anchor.diff:        CHARACTER*40 tag,ofile
         REAL*8 x1,x2,y1,y2,z,dx,dy,ref(5)
         INTEGER narg,i,j,nx,ny,p,xsec,xz
  +C Initialize variable values
         x1 = 0.0d0
         x2 = 0.0d0
         nx = -1
         dx = -1.0d0
         y1 = 0.0d0
  -      y2 = 0.1d0
  +      y2 = 0.0d0
         ny = -1
         dy = -1.0d0
         z = 0.0d0
  
positive.code:           dx = (x2-x1)/dble(nx-1)
        endif
  
        if (dy.gt.0.0d0) then
            ny = int((y2-y1)/dy)+1
        elseif (ny.lt.1) then
            call usage('!! Error: NY must be 1 or greater')
        elseif (ny.eq.1) then
            dy = 0.0d0
        else
            dy = (y2-y1)/dble(ny-1)
        endif
        !print *,'DX',dx,'NX',nx
        !print *,'DY',dy,'NY',ny
  
  C----
  C Generate grid
  
negative.code:       PROGRAM grid
  C----
  C Create grids primarily for use with o92util
  C----
        IMPLICIT NONE
        REAL*8 pi,d2r
  