anchor.diff:     36 continue
   c
   
  -c then read the contents of the cc-file block in pairs,
  -c and assign the new indices
  -
  +c separate the complex spherical harmonic coefficients
  +c for the poloidal magnetic potential b(lm,1) into real and
  +c imaginary part and assign two new indices
  +c  
         do 37 lm=1,nlma
          c1=real(b(lm,1))
          c2=aimag(b(lm,1))
  
positive.code: c
  c   nominal Earth parameters
  c
        sigma=6.0e+05     ! Core electrical conductivity in S/m
        rho=11.e+03       ! Core mean density in kg m^{-3}
        omega=7.2924e-05  ! Rotation angular frequency
        escale=sqrt(rho*omega/sigma)  ! "Elsasser number" scaling
        re=6.371e+06      ! Earth radius in m
        rc=3.485e+06      ! Core radius in m
        ri=1.215e+06      ! Inner core radius in m
        cdepth=rc-ri      ! Depth of outer core
        rcre=rc/re        ! core/surface radius ratio
        rcsqinv=(cdepth/rc)**2  ! dim-less inverse squared core radius
  
  c
  c  write header to cc file
  
negative.code: 
  c   Convertion starts here
  c   the following code converts between Gauss coefficients (glm, hlm)
  c   and the spherical harmonic coefficients (alm,blm)
  c   of the magnetic potential at harmonic degree l
  c   and order m used by the numerical dynamo model MAG.
  c
  