An efficient numerical algorithm for solving integral equations of the
theory of liquid in the RISM approximation for infinitely diluted sol
ution of macromolecules with a large number of atoms is proposed. The
algorithm is based on applying the non-stationary iterative methods fo
r solving systems of linear algebraic equations. Using this technique
we have calculated the solvent-solute atom-atom correlation functions
for short fragment of DNA duplex of varying length in aqueous solution
.