c----------------------------------------
c
c this will perform the inverse
c distortion correction...
c
      subroutine wfc3ir_cg(xc,yc,xr,yr)
      implicit none
      real*8 xc,yc
      real*8 xr,yr

      real*8 xt, yt
      real*8 dx, dy, dd
      integer NIT
      real*8 xru, yru

      xr = xc
      yr = yc
      NIT = 0
 1    continue
      NIT = NIT + 1
      call wfc3ir_gc(xru,yru,xt,yt)
      dx = xc-xt
      dy = yc-yt
      dd = sqrt(dx**2+dy**2)
      xru = xru + (xc-xt)*0.5
      yru = yru + (yc-yt)*0.5
      if (dd.gt.0.001.and.NIT.lt.99) goto 1
 11   continue 

      xr = xru
      yr = yru
 
      return  
      end