carbon {<carbon-statement>} end

<carbon-statement> :==

  assign <atom-selection> <atom-selection> <atom-selection> <atom-selection>
         <atom-selection> <real> <real> <real> <real>
  --{values for Ci-1, Ni, CAi, Ci, Ni+1, CA-obs, CB-obs (in ppm)}
  class=<classname>
  --{Starts a new class which applies to all assignment and force entries
     until another class entry is issued.}
  expectation <integer> <integer> <real> <real> <real> <real>
  --{Psi-pos Psi-pos CAvalue CAerr CBvalue CBerr for expectation values.}
  forceconstant=<real>
  --{Force constant for all assignments in the current class. 
     Default = 50}
  nrestraints=<integer>
  --{Number of slots for carbon chemical shift restraints to 
     allocate in memory. Default = 200}
  phistep=<real>
  --{Number of steps in the phi dimension of the expectation array.}
  psistep=<real>
  --{Number of steps in the psi dimension of the expectation array.}
  potential=square|harmonic
  --{Use shift errors or not.}
  print threshold <real>
  --{Prints secondary shift violations of either CA or CB greater than
     the specified value (in ppm).}
  rcoil <atom-selection> <real> <real>
  --{Set the random coil a and b 13C shifts for the selected atoms.}
  reset
  --{Erases the chemical shift assignment table.}
  zero
  --{Zero out the expectation value arrays.}