ch set of Chebyshev polynomials, i.e. the
                  number of Chebyshev coefficients per coordinate minus
                  one. `polydg' must not exceed MAXDEG (see Parameters
                  below).
 
   cdata          Array containing all the sets of Chebyshev 
                  polynomial coefficients to be placed in the 
                  segment of the SPK file. The coefficients are 
                  stored in `cdata' in order as follows: 
 
                     the (polydg + 1) coefficient