anchor.diff:    INTEGER           ::  N,I,J,M,II,JJ
     REAL(DOUBLE),ALLOCATABLE, DIMENSION(:,:) ::  A, B, C1,C2,CDiff
     TYPE(QuTree),POINTER  :: qA,qB,qC
  -  REAL(DOUBLE)          :: CDiffNorm,CErrBound
  +  REAL(DOUBLE)          :: CNorm,CDiffNorm,CErrBound,CElementErr
     CHARACTER *100        :: Buffer
   
     CALL GETARG(1,BUFFER)
  
positive.code:        CTmp=MATMUL(qA%Blok,qB%Blok)
         ! Increment
         qC%Blok=qC%Blok+CTmp
         ! Bounds
         qC%Norm=qC%Norm+SUM(CTmp(1:BLOCK_SIZE,1:BLOCK_SIZE)**2)
         RETURN
  
negative.code:     qC%Lev=1
      SpAMM_multiplies=Zero
      qC%Box(:,1)=(/1,1/)
      qC%Box(:,2)=(/SpAMM_tiles,SpAMM_tiles/)*BLOCK_SIZE
      !
      CALL SpAMM_Multiply(qC,qA,qB)
    END FUNCTION SpAMM
  