MpC0 + MAX( MqA0 +
                     NUMROC( NUMROC( M+IROFFC, MB_A, 0, 0, NPROW ),
                             MB_A, 0, 0, LCMP ), NqC0 ) )*MB_A ) +
                     MB_A * MB_A
          else if SIDE = 'R',
            LWORK >= MAX( (MB_A*(MB_A-1))/2, (MpC0 + NqC0)*MB_A ) +
                     MB_A * MB_A
          end if
          where LCMP = LCM / NPROW with LCM = ICLM( NPROW, NPCOL ),
          IROFFA = MOD( IA-1, MB_A ), ICOFFA = MOD( JA-1, NB_A ),
          IACOL = INDXG2P( JA, NB_A, MYCOL, CSRC_A, NPCOL ),
          MqA0 = NUMROC( M+ICOFFA, NB_A, MYCOL, IACOL, NPCOL ),
          IROFFC = MOD( IC-1, MB_C ), ICOFFC = MOD( JC-1, NB_C ),
          ICROW = INDXG2P( IC, MB_C, MYROW, RSRC_C, NPROW ),
          ICCOL = INDXG2P( JC, NB_C, MYCOL, CSRC_C, NPCOL ),
          MpC0 = NUMROC( M+IROFFC, MB_C, MYROW, ICROW, NPROW ),
          NqC0 = NUMROC( N+ICOFFC, NB_C, MYCOL, ICCOL, NPCOL ),
          ILCM, INDXG2P and NUMROC are ScaLAPACK tool functions;
          MYROW, MYCOL, NPROW and NPCOL can be determined by calling
          the subroutine BLACS_GRIDINFO.
          If LWORK = -1, then LWORK is global input and a workspace
          query is assumed; the routine only calculates the minimum
          and optimal size for all work arrays. Each of these
          values is returned in the first entry of the corresponding
          work array, and no error message is issued by PXERBLA.
  INFO    (global output) INTEGER
          = 0:  successful exit
          < 0:  If the i-th argument is an array and the j-entry had
                an illegal value, then INFO = -(i*100+j), if the i-th
                argument is a scalar and had an illegal value, then
                INFO = -i.
  Alignment requirements
  ======================
  The distributed submatrices A(IA:*, JA:*) and C(IC:IC+M-1,JC:JC+N-1)
  must verify some alignment properties, namely the following
  expressions should be true:
  If SIDE = 'L',
    ( NB_A.EQ.MB_C .AND. ICOFFA.EQ.IROFFC )
  If SIDE = 'R',
    ( NB_A.EQ.NB_C .AND. ICOFFA.EQ.ICOFFC .AND. IACOL.EQ.ICCOL )
  =====================================================================
     .. Parameters ..

 
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001        SUBROUTINE PZUNMLQ( SIDE , TRANS , M , N , K , A , IA , JA , DESCA , TAU ,
002       $C , IC , JC , DESCC , WORK , LWORK , INFO )
003  
004  *     -- ScaLAPACK routine(version 1.7) --
005  *     University of Tennessee , Knoxville , Oak Ridge National Laboratory ,
006  *     and University of California , Berkeley.
007  *     May 25 , 2001
008  
009  *     .. Scalar Arguments ..
010        CHARACTER SIDE , TRANS
011        INTEGER IA , IC , INFO , JA , JC , K , LWORK , M , N
012        INTEGER BLOCK_CYCLIC_2D , CSRC_ , CTXT_ , DLEN_ , DTYPE_ ,
013       $LLD_ , MB_ , M_ , NB_ , N_ , RSRC_
014        PARAMETER( BLOCK_CYCLIC_2D = 1 , DLEN_ = 9 , DTYPE_ = 1 ,
015       $CTXT_ = 2 , M_ = 3 , N_ = 4 , MB_ = 5 , NB_ = 6 ,
016       $RSRC_ = 7 , CSRC_ = 8 , LLD_ = 9 )
017  *     ..
018  *     .. Local Scalars ..
019        LOGICAL LEFT , LQUERY , NOTRAN
020        CHARACTER COLBTOP , ROWBTOP , TRANST
021        INTEGER I , I1 , I2 , I3 , IACOL , IB , ICC , ICCOL , ICOFFA ,
022       $ICOFFC , ICROW , ICTXT , IINFO , IPW , IROFFC , JCC ,
023       $LCM , LCMP , LWMIN , MI , MPC0 , MQA0 , MYCOL , MYROW ,
024       $NI , NPCOL , NPROW , NQ , NQC0
025  *     ..
026  *     .. Local Arrays ..
027        INTEGER IDUM1( 4 ) , IDUM2( 4 )
028  *     ..
029  *     .. External Subroutines ..
030        EXTERNAL BLACS_GRIDINFO , CHK1MAT , PCHK2MAT , PB_TOPGET ,
031       $PB_TOPSET , PXERBLA , PZLARFB , PZLARFT ,
032       $PZUNML2  
033  *     ..
034  *     .. External Functions ..
035        LOGICAL LSAME
036        INTEGER ICEIL , ILCM , INDXG2P , NUMROC
037        EXTERNAL ICEIL , ILCM , INDXG2P , LSAME , NUMROC
038  *     ..
039  *     .. Intrinsic Functions ..
040        INTRINSIC DBLE , DCMPLX , ICHAR , MAX , MIN , MOD
041  *     ..
042  *     .. Executable Statements ..
043  
044  *     Get grid parameters
045  
046        ICTXT = DESCA( CTXT_ )
047        CALL BLACS_GRIDINFO( ICTXT , NPROW , NPCOL , MYROW , MYCOL )
048  
049  *     Test the input parameters
050  
051        INFO = 0
052        IF( NPROW.EQ. - 1 ) THEN
053            INFO = - (900 + CTXT_)
054        ELSE
055            LEFT = LSAME( SIDE , 'L' )
056            NOTRAN = LSAME( TRANS , 'N' )
057  
058  *         NQ is the order of Q
059  
060            IF( LEFT ) THEN
061                NQ = M
062                CALL CHK1MAT( K , 5 , M , 3 , IA , JA , DESCA , 9 , INFO )
063            ELSE
064                NQ = N
065                CALL CHK1MAT( K , 5 , N , 4 , IA , JA , DESCA , 9 , INFO )
066            END IF
067            CALL CHK1MAT( M , 3 , N , 4 , IC , JC , DESCC , 14 , INFO )
068            IF( INFO.EQ.0 ) THEN
069                ICOFFA = MOD( JA - 1 , DESCA( NB_ ) )
070                IROFFC = MOD( IC - 1 , DESCC( MB_ ) )
071                ICOFFC = MOD( JC - 1 , DESCC( NB_ ) )
072                IACOL = INDXG2P( JA , DESCA( NB_ ) , MYCOL , DESCA( CSRC_ ) ,
073       $        NPCOL )
074                ICROW = INDXG2P( IC , DESCC( MB_ ) , MYROW , DESCC( RSRC_ ) ,
075       $        NPROW )
076                ICCOL = INDXG2P( JC , DESCC( NB_ ) , MYCOL , DESCC( CSRC_ ) ,
077       $        NPCOL )
078                MPC0 = NUMROC( M + IROFFC , DESCC( MB_ ) , MYROW , ICROW , NPROW )
079                NQC0 = NUMROC( N + ICOFFC , DESCC( NB_ ) , MYCOL , ICCOL , NPCOL )
080  
081                IF( LEFT ) THEN
082                    MQA0 = NUMROC( M + ICOFFA , DESCA( NB_ ) , MYCOL , IACOL ,
083       $            NPCOL )
084                    LCM = ILCM( NPROW , NPCOL )
085                    LCMP = LCM / NPROW
086                    LWMIN = MAX(( DESCA( MB_ ) * ( DESCA( MB_ ) - 1 ) )
087       $            / 2 ,( MPC0 + MAX( MQA0 + NUMROC( NUMROC(
088       $            M + IROFFC , DESCA( MB_ ) , 0 , 0 , NPROW ) ,
089       $            DESCA( MB_ ) , 0 , 0 , LCMP ) , NQC0 ) ) *
090       $            DESCA( MB_ ) ) + DESCA( MB_ ) * DESCA( MB_ )
091                ELSE
092                    LWMIN = MAX(( DESCA( MB_ ) * ( DESCA( MB_ ) - 1 ) ) / 2 ,
093       $( MPC0 + NQC0 ) * DESCA( MB_ ) ) +
094       $            DESCA( MB_ ) * DESCA( MB_ )
095                END IF
096  
097                WORK( 1 ) = DCMPLX( DBLE( LWMIN ) )
098                LQUERY =( LWORK.EQ. - 1 )
099                IF( .NOT.LEFT .AND. .NOT.LSAME( SIDE , 'R' ) ) THEN
100                    INFO = - 1
101                ELSE IF( .NOT.NOTRAN .AND. .NOT.LSAME( TRANS , 'C' ) ) THEN
102                    INFO = - 2
103                ELSE IF( K.LT.0 .OR. K.GT.NQ ) THEN
104                    INFO = - 5
105                ELSE IF( LEFT .AND. DESCA( NB_ ).NE.DESCC( MB_ ) ) THEN
106                    INFO = - (900 + NB_)
107                ELSE IF( LEFT .AND. ICOFFA.NE.IROFFC ) THEN
108                    INFO = - 12
109                ELSE IF( .NOT.LEFT .AND. ICOFFA.NE.ICOFFC ) THEN
110                    INFO = - 13
111                ELSE IF( .NOT.LEFT .AND. IACOL.NE.ICCOL ) THEN
112                    INFO = - 13
113                ELSE IF( .NOT.LEFT .AND. DESCA( NB_ ).NE.DESCC( NB_ ) ) THEN
114                    INFO = - (1400 + NB_)
115                ELSE IF( ICTXT.NE.DESCC( CTXT_ ) ) THEN
116                    INFO = - (1400 + CTXT_)
117                ELSE IF( LWORK.LT.LWMIN .AND. .NOT.LQUERY ) THEN
118                    INFO = - 16
119                END IF
120            END IF
121            IF( LEFT ) THEN
122                IDUM1( 1 ) = ICHAR( 'L' )
123            ELSE
124                IDUM1( 1 ) = ICHAR( 'R' )
125            END IF
126            IDUM2( 1 ) = 1
127            IF( NOTRAN ) THEN
128                IDUM1( 2 ) = ICHAR( 'N' )
129            ELSE
130                IDUM1( 2 ) = ICHAR( 'C' )
131            END IF
132            IDUM2( 2 ) = 2
133            IDUM1( 3 ) = K
134            IDUM2( 3 ) = 5
135            IF( LWORK.EQ. - 1 ) THEN
136                IDUM1( 4 ) = - 1
137            ELSE
138                IDUM1( 4 ) = 1
139            END IF
140            IDUM2( 4 ) = 16
141            IF( LEFT ) THEN
142                CALL PCHK2MAT( K , 5 , M , 3 , IA , JA , DESCA , 9 , M , 3 , N , 4 , IC ,
143       $        JC , DESCC , 14 , 4 , IDUM1 , IDUM2 , INFO )
144            ELSE
145                CALL PCHK2MAT( K , 5 , N , 4 , IA , JA , DESCA , 9 , M , 3 , N , 4 , IC ,
146       $        JC , DESCC , 14 , 4 , IDUM1 , IDUM2 , INFO )
147            END IF
148        END IF
149  
150        IF( INFO.NE.0 ) THEN
151            CALL PXERBLA( ICTXT , 'PZUNMLQ' , - INFO )
152            RETURN
153        ELSE IF( LQUERY ) THEN
154            RETURN
155        END IF
156  
157  *     Quick return if possible
158  
159        IF( M.EQ.0 .OR. N.EQ.0 .OR. K.EQ.0 )
160       $    RETURN
161  
162            CALL PB_TOPGET( ICTXT , 'Broadcast' , 'Rowwise' , ROWBTOP )
163            CALL PB_TOPGET( ICTXT , 'Broadcast' , 'Columnwise' , COLBTOP )
164  
165            IF(( LEFT .AND. NOTRAN ) .OR.
166       $( .NOT.LEFT .AND. .NOT.NOTRAN ) ) THEN
167            I1 = MIN( ICEIL( IA , DESCA( MB_ ) ) * DESCA( MB_ ) , IA + K - 1 )
168       $    + 1
169            I2 = IA + K - 1
170            I3 = DESCA( MB_ )
171        ELSE
172            I1 = MAX(((IA + K - 2) / DESCA( MB_ ) ) * DESCA( MB_ ) + 1 , IA )
173            I2 = MIN( ICEIL( IA , DESCA( MB_ ) ) * DESCA( MB_ ) , IA + K - 1 )
174       $    + 1
175            I3 = - DESCA( MB_ )
176        END IF
177  
178        IF( LEFT ) THEN
179            NI = N
180            JCC = JC
181        ELSE
182            MI = M
183            ICC = IC
184            CALL PB_TOPSET( ICTXT , 'Broadcast' , 'Rowwise' , ' ' )
185            IF( NOTRAN ) THEN
186                CALL PB_TOPSET( ICTXT , 'Broadcast' , 'Columnwise' , 'D - ring' )
187            ELSE
188                CALL PB_TOPSET( ICTXT , 'Broadcast' , 'Columnwise' , 'I - ring' )
189            END IF
190        END IF
191  
192        IF( NOTRAN ) THEN
193            TRANST = 'C'
194        ELSE
195            TRANST = 'N'
196        END IF
197  
198        IF(( LEFT .AND. NOTRAN ) .OR.( .NOT.LEFT .AND. .NOT.NOTRAN ) )
199       $    CALL PZUNML2 ( SIDE , TRANS , M , N , I1 - IA , A , IA , JA , DESCA , TAU ,
200       $    C , IC , JC , DESCC , WORK , LWORK , IINFO )
201  
202            IPW = DESCA( MB_ ) * DESCA( MB_ ) + 1
203            DO 10 I = I1 , I2 , I3
204                IB = MIN( DESCA( MB_ ) , K - I + IA )
205  
206  *             Form the triangular factor of the block reflector
207  *             H = H(i) H(i + 1) . . . H(i + ib - 1)
208  
209                CALL PZLARFT ( 'Forward' , 'Rowwise' , NQ - I + IA , IB , A , I , JA + I - IA ,
210       $        DESCA , TAU , WORK , WORK( IPW ) )
211                IF( LEFT ) THEN
212  
213  *                 H or H' is applied to C(ic + i - ia : ic + m - 1 , jc : jc + n - 1)
214  
215                    MI = M - I + IA
216                    ICC = IC + I - IA
217                ELSE
218  
219  *                 H or H' is applied to C(ic : ic + m - 1 , jc + i - ia : jc + n - 1)
220  
221                    NI = N - I + IA
222                    JCC = JC + I - IA
223                END IF
224  
225  *             Apply H or H'
226  
227                CALL PZLARFB ( SIDE , TRANST , 'Forward' , 'Rowwise' , MI , NI , IB ,
228       $        A , I , JA + I - IA , DESCA , WORK , C , ICC , JCC , DESCC ,
229       $        WORK( IPW ) )
230     10     CONTINUE
231  
232            IF(( LEFT .AND. .NOT.NOTRAN ) .OR.( .NOT.LEFT .AND. NOTRAN ) )
233       $        CALL PZUNML2 ( SIDE , TRANS , M , N , I2 - IA , A , IA , JA , DESCA , TAU ,
234       $        C , IC , JC , DESCC , WORK , LWORK , IINFO )
235  
236                CALL PB_TOPSET( ICTXT , 'Broadcast' , 'Rowwise' , ROWBTOP )
237                CALL PB_TOPSET( ICTXT , 'Broadcast' , 'Columnwise' , COLBTOP )
238  
239                WORK( 1 ) = DCMPLX( DBLE( LWMIN ) )
240  
241                RETURN
242  
243  *             End of PZUNMLQ
244  
245            END