The above expression gives the absolute (quantum) entropy of the system. A precise determination of formula_34 would require a quantum model for the ideal chain, which is beyond the scope of this article. However, we have already calculated the probability density formula_17 associated with the end-to-end vector of the "unconstrained" ideal chain, above. Since all micro-states of the ideal chain are equally likely to occur, formula_17 is proportional to formula_34. This leads to the following expression for the classical (relative) entropy of the ideal chain: