anchor.diff:  ! because this is what is assumed in CDM03 (EUCLID_TN_ESA_AS_003_0-2.pdf)
   DO i=1,xdim
      DO j=1,ydim
  -      s(i,j) = sinp(i+iflip*(xdim+1-2*i),j+jflip*(ydim+1-2*j))
  +      s(j,i) = sinp(i+iflip*(xdim+1-2*i),j+jflip*(ydim+1-2*j))
      ENDDO
   ENDDO
   
  
positive.code: ! flip data back to the input orientation
  DO i=1,xdim
     DO j=1,ydim
        sout(i+iflip*(xdim+1-2*i),j+jflip*(ydim+1-2*j)) = s(i,j)
     ENDDO
  ENDDO
  
  
negative.code: alpha=st*sigma*vth*sfwc**beta/2./svg
  g=nt*2.*svg/sfwc**beta
  
  DO j=1,xdim
     gamm = g * REAL(j)
     DO k=1,zdim
        IF(tr(k).lt.t)THEN
           DO i=1,ydim
              nc=0.
              
              IF(s(i,j).gt.0.01)THEN
  