Routine: PSORMLQ()  File: SRC\psormlq.f

 
 
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..
     .. Array Arguments ..
     ..
  Purpose
  =======
  PSORMLQ overwrites the general real 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 = 'T':      Q**T * sub( C )      sub( C ) * Q**T
  where Q is a real orthogonal distributed matrix defined as the
  product of K elementary reflectors
        Q = H(k) . . . H(2) H(1)
  as returned by PSGELQF. 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**T from the Left;
          = 'R': apply Q or Q**T from the Right.
  TRANS   (global input) CHARACTER
          = 'N':  No transpose, apply Q;
          = 'T':  Transpose, apply Q**T.
  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) REAL 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 PSGELQF 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) REAL, array, dimension LOCc(IA+K-1).
          This array contains the scalar factors TAU(i) of the
          elementary reflectors H(i) as returned by PSGELQF.
          TAU is tied to the distributed matrix A.
  C       (local input/local output) REAL 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) REAL 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 PSORMLQ( 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 , PSLARFB ,
031       $PSLARFT , PSORML2 , PB_TOPGET , PB_TOPSET , PXERBLA
032  *     ..
033  *     .. External Functions ..
034        LOGICAL LSAME
035        INTEGER ICEIL , ILCM , INDXG2P , NUMROC
036        EXTERNAL ICEIL , ILCM , INDXG2P , LSAME , NUMROC
037  *     ..
038  *     .. Intrinsic Functions ..
039        INTRINSIC ICHAR , MAX , MIN , MOD , REAL
040  *     ..
041  *     .. Executable Statements ..
042  
043  *     Get grid parameters
044  
045        ICTXT = DESCA( CTXT_ )
046        CALL BLACS_GRIDINFO( ICTXT , NPROW , NPCOL , MYROW , MYCOL )
047  
048  *     Test the input parameters
049  
050        INFO = 0
051        IF( NPROW.EQ. - 1 ) THEN
052            INFO = - (900 + CTXT_)
053        ELSE
054            LEFT = LSAME( SIDE , 'L' )
055            NOTRAN = LSAME( TRANS , 'N' )
056  
057  *         NQ is the order of Q
058  
059            IF( LEFT ) THEN
060                NQ = M
061                CALL CHK1MAT( K , 5 , M , 3 , IA , JA , DESCA , 9 , INFO )
062            ELSE
063                NQ = N
064                CALL CHK1MAT( K , 5 , N , 4 , IA , JA , DESCA , 9 , INFO )
065            END IF
066            CALL CHK1MAT( M , 3 , N , 4 , IC , JC , DESCC , 14 , INFO )
067            IF( INFO.EQ.0 ) THEN
068                ICOFFA = MOD( JA - 1 , DESCA( NB_ ) )
069                IROFFC = MOD( IC - 1 , DESCC( MB_ ) )
070                ICOFFC = MOD( JC - 1 , DESCC( NB_ ) )
071                IACOL = INDXG2P( JA , DESCA( NB_ ) , MYCOL , DESCA( CSRC_ ) ,
072       $        NPCOL )
073                ICROW = INDXG2P( IC , DESCC( MB_ ) , MYROW , DESCC( RSRC_ ) ,
074       $        NPROW )
075                ICCOL = INDXG2P( JC , DESCC( NB_ ) , MYCOL , DESCC( CSRC_ ) ,
076       $        NPCOL )
077                MPC0 = NUMROC( M + IROFFC , DESCC( MB_ ) , MYROW , ICROW , NPROW )
078                NQC0 = NUMROC( N + ICOFFC , DESCC( NB_ ) , MYCOL , ICCOL , NPCOL )
079  
080                IF( LEFT ) THEN
081                    MQA0 = NUMROC( M + ICOFFA , DESCA( NB_ ) , MYCOL , IACOL ,
082       $            NPCOL )
083                    LCM = ILCM( NPROW , NPCOL )
084                    LCMP = LCM / NPROW
085                    LWMIN = MAX(( DESCA( MB_ ) * ( DESCA( MB_ ) - 1 ) )
086       $            / 2 ,( MPC0 + MAX( MQA0 + NUMROC( NUMROC(
087       $            M + IROFFC , DESCA( MB_ ) , 0 , 0 , NPROW ) ,
088       $            DESCA( MB_ ) , 0 , 0 , LCMP ) , NQC0 ) ) *
089       $            DESCA( MB_ ) ) + DESCA( MB_ ) * DESCA( MB_ )
090                ELSE
091                    LWMIN = MAX(( DESCA( MB_ ) * ( DESCA( MB_ ) - 1 ) ) / 2 ,
092       $( MPC0 + NQC0 ) * DESCA( MB_ ) ) +
093       $            DESCA( MB_ ) * DESCA( MB_ )
094                END IF
095  
096                WORK( 1 ) = REAL( LWMIN )
097                LQUERY =( LWORK.EQ. - 1 )
098                IF( .NOT.LEFT .AND. .NOT.LSAME( SIDE , 'R' ) ) THEN
099                    INFO = - 1
100                ELSE IF( .NOT.NOTRAN .AND. .NOT.LSAME( TRANS , 'T' ) ) THEN
101                    INFO = - 2
102                ELSE IF( K.LT.0 .OR. K.GT.NQ ) THEN
103                    INFO = - 5
104                ELSE IF( LEFT .AND. DESCA( NB_ ).NE.DESCC( MB_ ) ) THEN
105                    INFO = - (900 + NB_)
106                ELSE IF( LEFT .AND. ICOFFA.NE.IROFFC ) THEN
107                    INFO = - 12
108                ELSE IF( .NOT.LEFT .AND. ICOFFA.NE.ICOFFC ) THEN
109                    INFO = - 13
110                ELSE IF( .NOT.LEFT .AND. IACOL.NE.ICCOL ) THEN
111                    INFO = - 13
112                ELSE IF( .NOT.LEFT .AND. DESCA( NB_ ).NE.DESCC( NB_ ) ) THEN
113                    INFO = - (1400 + NB_)
114                ELSE IF( ICTXT.NE.DESCC( CTXT_ ) ) THEN
115                    INFO = - (1400 + CTXT_)
116                ELSE IF( LWORK.LT.LWMIN .AND. .NOT.LQUERY ) THEN
117                    INFO = - 16
118                END IF
119            END IF
120            IF( LEFT ) THEN
121                IDUM1( 1 ) = ICHAR( 'L' )
122            ELSE
123                IDUM1( 1 ) = ICHAR( 'R' )
124            END IF
125            IDUM2( 1 ) = 1
126            IF( NOTRAN ) THEN
127                IDUM1( 2 ) = ICHAR( 'N' )
128            ELSE
129                IDUM1( 2 ) = ICHAR( 'T' )
130            END IF
131            IDUM2( 2 ) = 2
132            IDUM1( 3 ) = K
133            IDUM2( 3 ) = 5
134            IF( LWORK.EQ. - 1 ) THEN
135                IDUM1( 4 ) = - 1
136            ELSE
137                IDUM1( 4 ) = 1
138            END IF
139            IDUM2( 4 ) = 16
140            IF( LEFT ) THEN
141                CALL PCHK2MAT( K , 5 , M , 3 , IA , JA , DESCA , 9 , M , 3 , N , 4 , IC ,
142       $        JC , DESCC , 14 , 4 , IDUM1 , IDUM2 , INFO )
143            ELSE
144                CALL PCHK2MAT( K , 5 , N , 4 , IA , JA , DESCA , 9 , M , 3 , N , 4 , IC ,
145       $        JC , DESCC , 14 , 4 , IDUM1 , IDUM2 , INFO )
146            END IF
147        END IF
148  
149        IF( INFO.NE.0 ) THEN
150            CALL PXERBLA( ICTXT , 'PSORMLQ' , - INFO )
151            RETURN
152        ELSE IF( LQUERY ) THEN
153            RETURN
154        END IF
155  
156  *     Quick return if possible
157  
158        IF( M.EQ.0 .OR. N.EQ.0 .OR. K.EQ.0 )
159       $    RETURN
160  
161            CALL PB_TOPGET( ICTXT , 'Broadcast' , 'Rowwise' , ROWBTOP )
162            CALL PB_TOPGET( ICTXT , 'Broadcast' , 'Columnwise' , COLBTOP )
163  
164            IF(( LEFT .AND. NOTRAN ) .OR.
165       $( .NOT.LEFT .AND. .NOT.NOTRAN ) ) THEN
166            I1 = MIN( ICEIL( IA , DESCA( MB_ ) ) * DESCA( MB_ ) , IA + K - 1 )
167       $    + 1
168            I2 = IA + K - 1
169            I3 = DESCA( MB_ )
170        ELSE
171            I1 = MAX(((IA + K - 2) / DESCA( MB_ ) ) * DESCA( MB_ ) + 1 , IA )
172            I2 = MIN( ICEIL( IA , DESCA( MB_ ) ) * DESCA( MB_ ) , IA + K - 1 )
173       $    + 1
174            I3 = - DESCA( MB_ )
175        END IF
176  
177        IF( LEFT ) THEN
178            NI = N
179            JCC = JC
180        ELSE
181            MI = M
182            ICC = IC
183            CALL PB_TOPSET( ICTXT , 'Broadcast' , 'Rowwise' , ' ' )
184            IF( NOTRAN ) THEN
185                CALL PB_TOPSET( ICTXT , 'Broadcast' , 'Columnwise' , 'D - ring' )
186            ELSE
187                CALL PB_TOPSET( ICTXT , 'Broadcast' , 'Columnwise' , 'I - ring' )
188            END IF
189        END IF
190  
191        IF( NOTRAN ) THEN
192            TRANST = 'T'
193        ELSE
194            TRANST = 'N'
195        END IF
196  
197        IF(( LEFT .AND. NOTRAN ) .OR.( .NOT.LEFT .AND. .NOT.NOTRAN ) )
198       $    CALL PSORML2 ( SIDE , TRANS , M , N , I1 - IA , A , IA , JA , DESCA , TAU ,
199       $    C , IC , JC , DESCC , WORK , LWORK , IINFO )
200  
201            IPW = DESCA( MB_ ) * DESCA( MB_ ) + 1
202            DO 10 I = I1 , I2 , I3
203                IB = MIN( DESCA( MB_ ) , K - I + IA )
204  
205  *             Form the triangular factor of the block reflector
206  *             H = H(i) H(i + 1) . . . H(i + ib - 1)
207  
208                CALL PSLARFT ( 'Forward' , 'Rowwise' , NQ - I + IA , IB , A , I , JA + I - IA ,
209       $        DESCA , TAU , WORK , WORK( IPW ) )
210                IF( LEFT ) THEN
211  
212  *                 H or H' is applied to C(ic + i - ia : ic + m - 1 , jc : jc + n - 1)
213  
214                    MI = M - I + IA
215                    ICC = IC + I - IA
216                ELSE
217  
218  *                 H or H' is applied to C(ic : ic + m - 1 , jc + i - ia : jc + n - 1)
219  
220                    NI = N - I + IA
221                    JCC = JC + I - IA
222                END IF
223  
224  *             Apply H or H'
225  
226                CALL PSLARFB ( SIDE , TRANST , 'Forward' , 'Rowwise' , MI , NI , IB ,
227       $        A , I , JA + I - IA , DESCA , WORK , C , ICC , JCC , DESCC ,
228       $        WORK( IPW ) )
229     10     CONTINUE
230  
231            IF(( LEFT .AND. .NOT.NOTRAN ) .OR.( .NOT.LEFT .AND. NOTRAN ) )
232       $        CALL PSORML2 ( SIDE , TRANS , M , N , I2 - IA , A , IA , JA , DESCA , TAU ,
233       $        C , IC , JC , DESCC , WORK , LWORK , IINFO )
234  
235                CALL PB_TOPSET( ICTXT , 'Broadcast' , 'Rowwise' , ROWBTOP )
236                CALL PB_TOPSET( ICTXT , 'Broadcast' , 'Columnwise' , COLBTOP )
237  
238                WORK( 1 ) = REAL( LWMIN )
239  
240                RETURN
241  
242  *             End of PSORMLQ
243  
244            END