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   10      CHARACTER          HOWMNY, SIDE
   11      INTEGER            INFO, M, MM, N
   12
   13
   14      LOGICAL            SELECT( * )
   15      INTEGER            DESCT( * ), DESCVL( * ), DESCVR( * )
   16      DOUBLE PRECISION   RWORK( * )
   17      COMPLEX*16         T( * ), VL( * ), VR( * ), WORK( * )
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  204      DOUBLE PRECISION   ZERO, ONE
  205      parameter( zero = 0.0d+0, one = 1.0d+0 )
  206      COMPLEX*16         CZERO, CONE
  207      parameter( czero = ( 0.0d+0, 0.0d+0 ),
  208     $                   cone = ( 1.0d+0, 0.0d+0 ) )
  209      INTEGER            BLOCK_CYCLIC_2D, DLEN_, DTYPE_, CTXT_, M_, N_,
  210     $                   MB_, NB_, RSRC_, CSRC_, LLD_
  211      parameter( block_cyclic_2d = 1, dlen_ = 9, dtype_ = 1,
  212     $                   ctxt_ = 2, m_ = 3, n_ = 4, mb_ = 5, nb_ = 6,
  213     $                   rsrc_ = 7, csrc_ = 8, lld_ = 9 )
  214
  215
  216      LOGICAL            ALLV, BOTHV, LEFTV, OVER, RIGHTV, SOMEV
  217      INTEGER            CONTXT, CSRC, I, ICOL, II, IROW, IS, ITMP1,
  218     $                   ITMP2, J, K, KI, LDT, LDVL, LDVR, LDW, MB,
  219     $                   MYCOL, MYROW, NB, NPCOL, NPROW, RSRC
  220      REAL               SELF
  221      DOUBLE PRECISION   OVFL, REMAXD, SCALE, SMLNUM, ULP, UNFL
  222      COMPLEX*16         CDUM, REMAXC, SHIFT
  223
  224
  225      INTEGER            DESCW( DLEN_ )
  226      DOUBLE PRECISION   SMIN( 1 )
  227
  228
  229      LOGICAL            LSAME
  230      DOUBLE PRECISION   PDLAMCH
  232
  233
  234      EXTERNAL           blacs_gridinfo, 
descinit, dgsum2d, igamn2d,
 
  237     $                   zgsum2d
  238
  239
  240      INTRINSIC          abs, dble, dcmplx, dconjg, dimag, 
max 
  241
  242
  243      DOUBLE PRECISION   CABS1
  244
  245
  246      cabs1( cdum ) = abs( dble( cdum ) ) + abs( dimag( cdum ) )
  247
  248
  249
  250
  251      IF( block_cyclic_2d*csrc_*ctxt_*dlen_*dtype_*lld_*mb_*m_*nb_*n_*
  252     $    rsrc_.LT.0 )RETURN
  253
  254      contxt = desct( ctxt_ )
  255      rsrc = desct( rsrc_ )
  256      csrc = desct( csrc_ )
  257      mb = desct( mb_ )
  258      nb = desct( nb_ )
  259      ldt = desct( lld_ )
  260      ldw = ldt
  261      ldvr = descvr( lld_ )
  262      ldvl = descvl( lld_ )
  263
  264      CALL blacs_gridinfo( contxt, nprow, npcol, myrow, mycol )
  265      self = myrow*npcol + mycol
  266
  267
  268
  269      bothv = 
lsame( side, 
'B' )
 
  270      rightv = 
lsame( side, 
'R' ) .OR. bothv
 
  271      leftv = 
lsame( side, 
'L' ) .OR. bothv
 
  272
  273      allv = 
lsame( howmny, 
'A' )
 
  274      over = 
lsame( howmny, 
'B' ) .OR. 
lsame( howmny, 
'O' )
 
  275      somev = 
lsame( howmny, 
'S' )
 
  276
  277
  278
  279
  280      IF( somev ) THEN
  281         m = 0
  282         DO 10 j = 1, n
  283            IF( SELECT( j ) )
  284     $         m = m + 1
  285   10    CONTINUE
  286      ELSE
  287         m = n
  288      END IF
  289
  290      info = 0
  291      IF( .NOT.rightv .AND. .NOT.leftv ) THEN
  292         info = -1
  293      ELSE IF( .NOT.allv .AND. .NOT.over .AND. .NOT.somev ) THEN
  294         info = -2
  295      ELSE IF( n.LT.0 ) THEN
  296         info = -4
  297      ELSE IF( mm.LT.m ) THEN
  298         info = -11
  299      END IF
  300      CALL igamn2d( contxt, 'ALL', ' ', 1, 1, info, 1, itmp1, itmp2, -1,
  301     $              -1, -1 )
  302      IF( info.LT.0 ) THEN
  303         CALL pxerbla( contxt, 
'PZTREVC', -info )
 
  304         RETURN
  305      END IF
  306
  307
  308
  309      IF( n.EQ.0 )
  310     $   RETURN
  311
  312
  313
  314      unfl = 
pdlamch( contxt, 
'Safe minimum' )
 
  315      ovfl = one / unfl
  316      CALL pdlabad( contxt, unfl, ovfl )
 
  317      ulp = 
pdlamch( contxt, 
'Precision' )
 
  318      smlnum = unfl*( n / ulp )
  319
  320
  321
  322      DO 20 i = 1, n
  323         CALL infog2l( i, i, desct, nprow, npcol, myrow, mycol, irow,
 
  324     $                 icol, itmp1, itmp2 )
  325         IF( ( myrow.EQ.itmp1 ) .AND. ( mycol.EQ.itmp2 ) ) THEN
  326            work( ldw+irow ) = t( ( icol-1 )*ldt+irow )
  327         END IF
  328   20 CONTINUE
  329
  330
  331
  332
  333
  334      rwork( 1 ) = zero
  335      DO 30 j = 2, n
  336         CALL pdzasum( j-1, rwork( j ), t, 1, j, desct, 1 )
  337   30 CONTINUE
  338
  339
  340      CALL dgsum2d( contxt, 'Row', ' ', n, 1, rwork, n, -1, -1 )
  341
  342      IF( rightv ) THEN
  343
  344
  345
  346
  347
  348         CALL descinit( descw, n, 1, nb, 1, rsrc, csrc, contxt, ldw,
 
  349     $                  info )
  350
  351         is = m
  352         DO 70 ki = n, 1, -1
  353
  354            IF( somev ) THEN
  355               IF( .NOT.SELECT( ki ) )
  356     $            GO TO 70
  357            END IF
  358
  359            smin( 1 ) = zero
  360            shift = czero
  361            CALL infog2l( ki, ki, desct, nprow, npcol, myrow, mycol,
 
  362     $                    irow, icol, itmp1, itmp2 )
  363            IF( ( myrow.EQ.itmp1 ) .AND. ( mycol.EQ.itmp2 ) ) THEN
  364               shift = t( ( icol-1 )*ldt+irow )
  365               smin( 1 ) = 
max( ulp*( cabs1( shift ) ), smlnum )
 
  366            END IF
  367            CALL dgsum2d( contxt, 'ALL', ' ', 1, 1, smin, 1, -1, -1 )
  368            CALL zgsum2d( contxt, 'ALL', ' ', 1, 1, shift, 1, -1, -1 )
  369
  370            CALL infog2l( 1, 1, descw, nprow, npcol, myrow, mycol, irow,
 
  371     $                    icol, itmp1, itmp2 )
  372            IF( ( myrow.EQ.itmp1 ) .AND. ( mycol.EQ.itmp2 ) ) THEN
  373               work( 1 ) = cone
  374            END IF
  375
  376
  377
  378
  379            IF( ki.GT.1 ) THEN
  380               CALL pzcopy( ki-1, t, 1, ki, desct, 1, work, 1, 1, descw,
  381     $                      1 )
  382            END IF
  383            DO 40 k = 1, ki - 1
  384               CALL infog2l( k, 1, descw, nprow, npcol, myrow, mycol,
 
  385     $                       irow, icol, itmp1, itmp2 )
  386               IF( myrow.EQ.itmp1 .AND. mycol.EQ.itmp2 ) THEN
  387                  work( irow ) = -work( irow )
  388               END IF
  389   40       CONTINUE
  390
  391
  392
  393
  394            DO 50 k = 1, ki - 1
  395               CALL infog2l( k, k, desct, nprow, npcol, myrow, mycol,
 
  396     $                       irow, icol, itmp1, itmp2 )
  397               IF( ( myrow.EQ.itmp1 ) .AND. ( mycol.EQ.itmp2 ) ) THEN
  398                  t( ( icol-1 )*ldt+irow ) = t( ( icol-1 )*ldt+irow ) -
  399     $               shift
  400                  IF( cabs1( t( ( icol-1 )*ldt+irow ) ).LT.smin( 1 ) )
  401     $            THEN
  402                     t( ( icol-1 )*ldt+irow ) = dcmplx( smin( 1 ) )
  403                  END IF
  404               END IF
  405   50       CONTINUE
  406
  407            IF( ki.GT.1 ) THEN
  408               CALL pzlattrs( 
'Upper', 
'No transpose', 
'Non-unit', 
'Y',
 
  409     $                        ki-1, t, 1, 1, desct, work, 1, 1, descw,
  410     $                        scale, rwork, info )
  411               CALL infog2l( ki, 1, descw, nprow, npcol, myrow, mycol,
 
  412     $                       irow, icol, itmp1, itmp2 )
  413               IF( myrow.EQ.itmp1 .AND. mycol.EQ.itmp2 ) THEN
  414                  work( irow ) = dcmplx( scale )
  415               END IF
  416            END IF
  417
  418
  419
  420            IF( .NOT.over ) THEN
  421               CALL pzcopy( ki, work, 1, 1, descw, 1, vr, 1, is, descvr,
  422     $                      1 )
  423
  424               CALL pzamax( ki, remaxc, ii, vr, 1, is, descvr, 1 )
  425               remaxd = one / 
max( cabs1( remaxc ), unfl )
 
  426               CALL pzdscal( ki, remaxd, vr, 1, is, descvr, 1 )
  427
  428               CALL pzlaset( 
' ', n-ki, 1, czero, czero, vr, ki+1, is,
 
  429     $                       descvr )
  430            ELSE
  431               IF( ki.GT.1 )
  432     $            CALL pzgemv( 'N', n, ki-1, cone, vr, 1, 1, descvr,
  433     $                         work, 1, 1, descw, 1, dcmplx( scale ),
  434     $                         vr, 1, ki, descvr, 1 )
  435
  436               CALL pzamax( n, remaxc, ii, vr, 1, ki, descvr, 1 )
  437               remaxd = one / 
max( cabs1( remaxc ), unfl )
 
  438               CALL pzdscal( n, remaxd, vr, 1, ki, descvr, 1 )
  439            END IF
  440
  441
  442
  443            DO 60 k = 1, ki - 1
  444               CALL infog2l( k, k, desct, nprow, npcol, myrow, mycol,
 
  445     $                       irow, icol, itmp1, itmp2 )
  446               IF( ( myrow.EQ.itmp1 ) .AND. ( mycol.EQ.itmp2 ) ) THEN
  447                  t( ( icol-1 )*ldt+irow ) = work( ldw+irow )
  448               END IF
  449   60       CONTINUE
  450
  451            is = is - 1
  452   70    CONTINUE
  453      END IF
  454
  455      IF( leftv ) THEN
  456
  457
  458
  459
  460
  461         CALL descinit( descw, n, 1, mb, 1, rsrc, csrc, contxt, ldw,
 
  462     $                  info )
  463
  464         is = 1
  465         DO 110 ki = 1, n
  466
  467            IF( somev ) THEN
  468               IF( .NOT.SELECT( ki ) )
  469     $            GO TO 110
  470            END IF
  471
  472            smin( 1 ) = zero
  473            shift = czero
  474            CALL infog2l( ki, ki, desct, nprow, npcol, myrow, mycol,
 
  475     $                    irow, icol, itmp1, itmp2 )
  476            IF( ( myrow.EQ.itmp1 ) .AND. ( mycol.EQ.itmp2 ) ) THEN
  477               shift = t( ( icol-1 )*ldt+irow )
  478               smin( 1 ) = 
max( ulp*( cabs1( shift ) ), smlnum )
 
  479            END IF
  480            CALL dgsum2d( contxt, 'ALL', ' ', 1, 1, smin, 1, -1, -1 )
  481            CALL zgsum2d( contxt, 'ALL', ' ', 1, 1, shift, 1, -1, -1 )
  482
  483            CALL infog2l( n, 1, descw, nprow, npcol, myrow, mycol, irow,
 
  484     $                    icol, itmp1, itmp2 )
  485            IF( ( myrow.EQ.itmp1 ) .AND. ( mycol.EQ.itmp2 ) ) THEN
  486               work( irow ) = cone
  487            END IF
  488
  489
  490
  491            IF( ki.LT.n ) THEN
  492               CALL pzcopy( n-ki, t, ki, ki+1, desct, n, work, ki+1, 1,
  493     $                      descw, 1 )
  494            END IF
  495            DO 80 k = ki + 1, n
  496               CALL infog2l( k, 1, descw, nprow, npcol, myrow, mycol,
 
  497     $                       irow, icol, itmp1, itmp2 )
  498               IF( myrow.EQ.itmp1 .AND. mycol.EQ.itmp2 ) THEN
  499                  work( irow ) = -dconjg( work( irow ) )
  500               END IF
  501   80       CONTINUE
  502
  503
  504
  505
  506            DO 90 k = ki + 1, n
  507               CALL infog2l( k, k, desct, nprow, npcol, myrow, mycol,
 
  508     $                       irow, icol, itmp1, itmp2 )
  509               IF( ( myrow.EQ.itmp1 ) .AND. ( mycol.EQ.itmp2 ) ) THEN
  510                  t( ( icol-1 )*ldt+irow ) = t( ( icol-1 )*ldt+irow ) -
  511     $               shift
  512                  IF( cabs1( t( ( icol-1 )*ldt+irow ) ).LT.smin( 1 ) )
  513     $               t( ( icol-1 )*ldt+irow ) = dcmplx( smin( 1 ) )
  514               END IF
  515   90       CONTINUE
  516
  517            IF( ki.LT.n ) THEN
  518               CALL pzlattrs( 
'Upper', 
'Conjugate transpose', 
'Nonunit',
 
  519     $                        'Y', n-ki, t, ki+1, ki+1, desct, work,
  520     $                        ki+1, 1, descw, scale, rwork, info )
  521               CALL infog2l( ki, 1, descw, nprow, npcol, myrow, mycol,
 
  522     $                       irow, icol, itmp1, itmp2 )
  523               IF( myrow.EQ.itmp1 .AND. mycol.EQ.itmp2 ) THEN
  524                  work( irow ) = dcmplx( scale )
  525               END IF
  526            END IF
  527
  528
  529
  530            IF( .NOT.over ) THEN
  531               CALL pzcopy( n-ki+1, work, ki, 1, descw, 1, vl, ki, is,
  532     $                      descvl, 1 )
  533
  534               CALL pzamax( n-ki+1, remaxc, ii, vl, ki, is, descvl, 1 )
  535               remaxd = one / 
max( cabs1( remaxc ), unfl )
 
  536               CALL pzdscal( n-ki+1, remaxd, vl, ki, is, descvl, 1 )
  537
  538               CALL pzlaset( 
' ', ki-1, 1, czero, czero, vl, 1, is,
 
  539     $                       descvl )
  540            ELSE
  541               IF( ki.LT.n )
  542     $            CALL pzgemv( 'N', n, n-ki, cone, vl, 1, ki+1, descvl,
  543     $                         work, ki+1, 1, descw, 1, dcmplx( scale ),
  544     $                         vl, 1, ki, descvl, 1 )
  545
  546               CALL pzamax( n, remaxc, ii, vl, 1, ki, descvl, 1 )
  547               remaxd = one / 
max( cabs1( remaxc ), unfl )
 
  548               CALL pzdscal( n, remaxd, vl, 1, ki, descvl, 1 )
  549            END IF
  550
  551
  552
  553            DO 100 k = ki + 1, n
  554               CALL infog2l( k, k, desct, nprow, npcol, myrow, mycol,
 
  555     $                       irow, icol, itmp1, itmp2 )
  556               IF( ( myrow.EQ.itmp1 ) .AND. ( mycol.EQ.itmp2 ) ) THEN
  557                  t( ( icol-1 )*ldt+irow ) = work( ldw+irow )
  558               END IF
  559  100       CONTINUE
  560
  561            is = is + 1
  562  110    CONTINUE
  563      END IF
  564
  565      RETURN
  566
  567
  568
subroutine descinit(desc, m, n, mb, nb, irsrc, icsrc, ictxt, lld, info)
 
subroutine infog2l(grindx, gcindx, desc, nprow, npcol, myrow, mycol, lrindx, lcindx, rsrc, csrc)
 
double precision function pdlamch(ictxt, cmach)
 
subroutine pdlabad(ictxt, small, large)
 
subroutine pxerbla(ictxt, srname, info)
 
subroutine pzlaset(uplo, m, n, alpha, beta, a, ia, ja, desca)
 
subroutine pzlattrs(uplo, trans, diag, normin, n, a, ia, ja, desca, x, ix, jx, descx, scale, cnorm, info)