As continuous absorption by hydrogen-like atoms and ions and the solution of the relation f(Pg,Pe,T,Q)=O are important topics in the calculation of model stellar atmospheres, we here devoted some effort to the analysis of elements involved in their numerical evaluation. So, we have studied the differences between several approximations employed in the calculation of Gaunt's factors (bound-free [bf] and free-free [ff]) , the number of spectroscopic series to be included in the evaluation of the continuous absorption coefficient (so that the error in the result is smaller than a prefixed value), the possibility of developing a routine for evaluating the relation f(Pg,Pe,T,Q)=0 , and the calculation of partition functions for atoms and ions.