C
C  This file is part of MUMPS 5.5.1, released
C  on Tue Jul 12 13:17:24 UTC 2022
C
C
C  Copyright 1991-2022 CERFACS, CNRS, ENS Lyon, INP Toulouse, Inria,
C  Mumps Technologies, University of Bordeaux.
C
C  This version of MUMPS is provided to you free of charge. It is
C  released under the CeCILL-C license 
C  (see doc/CeCILL-C_V1-en.txt, doc/CeCILL-C_V1-fr.txt, and
C  https://cecill.info/licences/Licence_CeCILL-C_V1-en.html)
C
      SUBROUTINE SMUMPS_SOLVE_NODE_BWD( INODE,
     &       N, IPOOL, LPOOL, IIPOOL, NBFINF,
     &       A, LA, IW, LIW, W, LWC, NRHS, 
     &       POSWCB, PLEFTW, POSIWCB,
     &    RHSCOMP, LRHSCOMP, POSINRHSCOMP_BWD,
     &    PTRICB, PTRACB, IWCB, LIWW, W2, 
     &    NE_STEPS, STEP,
     &    FRERE, FILS, PTRIST, PTRFAC, 
     &    MYLEAF_LEFT, INFO, 
     &    PROCNODE_STEPS, DEJA_SEND,
     &    SLAVEF, COMM, MYID, BUFR, LBUFR, LBUFR_BYTES,
     &    KEEP,KEEP8, DKEEP, RHS_ROOT, LRHS_ROOT, MTYPE, 
     &    ISTEP_TO_INIV2, TAB_POS_IN_PERE, PANEL_POS, LPANEL_POS,
     &    PRUN_BELOW, TO_PROCESS, SIZE_TO_PROCESS
     &    , RHS_BOUNDS, LRHS_BOUNDS, DO_NBSPARSE, FROM_PP
     &    , ERROR_WAS_BROADCASTED
     &    , DO_MCAST2_TERMBWD
     &    )
      USE SMUMPS_OOC
      USE SMUMPS_BUF
      USE SMUMPS_SOL_LR, only : SMUMPS_SOL_BWD_LR_SU
      IMPLICIT NONE
      INTEGER                     :: KEEP( 500 )
      INTEGER(8)                  :: KEEP8(150)
      REAL, INTENT(INOUT)         :: DKEEP(230)
      INTEGER                     :: INFO(80)
      INTEGER, INTENT( IN )       :: INODE, N, NRHS, MTYPE, LIW, LIWW
      INTEGER, INTENT( IN )       :: SLAVEF, COMM, MYID
      INTEGER, INTENT (IN )       :: PROCNODE_STEPS(KEEP(28))
      INTEGER, INTENT( IN )       :: NE_STEPS(KEEP(28))
      INTEGER(8), INTENT( IN )    :: LA, LWC
      INTEGER(8), INTENT( INOUT ) :: POSWCB, PLEFTW
      INTEGER, INTENT( INOUT )    :: POSIWCB
      INTEGER, INTENT( IN )       :: LPANEL_POS
      INTEGER                     :: PANEL_POS(LPANEL_POS) 
      LOGICAL, INTENT(INOUT)      :: DEJA_SEND(0:SLAVEF-1) 
      INTEGER, INTENT(IN)         :: LPOOL
      INTEGER, INTENT(INOUT)      :: IPOOL(LPOOL), IIPOOL
      INTEGER, INTENT(INOUT)      :: NBFINF, MYLEAF_LEFT
      INTEGER                     :: PTRIST(KEEP(28)), PTRICB(KEEP(28))
      INTEGER(8) :: PTRACB(KEEP(28))
      INTEGER(8) :: PTRFAC(KEEP(28))
      REAL   :: A( LA )
      REAL :: W(LWC)
      REAL :: W2(KEEP(133))
      INTEGER :: IW(LIW),IWCB(LIWW)
      INTEGER STEP(N), FRERE(KEEP(28)),FILS(N)
      INTEGER LBUFR, LBUFR_BYTES
      INTEGER BUFR(LBUFR)
      INTEGER ISTEP_TO_INIV2(KEEP(71)), 
     &        TAB_POS_IN_PERE(SLAVEF+2,max(1,KEEP(56)))
      INTEGER LRHSCOMP, POSINRHSCOMP_BWD(N)
      REAL RHSCOMP(LRHSCOMP,NRHS)
      INTEGER(8), intent(in) :: LRHS_ROOT
      REAL RHS_ROOT( LRHS_ROOT )
      LOGICAL, INTENT( IN ) :: PRUN_BELOW
      INTEGER, INTENT(IN)           :: SIZE_TO_PROCESS
      LOGICAL, INTENT(IN)           :: TO_PROCESS(SIZE_TO_PROCESS)
      LOGICAL, INTENT(IN) :: DO_NBSPARSE
      INTEGER, INTENT(IN) :: LRHS_BOUNDS
      INTEGER, INTENT(IN) :: RHS_BOUNDS(LRHS_BOUNDS)
      LOGICAL, INTENT(IN) :: FROM_PP
      LOGICAL, INTENT( OUT ) :: ERROR_WAS_BROADCASTED
      LOGICAL, INTENT( OUT ) :: DO_MCAST2_TERMBWD
      INCLUDE 'mpif.h'
      INCLUDE 'mumps_tags.h'
      INTEGER IERR
      LOGICAL FLAG
      INCLUDE 'mumps_headers.h' 
      LOGICAL COMPRESS_PANEL, LR_ACTIVATED
      LOGICAL OOCWRITE_COMPATIBLE_WITH_BLR 
      LOGICAL LTLEVEL2, IN_SUBTREE
      INTEGER TYPENODE
      INTEGER TMP_NBPANELS, I_PIVRPTR, I_PIVR
      LOGICAL MUST_BE_PERMUTED
      LOGICAL NO_CHILDREN
      LOGICAL :: ALLOW_OTHERS_TO_LEAVE
      INTEGER :: K, JBDEB, JBFIN, NRHS_B
      INTEGER IWHDLR
      INTEGER NPIV
      INTEGER IPOS,LIELL,NELIM,JJ,I
      INTEGER J1,J2,J,NCB
      INTEGER NSLAVES
      INTEGER IN,IF,LONG,POOL_FIRST_POS,TMP
      INTEGER :: NBFILS
      INTEGER :: PROCDEST, DEST
      INTEGER(8) :: PTWCB, PPIV_COURANT
      INTEGER :: Offset, EffectiveSize, ISLAVE, FirstIndex
      INTEGER :: POSINDICES, IPOSINRHSCOMP, IPOSINRHSCOMP_PANEL
      INTEGER(8) :: APOS, IST
      INTEGER(8) :: IFR8
      INTEGER(8) :: APOSDEB, NBENTRIES_ALLPANELS
      INTEGER(8) :: PTWCB_PANEL
      INTEGER LDAJ, NBJ, LIWFAC,
     &        NBJLAST, NPIV_LAST, PANEL_SIZE,
     &        NCB_PANEL, TYPEF
      INTEGER BEG_PANEL
      LOGICAL TWOBYTWO
      INTEGER NPANELS, IPANEL
      REAL ALPHA,ONE,ZERO
      PARAMETER (ZERO=0.0E0, ONE = 1.0E0, ALPHA=-1.0E0)
      LOGICAL, EXTERNAL :: MUMPS_IN_OR_ROOT_SSARBR
      INTEGER, EXTERNAL :: MUMPS_TYPENODE
      INTEGER, EXTERNAL :: MUMPS_PROCNODE
      ERROR_WAS_BROADCASTED = .FALSE.
      DO_MCAST2_TERMBWD = .FALSE.
      NO_CHILDREN = .FALSE.
      IF (DO_NBSPARSE) THEN
        JBDEB= RHS_BOUNDS(2*STEP(INODE)-1)
        JBFIN= RHS_BOUNDS(2*STEP(INODE))
        NRHS_B = JBFIN-JBDEB+1
      ELSE
        JBDEB = 1
        JBFIN = NRHS
        NRHS_B = NRHS
      ENDIF
      IF ( INODE .EQ. KEEP( 38 ) .OR. INODE .EQ. KEEP( 20 ) ) THEN
         IPOS = PTRIST(STEP(INODE))+KEEP(IXSZ)
         NPIV  = IW(IPOS+3)
         LIELL = IW(IPOS) + NPIV  
         IPOS =  PTRIST(STEP(INODE)) + 5 + KEEP(IXSZ)
         IF ( MTYPE .EQ. 1 .AND. KEEP(50) .EQ. 0) THEN
            J1   = IPOS + LIELL + 1
            J2   = IPOS + LIELL + NPIV
         ELSE
            J1   = IPOS + 1
            J2   = IPOS + NPIV
         END IF
         IFR8  = 0_8
         IPOSINRHSCOMP = POSINRHSCOMP_BWD(IW(J1))  
         CALL SMUMPS_SOL_CPY_FS2RHSCOMP(JBDEB, JBFIN, J2-J1+1,
     &          KEEP, RHSCOMP, NRHS, LRHSCOMP, IPOSINRHSCOMP,
     &          RHS_ROOT(1+NPIV*(JBDEB-1)), NPIV, 1)
        IN = INODE
 270    IN = FILS(IN)
        IF (IN .GT. 0) GOTO 270
        IF (IN .EQ. 0) THEN
          MYLEAF_LEFT = MYLEAF_LEFT - 1
          ALLOW_OTHERS_TO_LEAVE = ( MYLEAF_LEFT .EQ. 0 .AND.
     &                              KEEP(31) .EQ. 0)
          IF (KEEP(31) .NE. 0) THEN
            IF ( .NOT. MUMPS_IN_OR_ROOT_SSARBR( 
     &         PROCNODE_STEPS(STEP(INODE)), KEEP(199) ) ) THEN
              KEEP(31) = KEEP(31) - 1
              IF (KEEP(31) .EQ. 1) THEN
                ALLOW_OTHERS_TO_LEAVE = .TRUE.
              ENDIF
            ENDIF
          ENDIF
          IF (ALLOW_OTHERS_TO_LEAVE) THEN
            DO_MCAST2_TERMBWD = .TRUE.
            NBFINF = NBFINF - 1
          ENDIF
          RETURN 
        ENDIF
        IF   = -IN
        LONG = NPIV
        NBFILS = NE_STEPS(STEP(INODE))
        IF ( PRUN_BELOW ) THEN
           I = NBFILS
           NBFILS = 0
           DO WHILE (I.GT.0)
              IF ( TO_PROCESS(STEP(IF)) ) NBFILS = NBFILS+1
              IF = FRERE(STEP(IF))
              I = I -1
           ENDDO
           IF (NBFILS.EQ.0) THEN
              NO_CHILDREN = .TRUE.
           ELSE
              NO_CHILDREN = .FALSE.
           ENDIF
           IF = -IN
        ENDIF
        DO I = 0, SLAVEF - 1
           DEJA_SEND( I ) = .FALSE.
        END DO
        POOL_FIRST_POS=IIPOOL
        DO I = 1, NBFILS
          IF ( PRUN_BELOW ) THEN
 1030       IF ( .NOT.TO_PROCESS(STEP(IF)) ) THEN
               IF = FRERE(STEP(IF))
               GOTO 1030
            ENDIF
            NO_CHILDREN = .FALSE.
          ENDIF
          IF (MUMPS_PROCNODE(PROCNODE_STEPS(STEP(IF)),KEEP(199))
     &       .EQ. MYID) THEN
            IPOOL(IIPOOL) = IF
            IIPOOL = IIPOOL + 1
          ELSE
            PROCDEST = MUMPS_PROCNODE(PROCNODE_STEPS(STEP(IF)),
     &                 KEEP(199))
            IF (.NOT. DEJA_SEND( PROCDEST ))  THEN
 600          CONTINUE
                CALL SMUMPS_BUF_SEND_VCB( NRHS_B, IF, 0, 0,
     &                 LONG, LONG, IW( J1 ),
     &                 RHS_ROOT( 1+NPIV*(JBDEB-1) ), 
     &                 JBDEB, JBFIN,
     &                 RHSCOMP(1, 1), NRHS, LRHSCOMP,
     &                 IPOSINRHSCOMP, NPIV,
     &                 KEEP, PROCDEST,
     &                 NOEUD, COMM, IERR )
                IF ( IERR .EQ. -1 ) THEN
                  CALL SMUMPS_BACKSLV_RECV_AND_TREAT(
     &                  .FALSE., FLAG,
     &                  BUFR, LBUFR, LBUFR_BYTES,
     &                  MYID, SLAVEF, COMM,
     &                  N, IWCB, LIWW, POSIWCB,
     &                  W, LWC, POSWCB,
     &                  IIPOOL, NBFINF, PTRICB, PTRACB, INFO,
     &                  IPOOL, LPOOL, PANEL_POS, LPANEL_POS,
     &                  STEP, FRERE, FILS, PROCNODE_STEPS,
     &                  PLEFTW, KEEP,KEEP8, DKEEP,
     &                  PTRIST, PTRFAC, IW, LIW, A, LA, W2,
     &                  MYLEAF_LEFT, 
     &                  NRHS, MTYPE,
     &                  RHSCOMP, LRHSCOMP, POSINRHSCOMP_BWD,
     &                  PRUN_BELOW, TO_PROCESS, SIZE_TO_PROCESS
     &                  , FROM_PP
     &                  )
                  IF ( INFO( 1 ) .LT. 0 ) THEN
                    ERROR_WAS_BROADCASTED = .TRUE.
                    RETURN
                  ENDIF
                  GOTO 600
                ELSE IF ( IERR .EQ. -2 ) THEN
                  INFO( 1 ) = -17
                  INFO( 2 ) = NRHS_B * LONG * KEEP(35) +
     &                        ( LONG + 4 ) * KEEP(34)
                  ERROR_WAS_BROADCASTED = .FALSE.
                  RETURN
                ELSE IF ( IERR .EQ. -3 ) THEN
                  INFO( 1 ) = -20
                  INFO( 2 ) = NRHS_B * LONG * KEEP(35) +
     &                        ( LONG + 4 ) * KEEP(34)
                  ERROR_WAS_BROADCASTED = .FALSE.
                  RETURN
                ELSE IF ( IERR .NE. 0 ) THEN
                  WRITE(*,*) "Internal error 2 SMUMPS_SOLVE_NODE_BWD",
     &            IERR
                  CALL MUMPS_ABORT()
                END IF
                DEJA_SEND( PROCDEST ) = .TRUE.
            END IF
          ENDIF
          IF = FRERE(STEP(IF))
        ENDDO
        ALLOW_OTHERS_TO_LEAVE = .FALSE.
        IF ( PRUN_BELOW .AND. NO_CHILDREN ) THEN
           MYLEAF_LEFT = MYLEAF_LEFT - 1
           ALLOW_OTHERS_TO_LEAVE = ( MYLEAF_LEFT .EQ. 0 .AND.
     &                               KEEP(31) .EQ. 0)
        ENDIF
        IF ( KEEP(31). NE. 0) THEN
          IF ( .NOT. MUMPS_IN_OR_ROOT_SSARBR( 
     &         PROCNODE_STEPS(STEP(INODE)), KEEP(199) ) ) THEN
            KEEP(31) = KEEP(31) - 1
            IF (KEEP(31) .EQ. 1) THEN
              ALLOW_OTHERS_TO_LEAVE = .TRUE.
            ENDIF
          ENDIF
        ENDIF
        IF ( ALLOW_OTHERS_TO_LEAVE ) THEN
          DO_MCAST2_TERMBWD = .TRUE.
          NBFINF = NBFINF - 1
        ENDIF
        IF (IIPOOL.NE.POOL_FIRST_POS) THEN
          DO I=1,(IIPOOL-POOL_FIRST_POS)/2
            TMP = IPOOL(POOL_FIRST_POS+I-1)
            IPOOL(POOL_FIRST_POS+I-1) = IPOOL(IIPOOL-I)
            IPOOL(IIPOOL-I) = TMP
          ENDDO
        ENDIF
        RETURN
      END IF
      IN_SUBTREE = MUMPS_IN_OR_ROOT_SSARBR( 
     &               PROCNODE_STEPS(STEP(INODE)), KEEP(199) ) 
      TYPENODE = MUMPS_TYPENODE(PROCNODE_STEPS(STEP(INODE)),
     &         KEEP(199))
      LTLEVEL2= ( 
     &   (TYPENODE .eq.2 ) .AND.
     &   (MTYPE.NE.1)   )
      NPIV = IW(PTRIST(STEP(INODE))+2+KEEP(IXSZ)+1)
      IF ((NPIV.NE.0).AND.(LTLEVEL2)) THEN
            IPOS  = PTRIST(STEP(INODE)) + 2 + KEEP(IXSZ)
            LIELL = IW(IPOS-2)+IW(IPOS+1)
            NELIM = IW(IPOS-1)
            IPOS  = IPOS + 1
            NPIV  = IW(IPOS)
            NCB   = LIELL - NPIV - NELIM
            IPOS  = IPOS + 2
            NSLAVES = IW( IPOS )
            Offset = 0  
            IPOS = IPOS + NSLAVES   
            IW(PTRIST(STEP(INODE))+XXS)= C_FINI+NSLAVES
           IF ( POSIWCB - 2 .LT. 0 .or.
     &          POSWCB-int(NCB,8)*int(NRHS_B,8) .LT. PLEFTW-1_8 ) THEN
             CALL SMUMPS_COMPSO( N, KEEP(28), IWCB, LIWW, W, LWC,
     &          POSWCB, POSIWCB, PTRICB, PTRACB)
             IF ( POSWCB-int(NCB,8)*int(NRHS_B,8) .LT. PLEFTW-1_8 ) THEN
               INFO( 1 ) = -11
               CALL MUMPS_SET_IERROR(NCB * NRHS_B - POSWCB-PLEFTW+1_8,
     &                              INFO(2))
               ERROR_WAS_BROADCASTED = .FALSE.
               RETURN
             END IF
             IF ( POSIWCB - 2 .LT. 0 ) THEN
               INFO( 1 ) = -14
               INFO( 2 ) = 2 - POSIWCB
               ERROR_WAS_BROADCASTED = .FALSE.
               RETURN
             END IF
           END IF
           POSIWCB = POSIWCB - 2
           POSWCB  = POSWCB - int(NCB,8)*int(NRHS_B,8)
           PTRICB(STEP( INODE )) = POSIWCB + 1
           PTRACB(STEP( INODE )) = POSWCB  + 1_8
           IWCB( PTRICB(STEP( INODE ))     ) = NCB*NRHS_B
           IWCB( PTRICB(STEP( INODE )) + 1 ) = 1  
           IF ( MTYPE.EQ.1 .AND. KEEP(50).EQ.0 ) THEN
              POSINDICES = IPOS + LIELL + 1
           ELSE
              POSINDICES = IPOS + 1
           END IF
           IF ( NCB.EQ.0 ) THEN
             write(6,*) ' Internal Error type 2 node with no CB '
             CALL MUMPS_ABORT()
           ENDIF
           IF ( MTYPE .EQ. 1 .AND. KEEP(50).EQ.0 ) THEN
               J1 = IPOS + LIELL + NPIV + NELIM +1
               J2 = IPOS + 2 * LIELL
           ELSE
               J1 = IPOS + NPIV + NELIM +1
               J2 = IPOS + LIELL
           END IF
           IFR8 = PTRACB(STEP( INODE )) - 1_8
          CALL SMUMPS_SOL_BWD_GTHR( JBDEB, JBFIN, J1, J2,
     &       RHSCOMP, NRHS, LRHSCOMP,
     &       W(PTRACB(STEP(INODE))), NCB, 1,
     &       IW, LIW, KEEP, N, POSINRHSCOMP_BWD )
             IFR8 = IFR8 + int(J2-KEEP(253)-J1+1,8)
           IF (KEEP(252).NE.0) THEN
             DO JJ = J2-KEEP(253)+1, J2
              IFR8 = IFR8 + 1_8
              DO K=JBDEB, JBFIN
               IF (K.EQ.JJ-J2+KEEP(253)) THEN
                 W(IFR8+int(K-JBDEB,8)*int(NCB,8)) = ALPHA
               ELSE
                 W(IFR8+int(K-JBDEB,8)*int(NCB,8)) = ZERO
               ENDIF
              ENDDO
             ENDDO
           ENDIF
           DO ISLAVE = 1, NSLAVES
             CALL MUMPS_BLOC2_GET_SLAVE_INFO( 
     &                KEEP,KEEP8, INODE, STEP, N, SLAVEF,
     &                ISTEP_TO_INIV2, TAB_POS_IN_PERE,
     &                ISLAVE, NCB, 
     &                NSLAVES, 
     &                EffectiveSize,
     &                FirstIndex )
 500         CONTINUE
             DEST = IW( PTRIST(STEP(INODE))+5+ISLAVE+KEEP(IXSZ))
             CALL SMUMPS_BUF_SEND_BACKVEC(NRHS_B, INODE,
     &             W(Offset+PTRACB(STEP(INODE))), 
     &             EffectiveSize, 
     &             NCB, DEST,
     &             BACKSLV_MASTER2SLAVE, JBDEB, JBFIN,
     &             KEEP, COMM, IERR )
             IF ( IERR .EQ. -1 ) THEN
                CALL SMUMPS_BACKSLV_RECV_AND_TREAT(
     &              .FALSE., FLAG,
     &              BUFR, LBUFR, LBUFR_BYTES,
     &              MYID, SLAVEF, COMM,
     &              N, IWCB, LIWW, POSIWCB,
     &              W, LWC, POSWCB,
     &              IIPOOL, NBFINF, PTRICB, PTRACB, INFO,
     &              IPOOL, LPOOL, PANEL_POS, LPANEL_POS,
     &              STEP, FRERE, FILS,
     &              PROCNODE_STEPS, PLEFTW, KEEP,KEEP8, DKEEP,
     &              PTRIST, PTRFAC, IW, LIW, A, LA, W2, MYLEAF_LEFT,
     &              NRHS, MTYPE,
     &              RHSCOMP, LRHSCOMP, POSINRHSCOMP_BWD,
     &              PRUN_BELOW , TO_PROCESS, SIZE_TO_PROCESS
     &               , FROM_PP
     &               )
               IF ( INFO( 1 ) .LT. 0 ) THEN
                 ERROR_WAS_BROADCASTED = .TRUE.
                 RETURN
               ENDIF
               GOTO 500
             ELSE IF ( IERR .EQ. -2 ) THEN
                INFO( 1 ) = -17
                INFO( 2 ) = NRHS_B * EffectiveSize * KEEP(35) +
     &               2 * KEEP(34)
                ERROR_WAS_BROADCASTED = .FALSE.
                RETURN
             ELSE IF ( IERR .EQ. -3 ) THEN
                INFO( 1 ) = -20
                INFO( 2 ) = NRHS_B * EffectiveSize * KEEP(35) +
     &                            2 * KEEP(34)
                ERROR_WAS_BROADCASTED = .FALSE.
                RETURN
             END IF
             Offset = Offset + EffectiveSize
           END DO
           IWCB( PTRICB(STEP( INODE )) + 1 ) = 0
           CALL SMUMPS_FREETOPSO(N, KEEP(28), IWCB, LIWW, W, LWC,
     &             POSWCB,POSIWCB,PTRICB,PTRACB)
           RETURN
      ENDIF   
      LR_ACTIVATED = (IW(PTRIST(STEP(INODE))+XXLR).GT.0)
      COMPRESS_PANEL = (IW(PTRIST(STEP(INODE))+XXLR).GE.2)
      OOCWRITE_COMPATIBLE_WITH_BLR =
     &     (.NOT.LR_ACTIVATED.OR.(.NOT.COMPRESS_PANEL).OR.
     &            (KEEP(485).EQ.0) 
     &     )
      IPOS = PTRIST(STEP(INODE)) + 2 + KEEP(IXSZ)
      LIELL = IW(IPOS-2)+IW(IPOS+1)
      NELIM = IW(IPOS-1)
      IPOS = IPOS + 1
      NPIV = IW(IPOS)
      NCB   = LIELL - NPIV
      IPOS = IPOS + 1
      IF (KEEP(201).GT.0.AND.OOCWRITE_COMPATIBLE_WITH_BLR) THEN
        CALL SMUMPS_SOLVE_GET_OOC_NODE(
     &        INODE,PTRFAC,KEEP,A,LA,STEP,
     &        KEEP8,N,MUST_BE_PERMUTED,IERR)
        IF(IERR.LT.0)THEN
          INFO(1)=IERR
          INFO(2)=0
          ERROR_WAS_BROADCASTED = .FALSE.
          RETURN
         ENDIF
      ENDIF                     
      APOS = PTRFAC( STEP(INODE))
      NSLAVES = IW( PTRIST(STEP(INODE)) + 5 + KEEP(IXSZ) )
      IPOS = IPOS + 1 + NSLAVES
      IF (KEEP(201).EQ.1.AND.OOCWRITE_COMPATIBLE_WITH_BLR) THEN 
         LIWFAC =  IW(PTRIST(STEP(INODE))+XXI)
         IF (MTYPE.NE.1) THEN
           TYPEF = TYPEF_L
         ELSE
           TYPEF = TYPEF_U
         ENDIF
         PANEL_SIZE =  SMUMPS_OOC_PANEL_SIZE( LIELL )
         IF (KEEP(50).NE.1) THEN
           CALL SMUMPS_OOC_PP_CHECK_PERM_FREED(
     &                 IW(IPOS+1+2*LIELL),
     &                 MUST_BE_PERMUTED )
         ENDIF
      ENDIF  
      LONG = 0
      IF ( MTYPE .EQ. 1 .AND. KEEP(50).EQ.0 ) THEN
        J1 = IPOS + LIELL + 1
        J2 = IPOS + NPIV + LIELL
      ELSE
        J1 = IPOS + 1
        J2 = IPOS + NPIV
      ENDIF
      IF (IN_SUBTREE) THEN
        PTWCB = PLEFTW
        IF ( POSWCB .LT. int(LIELL,8)*int(NRHS_B,8) ) THEN
          CALL SMUMPS_COMPSO( N, KEEP(28), IWCB, LIWW, W, LWC,
     &                POSWCB, POSIWCB, PTRICB, PTRACB)
          IF ( POSWCB .LT. int(LIELL,8)*int(NRHS_B,8) ) THEN
            INFO(1) = -11
            CALL MUMPS_SET_IERROR(int(LIELL,8)*int(NRHS_B,8)-POSWCB,
     &                 INFO(2))
            ERROR_WAS_BROADCASTED = .FALSE.
            RETURN
          END IF
        END IF
      ELSE
        IF ( POSIWCB - 2 .LT. 0 .or.
     &     POSWCB-int(LIELL,8)*int(NRHS_B,8) .LT. PLEFTW-1_8 ) THEN
          CALL SMUMPS_COMPSO( N, KEEP(28), IWCB, LIWW, W, LWC,
     &          POSWCB, POSIWCB, PTRICB, PTRACB )
          IF ( POSWCB-int(LIELL,8)*int(NRHS_B,8) .LT. PLEFTW-1_8 ) THEN
            INFO( 1 ) = -11
            CALL MUMPS_SET_IERROR( int(LIELL,8)*int(NRHS_B,8)-
     &                            POSWCB-PLEFTW+1_8,
     &                            INFO(2) )
            ERROR_WAS_BROADCASTED = .FALSE.
            RETURN
          END IF
          IF ( POSIWCB - 2 .LT. 0 ) THEN
            INFO( 1 ) = -14
            INFO( 2 ) = 2 - POSIWCB
            ERROR_WAS_BROADCASTED = .FALSE.
            RETURN
          END IF
        END IF
        POSIWCB = POSIWCB - 2
        POSWCB  = POSWCB - int(LIELL,8)*int(NRHS_B,8)
        PTRICB(STEP( INODE )) = POSIWCB + 1
        PTRACB(STEP( INODE )) = POSWCB  + 1_8
        IWCB( PTRICB(STEP( INODE ))     ) = LIELL*NRHS_B
        IWCB( PTRICB(STEP( INODE )) + 1 ) = 1  
        IF ( MTYPE.EQ.1 .AND. KEEP(50).EQ.0 ) THEN
           POSINDICES = IPOS + LIELL + 1
        ELSE
           POSINDICES = IPOS + 1
        END IF
        PTWCB = PTRACB(STEP( INODE ))
      ENDIF
      IF (J2.GE.J1) THEN
        IPOSINRHSCOMP = POSINRHSCOMP_BWD(IW(J1)) 
      ELSE
        IPOSINRHSCOMP = -99999
      ENDIF
      IF (J2.GE.J1) THEN
        DO K=JBDEB, JBFIN
            IF (KEEP(252).NE.0) THEN
              DO JJ = J1, J2
                RHSCOMP(IPOSINRHSCOMP+JJ-J1,K) = ZERO
              ENDDO
            ENDIF
        END DO
      ENDIF
      IFR8   = PTWCB + int(NPIV - 1,8)
      IF ( LIELL .GT. NPIV ) THEN
        IF ( MTYPE .EQ. 1 .AND. KEEP(50).EQ.0 ) THEN
          J1 = IPOS + LIELL + NPIV + 1
          J2 = IPOS + 2 * LIELL
        ELSE
          J1 = IPOS + NPIV + 1
          J2 = IPOS + LIELL
        END IF
        CALL SMUMPS_SOL_BWD_GTHR( JBDEB, JBFIN, J1, J2,
     &       RHSCOMP, NRHS, LRHSCOMP,
     &       W(PTWCB), LIELL, NPIV+1,
     &       IW, LIW, KEEP, N, POSINRHSCOMP_BWD )
          IFR8 = IFR8 + int(J2-KEEP(253)-J1+1,8)
        IF (KEEP(252).NE.0) THEN
          DO JJ = J2-KEEP(253)+1, J2
           IFR8 = IFR8 + 1_8
           DO K=JBDEB, JBFIN
            IF (K.EQ.JJ-J2+KEEP(253)) THEN
              W(IFR8+int(K-JBDEB,8)*int(LIELL,8)) = ALPHA 
            ELSE
              W(IFR8+int(K-JBDEB,8)*int(LIELL,8)) = ZERO
            ENDIF
           ENDDO
          ENDDO
        ENDIF
        NCB = LIELL - NPIV
        IF (NPIV .EQ. 0) GOTO 160
      ENDIF
      IF (KEEP(201).EQ.1.AND.OOCWRITE_COMPATIBLE_WITH_BLR) THEN 
        J = NPIV / PANEL_SIZE 
        TWOBYTWO = KEEP(50).EQ.2 .AND.
     &  ((TYPENODE.EQ.1.AND.KEEP(103).GT.0) .OR.
     &  (TYPENODE.EQ.2.AND.KEEP(105).GT.0))
        IF (TWOBYTWO) THEN 
          CALL SMUMPS_BUILD_PANEL_POS(PANEL_SIZE, PANEL_POS, LPANEL_POS,
     &        IW(IPOS+1+LIELL), NPIV, NPANELS, LIELL,
     &        NBENTRIES_ALLPANELS)
        ELSE
          IF (NPIV.EQ.J*PANEL_SIZE) THEN
            NPIV_LAST = NPIV
            NBJLAST   = PANEL_SIZE
            NPANELS   = J
          ELSE
            NPIV_LAST = (J+1)* PANEL_SIZE
            NBJLAST   = NPIV-J*PANEL_SIZE
            NPANELS   = J+1
          ENDIF
          NBENTRIES_ALLPANELS =
     &    int(LIELL,8) * int(NPIV,8) 
     &  - int( ( J * ( J - 1 ) ) /2,8 ) 
     &    * int(PANEL_SIZE,8) * int(PANEL_SIZE,8) 
     &  - int(J,8)                       
     &    * int(mod(NPIV, PANEL_SIZE),8) 
     &    * int(PANEL_SIZE,8)    
          JJ=NPIV_LAST
        ENDIF
        APOSDEB = APOS + NBENTRIES_ALLPANELS 
        DO IPANEL = NPANELS, 1, -1
            IF (TWOBYTWO) THEN
              NBJ = PANEL_POS(IPANEL+1)-PANEL_POS(IPANEL)
              BEG_PANEL = PANEL_POS(IPANEL)
            ELSE
              IF (JJ.EQ.NPIV_LAST) THEN
                NBJ = NBJLAST
              ELSE
                NBJ = PANEL_SIZE
              ENDIF
              BEG_PANEL = JJ- PANEL_SIZE+1
            ENDIF
            LDAJ    = LIELL-BEG_PANEL+1 
            APOSDEB = APOSDEB - int(NBJ,8)*int(LDAJ,8)
            PTWCB_PANEL = PTWCB + int(BEG_PANEL - 1,8)
            IPOSINRHSCOMP_PANEL = IPOSINRHSCOMP + BEG_PANEL - 1
            NCB_PANEL   = LDAJ - NBJ
            IF (KEEP(50).NE.1.AND.MUST_BE_PERMUTED) THEN
              CALL SMUMPS_GET_OOC_PERM_PTR(TYPEF, TMP_NBPANELS,
     &        I_PIVRPTR, I_PIVR, IPOS + 1 + 2 * LIELL, IW, LIW)
              IF (NPIV.EQ.(IW(I_PIVRPTR)-1)) THEN
                MUST_BE_PERMUTED=.FALSE. 
              ELSE
              CALL SMUMPS_PERMUTE_PANEL(
     &        IW(I_PIVR + IW(I_PIVRPTR+IPANEL-1)-IW(I_PIVRPTR)),
     &        NPIV-IW(I_PIVRPTR+IPANEL-1)+1,
     &        IW(I_PIVRPTR+IPANEL-1)-1,
     &        A(APOSDEB),
     &        LDAJ, NBJ, BEG_PANEL-1)
              ENDIF
            ENDIF
#if defined(MUMPS_USE_BLAS2)
            IF ( NRHS_B == 1 ) THEN
              IF (NCB_PANEL.NE.0) THEN
                  IF (NCB_PANEL - NCB.NE. 0) THEN
                    CALL sgemv( 'T', NCB_PANEL-NCB, NBJ, ALPHA, 
     &              A( APOSDEB + int(NBJ,8) ), LDAJ,
     &              RHSCOMP(IPOSINRHSCOMP_PANEL+NBJ,JBDEB),
     &              1, ONE,
     &              RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB), 1 )
                  ENDIF
                  IF (NCB .NE. 0) THEN
                    CALL sgemv( 'T', NCB, NBJ, ALPHA,
     &              A( APOSDEB + int(LDAJ-NCB,8) ), LDAJ,
     &              W( PTWCB  + int(NPIV,8) ),
     &              1, ONE,
     &              RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB), 1 )
                  ENDIF
              ENDIF
              IF (MTYPE.NE.1) THEN
                CALL strsv('L','T','U', NBJ, A(APOSDEB), LDAJ,
     &            RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB), 1)
              ELSE
                CALL strsv('L','T','N', NBJ, A(APOSDEB), LDAJ,
     &              RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB), 1)
              ENDIF
            ELSE
#endif
              IF (NCB_PANEL.NE.0) THEN
                  IF (NCB_PANEL - NCB .NE. 0) THEN
                  CALL sgemm( 'T', 'N', NBJ, NRHS_B,
     &                                         NCB_PANEL-NCB, ALPHA,
     &              A(APOSDEB +int(NBJ,8)), LDAJ,
     &              RHSCOMP(IPOSINRHSCOMP_PANEL+NBJ,JBDEB), LRHSCOMP,
     &              ONE, RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB), LRHSCOMP)
                  ENDIF
                  IF (NCB .NE. 0) THEN
                  CALL sgemm( 'T', 'N', NBJ, NRHS_B, NCB, ALPHA,
     &              A(APOSDEB +int(LDAJ-NCB,8)), LDAJ,
     &              W( PTWCB+int(NPIV,8) ), LIELL,
     &              ONE, RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB),LRHSCOMP)
                  ENDIF
              ENDIF
              IF (MTYPE.NE.1) THEN
                CALL strsm('L','L','T','U',NBJ, NRHS_B, ONE,
     &          A(APOSDEB), 
     &          LDAJ, RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB), LRHSCOMP)
              ELSE
                CALL strsm('L','L','T','N',NBJ, NRHS_B, ONE,
     &          A(APOSDEB),
     &          LDAJ, RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB), LRHSCOMP)
              ENDIF
#if defined(MUMPS_USE_BLAS2)
            ENDIF
#endif
            IF (.NOT. TWOBYTWO) JJ=BEG_PANEL-1 
        ENDDO 
      ELSE 
        IF ( IW(PTRIST(STEP(INODE))+XXLR) .GE. 2
     &        .AND. KEEP(485) .EQ. 1 ) THEN
          IWHDLR = IW(PTRIST(STEP(INODE))+XXF)
          CALL SMUMPS_SOL_BWD_LR_SU (
     &           INODE, IWHDLR, NPIV, NSLAVES, 
     &           LIELL, W, LWC, NRHS_B, PTWCB,
     &           RHSCOMP, LRHSCOMP, NRHS,
     &           IPOSINRHSCOMP, JBDEB, 
     &           MTYPE, KEEP, KEEP8,
     &           INFO(1), INFO(2) )
          IF (INFO(1).LT.0) THEN
            ERROR_WAS_BROADCASTED = .FALSE.
            RETURN
          ENDIF
        ELSE
          IF ( LIELL .GT. NPIV ) THEN
#if defined(LDLTPANEL_DEBUG)
          WRITE(*,*) 'before gemm LIELL, NPIV, PTWCB=',LIELL,NPIV,PTWCB
          WRITE(*,*) 'before gemm RHSCOMP=',
     &        RHSCOMP(IPOSINRHSCOMP:IPOSINRHSCOMP+NPIV-1,1)
          WRITE(*,*) 'before gemm W',
     &        W(PTWCB+NPIV:PTWCB+LIELL-1)
          CALL MUMPS_GETI8(IST, IW(PTRIST(STEP(INODE))+XXR))
          WRITE(*,*) "FACTORS=",A(APOS:APOS+IST-1)
#endif
            IF ( MTYPE .eq. 1 ) THEN
              IST = APOS + int(NPIV,8)
#if defined(MUMPS_USE_BLAS2)
              IF (NRHS_B == 1) THEN
                CALL sgemv( 'T', NCB, NPIV, ALPHA, A(IST), LIELL,
     &                 W(PTWCB+int(NPIV,8)), 1,
     &                 ONE,
     &                 RHSCOMP(IPOSINRHSCOMP,JBDEB), 1 )
              ELSE
#endif
                CALL sgemm('T','N', NPIV, NRHS_B, NCB, ALPHA,
     &                 A(IST),
     &                 LIELL, W(PTWCB+int(NPIV,8)), LIELL, ONE,
     &                 RHSCOMP(IPOSINRHSCOMP,JBDEB), LRHSCOMP)
#if defined(MUMPS_USE_BLAS2)
              ENDIF
#endif
            ELSE
              IF ( KEEP(50) .eq. 0 ) THEN
                IST = APOS + int(NPIV,8) * int(LIELL,8)
              ELSE
                 IF( KEEP(459) .GT. 1) THEN
          CALL MUMPS_GETI8(IST, IW(PTRIST(STEP(INODE))+XXR))
                   IST = APOS + IST - int(NPIV,8) * int(LIELL-NPIV,8)
                 ELSE
                   IST = APOS + int(NPIV,8) * int(NPIV,8)
                 ENDIF
              END IF
#if defined(MUMPS_USE_BLAS2)
              IF ( NRHS_B == 1 ) THEN
                 CALL sgemv( 'N', NPIV, NCB, ALPHA, A( IST ), NPIV,
     &                W( PTWCB + int(NPIV,8) ),
     &                1, ONE,
     &                RHSCOMP(IPOSINRHSCOMP,JBDEB), 1 )
              ELSE
#endif
                 CALL sgemm( 'N', 'N', NPIV, NRHS_B, NCB, ALPHA,
     &                A(IST),
     &                NPIV, W(PTWCB+int(NPIV,8)), LIELL,
     &                ONE, RHSCOMP(IPOSINRHSCOMP,JBDEB), LRHSCOMP)
#if defined(MUMPS_USE_BLAS2)
              END IF
#endif
            END IF 
          ENDIF  
          IF ( MTYPE .eq. 1 ) THEN
            LDAJ = LIELL
          ELSE
            IF ( KEEP(50) .EQ. 0 ) THEN
              LDAJ=LIELL
            ELSE
              IF (KEEP(459).GT.1) THEN
                LDAJ=-999799
              ELSE
                LDAJ=NPIV
              ENDIF
            ENDIF
          END IF 
          PPIV_COURANT = int(JBDEB-1,8)*int(LRHSCOMP,8)
     &                 + int(IPOSINRHSCOMP,8)
          IF (KEEP(459).GT.1 .AND. KEEP(50).NE.0) THEN
          CALL SMUMPS_SOLVE_BWD_PANELS( A, LA, APOS,
     &      NPIV, IW(IPOS+1+LIELL),
     &      NRHS_B, RHSCOMP(1,1), KEEP8(25), LRHSCOMP, PPIV_COURANT, 
     &      MTYPE, KEEP )
          ELSE
          CALL SMUMPS_SOLVE_BWD_TRSOLVE( A, LA, APOS,
     &      NPIV, LDAJ,
     &      NRHS_B, RHSCOMP(1,1), KEEP8(25), LRHSCOMP, PPIV_COURANT, 
     &      MTYPE, KEEP )
          ENDIF
        ENDIF  
      ENDIF 
      IF ( MTYPE .EQ. 1 .AND. KEEP(50).EQ.0) THEN
        J1 = IPOS + LIELL + 1
      ELSE
        J1 = IPOS + 1
      END IF
      IPOSINRHSCOMP =  POSINRHSCOMP_BWD(IW(J1)) 
  160 CONTINUE
      IF (KEEP(201).GT.0.AND.OOCWRITE_COMPATIBLE_WITH_BLR) THEN
         CALL SMUMPS_FREE_FACTORS_FOR_SOLVE(INODE,PTRFAC,KEEP(28),
     &        A,LA,.TRUE.,IERR)
         IF(IERR.LT.0)THEN
            INFO(1)=IERR
            INFO(2)=0
            ERROR_WAS_BROADCASTED = .FALSE.
            RETURN
         ENDIF
      ENDIF
      IN = INODE
  170 IN = FILS(IN)
      IF (IN .GT. 0) GOTO 170
      IF (IN .EQ. 0) THEN
        MYLEAF_LEFT = MYLEAF_LEFT - 1
        IF (.NOT. IN_SUBTREE ) THEN
          IWCB(PTRICB(STEP(INODE))+1) = IWCB(PTRICB(STEP(INODE))+1)-1
          CALL SMUMPS_FREETOPSO(N, KEEP(28), IWCB, LIWW, 
     &    W, LWC,
     &    POSWCB,POSIWCB,PTRICB,PTRACB)
        ENDIF
        ALLOW_OTHERS_TO_LEAVE = ( MYLEAF_LEFT .EQ. 0 .AND.
     &                          KEEP(31) .EQ. 0)
        IF ( KEEP(31) .NE. 0 .AND.
     &       .NOT. IN_SUBTREE ) THEN
          KEEP(31) = KEEP(31) - 1
          IF (KEEP(31).EQ. 1) THEN
            ALLOW_OTHERS_TO_LEAVE = .TRUE.
          ENDIF
        ENDIF
        IF (ALLOW_OTHERS_TO_LEAVE) THEN
          DO_MCAST2_TERMBWD = .TRUE.
          NBFINF = NBFINF - 1
        ENDIF
        RETURN
      ENDIF
      IF = -IN
      NBFILS = NE_STEPS(STEP(INODE))
      IF ( PRUN_BELOW ) THEN
         I = NBFILS
         NBFILS = 0
         DO WHILE (I.GT.0)
            IF ( TO_PROCESS(STEP(IF)) ) NBFILS = NBFILS+1
            IF = FRERE(STEP(IF))
            I = I -1
         ENDDO
         IF (NBFILS.EQ.0) THEN
            NO_CHILDREN = .TRUE.
         ELSE
            NO_CHILDREN = .FALSE.
         ENDIF
         IF = -IN
      ENDIF
      IF (IN_SUBTREE) THEN
         DO I = 1, NBFILS
            IF ( PRUN_BELOW ) THEN
 1010          CONTINUE
               IF ( .NOT.TO_PROCESS(STEP(IF)) )  THEN
                  IF = FRERE(STEP(IF))
                  GOTO 1010
               ENDIF
               NO_CHILDREN = .FALSE.
            ENDIF
            IPOOL((IIPOOL-I+1)+NBFILS-I) = IF
            IIPOOL = IIPOOL + 1
            IF = FRERE(STEP(IF))
         ENDDO
         IF (PRUN_BELOW .AND. NO_CHILDREN) THEN
            MYLEAF_LEFT = MYLEAF_LEFT - 1
            ALLOW_OTHERS_TO_LEAVE = ( MYLEAF_LEFT .EQ. 0 .AND.
     &                                KEEP(31) .EQ. 0)
            IF (ALLOW_OTHERS_TO_LEAVE ) THEN
               DO_MCAST2_TERMBWD = .TRUE.
               NBFINF = NBFINF - 1
               RETURN
            ENDIF
         ENDIF
      ELSE
        DO I = 0, SLAVEF - 1
          DEJA_SEND( I ) = .FALSE.
        END DO
        POOL_FIRST_POS=IIPOOL
        DO 190 I = 1, NBFILS
          IF ( PRUN_BELOW ) THEN
1020          IF ( .NOT.TO_PROCESS(STEP(IF)) ) THEN
                 IF = FRERE(STEP(IF))
                 GOTO 1020
              ENDIF
             NO_CHILDREN = .FALSE.
          ENDIF
          IF (MUMPS_PROCNODE(PROCNODE_STEPS(STEP(IF)),
     &      KEEP(199)) .EQ. MYID) THEN
                IPOOL(IIPOOL) = IF
                IIPOOL = IIPOOL + 1
            IF = FRERE(STEP(IF))
          ELSE
            PROCDEST = MUMPS_PROCNODE(PROCNODE_STEPS(STEP(IF)),
     &                 KEEP(199))
            IF (.not. DEJA_SEND( PROCDEST ))  THEN
 400          CONTINUE
              CALL SMUMPS_BUF_SEND_VCB( NRHS_B, IF, 0, 0,
     &          LIELL, LIELL - KEEP(253),
     &          IW( POSINDICES ),
     &          W( PTRACB(STEP(INODE)) ), JBDEB, JBFIN,
     &          RHSCOMP(1, 1), NRHS, LRHSCOMP,
     &          IPOSINRHSCOMP, NPIV,
     &          KEEP, PROCDEST, NOEUD, COMM, IERR )
              IF ( IERR .EQ. -1 ) THEN
                CALL SMUMPS_BACKSLV_RECV_AND_TREAT(
     &          .FALSE., FLAG,
     &          BUFR, LBUFR, LBUFR_BYTES,
     &          MYID, SLAVEF, COMM,
     &          N, IWCB, LIWW, POSIWCB,
     &          W, LWC, POSWCB,
     &          IIPOOL, NBFINF, PTRICB, PTRACB, INFO,
     &          IPOOL, LPOOL, PANEL_POS, LPANEL_POS,
     &          STEP, FRERE, FILS, PROCNODE_STEPS,
     &          PLEFTW, KEEP, KEEP8, DKEEP,
     &          PTRIST, PTRFAC, IW, LIW, A, LA, W2, MYLEAF_LEFT,
     &          NRHS, MTYPE, 
     &          RHSCOMP, LRHSCOMP, POSINRHSCOMP_BWD,
     &          PRUN_BELOW, TO_PROCESS, SIZE_TO_PROCESS
     &            , FROM_PP
     &            )
                IF ( INFO( 1 ) .LT. 0 ) THEN
                  ERROR_WAS_BROADCASTED = .TRUE.
                  RETURN
                ENDIF
                GOTO 400
             ELSE IF ( IERR .EQ. -2 ) THEN
                INFO( 1 ) = -17
                INFO( 2 ) = NRHS_B * LIELL * KEEP(35) + 4 * KEEP(34)
                ERROR_WAS_BROADCASTED = .FALSE.
                RETURN
             ELSE IF ( IERR .EQ. -3 ) THEN
                INFO( 1 ) = -20
                INFO( 2 ) = NRHS_B * LIELL * KEEP(35) + 4 * KEEP(34)
                ERROR_WAS_BROADCASTED = .FALSE.
                RETURN
              END IF
              DEJA_SEND( PROCDEST ) = .TRUE.
            END IF
            IF = FRERE(STEP(IF))
          ENDIF
  190   CONTINUE
        IF ( PRUN_BELOW .AND. NO_CHILDREN ) THEN
           MYLEAF_LEFT = MYLEAF_LEFT - 1
           ALLOW_OTHERS_TO_LEAVE = ( MYLEAF_LEFT .EQ. 0 .AND.
     &                               KEEP(31) .EQ. 0)
           IF ( ALLOW_OTHERS_TO_LEAVE ) THEN
              DO_MCAST2_TERMBWD = .TRUE.
              NBFINF = NBFINF - 1
              RETURN
           ENDIF
        ENDIF
        DO I=1,(IIPOOL-POOL_FIRST_POS)/2
           TMP=IPOOL(POOL_FIRST_POS+I-1)
           IPOOL(POOL_FIRST_POS+I-1)=IPOOL(IIPOOL-I)
           IPOOL(IIPOOL-I)=TMP
        ENDDO 
        IF ( KEEP(31) .NE. 0 ) 
     &       THEN
          KEEP(31) = KEEP(31) - 1
          ALLOW_OTHERS_TO_LEAVE = (KEEP(31) .EQ. 1)
          IF (ALLOW_OTHERS_TO_LEAVE) THEN
            DO_MCAST2_TERMBWD = .TRUE.
            NBFINF = NBFINF - 1
          ENDIF
        ENDIF
        IWCB(PTRICB(STEP(INODE))+1) = IWCB(PTRICB(STEP(INODE))+1)-1
        CALL SMUMPS_FREETOPSO(N, KEEP(28), IWCB, LIWW, 
     &     W, LWC,
     &     POSWCB,POSIWCB,PTRICB,PTRACB)
      ENDIF
      RETURN
      END SUBROUTINE SMUMPS_SOLVE_NODE_BWD
      RECURSIVE SUBROUTINE SMUMPS_BACKSLV_RECV_AND_TREAT(
     &     BLOQ, FLAG,
     &     BUFR, LBUFR, LBUFR_BYTES,
     &     MYID, SLAVEF, COMM,
     &     N, IWCB, LIWW, POSIWCB,
     &     W, LWC, POSWCB,
     &     IIPOOL, NBFINF, PTRICB, PTRACB, INFO,
     &     IPOOL, LPOOL, PANEL_POS, LPANEL_POS,
     &     STEP, FRERE, FILS, PROCNODE_STEPS,
     &     PLEFTW, KEEP, KEEP8, DKEEP,
     &     PTRIST, PTRFAC, IW, LIW, A, LA, W2, MYLEAF_LEFT, 
     &     NRHS, MTYPE,
     &     RHSCOMP, LRHSCOMP, POSINRHSCOMP_BWD,
     &     PRUN_BELOW, TO_PROCESS, SIZE_TO_PROCESS
     &     , FROM_PP
     &    )
      IMPLICIT NONE
      LOGICAL BLOQ, FLAG
      INTEGER LBUFR, LBUFR_BYTES
      INTEGER BUFR( LBUFR )
      INTEGER MYID, SLAVEF, COMM
      INTEGER N, LIWW
      INTEGER IWCB( LIWW )
      INTEGER(8), intent(in) :: LWC
      REAL W( LWC )
      INTEGER POSIWCB
      INTEGER IIPOOL, LPOOL
      INTEGER IPOOL( LPOOL )
      INTEGER LPANEL_POS
      INTEGER PANEL_POS( LPANEL_POS )
      INTEGER NBFINF, INFO(80), KEEP(500)
      INTEGER(8) :: POSWCB, PLEFTW
      INTEGER(8) KEEP8(150)
      REAL, INTENT(INOUT) :: DKEEP(230)
      INTEGER PROCNODE_STEPS( KEEP(28) ), FRERE( KEEP(28) )
      INTEGER PTRICB(KEEP(28)), STEP( N ), FILS( N )
      INTEGER(8) :: PTRACB(KEEP(28))
      INTEGER LIW
      INTEGER(8) :: LA
      INTEGER PTRIST(KEEP(28)), IW( LIW )
      INTEGER (8) :: PTRFAC(KEEP(28))
      REAL A( LA ), W2( KEEP(133) )
      INTEGER NRHS
      INTEGER MYLEAF_LEFT, MTYPE
      INTEGER LRHSCOMP, POSINRHSCOMP_BWD(N)
      REAL RHSCOMP(LRHSCOMP,NRHS)
      LOGICAL, INTENT(IN) :: PRUN_BELOW
      INTEGER SIZE_TO_PROCESS
      LOGICAL TO_PROCESS(SIZE_TO_PROCESS)
      LOGICAL, intent(in) :: FROM_PP
      INCLUDE 'mpif.h'
      INCLUDE 'mumps_tags.h'
      INTEGER MSGSOU, MSGTAG, MSGLEN
      INTEGER :: STATUS(MPI_STATUS_SIZE)
      INTEGER :: IERR
      FLAG = .FALSE.
      IF ( BLOQ ) THEN
           CALL MPI_PROBE( MPI_ANY_SOURCE, MPI_ANY_TAG,
     &                     COMM, STATUS, IERR )
        FLAG = .TRUE.
      ELSE
        CALL MPI_IPROBE( MPI_ANY_SOURCE, MPI_ANY_TAG, COMM,
     &                   FLAG, STATUS, IERR )
      END IF
      IF (FLAG) THEN
         KEEP(266)=KEEP(266)-1
         MSGSOU=STATUS(MPI_SOURCE)
         MSGTAG=STATUS(MPI_TAG)
         CALL MPI_GET_COUNT( STATUS, MPI_PACKED, MSGLEN, IERR )
         IF ( MSGLEN .GT. LBUFR_BYTES ) THEN
           INFO(1) = -20
           INFO(2) = MSGLEN
           IF (NBFINF .NE. 0) THEN
             CALL SMUMPS_BDC_ERROR( MYID, SLAVEF, COMM, KEEP )
           ENDIF
         ELSE
           CALL MPI_RECV(BUFR, LBUFR_BYTES, MPI_PACKED, MSGSOU,
     &                   MSGTAG, COMM, STATUS, IERR)
           CALL SMUMPS_BACKSLV_TRAITER_MESSAGE( MSGTAG, MSGSOU,
     &                BUFR, LBUFR, LBUFR_BYTES,
     &                MYID, SLAVEF, COMM,
     &                N, IWCB, LIWW, POSIWCB,
     &                W, LWC, POSWCB,
     &                IIPOOL, NBFINF, PTRICB, PTRACB, INFO,
     &                IPOOL, LPOOL, PANEL_POS, LPANEL_POS, STEP,
     &                FRERE, FILS, PROCNODE_STEPS, PLEFTW,
     &                KEEP, KEEP8, DKEEP,
     &                PTRIST, PTRFAC, IW, LIW, A, LA, W2, MYLEAF_LEFT, 
     &                NRHS, MTYPE, 
     &                RHSCOMP, LRHSCOMP, POSINRHSCOMP_BWD,
     &               PRUN_BELOW, TO_PROCESS, SIZE_TO_PROCESS
     &               , FROM_PP
     &          )
         END IF
      END IF
      RETURN
      END SUBROUTINE SMUMPS_BACKSLV_RECV_AND_TREAT
      RECURSIVE SUBROUTINE SMUMPS_BACKSLV_TRAITER_MESSAGE(
     &                MSGTAG, MSGSOU,
     &                BUFR, LBUFR, LBUFR_BYTES,
     &                MYID, SLAVEF, COMM,
     &                N, IWCB, LIWW, POSIWCB,
     &                W, LWC, POSWCB,
     &                IIPOOL, NBFINF, PTRICB, PTRACB, INFO,
     &                IPOOL, LPOOL, PANEL_POS, LPANEL_POS, STEP,
     &                FRERE, FILS, PROCNODE_STEPS, PLEFTW,
     &                KEEP, KEEP8, DKEEP,
     &                PTRIST, PTRFAC, IW, LIW, A, LA, W2, MYLEAF_LEFT, 
     &                NRHS, MTYPE, 
     &                RHSCOMP, LRHSCOMP, POSINRHSCOMP_BWD,
     &                PRUN_BELOW, TO_PROCESS, SIZE_TO_PROCESS
     &               , FROM_PP
     &           )
      USE SMUMPS_OOC
      USE SMUMPS_SOL_LR, ONLY: SMUMPS_SOL_SLAVE_LR_U,
     &                         SMUMPS_SOL_BWD_LR_SU
      USE SMUMPS_BUF
      IMPLICIT NONE
      INTEGER MSGTAG, MSGSOU
      INTEGER LBUFR, LBUFR_BYTES
      INTEGER BUFR( LBUFR )
      INTEGER MYID, SLAVEF, COMM
      INTEGER N, LIWW
      INTEGER IWCB( LIWW )
      INTEGER(8), intent(in) :: LWC
      REAL W( LWC )
      INTEGER POSIWCB
      INTEGER IIPOOL, LPOOL, LPANEL_POS
      INTEGER IPOOL( LPOOL )
      INTEGER PANEL_POS( LPANEL_POS )
      INTEGER NBFINF, INFO(80), KEEP(500)
      INTEGER(8) :: POSWCB, PLEFTW
      INTEGER(8) KEEP8(150)
      REAL, INTENT(INOUT) :: DKEEP(230)
      INTEGER PTRICB(KEEP(28)), STEP( N ), FILS( N )
      INTEGER(8) :: PTRACB(KEEP(28))
      INTEGER FRERE(KEEP(28))
      INTEGER PROCNODE_STEPS(KEEP(28))
      INTEGER LIW
      INTEGER(8) :: LA
      INTEGER IW( LIW ), PTRIST( KEEP(28) )
      INTEGER(8) :: PTRFAC(KEEP(28))
      REAL A( LA ), W2( KEEP(133) )
      INTEGER NRHS
      INTEGER MYLEAF_LEFT, MTYPE
      INTEGER LRHSCOMP, POSINRHSCOMP_BWD(N)
      REAL RHSCOMP(LRHSCOMP,NRHS)
      LOGICAL, INTENT(IN) :: PRUN_BELOW
      INTEGER  SIZE_TO_PROCESS
      LOGICAL TO_PROCESS(SIZE_TO_PROCESS), NO_CHILDREN
      LOGICAL, intent(in) :: FROM_PP
      INCLUDE 'mpif.h'
      INCLUDE 'mumps_tags.h'
      INTEGER POSITION, IF, INODE, IERR, LONG, DUMMY(1)
      INTEGER    :: LIELL, K
      INTEGER(8) :: APOS, IST
      INTEGER NPIV, NROW_L, IPOS, NROW_RECU
      INTEGER(8) :: IFR8
      INTEGER I, JJ, IN, PROCDEST, J1, J2, LDA
      INTEGER NSLAVES, NELIM, J, POSINDICES, INODEPOS,
     &     IPOSINRHSCOMP, IPOSINRHSCOMP_PANEL
      INTEGER JBDEB, JBFIN, NRHS_B, allocok
      INTEGER(8) :: P_UPDATE, P_SOL_MAS         
      INTEGER :: IWHDLR, MTYPE_SLAVE, LDA_SLAVE 
      LOGICAL FLAG
      REAL ZERO, ALPHA, ONE
      PARAMETER (ZERO=0.0E0, ONE = 1.0E0, ALPHA=-1.0E0)
      INCLUDE 'mumps_headers.h'
      INTEGER POOL_FIRST_POS, TMP
      LOGICAL, DIMENSION(:), ALLOCATABLE :: DEJA_SEND
      INTEGER :: NCB
      INTEGER(8) :: APOSDEB, NBENTRIES_ALLPANELS
      INTEGER(8) :: PTWCB_PANEL
      INTEGER(8) :: PTWCB, PPIV_COURANT
      INTEGER LDAJ, NBJ, LIWFAC,
     &        NBJLAST, NPIV_LAST, PANEL_SIZE,
     &        NCB_PANEL, TYPEF
      LOGICAL TWOBYTWO
      INTEGER BEG_PANEL
      INTEGER IPANEL, NPANELS
      INTEGER TMP_NBPANELS, I_PIVRPTR, I_PIVR
      LOGICAL MUST_BE_PERMUTED
      LOGICAL COMPRESS_PANEL, LR_ACTIVATED
      LOGICAL  OOCWRITE_COMPATIBLE_WITH_BLR 
      LOGICAL :: ALLOW_OTHERS_TO_LEAVE
      LOGICAL, EXTERNAL :: MUMPS_IN_OR_ROOT_SSARBR
      INTEGER, EXTERNAL :: MUMPS_PROCNODE
      ALLOCATE(DEJA_SEND( 0:SLAVEF-1 ), stat=allocok)
      if(allocok.ne.0) then
         INFO(1)=-13
         INFO(2)=SLAVEF
         WRITE(6,*) MYID,' Allocation error of DEJA_SEND '
     &        //'in bwd solve COMPSO'
         GOTO 260
      END IF
      DUMMY(1)=0
      IF (MSGTAG .EQ. TERMBWD) THEN
          NBFINF = NBFINF - 1
      ELSE IF (MSGTAG .EQ. NOEUD) THEN
          POSITION = 0
          CALL MPI_UNPACK(BUFR, LBUFR_BYTES, POSITION,
     &        INODE, 1, MPI_INTEGER,
     &        COMM, IERR)
          CALL MPI_UNPACK( BUFR, LBUFR_BYTES, POSITION,
     &        JBDEB, 1, MPI_INTEGER, COMM, IERR )
          CALL MPI_UNPACK( BUFR, LBUFR_BYTES, POSITION,
     &        JBFIN, 1, MPI_INTEGER, COMM, IERR )
          CALL MPI_UNPACK(BUFR, LBUFR_BYTES, POSITION,
     &        LONG, 1, MPI_INTEGER,
     &        COMM, IERR)
          NRHS_B = JBFIN-JBDEB+1
          IF (   POSIWCB - LONG .LT. 0
     &      .OR. POSWCB - PLEFTW + 1_8 .LT. LONG ) THEN
            CALL SMUMPS_COMPSO(N, KEEP(28), IWCB,
     &      LIWW, W, LWC,
     &      POSWCB, POSIWCB, PTRICB, PTRACB)
            IF (POSIWCB - LONG .LT. 0) THEN
              INFO(1)=-14
              INFO(2)=-POSIWCB + LONG
              WRITE(6,*) MYID,' Internal error 1 in bwd solve COMPSO'
              GOTO 260
            END IF
            IF ( POSWCB - PLEFTW + 1_8 .LT. LONG ) THEN
              INFO(1) = -11
              CALL MUMPS_SET_IERROR(LONG + PLEFTW - POSWCB - 1_8,
     &                             INFO(2))
              WRITE(6,*) MYID,' Internal error 2 in bwd solve COMPSO'
              GOTO 260
            END IF
          ENDIF
          POSIWCB = POSIWCB - LONG
          POSWCB = POSWCB - LONG
          IF (LONG .GT. 0) THEN
            CALL MPI_UNPACK(BUFR, LBUFR_BYTES, POSITION,
     &          IWCB(POSIWCB + 1), 
     &          LONG, MPI_INTEGER, COMM, IERR)
            DO K=JBDEB,JBFIN
              CALL MPI_UNPACK(BUFR, LBUFR_BYTES, POSITION,
     &           W(POSWCB + 1), LONG, 
     &           MPI_REAL, COMM, IERR)
              DO JJ=0, LONG-1
                IPOSINRHSCOMP = abs( POSINRHSCOMP_BWD( IWCB(
     &                                    POSIWCB+1+JJ ) ) )
                IF ( (IPOSINRHSCOMP.EQ.0) .OR.
     &            ( IPOSINRHSCOMP.GT.N ) ) CYCLE  
                RHSCOMP(IPOSINRHSCOMP,K) = W(POSWCB+1+JJ)
              ENDDO
            ENDDO
            POSIWCB = POSIWCB + LONG
            POSWCB = POSWCB + LONG
          ENDIF
          POOL_FIRST_POS = IIPOOL
          IF ( PRUN_BELOW ) THEN
             IF (.NOT.TO_PROCESS(STEP(INODE))) 
     &            GOTO 1010
          ENDIF
             IPOOL( IIPOOL ) = INODE
             IIPOOL = IIPOOL + 1
 1010     CONTINUE
          IF = FRERE( STEP(INODE) )
          DO WHILE ( IF .GT. 0 )
             IF ( MUMPS_PROCNODE(PROCNODE_STEPS(STEP(IF)),
     &            KEEP(199)) .eq. MYID ) THEN
                IF ( PRUN_BELOW ) THEN
                   IF (.NOT.TO_PROCESS(STEP(IF))) THEN
                      IF = FRERE(STEP(IF))
                      CYCLE
                   ENDIF
                ENDIF
                   IPOOL( IIPOOL ) = IF
                   IIPOOL = IIPOOL + 1
             END IF
             IF = FRERE( STEP( IF ) )
          END DO
             DO I=1,(IIPOOL-POOL_FIRST_POS)/2
                TMP=IPOOL(POOL_FIRST_POS+I-1)
                IPOOL(POOL_FIRST_POS+I-1)=IPOOL(IIPOOL-I)
                IPOOL(IIPOOL-I)=TMP
             ENDDO      
      ELSE IF ( MSGTAG .EQ. BACKSLV_MASTER2SLAVE ) THEN
        POSITION = 0
        CALL MPI_UNPACK( BUFR, LBUFR_BYTES, POSITION,
     &                   INODE, 1, MPI_INTEGER, COMM, IERR )
        CALL MPI_UNPACK( BUFR, LBUFR_BYTES, POSITION,
     &                   NROW_RECU, 1, MPI_INTEGER, COMM, IERR )
        CALL MPI_UNPACK( BUFR, LBUFR_BYTES, POSITION,
     &                   JBDEB, 1, MPI_INTEGER, COMM, IERR )
        CALL MPI_UNPACK( BUFR, LBUFR_BYTES, POSITION,
     &                   JBFIN, 1, MPI_INTEGER, COMM, IERR )
        NRHS_B = JBFIN-JBDEB+1
        LR_ACTIVATED   = (IW(PTRIST(STEP(INODE))+XXLR).GT.0)
        COMPRESS_PANEL = (IW(PTRIST(STEP(INODE))+XXLR).GE.2)
        OOCWRITE_COMPATIBLE_WITH_BLR =
     &     ( .NOT.LR_ACTIVATED.OR.(.NOT.COMPRESS_PANEL).OR.
     &            (KEEP(485).EQ.0) 
     &     )
        IPOS   = PTRIST( STEP(INODE) ) + KEEP(IXSZ)
        NPIV   = - IW( IPOS     )
        NROW_L =   IW( IPOS + 1 )
        IF ( NROW_L .NE. NROW_RECU ) THEN
          WRITE(*,*) 'Error1 : NROW L/RECU=',NROW_L, NROW_RECU
          CALL MUMPS_ABORT()
        END IF
        LONG = NROW_L + NPIV
        IF ( POSWCB - int(LONG,8)*int(NRHS_B,8) .LT. PLEFTW - 1_8 ) THEN
           CALL SMUMPS_COMPSO( N, KEEP(28), IWCB,
     &          LIWW, W, LWC,
     &          POSWCB, POSIWCB, PTRICB, PTRACB)
           IF ( POSWCB - LONG*NRHS_B .LT. PLEFTW - 1_8 ) THEN
             INFO(1) = -11
             CALL MUMPS_SET_IERROR(LONG * NRHS_B- POSWCB,INFO(2))
             WRITE(6,*) MYID,' Internal error 3 in bwd solve COMPSO'
             GOTO 260
           END IF
        END IF
        P_UPDATE  = PLEFTW
        P_SOL_MAS = PLEFTW + int(NPIV,8) * int(NRHS_B,8)
        PLEFTW    = P_SOL_MAS + int(NROW_L,8) * int(NRHS_B,8)
        DO K=JBDEB, JBFIN
          CALL MPI_UNPACK( BUFR, LBUFR_BYTES, POSITION,
     &                   W( P_SOL_MAS+(K-JBDEB)*NROW_L),NROW_L,
     &                   MPI_REAL,
     &                   COMM, IERR )
        ENDDO
        IF (KEEP(201).GT.0.AND.OOCWRITE_COMPATIBLE_WITH_BLR) THEN
        CALL SMUMPS_SOLVE_GET_OOC_NODE(
     &        INODE,PTRFAC,KEEP,A,LA,STEP,
     &        KEEP8,N,MUST_BE_PERMUTED,IERR)
           IF(IERR.LT.0)THEN
              INFO(1)=IERR
              INFO(2)=0
              GOTO 260
           ENDIF
        ENDIF
        APOS = PTRFAC( STEP(INODE))
        IF ( IW(PTRIST(STEP(INODE))+XXLR) .GE. 2 .AND.
     &       KEEP(485) .EQ. 1 ) THEN
          IWHDLR = IW(PTRIST(STEP(INODE))+XXF)
          MTYPE_SLAVE = 0 
          W(P_UPDATE:P_UPDATE+NPIV*NRHS_B-1)=ZERO
          CALL SMUMPS_SOL_SLAVE_LR_U(INODE, IWHDLR, -9999,
     &         W, LWC,
     &         NROW_L, NPIV, 
     &         P_SOL_MAS, P_UPDATE,
     &         JBDEB, JBFIN,
     &         MTYPE_SLAVE, KEEP, KEEP8,
     &         INFO(1), INFO(2) )
        ELSE
          IF (KEEP(201) .EQ. 1.AND.OOCWRITE_COMPATIBLE_WITH_BLR) 
     &    THEN 
            MTYPE_SLAVE = 1
            LDA_SLAVE = NROW_L
          ELSE
            MTYPE_SLAVE = 0
            LDA_SLAVE = NPIV
          ENDIF
          CALL SMUMPS_SOLVE_GEMM_UPDATE(
     &           A, LA, APOS, NROW_L,
     &           LDA_SLAVE,    
     &           NPIV,
     &           NRHS_B, W, LWC,
     &           P_SOL_MAS, NROW_L,
     &           P_UPDATE, NPIV,
     &           MTYPE_SLAVE, KEEP, ZERO)
        ENDIF
        IF (KEEP(201) .EQ. 1.AND.OOCWRITE_COMPATIBLE_WITH_BLR) 
     &  THEN 
          CALL SMUMPS_FREE_FACTORS_FOR_SOLVE(INODE,PTRFAC,KEEP(28),
     &          A,LA,.TRUE.,IERR)
          IF(IERR.LT.0)THEN
            INFO(1)=IERR
            INFO(2)=0
            GOTO 260
          ENDIF
        ENDIF
        PLEFTW = PLEFTW - int(NROW_L,8) * int(NRHS_B,8)
 100    CONTINUE
        CALL SMUMPS_BUF_SEND_BACKVEC( NRHS_B, INODE, 
     &                               W(P_UPDATE),
     &                               NPIV, NPIV,
     &                                MSGSOU, 
     &                                BACKSLV_UPDATERHS,
     &                                JBDEB, JBFIN,
     &                                KEEP, COMM, IERR )
        IF ( IERR .EQ. -1 ) THEN
          CALL SMUMPS_BACKSLV_RECV_AND_TREAT(
     &     .FALSE., FLAG,
     &     BUFR, LBUFR, LBUFR_BYTES,
     &     MYID, SLAVEF, COMM,
     &     N, IWCB, LIWW, POSIWCB,
     &     W, LWC, POSWCB,
     &     IIPOOL, NBFINF, PTRICB, PTRACB, INFO,
     &     IPOOL, LPOOL, PANEL_POS, LPANEL_POS, STEP,
     &     FRERE, FILS, PROCNODE_STEPS, PLEFTW,
     &     KEEP, KEEP8, DKEEP,
     &     PTRIST, PTRFAC, IW, LIW, A, LA, W2, MYLEAF_LEFT,
     &     NRHS, MTYPE,
     &     RHSCOMP, LRHSCOMP, POSINRHSCOMP_BWD,
     &     PRUN_BELOW, TO_PROCESS, SIZE_TO_PROCESS
     &      , FROM_PP
     &      )
          IF ( INFO( 1 ) .LT. 0 ) GOTO 270
          GOTO 100
       ELSE IF ( IERR .EQ. -2 ) THEN
          INFO( 1 ) = -17
          INFO( 2 ) = NRHS_B * NPIV * KEEP(35) + 4 * KEEP(34)
          GOTO 260
       ELSE IF ( IERR .EQ. -3 ) THEN
          INFO( 1 ) = -20
          INFO( 2 ) = NRHS_B * NPIV * KEEP(35) + 4 * KEEP(34)
          GOTO 260
        END IF
        PLEFTW = PLEFTW - NPIV * NRHS_B
      ELSE IF ( MSGTAG .EQ. BACKSLV_UPDATERHS ) THEN
        POSITION = 0
        CALL MPI_UNPACK( BUFR, LBUFR_BYTES, POSITION,
     &                   INODE, 1, MPI_INTEGER, COMM, IERR )
      LR_ACTIVATED = (IW(PTRIST(STEP(INODE))+XXLR).GT.0)
      COMPRESS_PANEL = (IW(PTRIST(STEP(INODE))+XXLR).GE.2)
      OOCWRITE_COMPATIBLE_WITH_BLR =
     &     (.NOT.LR_ACTIVATED.OR.(.NOT.COMPRESS_PANEL).OR.
     &            (KEEP(485).EQ.0) 
     &     )
      IPOS = PTRIST(STEP(INODE)) + 2 + KEEP(IXSZ)
      LIELL = IW(IPOS-2)+IW(IPOS+1)
        CALL MPI_UNPACK( BUFR, LBUFR_BYTES, POSITION,
     &                   NPIV, 1, MPI_INTEGER, COMM, IERR )
        CALL MPI_UNPACK( BUFR, LBUFR_BYTES, POSITION,
     &                   JBDEB, 1, MPI_INTEGER, COMM, IERR )
        CALL MPI_UNPACK( BUFR, LBUFR_BYTES, POSITION,
     &                   JBFIN, 1, MPI_INTEGER, COMM, IERR )
      NRHS_B = JBFIN-JBDEB+1
        NELIM = IW(IPOS-1)
        IPOS = IPOS + 1
        NPIV = IW(IPOS)
        IPOS = IPOS + 1
        NSLAVES = IW( IPOS + 1 )
        IPOS = IPOS + 1 + NSLAVES
        INODEPOS = PTRIST(STEP(INODE)) + KEEP(IXSZ) + 4
        IF ( KEEP(50) .eq. 0 ) THEN
          LDA = LIELL
        ELSE
          LDA = NPIV
        ENDIF
      IF ( MTYPE .EQ. 1 .AND. KEEP(50).EQ.0 ) THEN
        J1 = IPOS + LIELL + 1
        J2 = IPOS + NPIV + LIELL
      ELSE
        J1 = IPOS + 1
        J2 = IPOS + NPIV
      ENDIF
        IPOSINRHSCOMP =  POSINRHSCOMP_BWD(IW(J1)) 
        DO K=JBDEB, JBFIN
          CALL MPI_UNPACK( BUFR, LBUFR_BYTES, POSITION,
     &                     W2, NPIV, MPI_REAL,
     &                     COMM, IERR )
          I = 1
          IF ( (KEEP(253).NE.0) .AND.
     &         (IW(PTRIST(STEP(INODE))+XXS).EQ.C_FINI+NSLAVES) 
     &       ) THEN
          DO JJ = J1,J2   
            RHSCOMP(IPOSINRHSCOMP+JJ-J1,K) = W2(I)
            I = I+1
          ENDDO
         ELSE
          DO JJ = J1,J2   
            RHSCOMP(IPOSINRHSCOMP+JJ-J1,K) = 
     &      RHSCOMP(IPOSINRHSCOMP+JJ-J1,K) + W2(I)
            I = I+1
          ENDDO
         ENDIF
        ENDDO  
        IW(PTRIST(STEP(INODE))+XXS) = 
     &      IW(PTRIST(STEP(INODE))+XXS) - 1
        IF ( IW(PTRIST(STEP(INODE))+XXS).EQ.C_FINI ) THEN
          IF (KEEP(201).GT.0.AND.OOCWRITE_COMPATIBLE_WITH_BLR) 
     &    THEN
             CALL SMUMPS_SOLVE_GET_OOC_NODE(
     &            INODE,PTRFAC,KEEP,A,LA,STEP,
     &            KEEP8,N,MUST_BE_PERMUTED,IERR)
             IF(IERR.LT.0)THEN
                INFO(1)=IERR
                INFO(2)=0
                GOTO 260
             ENDIF
             IF (KEEP(201).EQ.1 .AND. KEEP(50).NE.1) THEN
               CALL SMUMPS_OOC_PP_CHECK_PERM_FREED(
     &              IW(IPOS+1+2*LIELL),
     &              MUST_BE_PERMUTED )
             ENDIF
          ENDIF  
          APOS = PTRFAC(IW(INODEPOS))
          IF (KEEP(201).EQ.1.AND.OOCWRITE_COMPATIBLE_WITH_BLR) 
     &    THEN 
             LIWFAC =  IW(PTRIST(STEP(INODE))+XXI)
             TYPEF = TYPEF_L
             NROW_L   = NPIV+NELIM 
             PANEL_SIZE = SMUMPS_OOC_PANEL_SIZE(NROW_L)
             IF (PANEL_SIZE.LT.0) THEN
               WRITE(6,*) ' Internal error in bwd solve PANEL_SIZE=',
     &         PANEL_SIZE
               CALL MUMPS_ABORT()
             ENDIF
          ENDIF 
        IF ( POSIWCB - 2 .LT. 0 .or.
     &     POSWCB-int(LIELL,8)*int(NRHS_B,8) .LT. PLEFTW-1_8 ) THEN
          CALL SMUMPS_COMPSO( N, KEEP(28), IWCB, LIWW, W, LWC,
     &          POSWCB, POSIWCB, PTRICB, PTRACB )
          IF ( POSWCB-int(LIELL,8)*int(NRHS_B,8) .LT. PLEFTW-1_8 ) THEN
            INFO( 1 ) = -11
            CALL MUMPS_SET_IERROR( int(LIELL,8)*int(NRHS_B,8)-
     &                            POSWCB-PLEFTW+1_8,
     &                            INFO(2) )
            GOTO 260
          END IF
          IF ( POSIWCB - 2 .LT. 0 ) THEN
            INFO( 1 ) = -14
            INFO( 2 ) = 2 - POSIWCB
            GO TO 260
          END IF
        END IF
        POSIWCB = POSIWCB - 2
        POSWCB  = POSWCB - int(LIELL,8)*int(NRHS_B,8)
        PTRICB(STEP( INODE )) = POSIWCB + 1
        PTRACB(STEP( INODE )) = POSWCB  + 1_8
        IWCB( PTRICB(STEP( INODE ))     ) = LIELL*NRHS_B
        IWCB( PTRICB(STEP( INODE )) + 1 ) = 1  
        IPOS = PTRIST(STEP(INODE)) + KEEP(IXSZ) + 5 + NSLAVES
        IF ( MTYPE.EQ.1 .AND. KEEP(50).EQ.0 ) THEN
           POSINDICES = IPOS + LIELL + 1
        ELSE
           POSINDICES = IPOS + 1
        END IF
        PTWCB = PTRACB(STEP( INODE ))
        IPOSINRHSCOMP =  POSINRHSCOMP_BWD(IW(J1)) 
        IFR8 = PTRACB(STEP( INODE ))
      IFR8   = PTWCB + int(NPIV - 1,8)
        IF ( MTYPE .EQ. 1 .AND. KEEP(50).EQ.0 ) THEN
          J1 = IPOS + LIELL + NPIV + 1
          J2 = IPOS + 2 * LIELL
        ELSE
          J1 = IPOS + NPIV + 1
          J2 = IPOS + LIELL
        END IF
        CALL SMUMPS_SOL_BWD_GTHR( JBDEB, JBFIN, J1, J2,
     &       RHSCOMP, NRHS, LRHSCOMP,
     &       W(PTWCB), LIELL, NPIV+1,
     &       IW, LIW, KEEP, N, POSINRHSCOMP_BWD )
          IFR8 = IFR8 + int(J2-KEEP(253)-J1+1,8)
      IF ( KEEP(201).EQ.1 .AND. OOCWRITE_COMPATIBLE_WITH_BLR .AND.
     &    (( NELIM .GT. 0 ).OR. (MTYPE.NE.1 )))  THEN
        J = NPIV / PANEL_SIZE 
        TWOBYTWO = KEEP(50).EQ.2 .AND. KEEP(105).GT.0
        IF (TWOBYTWO) THEN 
          CALL SMUMPS_BUILD_PANEL_POS(PANEL_SIZE, PANEL_POS, LPANEL_POS,
     &        IW(IPOS+1+LIELL), NPIV, NPANELS, NROW_L,
     &        NBENTRIES_ALLPANELS)
        ELSE
          IF (NPIV.EQ.J*PANEL_SIZE) THEN
            NPIV_LAST = NPIV
            NBJLAST   = PANEL_SIZE
            NPANELS   = J
          ELSE
            NPIV_LAST = (J+1)* PANEL_SIZE
            NBJLAST   = NPIV-J*PANEL_SIZE
            NPANELS   = J+1
          ENDIF
          NBENTRIES_ALLPANELS =
     &    int(NROW_L,8) * int(NPIV,8) 
     &  - int( ( J * ( J - 1 ) ) /2,8 ) 
     &    * int(PANEL_SIZE,8) * int(PANEL_SIZE,8) 
     &  - int(J,8)                       
     &    * int(mod(NPIV, PANEL_SIZE),8) 
     &    * int(PANEL_SIZE,8)    
          JJ=NPIV_LAST
        ENDIF
        APOSDEB = APOS + NBENTRIES_ALLPANELS 
        DO IPANEL = NPANELS, 1, -1
            IF (TWOBYTWO) THEN
              NBJ = PANEL_POS(IPANEL+1)-PANEL_POS(IPANEL)
              BEG_PANEL = PANEL_POS(IPANEL)
            ELSE
              IF (JJ.EQ.NPIV_LAST) THEN
                NBJ = NBJLAST
              ELSE
                NBJ = PANEL_SIZE
              ENDIF
              BEG_PANEL = JJ- PANEL_SIZE+1
            ENDIF
            LDAJ    = NROW_L-BEG_PANEL+1 
            APOSDEB = APOSDEB - int(NBJ,8)*int(LDAJ,8)
            PTWCB   = PTRACB(STEP(INODE))
            PTWCB_PANEL =  PTRACB(STEP(INODE)) + int(BEG_PANEL - 1,8)
            IPOSINRHSCOMP_PANEL = IPOSINRHSCOMP + BEG_PANEL - 1
            NCB_PANEL   = LDAJ - NBJ
            NCB     = NROW_L - NPIV
            IF (KEEP(50).NE.1 .AND.MUST_BE_PERMUTED) THEN
              CALL SMUMPS_GET_OOC_PERM_PTR(TYPEF, TMP_NBPANELS,
     &        I_PIVRPTR, I_PIVR, IPOS + 1 + 2 * LIELL, IW, LIW)
              CALL SMUMPS_PERMUTE_PANEL(
     &        IW(I_PIVR + IW(I_PIVRPTR+IPANEL-1)-IW(I_PIVRPTR)),
     &        NPIV-IW(I_PIVRPTR+IPANEL-1)+1,
     &        IW(I_PIVRPTR+IPANEL-1)-1,
     &        A(APOSDEB),
     &        LDAJ, NBJ, BEG_PANEL-1)
            ENDIF
#if defined(MUMPS_USE_BLAS2)
            IF ( NRHS_B == 1 ) THEN
              IF (NCB_PANEL.NE.0) THEN
                  IF (NCB_PANEL - NCB.NE. 0) THEN
                    CALL sgemv( 'T', NCB_PANEL-NCB, NBJ, ALPHA, 
     &              A( APOSDEB + int(NBJ,8) ), LDAJ,
     &              RHSCOMP(IPOSINRHSCOMP_PANEL+NBJ,JBDEB),
     &              1, ONE,
     &              RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB), 1 )
                  ENDIF
                  IF (NCB .NE. 0) THEN
                    CALL sgemv( 'T', NCB, NBJ, ALPHA,
     &              A( APOSDEB + int(LDAJ-NCB,8) ), LDAJ,
     &              W( PTWCB  + int(NPIV,8) ),
     &              1, ONE,
     &              RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB), 1 )
                  ENDIF
              ENDIF
              IF (MTYPE.NE.1) THEN
                CALL strsv('L','T','U', NBJ, A(APOSDEB), LDAJ,
     &            RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB), 1)
              ELSE
                CALL strsv('L','T','N', NBJ, A(APOSDEB), LDAJ,
     &              RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB), 1)
              ENDIF
            ELSE
#endif
              IF (NCB_PANEL.NE.0) THEN
                  IF (NCB_PANEL - NCB .NE. 0) THEN
                  CALL sgemm( 'T', 'N', NBJ, NRHS_B,
     &                                         NCB_PANEL-NCB, ALPHA,
     &              A(APOSDEB +int(NBJ,8)), LDAJ,
     &              RHSCOMP(IPOSINRHSCOMP_PANEL+NBJ,JBDEB), LRHSCOMP,
     &              ONE, RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB), LRHSCOMP)
                  ENDIF
                  IF (NCB .NE. 0) THEN
                  CALL sgemm( 'T', 'N', NBJ, NRHS_B, NCB, ALPHA,
     &              A(APOSDEB +int(LDAJ-NCB,8)), LDAJ,
     &              W( PTWCB+int(NPIV,8) ), LIELL,
     &              ONE, RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB),LRHSCOMP)
                  ENDIF
              ENDIF
              IF (MTYPE.NE.1) THEN
                CALL strsm('L','L','T','U',NBJ, NRHS_B, ONE,
     &          A(APOSDEB), 
     &          LDAJ, RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB), LRHSCOMP)
              ELSE
                CALL strsm('L','L','T','N',NBJ, NRHS_B, ONE,
     &          A(APOSDEB),
     &          LDAJ, RHSCOMP(IPOSINRHSCOMP_PANEL,JBDEB), LRHSCOMP)
              ENDIF
#if defined(MUMPS_USE_BLAS2)
            ENDIF
#endif
            IF (.NOT. TWOBYTWO) JJ=BEG_PANEL-1 
        ENDDO 
        GOTO 1234  
       ENDIF 
        IF ( IW(PTRIST(STEP(INODE))+XXLR) .GE. 2
     &        .AND. KEEP(485) .EQ. 1 ) THEN
          IWHDLR = IW(PTRIST(STEP(INODE))+XXF)
          CALL SMUMPS_SOL_BWD_LR_SU (
     &           INODE, IWHDLR, NPIV, NSLAVES,
     &           LIELL, W, LWC, NRHS_B, PTRACB(STEP(INODE)), 
     &           RHSCOMP, LRHSCOMP, NRHS,
     &           IPOSINRHSCOMP, JBDEB, 
     &           MTYPE, KEEP, KEEP8,
     &           INFO(1), INFO(2) )
        ELSE
          IF (NELIM .GT.0) THEN
              IF ( KEEP(50) .eq. 0 ) THEN
                IST = APOS + int(NPIV,8) * int(LIELL,8)
              ELSE
                 IF( KEEP(459) .GT. 1) THEN
          CALL MUMPS_GETI8(IST, IW(PTRIST(STEP(INODE))+XXR))
                   IST = APOS + IST - int(NPIV,8) * int(NELIM,8)
                 ELSE
                   IST = APOS + int(NPIV,8) * int(NPIV,8)
                 ENDIF
              END IF
#if defined(MUMPS_USE_BLAS2)
              IF ( NRHS_B == 1 ) THEN
                 CALL sgemv( 'N', NPIV, NELIM, ALPHA, A( IST ), NPIV,
     &                 W( NPIV + PTRACB(STEP(INODE)) ),
     &                 1, ONE,
     &                 RHSCOMP(IPOSINRHSCOMP,JBDEB), 1 )
              ELSE
#endif
                 CALL sgemm( 'N', 'N', NPIV, NRHS_B, NELIM, ALPHA,
     &                A(IST), NPIV, W(NPIV+PTRACB(STEP(INODE))), LIELL,
     &                ONE, RHSCOMP(IPOSINRHSCOMP,JBDEB), LRHSCOMP)
#if defined(MUMPS_USE_BLAS2)
              END IF
#endif
          ENDIF 
          PPIV_COURANT = int(JBDEB-1,8)*int(LRHSCOMP,8)
     &                 + int(IPOSINRHSCOMP,8)
          IF (KEEP(459).GT.1 .AND. KEEP(50).NE.0) THEN
          CALL SMUMPS_SOLVE_BWD_PANELS( A, LA, APOS,
     &      NPIV, IW(IPOS+1+LIELL),
     &      NRHS_B, RHSCOMP(1,1), KEEP8(25), LRHSCOMP, PPIV_COURANT, 
     &      MTYPE, KEEP )
          ELSE
          CALL SMUMPS_SOLVE_BWD_TRSOLVE( A, LA, APOS,
     &      NPIV, LDA,
     &      NRHS_B, RHSCOMP(1,1), KEEP8(25), LRHSCOMP, PPIV_COURANT, 
     &      MTYPE, KEEP )
          ENDIF
       ENDIF
 1234     CONTINUE   
          IF (KEEP(201).GT.0.AND.OOCWRITE_COMPATIBLE_WITH_BLR) THEN
           CALL SMUMPS_FREE_FACTORS_FOR_SOLVE(INODE,PTRFAC,KEEP(28),
     &          A,LA,.TRUE.,IERR)
           IF(IERR.LT.0)THEN
              INFO(1)=IERR
              INFO(2)=0
              GOTO 260
           ENDIF
          ENDIF
          IPOS =   PTRIST(STEP(INODE)) +  KEEP(IXSZ) + 6 + NSLAVES
          IPOSINRHSCOMP     = POSINRHSCOMP_BWD(IW(IPOS))
          IN = INODE
  170     IN = FILS(IN)
          IF (IN .GT. 0) GOTO 170
          IF (IN .EQ. 0) THEN
            MYLEAF_LEFT = MYLEAF_LEFT - 1
            ALLOW_OTHERS_TO_LEAVE = ( MYLEAF_LEFT .EQ. 0 .AND.
     &                                KEEP(31) .EQ. 0 )
            IF (KEEP(31) .NE. 0) THEN
              IF (.NOT.  MUMPS_IN_OR_ROOT_SSARBR( 
     &                   PROCNODE_STEPS(STEP(INODE)),
     &                   KEEP(199) ) ) THEN
                KEEP(31) = KEEP(31) - 1
                IF (KEEP(31) .EQ. 1) THEN
                  ALLOW_OTHERS_TO_LEAVE = .TRUE.
                ENDIF
              ENDIF
            ENDIF
            IF ( ALLOW_OTHERS_TO_LEAVE ) THEN
              CALL SMUMPS_MCAST2( DUMMY, 1, MPI_INTEGER, MYID, COMM,
     &                       TERMBWD, SLAVEF, KEEP )
              NBFINF = NBFINF - 1
            ENDIF
            IWCB( PTRICB(STEP(INODE)) + 1 ) = 0
            CALL SMUMPS_FREETOPSO(N, KEEP(28),
     &          IWCB, LIWW, W, LWC,
     &          POSWCB, POSIWCB, PTRICB, PTRACB)
            GOTO 270
          ENDIF  
          DO I = 0, SLAVEF - 1
            DEJA_SEND( I ) = .FALSE.
          END DO
          IN = -IN
          IF ( PRUN_BELOW ) THEN 
            NO_CHILDREN = .TRUE. 
          ELSE
            NO_CHILDREN = .FALSE.
          ENDIF
          DO WHILE (IN.GT.0) 
            IF ( PRUN_BELOW ) THEN
               IF ( .NOT.TO_PROCESS(STEP(IN)) ) THEN
                  IN = FRERE(STEP(IN))
                  CYCLE
               ELSE
                 NO_CHILDREN = .FALSE.
               ENDIF
            ENDIF
           POOL_FIRST_POS  = IIPOOL
            IF (MUMPS_PROCNODE(PROCNODE_STEPS(STEP(IN)),
     &          KEEP(199)) .EQ. MYID) THEN
                  IPOOL(IIPOOL ) = IN
                  IIPOOL = IIPOOL + 1
            ELSE
              PROCDEST = MUMPS_PROCNODE( PROCNODE_STEPS(STEP(IN)), 
     &                   KEEP(199) )
              IF ( .NOT. DEJA_SEND( PROCDEST ) ) THEN
 400          CONTINUE
                CALL SMUMPS_BUF_SEND_VCB( NRHS_B, IN, 0, 0,
     &          LIELL, LIELL - KEEP(253),
     &          IW( POSINDICES ),
     &          W( PTRACB(STEP(INODE)) ), JBDEB, JBFIN,
     &          RHSCOMP(1, 1), NRHS, LRHSCOMP,
     &          IPOSINRHSCOMP, NPIV,
     &          KEEP, PROCDEST, NOEUD, COMM, IERR )
              IF ( IERR .EQ. -1 ) THEN
                CALL SMUMPS_BACKSLV_RECV_AND_TREAT(
     &          .FALSE., FLAG,
     &          BUFR, LBUFR, LBUFR_BYTES,
     &          MYID, SLAVEF, COMM,
     &          N, IWCB, LIWW, POSIWCB,
     &          W, LWC, POSWCB,
     &          IIPOOL, NBFINF, PTRICB, PTRACB, INFO,
     &          IPOOL, LPOOL, PANEL_POS, LPANEL_POS,
     &          STEP, FRERE, FILS, PROCNODE_STEPS,
     &          PLEFTW, KEEP, KEEP8, DKEEP,
     &          PTRIST, PTRFAC, IW, LIW, A, LA, W2, MYLEAF_LEFT,
     &          NRHS, MTYPE, 
     &          RHSCOMP, LRHSCOMP, POSINRHSCOMP_BWD,
     &          PRUN_BELOW, TO_PROCESS, SIZE_TO_PROCESS
     &            , FROM_PP
     &            )
                IF ( INFO( 1 ) .LT. 0 ) THEN
                  GOTO 270
                ENDIF
                GOTO 400
             ELSE IF ( IERR .EQ. -2 ) THEN
                INFO( 1 ) = -17
                INFO( 2 ) = NRHS_B * LIELL * KEEP(35) + 4 * KEEP(34)
                GOTO 260
             ELSE IF ( IERR .EQ. -3 ) THEN
                INFO( 1 ) = -20
                INFO( 2 ) = NRHS_B * LIELL * KEEP(35) + 4 * KEEP(34)
                GOTO 260
              END IF
              DEJA_SEND( PROCDEST ) = .TRUE.
            END IF
          END IF
            IN = FRERE( STEP( IN ) )
          END DO
          ALLOW_OTHERS_TO_LEAVE = .FALSE.
          IF (NO_CHILDREN) THEN
            MYLEAF_LEFT = MYLEAF_LEFT - 1
            ALLOW_OTHERS_TO_LEAVE = ( MYLEAF_LEFT .EQ. 0 .AND.
     &                                KEEP(31) .EQ. 0 )
          ENDIF
          IF (KEEP(31) .NE. 0) THEN
            IF ( .NOT.  MUMPS_IN_OR_ROOT_SSARBR( 
     &                  PROCNODE_STEPS(STEP(INODE)),
     &                  KEEP(199) ) ) THEN
              KEEP(31) = KEEP(31) - 1
              IF (KEEP(31) .EQ. 1) THEN
                ALLOW_OTHERS_TO_LEAVE = .TRUE.
              ENDIF
            ENDIF
          ENDIF
          IF ( ALLOW_OTHERS_TO_LEAVE ) THEN
            CALL SMUMPS_MCAST2( DUMMY, 1, MPI_INTEGER, MYID, 
     &                          COMM, TERMBWD, SLAVEF, KEEP )
            NBFINF = NBFINF - 1
          ENDIF
          IF ( .NOT. NO_CHILDREN ) THEN
            DO I=1,(IIPOOL-POOL_FIRST_POS)/2
              TMP=IPOOL(POOL_FIRST_POS+I-1)
              IPOOL(POOL_FIRST_POS+I-1)=IPOOL(IIPOOL-I)
              IPOOL(IIPOOL-I)=TMP
            ENDDO 
          ENDIF
          IWCB( PTRICB(STEP( INODE )) + 1 ) = 0
          CALL SMUMPS_FREETOPSO( N, KEEP(28),
     &          IWCB, LIWW, W, LWC,
     &          POSWCB, POSIWCB, PTRICB, PTRACB)
        END IF   
      ELSE IF (MSGTAG.EQ.TERREUR) THEN
          INFO(1) = -001
          INFO(2) = MSGSOU
          GO TO 270
       ELSE IF ( (MSGTAG.EQ.UPDATE_LOAD).OR.
     &      (MSGTAG.EQ.TAG_DUMMY) ) THEN
          GO TO 270
       ELSE
          INFO(1) = -100
          INFO(2) = MSGTAG
          GOTO 260
      ENDIF
      GO TO 270
 260  CONTINUE
      IF (NBFINF .NE. 0) THEN
        CALL SMUMPS_BDC_ERROR( MYID, SLAVEF, COMM, KEEP )
      ENDIF
 270  CONTINUE
      IF (allocated(DEJA_SEND)) DEALLOCATE(DEJA_SEND)
      RETURN
      END SUBROUTINE SMUMPS_BACKSLV_TRAITER_MESSAGE
      SUBROUTINE SMUMPS_BUILD_PANEL_POS(PANEL_SIZE, PANEL_POS,
     &                           LEN_PANEL_POS, INDICES, NPIV,
     &                           NPANELS, NFRONT_OR_NASS,
     &                           NBENTRIES_ALLPANELS)
      IMPLICIT NONE
      INTEGER, intent (in)   :: PANEL_SIZE, NPIV
      INTEGER, intent (in)   :: INDICES(NPIV)
      INTEGER, intent (in)   :: LEN_PANEL_POS
      INTEGER, intent (out)  :: NPANELS
      INTEGER, intent (out)  :: PANEL_POS(LEN_PANEL_POS)
      INTEGER, intent (in)   :: NFRONT_OR_NASS
      INTEGER(8), intent(out):: NBENTRIES_ALLPANELS
      INTEGER NPANELS_MAX, I, NBeff
      INTEGER(8) :: NBENTRIES_THISPANEL
      NBENTRIES_ALLPANELS = 0_8
      NPANELS_MAX = (NPIV+PANEL_SIZE-1)/PANEL_SIZE
      IF (LEN_PANEL_POS .LT. NPANELS_MAX + 1) THEN
        WRITE(*,*) "Error 1 in SMUMPS_BUILD_PANEL_POS",
     &              LEN_PANEL_POS,NPANELS_MAX
        CALL MUMPS_ABORT()
      ENDIF
      I = 1
      NPANELS = 0
      IF (I .GT. NPIV) RETURN 
 10   CONTINUE
      NPANELS = NPANELS + 1
      PANEL_POS(NPANELS) = I
      NBeff = min(PANEL_SIZE, NPIV-I+1)
      IF ( INDICES(I+NBeff-1) < 0) THEN
        NBeff=NBeff+1
      ENDIF
      NBENTRIES_THISPANEL = int(NFRONT_OR_NASS-I+1,8) * int(NBeff,8)
      NBENTRIES_ALLPANELS = NBENTRIES_ALLPANELS + NBENTRIES_THISPANEL
      I=I+NBeff
      IF ( I .LE. NPIV ) GOTO 10
      PANEL_POS(NPANELS+1)=NPIV+1
      RETURN
      END SUBROUTINE SMUMPS_BUILD_PANEL_POS
