psblas3/base/serial/coo/ccoosv.f

C
C             Parallel Sparse BLAS  version 2.2
C   (C) Copyright 2006/2007/2008
C                      Salvatore Filippone    University of Rome Tor Vergata
C                      Alfredo Buttari        University of Rome Tor Vergata
C
C Redistribution and use in source and binary forms, with or without
C modification, are permitted provided that the following conditions
C are met:
C   1. Redistributions of source code must retain the above copyright
C      notice, this list of conditions and the following disclaimer.
C   2. Redistributions in binary form must reproduce the above copyright
C      notice, this list of conditions, and the following disclaimer in the
C      documentation and/or other materials provided with the distribution.
C   3. The name of the PSBLAS group or the names of its contributors may
C      not be used to endorse or promote products derived from this
C      software without specific written permission.
C
C THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
C ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
C TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
C PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE PSBLAS GROUP OR ITS CONTRIBUTORS
C BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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C POSSIBILITY OF SUCH DAMAGE.
C
C
C  Assumption: the triangular matrix has the diagonal element in the 
C  "right" place, i.e. the last in its row for Lower and the first 
C  for Upper. 
C
      SUBROUTINE CCOOSV (UPLO,TRANS,DIAG,N,AS,IA,JA,INFOA,B,X,IERROR)
      use psb_const_mod
      use psb_error_mod
      complex(psb_spk_)         ZERO
      PARAMETER         (ZERO=(0.0,0.0))
      INTEGER           N,IERROR
      CHARACTER         DIAG, TRANS, UPLO
      complex(psb_spk_)        AS(*), B(*), X(*)
      INTEGER           IA(*), JA(*),INFOA(*)
      complex(psb_spk_)        ACC
      INTEGER           I, J, K, NNZ, II, JJ
      LOGICAL           LOW, TRA, UNI
      integer           :: debug_level, debug_unit
      character(len=20) :: name='ccoosv'
      
      debug_unit  = psb_get_debug_unit()
      debug_level = psb_get_debug_level()

      UNI = (DIAG.EQ.'U')
      TRA = (TRANS.EQ.'T')
      LOW = (UPLO.EQ.'L')
      NNZ = INFOA(1)
      IERROR = 0
      if (debug_level>=psb_debug_serial_comp_)
     +  write(debug_unit,*) trim(name),':',n,nnz,diag,trans,uplo
      IF ( .NOT. TRA) THEN
        if (debug_level>=psb_debug_serial_comp_)
     +    write(debug_unit,*) trim(name),':  NOT TRA'
        IF (LOW) THEN
          if (debug_level>=psb_debug_serial_comp_)
     +      write(debug_unit,*) trim(name),':  LOW'
          IF ( .NOT. UNI) THEN              
            if (debug_level>=psb_debug_serial_comp_)
     +        write(debug_unit,*) trim(name),':  NOT UNI'
            I    = 1
            J    = I
            DO WHILE (I.LE.NNZ)              
              DO WHILE ((J.LE.NNZ).AND.(IA(J).EQ.IA(I)))
                J = J+1
              ENDDO              
              ACC = ZERO
              IR = IA(I)
              DO K = I, J-2
                JC = JA(K)
                ACC = ACC + AS(K)*X(JC)
              ENDDO        
              X(IR) = (B(IR)-ACC)/AS(J-1)
              I = J 
            ENDDO

          ELSE IF (UNI) THEN
C
C    Bug warning: if UNI, some rows might be empty
C              
            I   = 1
            if (debug_level>=psb_debug_serial_comp_)
     +        write(debug_unit,*) trim(name),': UNILOW ',
     +        i,n,nnz,uni,tra,low
            DO II = 1, N 
              DO WHILE ((I.LE.NNZ).AND.(IA(I).LT.II))
                I = I + 1 
              ENDDO
              ACC = ZERO
              IF ((I.LE.NNZ).AND.(IA(I).EQ.II)) THEN
                J  = I + 1
                DO WHILE ((J.LE.NNZ).AND.(IA(J).EQ.IA(I)))
                  J = J+1
                ENDDO              
                DO K = I, J-1
                  JC = JA(K)
                  ACC = ACC + AS(K)*X(JC)
                ENDDO        
              ELSE 
                J = I 
              ENDIF
              X(II) = (B(II)-ACC)
              I = J                 
            ENDDO

          END IF

        ELSE IF ( .NOT. LOW) THEN
          if (debug_level>=psb_debug_serial_comp_)
     +      write(debug_unit,*) trim(name),':  NOT LOW'
          IF ( .NOT. UNI) THEN
            if (debug_level>=psb_debug_serial_comp_)
     +        write(debug_unit,*) trim(name),':   NOT UNI'
            I    = NNZ
            J    = NNZ
            DO WHILE (I.GT.0)              
              DO WHILE ((J.GT.0).AND.(IA(J).EQ.IA(I)))             
                J = J-1
              ENDDO              
              ACC = ZERO
              IR = IA(I)
              DO K = I, J+2,-1
                JC = JA(K)
                ACC = ACC + AS(K)*X(JC)
              ENDDO        
              X(IR) = (B(IR)-ACC)/AS(J+1)
              I = J 
            ENDDO

          ELSE IF (UNI) THEN
            if (debug_level>=psb_debug_serial_comp_)
     +        write(debug_unit,*) trim(name),':  UNI'
            I   = NNZ
            DO II = N,1,-1
              DO WHILE ((I.GT.0).AND.(IA(I).GT.II))
                I = I -1 
              ENDDO
              ACC = ZERO
              IF ((I.GT.0).AND.(IA(I).EQ.II)) THEN
                J  = I - 1
                DO WHILE ((J.GT.0).AND.(IA(J).EQ.IA(I)))
                  J = J-1
                ENDDO              
                DO K = I, J+1, -1
                  JC = JA(K)
                  ACC = ACC + AS(K)*X(JC)
                ENDDO 
              ELSE 
                J = I 
              ENDIF       
              X(II) = (B(II)-ACC)
              I = J 
            ENDDO

          END IF

        END IF

      ELSE IF (TRA) THEN
        if (debug_level>=psb_debug_serial_comp_)
     +    write(debug_unit,*) trim(name),':  TRA'
        IERROR = 3010
        return
CCCCCCCCCCCCCCCC
C
C  TBF
C
CCCCCCCCCCCCCCCC
        DO 180 I = 1, N
          X(I) = B(I)
 180    CONTINUE
        IF (LOW) THEN
          IF ( .NOT. UNI) THEN
            DO 220 I = N, 1, -1
              X(I) = X(I)/AS(IA(I+1)-1)
              ACC = X(I)
              DO 200 J = IA(I), IA(I+1) - 2
                K = JA(J)
                X(K) = X(K) - AS(J)*ACC
 200          CONTINUE
 220        CONTINUE
          ELSE IF (UNI) THEN
            DO 260 I = N, 1, -1
              ACC = X(I)
              DO 240 J = IA(I), IA(I+1) - 1
                K = JA(J)
                X(K) = X(K) - AS(J)*ACC
 240          CONTINUE
 260        CONTINUE
          END IF
        ELSE IF ( .NOT. LOW) THEN
          IF ( .NOT. UNI) THEN
            DO 300 I = 1, N
              X(I) = X(I)/AS(IA(I))
              ACC = X(I)
              DO 280 J = IA(I) + 1, IA(I+1) - 1
                K = JA(J)
                X(K) = X(K) - AS(J)*ACC
 280          CONTINUE
 300        CONTINUE
          ELSE IF (UNI) THEN
            DO 340 I = 1, N
              ACC = X(I)
              DO 320 J = IA(I), IA(I+1) - 1
                K = JA(J)
                X(K) = X(K) - AS(J)*ACC
 320          CONTINUE
 340        CONTINUE
          END IF
        END IF
      END IF
      RETURN
      END