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:     LOGICAL :: do00x00,do01x10,do10x00,do11x10, &
                 do00x01,do01x11,do10x01,do11x11
      ! Bounds
      qC%Box(1,1)=qA%Box(2,1)
      qC%Box(1,2)=qA%Box(2,2)
      qC%Box(2,1)=qB%Box(1,1)
      qC%Box(2,2)=qB%Box(1,2)
      ! Blocks
      IF(qA%Siz==BLOCK_SIZE)THEN
         IF(.NOT.ALLOCATED(qC%Blok))THEN
  
negative.code:     qA%Lev=1
      qA%Num=SpAMM_quadcount
      qA%Box(:,1)=(/1,1/)
      qA%Box(:,2)=(/SpAMM_tiles,SpAMM_tiles/)*BLOCK_SIZE
      CALL SpAMM_Mat2Quad(A,qA)
      qA%Norm=SQRT(qA%Norm)
    END FUNCTION Dense2Quad
  