anchor.diff:  
   ! Rewritten in Fortran 90 by David W. Wright November 2013
   
  -! TODO: For reasons currently beyond my comprehension this results in X having a
  -! start index of 0 and D of 1, this needs to be fixed as it is odd
  -! and makes the code difficult to understand
  -DIMENSION X(5000,3),D(5000)
  +REAL, DIMENSION(6000,3) :: X
  +REAL, DIMENSION(6000) :: D
   
   WRITE(6,"(A/)") "APS: VERSION 2.50"
   WRITE(6,"(A/)") "CALCULATION OF Rg FOR UP TO 5000 SPHERE MODELS"
  
positive.code:     END IF
      NSPHERE = NSPHERE + 1
  END DO
  
  CLOSE(5)
  
  
negative.code: PROGRAM APS
  
  ! Program to calculate the radius of gyration of sphere models
  ! Hard limit of 6000 spheres
  
  ! Original Fortran 77 code:
  ! S.J. Perkins July 1981
  