Routine: PSORMRZ()  File: SRC\psormrz.f

 
 
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# Variables:67
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# Callings:3
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# Keywords:181
 

 

..
     .. Array Arguments ..
     ..
  Purpose
  =======
  PSORMRZ 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(1) H(2) . . . H(k)
  as returned by PSTZRZF. 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.
  L       (global input) INTEGER
          The columns of the distributed submatrix sub( A ) containing
          the meaningful part of the Householder reflectors.
          If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 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 PSTZRZF 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 PSTZRZF.
          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 PSORMRZ( SIDE , TRANS , M , N , K , L , A , IA , JA , DESCA ,
002       $TAU , 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 , L , 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 , JAA ,
023       $JCC , LCM , LCMP , LWMIN , MI , MPC0 , MQA0 , MYCOL ,
024       $MYROW , NI , NPCOL , NPROW , NQ , NQC0
025  *     ..
026  *     .. Local Arrays ..
027        INTEGER IDUM1( 5 ) , IDUM2( 5 )
028  *     ..
029  *     .. External Subroutines ..
030        EXTERNAL BLACS_GRIDINFO , CHK1MAT , PCHK2MAT , PSLARZB ,
031       $PSLARZT , PSORMR3 , 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 , 10 , INFO )
062            ELSE
063                NQ = N
064                CALL CHK1MAT( K , 5 , N , 4 , IA , JA , DESCA , 10 , INFO )
065            END IF
066            CALL CHK1MAT( M , 3 , N , 4 , IC , JC , DESCC , 15 , 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( K.LT.0 .OR. K.GT.NQ ) THEN
105                    INFO = - 6
106                ELSE IF( LEFT .AND. DESCA( NB_ ).NE.DESCC( MB_ ) ) THEN
107                    INFO = - (1000 + NB_)
108                ELSE IF( LEFT .AND. ICOFFA.NE.IROFFC ) THEN
109                    INFO = - 13
110                ELSE IF( .NOT.LEFT .AND. ICOFFA.NE.ICOFFC ) THEN
111                    INFO = - 14
112                ELSE IF( .NOT.LEFT .AND. IACOL.NE.ICCOL ) THEN
113                    INFO = - 14
114                ELSE IF( .NOT.LEFT .AND. DESCA( NB_ ).NE.DESCC( NB_ ) ) THEN
115                    INFO = - (1500 + NB_)
116                ELSE IF( ICTXT.NE.DESCC( CTXT_ ) ) THEN
117                    INFO = - (1500 + CTXT_)
118                ELSE IF( LWORK.LT.LWMIN .AND. .NOT.LQUERY ) THEN
119                    INFO = - 17
120                END IF
121            END IF
122            IF( LEFT ) THEN
123                IDUM1( 1 ) = ICHAR( 'L' )
124            ELSE
125                IDUM1( 1 ) = ICHAR( 'R' )
126            END IF
127            IDUM2( 1 ) = 1
128            IF( NOTRAN ) THEN
129                IDUM1( 2 ) = ICHAR( 'N' )
130            ELSE
131                IDUM1( 2 ) = ICHAR( 'T' )
132            END IF
133            IDUM2( 2 ) = 2
134            IDUM1( 3 ) = K
135            IDUM2( 3 ) = 5
136            IDUM1( 4 ) = L
137            IDUM2( 4 ) = 6
138            IF( LWORK.EQ. - 1 ) THEN
139                IDUM1( 5 ) = - 1
140            ELSE
141                IDUM1( 5 ) = 1
142            END IF
143            IDUM2( 5 ) = 17
144            IF( LEFT ) THEN
145                CALL PCHK2MAT( K , 5 , M , 3 , IA , JA , DESCA , 10 , M , 3 , N , 4 ,
146       $        IC , JC , DESCC , 15 , 5 , IDUM1 , IDUM2 , INFO )
147            ELSE
148                CALL PCHK2MAT( K , 5 , N , 4 , IA , JA , DESCA , 10 , M , 3 , N , 4 ,
149       $        IC , JC , DESCC , 15 , 5 , IDUM1 , IDUM2 , INFO )
150            END IF
151        END IF
152  
153        IF( INFO.NE.0 ) THEN
154            CALL PXERBLA( ICTXT , 'PSORMRZ' , - INFO )
155            RETURN
156        ELSE IF( LQUERY ) THEN
157            RETURN
158        END IF
159  
160  *     Quick return if possible
161  
162        IF( M.EQ.0 .OR. N.EQ.0 .OR. K.EQ.0 )
163       $    RETURN
164  
165            CALL PB_TOPGET( ICTXT , 'Broadcast' , 'Rowwise' , ROWBTOP )
166            CALL PB_TOPGET( ICTXT , 'Broadcast' , 'Columnwise' , COLBTOP )
167  
168            IF(( LEFT .AND. .NOT.NOTRAN ) .OR.
169       $( .NOT.LEFT .AND. NOTRAN ) ) THEN
170            I1 = MIN( ICEIL( IA , DESCA( MB_ ) ) * DESCA( MB_ ) , IA + K - 1 )
171       $    + 1
172            I2 = IA + K - 1
173            I3 = DESCA( MB_ )
174        ELSE
175            I1 = MAX(((IA + K - 2) / DESCA( MB_ ) ) * DESCA( MB_ ) + 1 , IA )
176            I2 = MIN( ICEIL( IA , DESCA( MB_ ) ) * DESCA( MB_ ) , IA + K - 1 )
177       $    + 1
178            I3 = - DESCA( MB_ )
179        END IF
180  
181        IF( LEFT ) THEN
182            NI = N
183            JCC = JC
184            JAA = JA + M - L
185        ELSE
186            MI = M
187            ICC = IC
188            JAA = JA + N - L
189            CALL PB_TOPSET( ICTXT , 'Broadcast' , 'Rowwise' , ' ' )
190            IF( NOTRAN ) THEN
191                CALL PB_TOPSET( ICTXT , 'Broadcast' , 'Columnwise' , 'I - ring' )
192            ELSE
193                CALL PB_TOPSET( ICTXT , 'Broadcast' , 'Columnwise' , 'D - ring' )
194            END IF
195        END IF
196  
197        IF( NOTRAN ) THEN
198            TRANST = 'T'
199        ELSE
200            TRANST = 'N'
201        END IF
202  
203        IF(( LEFT .AND. .NOT.NOTRAN ) .OR.
204       $( .NOT.LEFT .AND. NOTRAN ) ) THEN
205        IB = I1 - IA
206        IF( LEFT ) THEN
207            MI = M
208        ELSE
209            NI = N
210        END IF
211        CALL PSORMR3 ( SIDE , TRANS , MI , NI , IB , L , A , IA , JA , DESCA ,
212       $TAU , C , IC , JC , DESCC , WORK , LWORK , IINFO )
213        END IF
214  
215        IPW = DESCA( MB_ )*DESCA( MB_ ) + 1
216        DO 10 I = I1 , I2 , I3
217            IB = MIN( DESCA( MB_ ) , K - I + IA )
218  
219  *         Form the triangular factor of the block reflector
220  *         H = H(i + ib - 1) . . . H(i + 1) H(i)
221  
222            CALL PSLARZT ( 'Backward' , 'Rowwise' , L , IB , A , I , JAA , DESCA ,
223       $    TAU , WORK , WORK( IPW ) )
224            IF( LEFT ) THEN
225  
226  *             H or H' is applied to C(ic + i - ia : ic + m - 1 , jc : jc + n - 1)
227  
228                MI = M - I + IA
229                ICC = IC + I - IA
230            ELSE
231  
232  *             H or H' is applied to C(ic : ic + m - 1 , jc + i - ia : jc + n - 1)
233  
234                NI = N - I + IA
235                JCC = JC + I - IA
236            END IF
237  
238  *         Apply H or H'
239  
240            CALL PSLARZB ( SIDE , TRANST , 'Backward' , 'Rowwise' , MI , NI , IB ,
241       $    L , A , I , JAA , DESCA , WORK , C , ICC , JCC , DESCC ,
242       $    WORK( IPW ) )
243     10 CONTINUE
244  
245        IF(( LEFT .AND. .NOT.NOTRAN ) .OR.
246       $( .NOT.LEFT .AND. NOTRAN ) ) THEN
247        IB = I2 - IA
248        IF( LEFT ) THEN
249            MI = M
250        ELSE
251            NI = N
252        END IF
253        CALL PSORMR3 ( SIDE , TRANS , MI , NI , IB , L , A , IA , JA , DESCA ,
254       $TAU , C , IC , JC , DESCC , WORK , LWORK , IINFO )
255        END IF
256  
257        CALL PB_TOPSET( ICTXT , 'Broadcast' , 'Rowwise' , ROWBTOP )
258        CALL PB_TOPSET( ICTXT , 'Broadcast' , 'Columnwise' , COLBTOP )
259  
260        WORK( 1 ) = REAL( LWMIN )
261  
262        RETURN
263  
264  *     End of PSORMRZ
265  
266        END