anchor.diff:  
   end subroutine cholsl
   
  -!***************************************************************************************************
  +!*******************************************************************************
  
positive.code: !***************************************************************************************************
  !
  !  File Name: makeapexsh.f90
  !  Authors: John Emmert, Art Richmond
  !  Date: 11/13/2009
  !  Version: 1.0
  !  Description: Creates and saves spherical harmonic expansion coefficients for QD coordinate
  !               conversion.
  !  References: Richmond, A. D., Ionospheric Electrodynamics Using Magnetic Apex Coordinates,
  !                J. Geomag. Geoelectr., 47, 191-212, 1995.
  !              Emmert, J. T., A. D. Richmond, and D. P. Drob, A computationally compact 
  !                representation of Magnetic-Apex and Quasi-Dipole coordinates with smooth base
  !                vectors, J. Geophys. Res., 115, Axxxxx, doi:10.1029/2010JA015326, 2010.
  !
  !***************************************************************************************************
  !
  !  MAKEAPXSH
  !  Computes and saves harmonic coefficients for coordinate conversions.
  
negative.code: 
  end subroutine choldc
  
  !*******************************************************************************
  
  subroutine cholsl(a,n,np,p,b,x)
    
  