  A known phase-functions method has been considered for calculation of a
single-channel nucleon-nucleon scattering. The phase shifts of np- scattering
turn out for modern realistic phenomenological nucleon-nucleon potentials
Reid93 but Argonne v18. Influence of choice of numeral method is explored on
the decision of phase equation. For the decision of phase equation as
differential equation of 1th order numeral methods are used: Euler method and
Runge-Kutta methods 2-, 3-, 4- and 5th orders of exactness. Numerically
calculated phase shifts of np- scattering for potentials Reid93 and Argonne v18
are in good agreement with the results obtained with the other methods of
original works. Based on the known phases of scattering one can obtain the full
amplitude, the full cross-section and the partial scattering amplitude
accordingly. The used Runge-Kutta methods can be applied for finding of phases
shifts of the mixed channels of nucleon-nucleon scattering.
